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Diffstat (limited to 'Documentation/iio')
| -rw-r--r-- | Documentation/iio/ad3552r.rst | 72 | ||||
| -rw-r--r-- | Documentation/iio/ad4000.rst | 220 | ||||
| -rw-r--r-- | Documentation/iio/ad4030.rst | 180 | ||||
| -rw-r--r-- | Documentation/iio/ad4695.rst | 269 | ||||
| -rw-r--r-- | Documentation/iio/ad7191.rst | 119 | ||||
| -rw-r--r-- | Documentation/iio/ad7380.rst | 212 | ||||
| -rw-r--r-- | Documentation/iio/ad7606.rst | 189 | ||||
| -rw-r--r-- | Documentation/iio/ad7625.rst | 91 | ||||
| -rw-r--r-- | Documentation/iio/ad7944.rst | 178 | ||||
| -rw-r--r-- | Documentation/iio/adis16475.rst | 384 | ||||
| -rw-r--r-- | Documentation/iio/adis16480.rst | 446 | ||||
| -rw-r--r-- | Documentation/iio/adis16550.rst | 376 | ||||
| -rw-r--r-- | Documentation/iio/adxl380.rst | 233 | ||||
| -rw-r--r-- | Documentation/iio/bno055.rst | 51 | ||||
| -rw-r--r-- | Documentation/iio/ep93xx_adc.rst | 2 | ||||
| -rw-r--r-- | Documentation/iio/iio_adc.rst | 305 | ||||
| -rw-r--r-- | Documentation/iio/iio_configfs.rst | 5 | ||||
| -rw-r--r-- | Documentation/iio/iio_devbuf.rst | 152 | ||||
| -rw-r--r-- | Documentation/iio/iio_dmabuf_api.rst | 54 | ||||
| -rw-r--r-- | Documentation/iio/iio_tools.rst | 27 | ||||
| -rw-r--r-- | Documentation/iio/index.rst | 25 | ||||
| -rw-r--r-- | Documentation/iio/opt4060.rst | 61 |
22 files changed, 3648 insertions, 3 deletions
diff --git a/Documentation/iio/ad3552r.rst b/Documentation/iio/ad3552r.rst new file mode 100644 index 000000000000..f5d59e4e86c7 --- /dev/null +++ b/Documentation/iio/ad3552r.rst @@ -0,0 +1,72 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============== +AD3552R driver +============== + +Device driver for Analog Devices Inc. AD35XXR series of DACs. The module name +is ``ad3552r``. +With the same module name, two different driver variants are available, the +``generic spi`` variant, to be used with any classic SPI controllers, and the +``hs`` (high speed) variant, for an ADI ``axi-dac`` (IP core) based controller +that allows to reach the maximum sample rate supported from the DACs, using the +DMA transfer and all the SPI lines available (D/QDSPI).. +The high speed driver variant is intended to be used with the ``adi-axi-dac`` +backend support enabled, that is enabled by default when the driver is selected. + +Supported devices +================= + +* `AD3541R <https://www.analog.com/en/products/ad3541r.html>`_ +* `AD3542R <https://www.analog.com/en/products/ad3542r.html>`_ +* `AD3551R <https://www.analog.com/en/products/ad3551r.html>`_ +* `AD3552R <https://www.analog.com/en/products/ad3552r.html>`_ + +Wiring connections +================== + +Generic SPI +----------- +Use the classic SPI S_CLK/CS/SDO/SDI connection. + +High speed (using axi-dac backend) +---------------------------------- + +:: + + .-----------------. .-------. + | |--- D/QSPI -----| | + | DAC IP CORE |--- SPI S_CLK --| DAC | + | |--- SPI CS -----| | + | |--- LDAC -------| | + | |--- RESET ------| | + |_________________| |_______| + + +High speed features +=================== + +Device attributes +----------------- + +The following table shows the ad35xxr related device debug files, found in the +specific debugfs path ``/sys/kernel/debug/iio/iio:deviceX``. + ++-----------------------+------------------------------------------------------+ +| Debugfs device files | Description | ++-----------------------+------------------------------------------------------+ +| data_source | The used data source, as | +| | ``normal``, ``ramp-16bit``, etc. | ++-----------------------+------------------------------------------------------+ +| data_source_available | The available data sources. | ++-----------------------+------------------------------------------------------+ + +Usage examples +-------------- + +. code-block:: bash + root:/sys/bus/iio/devices/iio:device0# cat data_source + normal + root:/sys/bus/iio/devices/iio:device0# echo -n ramp-16bit > data_source + root:/sys/bus/iio/devices/iio:device0# cat data_source + ramp-16bit diff --git a/Documentation/iio/ad4000.rst b/Documentation/iio/ad4000.rst new file mode 100644 index 000000000000..c1d04d3436d2 --- /dev/null +++ b/Documentation/iio/ad4000.rst @@ -0,0 +1,220 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD4000 driver +============= + +Device driver for Analog Devices Inc. AD4000 series of ADCs and similar devices. + +Supported devices +================= + +* `AD4000 <https://www.analog.com/AD4000>`_ +* `AD4001 <https://www.analog.com/AD4001>`_ +* `AD4002 <https://www.analog.com/AD4002>`_ +* `AD4003 <https://www.analog.com/AD4003>`_ +* `AD4004 <https://www.analog.com/AD4004>`_ +* `AD4005 <https://www.analog.com/AD4005>`_ +* `AD4006 <https://www.analog.com/AD4006>`_ +* `AD4007 <https://www.analog.com/AD4007>`_ +* `AD4008 <https://www.analog.com/AD4008>`_ +* `AD4010 <https://www.analog.com/AD4010>`_ +* `AD4011 <https://www.analog.com/AD4011>`_ +* `AD4020 <https://www.analog.com/AD4020>`_ +* `AD4021 <https://www.analog.com/AD4021>`_ +* `AD4022 <https://www.analog.com/AD4022>`_ +* `ADAQ4001 <https://www.analog.com/ADAQ4001>`_ +* `ADAQ4003 <https://www.analog.com/ADAQ4003>`_ +* `AD7685 <https://www.analog.com/AD7685>`_ +* `AD7686 <https://www.analog.com/AD7686>`_ +* `AD7687 <https://www.analog.com/AD7687>`_ +* `AD7688 <https://www.analog.com/AD7688>`_ +* `AD7690 <https://www.analog.com/AD7690>`_ +* `AD7691 <https://www.analog.com/AD7691>`_ +* `AD7693 <https://www.analog.com/AD7693>`_ +* `AD7942 <https://www.analog.com/AD7942>`_ +* `AD7946 <https://www.analog.com/AD7946>`_ +* `AD7980 <https://www.analog.com/AD7980>`_ +* `AD7982 <https://www.analog.com/AD7982>`_ +* `AD7983 <https://www.analog.com/AD7983>`_ +* `AD7984 <https://www.analog.com/AD7984>`_ +* `AD7988-1 <https://www.analog.com/AD7988-1>`_ +* `AD7988-5 <https://www.analog.com/AD7988-5>`_ + +Wiring connections +------------------ + +Devices of the AD4000 series can be connected to the SPI host controller in a +few different modes. + +CS mode, 3-wire turbo mode +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Datasheet "3-wire" mode is what most resembles standard SPI connection which, +for these devices, comprises of connecting the controller CS line to device CNV +pin and other SPI lines as usual. This configuration is (misleadingly) called +"CS Mode, 3-Wire Turbo Mode" connection in datasheets. +NOTE: The datasheet definition of 3-wire mode for the AD4000 series is NOT the +same of standard spi-3wire mode. +This is the only connection mode that allows configuration register access but +it requires the SPI controller to support the ``SPI_MOSI_IDLE_HIGH`` feature. + +Omit the ``adi,sdi-pin`` property in device tree to select this mode. + +:: + + +-------------+ + + ----------------------------------| SDO | + | | | + | +-------------------| CS | + | v | | + | +--------------------+ | HOST | + | | CNV | | | + +--->| SDI AD4000 SDO |-------->| SDI | + | SCK | | | + +--------------------+ | | + ^ | | + +--------------------| SCLK | + +-------------+ + +CS mode, 3-wire, without busy indicator +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Another wiring configuration supported as "3-wire" mode has the SDI pin +hard-wired to digital input/output interface supply (VIO). In this setup, the +controller is not required to support ``SPI_MOSI_IDLE_HIGH`` but register access +is not possible. This connection mode saves one wire and works with any SPI +controller. + +Set the ``adi,sdi-pin`` device tree property to ``"high"`` to select this mode. + +:: + + +-------------+ + +--------------------| CS | + v | | + VIO +--------------------+ | HOST | + | | CNV | | | + +--->| SDI AD4000 SDO |-------->| SDI | + | SCK | | | + +--------------------+ | | + ^ | | + +--------------------| SCLK | + +-------------+ + +Alternatively, a GPIO may be connected to the device CNV pin. This is similar to +the previous wiring configuration but saves the use of a CS line. + +:: + + +-------------+ + +--------------------| GPIO | + v | | + VIO +--------------------+ | HOST | + | | CNV | | | + +--->| SDI AD4000 SDO |-------->| SDI | + | SCK | | | + +--------------------+ | | + ^ | | + +--------------------| SCLK | + +-------------+ + +CS mode, 4-wire without busy indicator +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In datasheet "4-wire" mode, the controller CS line is connected to the ADC SDI +pin and a GPIO is connected to the ADC CNV pin. This connection mode may better +suit scenarios where multiple ADCs can share one CNV trigger. + +Set ``adi,sdi-pin`` to ``"cs"`` to select this mode. + + +:: + + +-------------+ + + ----------------------------------| CS | + | | | + | +-------------------| GPIO | + | v | | + | +--------------------+ | HOST | + | | CNV | | | + +--->| SDI AD4000 SDO |-------->| SDI | + | SCK | | | + +--------------------+ | | + ^ | | + +--------------------| SCLK | + +-------------+ + +IIO Device characteristics +========================== + +The AD4000 series driver supports differential and pseudo-differential ADCs. + +The span compression feature available in AD4000 series devices can be +enabled/disabled by changing the ``_scale_available`` attribute of the voltage +channel. Note that span compression configuration requires writing to AD4000 +configuration register, which is only possible when the ADC is wired in 3-wire +turbo mode, and the SPI controller is ``SPI_MOSI_IDLE_HIGH`` capable. If those +conditions are not met, no ``_scale_available`` attribute is provided. + +Besides that, differential and pseudo-differential voltage channels present +slightly different sysfs interfaces. + +Pseudo-differential ADCs +------------------------ + +Typical voltage channel attributes of a pseudo-differential AD4000 series device: + ++-------------------------------------------+------------------------------------------+ +| Voltage Channel Attributes | Description | ++===========================================+==========================================+ +| ``in_voltage0_raw`` | Raw ADC output code. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_offset`` | Offset to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_scale`` | Scale factor to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0_scale_available`` | Toggles input span compression | ++-------------------------------------------+------------------------------------------+ + +Differential ADCs +----------------- + +Typical voltage channel attributes of a differential AD4000 series device: + ++-------------------------------------------+------------------------------------------+ +| Voltage Channel Attributes | Description | ++===========================================+==========================================+ +| ``in_voltage0-voltage1_raw`` | Raw ADC output code. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0-voltage1_scale`` | Scale factor to convert raw value to mV. | ++-------------------------------------------+------------------------------------------+ +| ``in_voltage0-voltage1_scale_available`` | Toggles input span compression | ++-------------------------------------------+------------------------------------------+ + +SPI offload support +------------------- + +To be able to achieve the maximum sample rate, the driver can be used with SPI +offload engines such as the one usually present in `AXI SPI Engine`_, to provide +SPI offload support. + +.. _AXI SPI Engine: http://analogdevicesinc.github.io/hdl/projects/pulsar_adc/index.html + +To keep up with SPI offloading transfer speeds, the ADC must be connected either +in 3-wire turbo mode or in 3-wire without busy indicator mode and have SPI +controller CS line connected to the CNV pin. + +When set for SPI offload support, the IIO device will provide different +interfaces. + +* Either ``in_voltage0_sampling_frequency`` or + ``in_voltage0-voltage1_sampling_frequency`` file is provided to allow setting + the sample rate. +* IIO trigger device is not provided (no ``trigger`` directory). +* ``timestamp`` channel is not provided. + +Also, because the ADC output has a one sample latency (delay) when the device is +wired in "3-wire" mode and only one transfer per sample is done when using SPI +offloading, the first data sample in the buffer is not valid because it contains +the output of an earlier conversion result. diff --git a/Documentation/iio/ad4030.rst b/Documentation/iio/ad4030.rst new file mode 100644 index 000000000000..b57424b650a8 --- /dev/null +++ b/Documentation/iio/ad4030.rst @@ -0,0 +1,180 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD4030 driver +============= + +ADC driver for Analog Devices Inc. AD4030 and similar devices. The module name +is ``ad4030``. + + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD4030-24 <https://www.analog.com/AD4030-24>`_ +* `AD4032-24 <https://www.analog.com/AD4032-24>`_ +* `AD4630-16 <https://www.analog.com/AD4630-16>`_ +* `AD4630-24 <https://www.analog.com/AD4630-24>`_ +* `AD4632-16 <https://www.analog.com/AD4632-16>`_ +* `AD4632-24 <https://www.analog.com/AD4632-24>`_ + +IIO channels +============ + +Each "hardware" channel as described in the datasheet is split in 2 IIO +channels: + +- One channel for the differential data +- One channel for the common byte. + +The possible IIO channels depending on the numbers of "hardware" channel are: + ++------------------------------------+------------------------------------+ +| 1 channel ADC | 2 channels ADC | ++====================================+====================================+ +| - voltage0-voltage1 (differential) | - voltage0-voltage1 (differential) | +| - voltage2 (common-mode) | - voltage2-voltage3 (differential) | +| | - voltage4 (common-mode) | +| | - voltage5 (common-mode) | ++------------------------------------+------------------------------------+ + +Labels +------ + +For ease of use, the IIO channels provide a label. For a differential channel, +the label is ``differentialN`` where ``N`` is the "hardware" channel id. For a +common-mode channel, the label is ``common-modeN`` where ``N`` is the +"hardware" channel id. + +The possible labels are: + ++-----------------+-----------------+ +| 1 channel ADC | 2 channels ADC | ++=================+=================+ +| - differential0 | - differential0 | +| - common-mode0 | - differential1 | +| | - common-mode0 | +| | - common-mode1 | ++-----------------+-----------------+ + +Supported features +================== + +SPI wiring modes +---------------- + +The driver currently supports the following SPI wiring configurations: + +One lane mode +^^^^^^^^^^^^^ + +In this mode, each channel has its own SDO line to send the conversion results. +At the moment this mode can only be used on AD4030 which has one channel so only +one SDO line is used. + +.. code-block:: + + +-------------+ +-------------+ + | ADC | | HOST | + | | | | + | CNV |<--------| CNV | + | CS |<--------| CS | + | SDI |<--------| SDO | + | SDO0 |-------->| SDI | + | SCLK |<--------| SCLK | + +-------------+ +-------------+ + +Interleaved mode +^^^^^^^^^^^^^^^^ + +In this mode, both channels conversion results are bit interleaved one SDO line. +As such the wiring is the same as `One lane mode`_. + +SPI Clock mode +-------------- + +Only the SPI clocking mode is supported. + +Output modes +------------ + +There are more exposed IIO channels than channels as describe in the devices +datasheet. This is due to the `Differential data + common-mode`_ encoding +2 types of information in one conversion result. As such a "device" channel +provides 2 IIO channels, one for the differential data and one for the common +byte. + +Differential data +^^^^^^^^^^^^^^^^^ + +This mode is selected when: + +- Only differential channels are enabled in a buffered read +- Oversampling attribute is set to 1 + +Differential data + common-mode +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +This mode is selected when: + +- Differential and common-mode channels are enabled in a buffered read +- Oversampling attribute is set to 1 + +For the 24-bits chips, this mode is also available with 16-bits differential +data but is not selectable yet. + +Averaged differential data +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +This mode is selected when: + +- Only differential channels are selected enabled in a buffered read +- Oversampling attribute is greater than 1 + +Digital Gain and Offset +----------------------- + +Each differential data channel has a 16-bits unsigned configurable hardware +gain applied to it. By default it's equal to 1. Note that applying gain can +cause numerical saturation. + +Each differential data channel has a signed configurable hardware offset. +For the ADCs ending in ``-24``, the gain is encoded on 24-bits. +Likewise, the ADCs ending in ``-16`` have a gain encoded on 16-bits. Note that +applying an offset can cause numerical saturation. + +The final differential data returned by the ADC is computed by first applying +the gain, then the offset. + +The gain is controlled by the ``calibscale`` IIO attribute while the offset is +controlled by the ``calibbias`` attribute. + +Reference voltage +----------------- + +The chip supports an external reference voltage via the ``REF`` input or an +internal buffered reference voltage via the ``REFIN`` input. The driver looks +at the device tree to determine which is being used. If ``ref-supply`` is +present, then the external reference voltage is used and the internal buffer is +disabled. If ``refin-supply`` is present, then the internal buffered reference +voltage is used. + +Reset +----- + +Both hardware and software reset are supported. The driver looks first at the +device tree to see if the ``reset-gpio`` is populated. +If not present, the driver will fallback to a software reset by wiring to the +device's registers. + +Unimplemented features +---------------------- + +- ``BUSY`` indication +- Additional wiring modes +- Additional clock modes +- Differential data 16-bits + common-mode for 24-bits chips +- Overrange events +- Test patterns diff --git a/Documentation/iio/ad4695.rst b/Documentation/iio/ad4695.rst new file mode 100644 index 000000000000..f40593bcc37d --- /dev/null +++ b/Documentation/iio/ad4695.rst @@ -0,0 +1,269 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD4695 driver +============= + +ADC driver for Analog Devices Inc. AD4695 and similar devices. The module name +is ``ad4695``. + + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD4695 <https://www.analog.com/AD4695>`_ +* `AD4696 <https://www.analog.com/AD4696>`_ +* `AD4697 <https://www.analog.com/AD4697>`_ +* `AD4698 <https://www.analog.com/AD4698>`_ + + +Supported features +================== + +SPI wiring modes +---------------- + +The driver currently supports the following SPI wiring configuration: + +4-wire mode +^^^^^^^^^^^ + +In this mode, CNV and CS are tied together and there is a single SDO line. + +.. code-block:: + + +-------------+ +-------------+ + | CS |<-+------| CS | + | CNV |<-+ | | + | ADC | | HOST | + | | | | + | SDI |<--------| SDO | + | SDO |-------->| SDI | + | SCLK |<--------| SCLK | + +-------------+ +-------------+ + +To use this mode, in the device tree, omit the ``cnv-gpios`` and +``spi-rx-bus-width`` properties. + +SPI offload wiring +^^^^^^^^^^^^^^^^^^ + +When used with a SPI offload, the supported wiring configuration is: + +.. code-block:: + + +-------------+ +-------------+ + | GP0/BUSY |-------->| TRIGGER | + | CS |<--------| CS | + | | | | + | ADC | | SPI | + | | | | + | SDI |<--------| SDO | + | SDO |-------->| SDI | + | SCLK |<--------| SCLK | + | | | | + | | +-------------+ + | CNV |<-----+--| PWM | + | | +--| GPIO | + +-------------+ +-------------+ + +In this case, both the ``cnv-gpios`` and ``pwms`` properties are required. +The ``#trigger-source-cells = <2>`` property is also required to connect back +to the SPI offload. The SPI offload will have ``trigger-sources`` property +with cells to indicate the busy signal and which GPx pin is used, e.g +``<&ad4695 AD4695_TRIGGER_EVENT_BUSY AD4695_TRIGGER_PIN_GP0>``. + +.. seealso:: `SPI offload support`_ + +Channel configuration +--------------------- + +Since the chip supports multiple ways to configure each channel, this must be +described in the device tree based on what is actually wired up to the inputs. + +There are three typical configurations: + +An ``INx`` pin is used as the positive input with the ``REFGND``, ``COM`` or +the next ``INx`` pin as the negative input. + +Pairing with REFGND +^^^^^^^^^^^^^^^^^^^ + +Each ``INx`` pin can be used as a pseudo-differential input in conjunction with +the ``REFGND`` pin. The device tree will look like this: + +.. code-block:: + + channel@0 { + reg = <0>; /* IN0 */ + }; + +If no other channel properties are needed (e.g. ``adi,no-high-z``), the channel +node can be omitted entirely. + +This will appear on the IIO bus as the ``voltage0`` channel. The processed value +(*raw × scale*) will be the voltage present on the ``IN0`` pin relative to +``REFGND``. (Offset is always 0 when pairing with ``REFGND``.) + +Pairing with COM +^^^^^^^^^^^^^^^^ + +Each ``INx`` pin can be used as a pseudo-differential input in conjunction with +the ``COM`` pin. The device tree will look like this: + +.. code-block:: + + com-supply = <&vref_div_2>; + + channel@1 { + reg = <1>; /* IN1 */ + common-mode-channel = <AD4695_COMMON_MODE_COM>; + bipolar; + }; + +This will appear on the IIO bus as the ``voltage1`` channel. The processed value +(*(raw + offset) × scale*) will be the voltage measured on the ``IN1`` pin +relative to ``REFGND``. (The offset is determined by the ``com-supply`` voltage.) + +The macro comes from: + +.. code-block:: + + #include <dt-bindings/iio/adc/adi,ad4695.h> + +Pairing two INx pins +^^^^^^^^^^^^^^^^^^^^ + +An even-numbered ``INx`` pin and the following odd-numbered ``INx`` pin can be +used as a pseudo-differential input. The device tree for using ``IN2`` as the +positive input and ``IN3`` as the negative input will look like this: + +.. code-block:: + + in3-supply = <&vref_div_2>; + + channel@2 { + reg = <2>; /* IN2 */ + common-mode-channel = <3>; /* IN3 */ + bipolar; + }; + +This will appear on the IIO bus as the ``voltage2`` channel. The processed value +(*(raw + offset) × scale*) will be the voltage measured on the ``IN1`` pin +relative to ``REFGND``. (Offset is determined by the ``in3-supply`` voltage.) + +VCC supply +---------- + +The chip supports being powered by an external LDO via the ``VCC`` input or an +internal LDO via the ``LDO_IN`` input. The driver looks at the device tree to +determine which is being used. If ``ldo-supply`` is present, then the internal +LDO is used. If ``vcc-supply`` is present, then the external LDO is used and +the internal LDO is disabled. + +Reference voltage +----------------- + +The chip supports an external reference voltage via the ``REF`` input or an +internal buffered reference voltage via the ``REFIN`` input. The driver looks +at the device tree to determine which is being used. If ``ref-supply`` is +present, then the external reference voltage is used and the internal buffer is +disabled. If ``refin-supply`` is present, then the internal buffered reference +voltage is used. + +Gain/offset calibration +----------------------- + +System calibration is supported using the channel gain and offset registers via +the ``calibscale`` and ``calibbias`` attributes respectively. + +Oversampling +------------ + +The chip supports per-channel oversampling when SPI offload is being used, with +available oversampling ratios (OSR) of 1 (default), 4, 16, and 64. Enabling +oversampling on a channel raises the effective number of bits of sampled data to +17 (OSR == 4), 18 (16), or 19 (64), respectively. This can be set via the +``oversampling_ratio`` attribute. + +Setting the oversampling ratio for a channel also changes the sample rate for +that channel, since it requires multiple conversions per 1 sample. Specifically, +the new sampling frequency is the PWM sampling frequency divided by the +particular OSR. This is set automatically by the driver when setting the +``oversampling_ratio`` attribute. For example, if the device's current +``sampling_frequency`` is 10000 and an OSR of 4 is set on channel ``voltage0``, +the new reported sampling rate for that channel will be 2500 (ignoring PWM API +rounding), while all others will remain at 10000. Subsequently setting the +sampling frequency to a higher value on that channel will adjust the CNV trigger +period for all channels, e.g. if ``voltage0``'s sampling frequency is adjusted +from 2500 (with an OSR of 4) to 10000, the value reported by +``in_voltage0_sampling_frequency`` will be 10000, but all other channels will +now report 40000. + +For simplicity, the sampling frequency of the device should be set (considering +the highest desired OSR value to be used) first, before configuring oversampling +for specific channels. + +Unimplemented features +---------------------- + +- Additional wiring modes +- Threshold events +- GPIO support +- CRC support + +SPI offload support +=================== + +To be able to achieve the maximum sample rate, the driver can be used with the +`AXI SPI Engine`_ to provide SPI offload support. + +.. _AXI SPI Engine: http://analogdevicesinc.github.io/hdl/projects/ad469x_fmc/index.html + +.. seealso:: `SPI offload wiring`_ + +When SPI offload is being used, some attributes will be different. + +* ``trigger`` directory is removed. +* ``in_voltage0_sampling_frequency`` attributes are added for setting the sample + rate. +* ``in_voltage0_sampling_frequency_available`` attributes are added for querying + the max sample rate. +* ``timestamp`` channel is removed. +* Buffer data format may be different compared to when offload is not used, + e.g. the ``buffer0/in_voltage0_type`` attribute. + +Device buffers +============== + +This driver supports hardware triggered buffers. This uses the "advanced +sequencer" feature of the chip to trigger a burst of conversions. + +Also see :doc:`iio_devbuf` for more general information. + +Effective sample rate for buffered reads +---------------------------------------- + +When SPI offload is not used, the sample rate is determined by the trigger that +is manually configured in userspace. All enabled channels will be read in a +burst when the trigger is received. + +When SPI offload is used, the sample rate is configured per channel. All +channels will have the same rate, so only one ``in_voltageY_sampling_frequency`` +attribute needs to be set. Since this rate determines the delay between each +individual conversion, the effective sample rate for each sample is actually +the sum of the periods of each enabled channel in a buffered read. In other +words, it is the value of the ``in_voltageY_sampling_frequency`` attribute +divided by the number of enabled channels. So if 4 channels are enabled, with +the ``in_voltageY_sampling_frequency`` attributes set to 1 MHz, the effective +sample rate is 250 kHz. + +With oversampling enabled, the effective sample rate also depends on the OSR +assigned to each channel. For example, if one of the 4 channels mentioned in the +previous case is configured with an OSR of 4, the effective sample rate for that +channel becomes (1 MHz / 4 ) = 250 kHz. The effective sample rate for all +four channels is then 1 / ( (3 / 1 MHz) + ( 1 / 250 kHz) ) ~= 142.9 kHz. Note +that in this case "sample" refers to one read of all enabled channels (i.e. one +full cycle through the auto-sequencer). diff --git a/Documentation/iio/ad7191.rst b/Documentation/iio/ad7191.rst new file mode 100644 index 000000000000..977d4fea14b0 --- /dev/null +++ b/Documentation/iio/ad7191.rst @@ -0,0 +1,119 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD7191 driver +============= + +Device driver for Analog Devices AD7191 ADC. + +Supported devices +================= + +* `AD7191 <https://www.analog.com/AD7191>`_ + +The AD7191 is a high precision, low noise, 24-bit Σ-Δ ADC with integrated PGA. +It features two differential input channels, an internal temperature sensor, and +configurable sampling rates. + +Devicetree +========== + +Pin Configuration +----------------- + +The driver supports both pin-strapped and GPIO-controlled configurations for ODR +(Output Data Rate) and PGA (Programmable Gain Amplifier) settings. These +configurations are mutually exclusive - you must use either pin-strapped or GPIO +control for each setting, not both. + +ODR Configuration +^^^^^^^^^^^^^^^^^ + +The ODR can be configured either through GPIO control or pin-strapping: + +- When using GPIO control, specify the "odr-gpios" property in the device tree +- For pin-strapped configuration, specify the "adi,odr-value" property in the + device tree + +Available ODR settings: + + - 120 Hz (ODR1=0, ODR2=0) + - 60 Hz (ODR1=0, ODR2=1) + - 50 Hz (ODR1=1, ODR2=0) + - 10 Hz (ODR1=1, ODR2=1) + +PGA Configuration +^^^^^^^^^^^^^^^^^ + +The PGA can be configured either through GPIO control or pin-strapping: + +- When using GPIO control, specify the "pga-gpios" property in the device tree +- For pin-strapped configuration, specify the "adi,pga-value" property in the + device tree + +Available PGA gain settings: + + - 1x (PGA1=0, PGA2=0) + - 8x (PGA1=0, PGA2=1) + - 64x (PGA1=1, PGA2=0) + - 128x (PGA1=1, PGA2=1) + +Clock Configuration +------------------- + +The AD7191 supports both internal and external clock sources: + +- When CLKSEL pin is tied LOW: Uses internal 4.92MHz clock (no clock property + needed) +- When CLKSEL pin is tied HIGH: Requires external clock source + - Can be a crystal between MCLK1 and MCLK2 pins + - Or a CMOS-compatible clock driving MCLK2 pin + - Must specify the "clocks" property in device tree when using external clock + +SPI Interface Requirements +-------------------------- + +The AD7191 has specific SPI interface requirements: + +- The DOUT/RDY output is dual-purpose and requires SPI bus locking +- DOUT/RDY must be connected to an interrupt-capable GPIO +- The SPI controller's chip select must be connected to the PDOWN pin of the ADC +- When CS (PDOWN) is high, the device powers down and resets internal circuitry +- SPI mode 3 operation (CPOL=1, CPHA=1) is required + +Power Supply Requirements +------------------------- + +The device requires the following power supplies: + +- AVdd: Analog power supply +- DVdd: Digital power supply +- Vref: Reference voltage supply (external) + +All power supplies must be specified in the device tree. + +Channel Configuration +===================== + +The device provides three channels: + +1. Temperature Sensor + - 24-bit unsigned + - Internal temperature measurement + - Temperature in millidegrees Celsius + +2. Differential Input (AIN1-AIN2) + - 24-bit unsigned + - Differential voltage measurement + - Configurable gain via PGA + +3. Differential Input (AIN3-AIN4) + - 24-bit unsigned + - Differential voltage measurement + - Configurable gain via PGA + +Buffer Support +============== + +This driver supports IIO triggered buffers. See Documentation/iio/iio_devbuf.rst +for more information about IIO triggered buffers. diff --git a/Documentation/iio/ad7380.rst b/Documentation/iio/ad7380.rst new file mode 100644 index 000000000000..d51f9ee3e939 --- /dev/null +++ b/Documentation/iio/ad7380.rst @@ -0,0 +1,212 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD7380 driver +============= + +ADC driver for Analog Devices Inc. AD7380 and similar devices. The module name +is ``ad7380``. + + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD7380 <https://www.analog.com/en/products/ad7380.html>`_ +* `AD7381 <https://www.analog.com/en/products/ad7381.html>`_ +* `AD7383 <https://www.analog.com/en/products/ad7383.html>`_ +* `AD7384 <https://www.analog.com/en/products/ad7384.html>`_ +* `AD7386 <https://www.analog.com/en/products/ad7386.html>`_ +* `AD7387 <https://www.analog.com/en/products/ad7387.html>`_ +* `AD7388 <https://www.analog.com/en/products/ad7388.html>`_ +* `AD7380-4 <https://www.analog.com/en/products/ad7380-4.html>`_ +* `AD7381-4 <https://www.analog.com/en/products/ad7381-4.html>`_ +* `AD7383-4 <https://www.analog.com/en/products/ad7383-4.html>`_ +* `AD7384-4 <https://www.analog.com/en/products/ad7384-4.html>`_ +* `AD7386-4 <https://www.analog.com/en/products/ad7386-4.html>`_ +* `AD7387-4 <https://www.analog.com/en/products/ad7387-4.html>`_ +* `AD7388-4 <https://www.analog.com/en/products/ad7388-4.html>`_ +* `AD7389-4 <https://www.analog.com/en/products/ad7389-4.html>`_ +* `ADAQ4370-4 <https://www.analog.com/en/products/adaq4370-4.html>`_ +* `ADAQ4380-4 <https://www.analog.com/en/products/adaq4380-4.html>`_ +* `ADAQ4381-4 <https://www.analog.com/en/products/adaq4381-4.html>`_ + + +Supported features +================== + +SPI wiring modes +---------------- + +ad738x ADCs can output data on several SDO lines (1/2/4). The driver currently +supports only 1 SDO line. + +Reference voltage +----------------- + +ad7380-4 +~~~~~~~~ + +ad7380-4 supports only an external reference voltage (2.5V to 3.3V). It must be +declared in the device tree as ``refin-supply``. + +ad7389-4 +~~~~~~~~ + +ad7389-4 supports only an internal reference voltage. ``refin-supply`` and +``refio-supply`` properties are both omitted in this case. + +ADAQ devices +~~~~~~~~~~~~ + +ADAQ devices don't have an external reference, but use a 3.3V internal reference +derived from one of its supplies (``refin-supply``) + +All other devices from ad738x family +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +All other devices from ad738x support 2 possible reference voltage sources: + +- Internal reference (2.5V) +- External reference (2.5V to 3.3V) + +The source is determined by the device tree. If ``refio-supply`` is present, +then it is used as external reference, else the internal reference is used. + +Oversampling and resolution boost +--------------------------------- + +This family supports 2 types of oversampling: normal average and rolling +average. Only normal average is supported by the driver, as rolling average can +be achieved by processing a captured data buffer. The following ratios are +available: 1 (oversampling disabled)/2/4/8/16/32. + +When the on-chip oversampling function is enabled the performance of the ADC can +exceed the default resolution. To accommodate the performance boost achievable, +it is possible to enable an additional two bits of resolution. Because the +resolution boost feature can only be enabled when oversampling is enabled and +oversampling is not as useful without the resolution boost, the driver +automatically enables the resolution boost if and only if oversampling is +enabled. + +Since the resolution boost feature causes 16-bit chips to now have 18-bit data +which means the storagebits has to change from 16 to 32 bits, we use the new +ext_scan_type feature to allow changing the scan_type at runtime. Unfortunately +libiio does not support it. So when enabling or disabling oversampling, user +must restart iiod using the following command: + +.. code-block:: bash + + root:~# systemctl restart iiod + +Alert +----- + +2 channels variants of the ad738x family, can use the SDOB line as an alert pin +when configured in 1 SDO line mode. 4 channels variants, can use SDOD as an +alert pin when configured in 1 or 2 SDO line(s) mode, although only 1 SDO line +mode is currently supported by the driver (see `SPI wiring modes`_). + +At the end of a conversion the active-low alert pin gets asserted if the +conversion result exceeds the alert high limit or falls below the alert low +limit. It is cleared, on a falling edge of CS. The alert pin is common to all +channels. + +User can enable alert using the regular iio events attribute: + +.. code-block:: bash + + events/thresh_either_en + +The high and low thresholds are common to all channels and can also be set using +regular iio events attributes: + +.. code-block:: bash + + events/in_thresh_falling_value + events/in_thresh_rising_value + +If debugfs is available, user can read the ALERT register to determine the +faulty channel and direction. + +In most use cases, user will hardwire the alert pin to trigger a shutdown. + +Channel selection and sequencer (single-end chips only) +------------------------------------------------------- + +Single-ended chips of this family (ad7386/7/8(-4)) have a 2:1 multiplexer in +front of each ADC. They also include additional configuration registers that +allow for either manual selection or automatic switching (sequencer mode), of +the multiplexer inputs. + +From an IIO point of view, all inputs are exported, i.e ad7386/7/8 +export 4 channels and ad7386-4/7-4/8-4 export 8 channels. + +Inputs ``AinX0`` of multiplexers correspond to the first half of IIO channels (i.e +0-1 or 0-3) and inputs ``AinX1`` correspond to second half (i.e 2-3 or 4-7). +Example for AD7386/7/8 (2 channels parts): + +.. code-block:: + + IIO | AD7386/7/8 + | +---------------------------- + | | _____ ______ + | | | | | | + voltage0 | AinA0 --|--->| | | | + | | | mux |----->| ADCA |--- + voltage2 | AinA1 --|--->| | | | + | | |_____| |_____ | + | | _____ ______ + | | | | | | + voltage1 | AinB0 --|--->| | | | + | | | mux |----->| ADCB |--- + voltage3 | AinB1 --|--->| | | | + | | |_____| |______| + | | + | +---------------------------- + + +When enabling sequencer mode, the effective sampling rate is divided by two. + +Gain (ADAQ devices only) +~~~~~~~~~~~~~~~~~~~~~~~~ + +ADAQ devices have a pin selectable gain in front of each ADC. The appropriate +gain is selectable from device tree using the ``adi,gain-milli`` property. +Refer to the typical connection diagrams section of the datasheet for pin +wiring. + +Unimplemented features +---------------------- + +- 2/4 SDO lines +- Rolling average oversampling +- Power down mode +- CRC indication + +SPI offload support +=================== + +To be able to achieve the maximum sample rate, the driver can be used with the +`AXI SPI Engine`_ to provide SPI offload support. + +.. _AXI SPI Engine: http://analogdevicesinc.github.io/hdl/projects/pulsar_adc/index.html + +When SPI offload is being used, some attributes will be different. + +* ``trigger`` directory is removed. +* ``in_voltage0_sampling_frequency`` attribute is added for setting the sample + rate. +* ``in_voltage0_sampling_frequency_available`` attribute is added for querying + the max sample rate. +* ``timestamp`` channel is removed. +* Buffer data format may be different compared to when offload is not used, + e.g. the ``in_voltage0_type`` attribute. + +Device buffers +============== + +This driver supports IIO triggered buffers. + +See :doc:`iio_devbuf` for more information. diff --git a/Documentation/iio/ad7606.rst b/Documentation/iio/ad7606.rst new file mode 100644 index 000000000000..5e02516bab40 --- /dev/null +++ b/Documentation/iio/ad7606.rst @@ -0,0 +1,189 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD7606 driver +============= + +ADC driver for Analog Devices Inc. AD7606 and similar devices. The module name +is ``ad7606``. + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD7605 <https://www.analog.com/en/products/ad7605.html>`_ +* `AD7606 <https://www.analog.com/en/products/ad7606.html>`_ +* `AD7606B <https://www.analog.com/en/products/ad7606b.html>`_ +* `AD7616 <https://www.analog.com/en/products/ad7616.html>`_ + +Supported features +================== + +SPI wiring modes +---------------- + +These ADCs can output data on several SDO lines (1/2/4/8). The driver +currently supports only 1 SDO line. + +SPI offload wiring +------------------ +When used with a SPI offload, the supported wiring configuration is: + +.. code-block:: + + +-------------+ +-------------+ + | BUSY |-------->| TRIGGER | + | CS |<--------| CS | + | | | | + | ADC | | SPI | + | | | | + | SDI |<--------| SDO | + | DOUTA |-------->| SDI | + | SCLK |<--------| SCLK | + | | | | + | | +-------------+ + | CONVST |<--------| PWM | + +-------------+ +-------------+ + +In this case, the ``pwms`` property is required. +The ``#trigger-source-cells = <1>`` property is also required to connect back +to the SPI offload. The SPI offload will have ``trigger-sources`` property +with a cell to indicate the busy signal: +``<&ad7606 AD4695_TRIGGER_EVENT_BUSY>``. + +.. seealso:: `SPI offload support`_ + + +Parallel wiring mode +-------------------- + +There is also a parallel interface, with 16 lines (that can be reduced to 8 in +byte mode). The parallel interface is selected by declaring the device as +platform in the device tree (with no io-backends node defined, see below). + +IIO-backend mode +---------------- + +This mode allows to reach the best sample rates, but it requires an external +hardware (eg HDL or APU) to handle the low level communication. +The backend mode is enabled when through the definition of the "io-backends" +property in the device tree. + +The reference configuration for the current implementation of IIO-backend mode +is the HDL reference provided by ADI: +https://wiki.analog.com/resources/eval/user-guides/ad7606x-fmc/hdl + +This implementation embeds an IIO-backend compatible IP (adi-axi-adc) and a PWM +connected to the conversion trigger pin. + +.. code-block:: + + +---+ +---------------------------- + | | +-------+ |AD76xx + | A | controls | | | + | D |-------------->| PWM |-------------->| cnvst + | 7 | | | | + | 6 | +-------+ | + | 0 | controls +-----------+-----------+ | + | 6 |---------->| | |<--| frstdata + | | | Backend | Backend |<--| busy + | D | | Driver | | | + | R | | | |-->| clk + | I | requests |+---------+| DMA | | + | V |----------->| Buffer ||<---- |<=>| DATA + | E | |+---------+| | | + | R | +-----------+-----------+ | + | |-------------------------------------->| reset/configuration gpios + +---+ +----------------------------- + + +Software and hardware modes +--------------------------- + +While all the AD7606/AD7616 series parts can be configured using GPIOs, some of +them can be configured using register. + +The chips that support software mode have more values available for configuring +the device, as well as more settings, and allow to control the range and +calibration per channel. + +The following settings are available per channel in software mode: + - Scale + +Also, there is a broader choice of oversampling ratios in software mode. + +Conversion triggering +--------------------- + +The conversion can be triggered by two distinct ways: + + - A GPIO is connected to the conversion trigger pin, and this GPIO is controlled + by the driver directly. In this configuration, the driver sets back the + conversion trigger pin to high as soon as it has read all the conversions. + + - An external source is connected to the conversion trigger pin. In the + current implementation, it must be a PWM. In this configuration, the driver + does not control directly the conversion trigger pin. Instead, it can + control the PWM's frequency. This trigger is enabled only for iio-backend. + +Reference voltage +----------------- + +2 possible reference voltage sources are supported: + + - Internal reference (2.5V) + - External reference (2.5V) + +The source is determined by the device tree. If ``refin-supply`` is present, +then the external reference is used, otherwise the internal reference is used. + +Oversampling +------------ + +This family supports oversampling to improve SNR. +In software mode, the following ratios are available: +1 (oversampling disabled)/2/4/8/16/32/64/128/256. + +Unimplemented features +---------------------- + +- 2/4/8 SDO lines +- CRC indication +- Calibration + +SPI offload support +=================== + +To be able to achieve the maximum sample rate, the driver can be used with the +`AXI SPI Engine`_ to provide SPI offload support. + +.. _AXI SPI Engine: https://analogdevicesinc.github.io/hdl/library/spi_engine/index.html + +When SPI offload is being used, some attributes will be different. + +* ``trigger`` directory is removed. +* ``sampling_frequency`` attribute is added for setting the sample rate. +* ``timestamp`` channel is removed. +* Buffer data format may be different compared to when offload is not used, + e.g. the ``in_voltage0_type`` attribute. + +Device buffers +============== + +IIO triggered buffer +-------------------- + +This driver supports IIO triggered buffers, with a "built in" trigger, i.e the +trigger is allocated and linked by the driver, and a new conversion is triggered +as soon as the samples are transferred, and a timestamp channel is added to make +up for the potential jitter induced by the delays in the interrupt handling. + +IIO backend buffer +------------------ + +When IIO backend is used, the trigger is not needed, and the sample rate is +considered as stable. There is no timestamp channel. The communication is +delegated to an external logic, called a backend, and the backend's driver +handles the buffer. When this mode is enabled, the driver cannot control the +conversion pin, because the busy pin is bound to the backend. diff --git a/Documentation/iio/ad7625.rst b/Documentation/iio/ad7625.rst new file mode 100644 index 000000000000..61761e3b75c3 --- /dev/null +++ b/Documentation/iio/ad7625.rst @@ -0,0 +1,91 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +==================== +AD7625 driver +==================== + +ADC driver for Analog Devices Inc. AD7625, AD7626, AD7960, and AD7961 +devices. The module name is ``ad7625``. + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD7625 <https://www.analog.com/AD7625>`_ +* `AD7626 <https://www.analog.com/AD7626>`_ +* `AD7960 <https://www.analog.com/AD7960>`_ +* `AD7961 <https://www.analog.com/AD7961>`_ + +The driver requires use of the Pulsar LVDS HDL project: + +* `Pulsar LVDS HDL <http://analogdevicesinc.github.io/hdl/projects/pulsar_lvds/index.html>`_ + +To trigger conversions and enable subsequent data transfer, the devices +require coupled PWM signals with a phase offset. + +Supported features +================== + +Conversion control modes +------------------------ + +The driver currently supports one of two possible LVDS conversion control methods. + +Echoed-Clock interface mode +^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: + + +----------------+ + +xxxxxxxxxxxxxxxxxxxxxxxxxx| CNV | + X | | + v | HOST | + +----------------------------+ | | + | CNV+/CNV- DCO+/DCO- |xxxxxxx>| CLK_IN | + | | | | + | | | | + | AD7625 D+/D- |xxxxxxx>| DATA_IN | + | | | | + | | | | + | CLK+/CLK- |<xxxxxxx| CLK & CLK_GATE | + +----------------------------+ | | + +----------------+ + +Reference voltage +----------------- + +Three possible reference voltage sources are supported: + +- Internal reference (only available on AD7625 and AD7626) +- External reference and internal buffer +- External reference + +The source is determined by the device tree. If ``ref-supply`` is present, then +the external reference is used. If ``refin-supply`` is present, then the internal +buffer is used. If neither is present, then the internal reference is used. + +Unimplemented features +---------------------- + +- Self-clocked mode + + +Device attributes +================= + +The AD762x is a fully-differential ADC and has the following attributes: + ++---------------------------------------+--------------------------------------------------------------+ +| Attribute | Description | ++=======================================+==============================================================+ +| ``scale`` | Scale factor to convert raw value from buffered reads to mV. | ++---------------------------------------+--------------------------------------------------------------+ + + +Device buffers +============== + +This driver supports IIO triggered buffers. + +See :doc:`iio_devbuf` for more information. diff --git a/Documentation/iio/ad7944.rst b/Documentation/iio/ad7944.rst new file mode 100644 index 000000000000..e6dbe4d7f58c --- /dev/null +++ b/Documentation/iio/ad7944.rst @@ -0,0 +1,178 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +============= +AD7944 driver +============= + +ADC driver for Analog Devices Inc. AD7944 and similar devices. The module name +is ``ad7944``. + + +Supported devices +================= + +The following chips are supported by this driver: + +* `AD7944 <https://www.analog.com/AD7944>`_ +* `AD7985 <https://www.analog.com/AD7985>`_ +* `AD7986 <https://www.analog.com/AD7986>`_ + + +Supported features +================== + +SPI wiring modes +---------------- + +The driver currently supports three of the many possible SPI wiring configurations. + +CS mode, 3-wire, without busy indicator +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: + + +-------------+ + +--------------------| CS | + v | | + VIO +--------------------+ | HOST | + | | CNV | | | + +--->| SDI AD7944 SDO |-------->| SDI | + | SCK | | | + +--------------------+ | | + ^ | | + +--------------------| SCLK | + +-------------+ + +To select this mode in the device tree, set the ``adi,spi-mode`` property to +``"single"`` and omit the ``cnv-gpios`` property. + +This is the only wiring configuration supported when using `SPI offload support`_. + +CS mode, 4-wire, without busy indicator +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: + + +-------------+ + +-----------------------------------| CS | + | | | + | +--------------------| GPIO | + | v | | + | +--------------------+ | HOST | + | | CNV | | | + +--->| SDI AD7944 SDO |-------->| SDI | + | SCK | | | + +--------------------+ | | + ^ | | + +--------------------| SCLK | + +-------------+ + +To select this mode in the device tree, omit the ``adi,spi-mode`` property and +provide the ``cnv-gpios`` property. + +Chain mode, without busy indicator +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. code-block:: + + +-------------+ + +-------------------------+--------------------| CS | + v v | | + +--------------------+ +--------------------+ | HOST | + | CNV | | CNV | | | + +--->| SDI AD7944 SDO |--->| SDI AD7944 SDO |-------->| SDI | + | | SCK | | SCK | | | + GND +--------------------+ +--------------------+ | | + ^ ^ | | + +-------------------------+--------------------| SCLK | + +-------------+ + +To select this mode in the device tree, set the ``adi,spi-mode`` property to +``"chain"``, add the ``spi-cs-high`` flag, add the ``#daisy-chained-devices`` +property, and omit the ``cnv-gpios`` property. + +Reference voltage +----------------- + +All 3 possible reference voltage sources are supported: + +- Internal reference +- External 1.2V reference and internal buffer +- External reference + +The source is determined by the device tree. If ``ref-supply`` is present, then +the external reference is used. If ``refin-supply`` is present, then the internal +buffer is used. If neither is present, then the internal reference is used. + +Unimplemented features +---------------------- + +- ``BUSY`` indication + + +Device attributes +================= + +There are two types of ADCs in this family, pseudo-differential and fully +differential. The channel name is different depending on the type of ADC. + +Pseudo-differential ADCs +------------------------ + +AD7944 and AD7985 are pseudo-differential ADCs and have the following attributes: + ++---------------------------------------+--------------------------------------------------------------+ +| Attribute | Description | ++=======================================+==============================================================+ +| ``in_voltage0_raw`` | Raw ADC voltage value (*IN+* referenced to ground sense). | ++---------------------------------------+--------------------------------------------------------------+ +| ``in_voltage0_scale`` | Scale factor to convert raw value to mV. | ++---------------------------------------+--------------------------------------------------------------+ + +In "chain" mode, additional chips will appear as additional voltage input +channels, e.g. ``in_voltage1_raw``. + +Fully-differential ADCs +----------------------- + +AD7986 is a fully-differential ADC and has the following attributes: + ++---------------------------------------+--------------------------------------------------------------+ +| Attribute | Description | ++=======================================+==============================================================+ +| ``in_voltage0-voltage1_raw`` | Raw ADC voltage value (*IN+* - *IN-*). | ++---------------------------------------+--------------------------------------------------------------+ +| ``in_voltage0-voltage1_scale`` | Scale factor to convert raw value to mV. | ++---------------------------------------+--------------------------------------------------------------+ + +In "chain" mode, additional chips will appear as additional voltage input +channels, e.g. ``in_voltage2-voltage3_raw``. + +SPI offload support +=================== + +To be able to achieve the maximum sample rate, the driver can be used with the +`AXI SPI Engine`_ to provide SPI offload support. + +.. _AXI SPI Engine: http://analogdevicesinc.github.io/hdl/projects/pulsar_adc/index.html + +When SPI offload is being used, some attributes will be different. + +* ``trigger`` directory is removed. +* ``in_voltage0_sampling_frequency`` attribute is added for setting the sample + rate. +* ``in_voltage0_sampling_frequency_available`` attribute is added for querying + the max sample rate. +* ``timestamp`` channel is removed. +* Buffer data format may be different compared to when offload is not used, + e.g. the ``in_voltage0_type`` attribute. + +If the ``turbo-gpios`` property is present in the device tree, the driver will +turn on TURBO during buffered reads and turn it off otherwise. + +Device buffers +============== + +This driver supports IIO triggered buffers. + +See :doc:`iio_devbuf` for more information. diff --git a/Documentation/iio/adis16475.rst b/Documentation/iio/adis16475.rst new file mode 100644 index 000000000000..4bf0998be36e --- /dev/null +++ b/Documentation/iio/adis16475.rst @@ -0,0 +1,384 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +ADIS16475 driver +================ + +This driver supports Analog Device's IMUs on SPI bus. + +1. Supported devices +==================== + +* `ADIS16465 <https://www.analog.com/ADIS16465>`_ +* `ADIS16467 <https://www.analog.com/ADIS16467>`_ +* `ADIS16470 <https://www.analog.com/ADIS16470>`_ +* `ADIS16475 <https://www.analog.com/ADIS16475>`_ +* `ADIS16477 <https://www.analog.com/ADIS16477>`_ +* `ADIS16500 <https://www.analog.com/ADIS16500>`_ +* `ADIS16505 <https://www.analog.com/ADIS16505>`_ +* `ADIS16507 <https://www.analog.com/ADIS16507>`_ + +Each supported device is a precision, miniature microelectromechanical system +(MEMS) inertial measurement unit (IMU) that includes a triaxial gyroscope and a +triaxial accelerometer. Each inertial sensor in the IMU device combines with +signal conditioning that optimizes dynamic performance. The factory calibration +characterizes each sensor for sensitivity, bias, alignment, linear acceleration +(gyroscope bias), and point of percussion (accelerometer location). As a result, +each sensor has dynamic compensation formulas that provide accurate sensor +measurements over a broad set of conditions. + +2. Device attributes +==================== + +Accelerometer, gyroscope measurements are always provided. Furthermore, the +driver offers the capability to retrieve the delta angle and the delta velocity +measurements computed by the device. + +The delta angle measurements represent a calculation of angular displacement +between each sample update, while the delta velocity measurements represent a +calculation of linear velocity change between each sample update. + +Finally, temperature data are provided which show a coarse measurement of +the temperature inside of the IMU device. This data is most useful for +monitoring relative changes in the thermal environment. + +The signal chain of each inertial sensor (accelerometers and gyroscopes) +includes the application of unique correction formulas, which are derived from +extensive characterization of bias, sensitivity, alignment, response to linear +acceleration (gyroscopes), and point of percussion (accelerometer location) +over a temperature range of −40°C to +85°C, for each ADIS device. These +correction formulas are not accessible, but users do have the opportunity to +adjust the bias for each sensor individually through the calibbias attribute. + +Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``, +where X is the IIO index of the device. Under these folders reside a set of +device files, depending on the characteristics and features of the hardware +device in questions. These files are consistently generalized and documented in +the IIO ABI documentation. + +The following tables show the adis16475 related device files, found in the +specific device folder path ``/sys/bus/iio/devices/iio:deviceX``. + ++-------------------------------------------+----------------------------------------------------------+ +| 3-Axis Accelerometer related device files | Description | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_scale | Scale for the accelerometer channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibbias | Calibration offset for the X-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_raw | Raw X-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibbias | Calibration offset for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_raw | Raw Y-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibbias | Calibration offset for the Z-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_raw | Raw Z-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_scale | Scale for delta velocity channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_x_raw | Raw X-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_y_raw | Raw Y-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_z_raw | Raw Z-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ + ++---------------------------------------+------------------------------------------------------+ +| 3-Axis Gyroscope related device files | Description | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_scale | Scale for the gyroscope channels. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_x_calibbias | Calibration offset for the X-axis gyroscope channel. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_x_raw | Raw X-axis gyroscope channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_y_calibbias | Calibration offset for the Y-axis gyroscope channel. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_y_raw | Raw Y-axis gyroscope channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_z_calibbias | Calibration offset for the Z-axis gyroscope channel. | ++---------------------------------------+------------------------------------------------------+ +| in_anglvel_z_raw | Raw Z-axis gyroscope channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_scale | Scale for delta angle channels. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_x_raw | Raw X-axis delta angle channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_y_raw | Raw Y-axis delta angle channel value. | ++---------------------------------------+------------------------------------------------------+ +| in_deltaangl_z_raw | Raw Z-axis delta angle channel value. | ++---------------------------------------+------------------------------------------------------+ + ++----------------------------------+-------------------------------------------+ +| Temperature sensor related files | Description | ++----------------------------------+-------------------------------------------+ +| in_temp0_raw | Raw temperature channel value. | ++----------------------------------+-------------------------------------------+ +| in_temp0_scale | Scale for the temperature sensor channel. | ++----------------------------------+-------------------------------------------+ + ++-------------------------------+---------------------------------------------------------+ +| Miscellaneous device files | Description | ++-------------------------------+---------------------------------------------------------+ +| name | Name of the IIO device. | ++-------------------------------+---------------------------------------------------------+ +| sampling_frequency | Currently selected sample rate. | ++-------------------------------+---------------------------------------------------------+ +| filter_low_pass_3db_frequency | Bandwidth for the accelerometer and gyroscope channels. | ++-------------------------------+---------------------------------------------------------+ + +The following table shows the adis16475 related device debug files, found in the +specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``. + ++----------------------+-------------------------------------------------------------------------+ +| Debugfs device files | Description | ++----------------------+-------------------------------------------------------------------------+ +| serial_number | The serial number of the chip in hexadecimal format. | ++----------------------+-------------------------------------------------------------------------+ +| product_id | Chip specific product id (e.g. 16475, 16500, 16505, etc.). | ++----------------------+-------------------------------------------------------------------------+ +| flash_count | The number of flash writes performed on the device. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_revision | String containing the firmware revision in the following format ##.##. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_date | String containing the firmware date in the following format mm-dd-yyyy. | ++----------------------+-------------------------------------------------------------------------+ + +Channels processed values +------------------------- + +A channel value can be read from its _raw attribute. The value returned is the +raw value as reported by the devices. To get the processed value of the channel, +apply the following formula: + +.. code-block:: bash + + processed value = (_raw + _offset) * _scale + +Where _offset and _scale are device attributes. If no _offset attribute is +present, simply assume its value is 0. + +The adis16475 driver offers data for 5 types of channels, the table below shows +the measurement units for the processed value, which are defined by the IIO +framework: + ++-------------------------------------+---------------------------+ +| Channel type | Measurement unit | ++-------------------------------------+---------------------------+ +| Acceleration on X, Y, and Z axis | Meters per Second squared | ++-------------------------------------+---------------------------+ +| Angular velocity on X, Y and Z axis | Radians per second | ++-------------------------------------+---------------------------+ +| Delta velocity on X. Y, and Z axis | Meters per Second | ++-------------------------------------+---------------------------+ +| Delta angle on X, Y, and Z axis | Radians | ++-------------------------------------+---------------------------+ +| Temperature | Millidegrees Celsius | ++-------------------------------------+---------------------------+ + +Usage examples +-------------- + +Show device name: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat name + adis16505-2 + +Show accelerometer channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw + -275924 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw + -30142222 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw + 261265769 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale + 0.000000037 + +- X-axis acceleration = in_accel_x_raw * in_accel_scale = −0.010209188 m/s^2 +- Y-axis acceleration = in_accel_y_raw * in_accel_scale = −1.115262214 m/s^2 +- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.666833453 m/s^2 + +Show gyroscope channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw + -3324626 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw + 1336980 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw + -602983 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale + 0.000000006 + +- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = −0.019947756 rad/s +- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = 0.00802188 rad/s +- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = −0.003617898 rad/s + +Set calibration offset for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 5000 + +Set calibration offset for gyroscope channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + -5000 + +Set sampling frequency: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency + 2000.000000 + + root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency + 1000.000000 + +Set bandwidth for accelerometer and gyroscope: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat filter_low_pass_3db_frequency + 720 + + root:/sys/bus/iio/devices/iio:device0> echo 360 > filter_low_pass_3db_frequency + root:/sys/bus/iio/devices/iio:device0> cat filter_low_pass_3db_frequency + 360 + +Show serial number: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat serial_number + 0x04f9 + +Show product id: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat product_id + 16505 + +Show flash count: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat flash_count + 150 + +Show firmware revision: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision + 1.6 + +Show firmware date: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_date + 06-27-2019 + +3. Device buffers +================= + +This driver supports IIO buffers. + +All devices support retrieving the raw acceleration, gyroscope and temperature +measurements using buffers. + +The following device families also support retrieving the delta velocity, delta +angle and temperature measurements using buffers: + +- ADIS16477 +- ADIS16500 +- ADIS16505 +- ADIS16507 + +However, when retrieving acceleration or gyroscope data using buffers, delta +readings will not be available and vice versa. + +Usage examples +-------------- + +Set device trigger in current_trigger, if not already set: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + + root:/sys/bus/iio/devices/iio:device0> echo adis16505-2-dev0 > trigger/current_trigger + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + adis16505-2-dev0 + +Select channels for buffer read: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_en + +Set the number of samples to be stored in the buffer: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length + +Enable buffer readings: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable + +Obtain buffered data: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0 + ... + 00001680 01 1f 00 00 ff ff fe ef 00 00 47 bf 00 03 35 55 |..........G...5U| + 00001690 01 1f 00 00 ff ff ff d9 00 00 46 f1 00 03 35 35 |..........F...55| + 000016a0 01 1f 00 00 ff ff fe fc 00 00 46 cb 00 03 35 7b |..........F...5{| + 000016b0 01 1f 00 00 ff ff fe 41 00 00 47 0d 00 03 35 8b |.......A..G...5.| + 000016c0 01 1f 00 00 ff ff fe 37 00 00 46 b4 00 03 35 90 |.......7..F...5.| + 000016d0 01 1d 00 00 ff ff fe 5a 00 00 45 d7 00 03 36 08 |.......Z..E...6.| + 000016e0 01 1b 00 00 ff ff fe fb 00 00 45 e7 00 03 36 60 |..........E...6`| + 000016f0 01 1a 00 00 ff ff ff 17 00 00 46 bc 00 03 36 de |..........F...6.| + 00001700 01 1a 00 00 ff ff fe 59 00 00 46 d7 00 03 37 b8 |.......Y..F...7.| + 00001710 01 1a 00 00 ff ff fe ae 00 00 46 95 00 03 37 ba |..........F...7.| + 00001720 01 1a 00 00 ff ff fe c5 00 00 46 63 00 03 37 9f |..........Fc..7.| + 00001730 01 1a 00 00 ff ff fe 55 00 00 46 89 00 03 37 c1 |.......U..F...7.| + 00001740 01 1a 00 00 ff ff fe 31 00 00 46 aa 00 03 37 f7 |.......1..F...7.| + ... + +See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered +data is structured. + +4. IIO Interfacing Tools +======================== + +See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO +interfacing tools. diff --git a/Documentation/iio/adis16480.rst b/Documentation/iio/adis16480.rst new file mode 100644 index 000000000000..4a2d40e0daa7 --- /dev/null +++ b/Documentation/iio/adis16480.rst @@ -0,0 +1,446 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +ADIS16480 driver +================ + +This driver supports Analog Device's IMUs on SPI bus. + +1. Supported devices +==================== + +* `ADIS16375 <https://www.analog.com/ADIS16375>`_ +* `ADIS16480 <https://www.analog.com/ADIS16480>`_ +* `ADIS16485 <https://www.analog.com/ADIS16485>`_ +* `ADIS16486 <https://www.analog.com/ADIS16486>`_ +* `ADIS16487 <https://www.analog.com/ADIS16487>`_ +* `ADIS16488 <https://www.analog.com/ADIS16488>`_ +* `ADIS16489 <https://www.analog.com/ADIS16489>`_ +* `ADIS16490 <https://www.analog.com/ADIS16490>`_ +* `ADIS16495 <https://www.analog.com/ADIS16495>`_ +* `ADIS16497 <https://www.analog.com/ADIS16497>`_ +* `ADIS16545 <https://www.analog.com/ADIS16545>`_ +* `ADIS16547 <https://www.analog.com/ADIS16547>`_ + +Each supported device is a complete inertial system that includes a triaxial +gyroscope and a triaxial accelerometer. Each inertial sensor in device combines +with signal conditioning that optimizes dynamic performance. The factory +calibration characterizes each sensor for sensitivity, bias, and alignment. As +a result, each sensor has its own dynamic compensation formulas that provide +accurate sensor measurements. + +2. Device attributes +==================== + +Accelerometer, gyroscope measurements are always provided. Furthermore, the +driver offers the capability to retrieve the delta angle and the delta velocity +measurements computed by the device. + +The delta angle measurements represent a calculation of angular displacement +between each sample update, while the delta velocity measurements represent a +calculation of linear velocity change between each sample update. + +Finally, temperature data are provided which show a coarse measurement of +the temperature inside of the IMU device. This data is most useful for +monitoring relative changes in the thermal environment. + +ADIS16480 and ADIS16488 also provide access to barometric pressure data and +triaxial magnetometer measurements. + +Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``, +where X is the IIO index of the device. Under these folders reside a set of +device files, depending on the characteristics and features of the hardware +device in questions. These files are consistently generalized and documented in +the IIO ABI documentation. + +The following tables show the adis16480 related device files, found in the +specific device folder path ``/sys/bus/iio/devices/iio:deviceX``. + +**Available only for ADIS16480 and ADIS16488:** + ++------------------------------------------+---------------------------------------------------------+ +| 3-Axis Magnetometer related device files | Description | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_scale | Scale for the magnetometer channels. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_x_calibbias | Calibration offset for the X-axis magnetometer channel. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_x_filter_low_pass_3db_frequency | Bandwidth for the X-axis magnetometer channel. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_x_raw | Raw X-axis magnetometer channel value. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_y_calibbias | Calibration offset for the Y-axis magnetometer channel. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_y_filter_low_pass_3db_frequency | Bandwidth for the Y-axis magnetometer channel. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_y_raw | Raw Y-axis magnetometer channel value. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_z_calibbias | Calibration offset for the Z-axis magnetometer channel. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_z_filter_low_pass_3db_frequency | Bandwidth for the Z-axis magnetometer channel. | ++------------------------------------------+---------------------------------------------------------+ +| in_magn_z_raw | Raw Z-axis magnetometer channel value. | ++------------------------------------------+---------------------------------------------------------+ + ++------------------------------------------+-----------------------------------------------------+ +| Barometric pressure sensor related files | Description | ++------------------------------------------+-----------------------------------------------------+ +| in_pressure0_calibbias | Calibration offset for barometric pressure channel. | ++------------------------------------------+-----------------------------------------------------+ +| in_pressure0_raw | Raw barometric pressure channel value. | ++------------------------------------------+-----------------------------------------------------+ +| in_pressure0_scale | Scale for the barometric pressure sensor channel. | ++------------------------------------------+-----------------------------------------------------+ + +**Available for all supported devices:** + ++-------------------------------------------+----------------------------------------------------------+ +| 3-Axis Accelerometer related device files | Description | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_scale | Scale for the accelerometer channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibbias | Calibration offset for the X-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibscale | Calibration scale for the X-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_filter_low_pass_3db_frequency | Bandwidth for the X-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_raw | Raw X-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibbias | Calibration offset for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibscale | Calibration scale for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_filter_low_pass_3db_frequency | Bandwidth for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_raw | Raw Y-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibbias | Calibration offset for the Z-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibscale | Calibration scale for the Z-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_filter_low_pass_3db_frequency | Bandwidth for the Z-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_raw | Raw Z-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_scale | Scale for delta velocity channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_x_raw | Raw X-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_y_raw | Raw Y-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_z_raw | Raw Z-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ + ++--------------------------------------------+------------------------------------------------------+ +| 3-Axis Gyroscope related device files | Description | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_scale | Scale for the gyroscope channels. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_calibbias | Calibration offset for the X-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_calibscale | Calibration scale for the X-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_filter_low_pass_3db_frequency | Bandwidth for the X-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_raw | Raw X-axis gyroscope channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_calibbias | Calibration offset for the Y-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_calibscale | Calibration scale for the Y-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_filter_low_pass_3db_frequency | Bandwidth for the Y-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_raw | Raw Y-axis gyroscope channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_calibbias | Calibration offset for the Z-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_calibscale | Calibration scale for the Z-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_filter_low_pass_3db_frequency | Bandwidth for the Z-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_raw | Raw Z-axis gyroscope channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_scale | Scale for delta angle channels. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_x_raw | Raw X-axis delta angle channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_y_raw | Raw Y-axis delta angle channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_z_raw | Raw Z-axis delta angle channel value. | ++--------------------------------------------+------------------------------------------------------+ + ++----------------------------------+-------------------------------------------+ +| Temperature sensor related files | Description | ++----------------------------------+-------------------------------------------+ +| in_temp0_raw | Raw temperature channel value. | ++----------------------------------+-------------------------------------------+ +| in_temp0_offset | Offset for the temperature sensor channel.| ++----------------------------------+-------------------------------------------+ +| in_temp0_scale | Scale for the temperature sensor channel. | ++----------------------------------+-------------------------------------------+ + ++-------------------------------+---------------------------------------------------------+ +| Miscellaneous device files | Description | ++-------------------------------+---------------------------------------------------------+ +| name | Name of the IIO device. | ++-------------------------------+---------------------------------------------------------+ +| sampling_frequency | Currently selected sample rate. | ++-------------------------------+---------------------------------------------------------+ + +The following table shows the adis16480 related device debug files, found in the +specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``. + ++----------------------+-------------------------------------------------------------------------+ +| Debugfs device files | Description | ++----------------------+-------------------------------------------------------------------------+ +| serial_number | The serial number of the chip in hexadecimal format. | ++----------------------+-------------------------------------------------------------------------+ +| product_id | Chip specific product id (e.g. 16480, 16488, 16545, etc.). | ++----------------------+-------------------------------------------------------------------------+ +| flash_count | The number of flash writes performed on the device. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_revision | String containing the firmware revision in the following format ##.##. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_date | String containing the firmware date in the following format mm-dd-yyyy. | ++----------------------+-------------------------------------------------------------------------+ + +Channels processed values +------------------------- + +A channel value can be read from its _raw attribute. The value returned is the +raw value as reported by the devices. To get the processed value of the channel, +apply the following formula: + +.. code-block:: bash + + processed value = (_raw + _offset) * _scale + +Where _offset and _scale are device attributes. If no _offset attribute is +present, simply assume its value is 0. + +The adis16480 driver offers data for 7 types of channels, the table below shows +the measurement units for the processed value, which are defined by the IIO +framework: + ++--------------------------------------+---------------------------+ +| Channel type | Measurement unit | ++--------------------------------------+---------------------------+ +| Acceleration on X, Y, and Z axis | Meters per Second squared | ++--------------------------------------+---------------------------+ +| Angular velocity on X, Y and Z axis | Radians per second | ++--------------------------------------+---------------------------+ +| Delta velocity on X. Y, and Z axis | Meters per Second | ++--------------------------------------+---------------------------+ +| Delta angle on X, Y, and Z axis | Radians | ++--------------------------------------+---------------------------+ +| Temperature | Millidegrees Celsius | ++--------------------------------------+---------------------------+ +| Magnetic field along X, Y and Z axis | Gauss | ++--------------------------------------+---------------------------+ +| Barometric pressure | kilo Pascal | ++--------------------------------------+---------------------------+ + +Usage examples +-------------- + +Show device name: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat name + adis16545-1 + +Show accelerometer channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw + 1376728 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw + 4487621 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw + 262773792 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale + 0.000000037 + +- X-axis acceleration = in_accel_x_raw * in_accel_scale = 0.050938936 m/s^2 +- Y-axis acceleration = in_accel_y_raw * in_accel_scale = 0.166041977 m/s^2 +- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.722630304 m/s^2 + +Show gyroscope channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw + -1041702 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw + -273013 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw + 2745116 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale + 0.000000001 + +- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = −0.001041702 rad/s +- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = −0.000273013 rad/s +- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = 0.002745116 rad/s + +Set calibration offset for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 5000 + +Set calibration offset for gyroscope channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + -5000 + +Set sampling frequency: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency + 4250.000000 + + root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency + 1062.500000 + +Set bandwidth for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 300 > in_accel_x_filter_low_pass_3db_frequency + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_filter_low_pass_3db_frequency + 300 + +Show serial number: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat serial_number + 0x000c + +Show product id: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat product_id + 16545 + +Show flash count: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat flash_count + 88 + +Show firmware revision: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision + 1.4 + +Show firmware date: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_date + 09-23-2023 + +3. Device buffers +================= + +This driver supports IIO buffers. + +All devices support retrieving the raw acceleration, gyroscope and temperature +measurements using buffers. + +The following device families also support retrieving the delta velocity, delta +angle and temperature measurements using buffers: + +- ADIS16545 +- ADIS16547 + +However, when retrieving acceleration or gyroscope data using buffers, delta +readings will not be available and vice versa. This is because the device only +allows to read either acceleration and gyroscope data or delta velocity and +delta angle data at a time and switching between these two burst data selection +modes is time consuming. + +Usage examples +-------------- + +Set device trigger in current_trigger, if not already set: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + + root:/sys/bus/iio/devices/iio:device0> echo adis16545-1-dev0 > trigger/current_trigger + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + adis16545-1-dev0 + +Select channels for buffer read: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_en + +Set the number of samples to be stored in the buffer: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length + +Enable buffer readings: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable + +Obtain buffered data:: + + root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0 + ... + 00006aa0 09 62 00 00 ff ff fc a4 00 00 01 69 00 03 3c 08 |.b.........i..<.| + 00006ab0 09 61 00 00 00 00 02 96 00 00 02 8f 00 03 37 50 |.a............7P| + 00006ac0 09 61 00 00 00 00 12 3d 00 00 0b 89 00 03 2c 0b |.a.....=......,.| + 00006ad0 09 61 00 00 00 00 1e dc 00 00 16 dd 00 03 25 bf |.a............%.| + 00006ae0 09 61 00 00 00 00 1e e3 00 00 1b bf 00 03 27 0b |.a............'.| + 00006af0 09 61 00 00 00 00 15 50 00 00 19 44 00 03 30 fd |.a.....P...D..0.| + 00006b00 09 61 00 00 00 00 09 0e 00 00 14 41 00 03 3d 7f |.a.........A..=.| + 00006b10 09 61 00 00 ff ff ff f0 00 00 0e bc 00 03 48 d0 |.a............H.| + 00006b20 09 63 00 00 00 00 00 9f 00 00 0f 37 00 03 4c fe |.c.........7..L.| + 00006b30 09 64 00 00 00 00 0b f6 00 00 18 92 00 03 43 22 |.d............C"| + 00006b40 09 64 00 00 00 00 18 df 00 00 22 33 00 03 33 ab |.d........"3..3.| + 00006b50 09 63 00 00 00 00 1e 81 00 00 26 be 00 03 29 60 |.c........&...)`| + 00006b60 09 63 00 00 00 00 1b 13 00 00 22 2f 00 03 23 91 |.c........"/..#.| + ... + +See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered +data is structured. + +4. IIO Interfacing Tools +======================== + +See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO +interfacing tools. diff --git a/Documentation/iio/adis16550.rst b/Documentation/iio/adis16550.rst new file mode 100644 index 000000000000..25db7b8060c4 --- /dev/null +++ b/Documentation/iio/adis16550.rst @@ -0,0 +1,376 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +ADIS16550 driver +================ + +This driver supports Analog Device's IMUs on SPI bus. + +1. Supported devices +==================== + +* `ADIS16550 <https://www.analog.com/ADIS16550>`_ + +The ADIS16550 is a complete inertial system that includes a triaxis gyroscope +and a triaxis accelerometer. The factory calibration characterizes each sensor for +sensitivity, bias, and alignment. As a result, each sensor has its own dynamic +compensation formulas that provide accurate sensor measurements. + +2. Device attributes +==================== + +Accelerometer, gyroscope measurements are always provided. Furthermore, the +driver offers the capability to retrieve the delta angle and the delta velocity +measurements computed by the device. + +The delta angle measurements represent a calculation of angular displacement +between each sample update, while the delta velocity measurements represent a +calculation of linear velocity change between each sample update. + +Finally, temperature data are provided which show a coarse measurement of +the temperature inside of the IMU device. This data is most useful for +monitoring relative changes in the thermal environment. + +Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``, +where X is the IIO index of the device. Under these folders reside a set of +device files, depending on the characteristics and features of the hardware +device in questions. These files are consistently generalized and documented in +the IIO ABI documentation. + +The following tables show the adis16550 related device files, found in the +specific device folder path ``/sys/bus/iio/devices/iio:deviceX``. + ++-------------------------------------------+----------------------------------------------------------+ +| 3-Axis Accelerometer related device files | Description | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_scale | Scale for the accelerometer channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_filter_low_pass_3db_frequency | Bandwidth for the accelerometer channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibbias | Calibration offset for the X-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibscale | Calibration scale for the X-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_x_raw | Raw X-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibbias | Calibration offset for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibscale | Calibration scale for the Y-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_y_raw | Raw Y-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibbias | Calibration offset for the Z-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibscale | Calibration scale for the Z-axis accelerometer channel. | ++-------------------------------------------+----------------------------------------------------------+ +| in_accel_z_raw | Raw Z-axis accelerometer channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_scale | Scale for delta velocity channels. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_x_raw | Raw X-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_y_raw | Raw Y-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ +| in_deltavelocity_z_raw | Raw Z-axis delta velocity channel value. | ++-------------------------------------------+----------------------------------------------------------+ + ++--------------------------------------------+------------------------------------------------------+ +| 3-Axis Gyroscope related device files | Description | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_scale | Scale for the gyroscope channels. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_filter_low_pass_3db_frequency | Scale for the gyroscope channels. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_calibbias | Calibration offset for the X-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_calibscale | Calibration scale for the X-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_x_raw | Raw X-axis gyroscope channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_calibbias | Calibration offset for the Y-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_calibscale | Calibration scale for the Y-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_y_raw | Raw Y-axis gyroscope channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_calibbias | Calibration offset for the Z-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_calibscale | Calibration scale for the Z-axis gyroscope channel. | ++--------------------------------------------+------------------------------------------------------+ +| in_anglvel_z_raw | Raw Z-axis gyroscope channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_scale | Scale for delta angle channels. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_x_raw | Raw X-axis delta angle channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_y_raw | Raw Y-axis delta angle channel value. | ++--------------------------------------------+------------------------------------------------------+ +| in_deltaangl_z_raw | Raw Z-axis delta angle channel value. | ++--------------------------------------------+------------------------------------------------------+ + ++----------------------------------+-------------------------------------------+ +| Temperature sensor related files | Description | ++----------------------------------+-------------------------------------------+ +| in_temp0_raw | Raw temperature channel value. | ++----------------------------------+-------------------------------------------+ +| in_temp0_offset | Offset for the temperature sensor channel.| ++----------------------------------+-------------------------------------------+ +| in_temp0_scale | Scale for the temperature sensor channel. | ++----------------------------------+-------------------------------------------+ + ++----------------------------+--------------------------------------------------------------------------------+ +| Miscellaneous device files | Description | ++----------------------------+--------------------------------------------------------------------------------+ +| name | Name of the IIO device. | ++----------------------------+--------------------------------------------------------------------------------+ +| sampling_frequency | Currently selected sample rate. | ++----------------------------+--------------------------------------------------------------------------------+ + +The following table shows the adis16550 related device debug files, found in the +specific device debug folder path ``/sys/kernel/debug/iio/iio:deviceX``. + ++----------------------+-------------------------------------------------------------------------+ +| Debugfs device files | Description | ++----------------------+-------------------------------------------------------------------------+ +| serial_number | The serial number of the chip in hexadecimal format. | ++----------------------+-------------------------------------------------------------------------+ +| product_id | Chip specific product id (16550). | ++----------------------+-------------------------------------------------------------------------+ +| flash_count | The number of flash writes performed on the device. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_revision | String containing the firmware revision in the following format ##.##. | ++----------------------+-------------------------------------------------------------------------+ +| firmware_date | String containing the firmware date in the following format mm-dd-yyyy. | ++----------------------+-------------------------------------------------------------------------+ + +Channels processed values +------------------------- + +A channel value can be read from its _raw attribute. The value returned is the +raw value as reported by the devices. To get the processed value of the channel, +apply the following formula: + +.. code-block:: bash + + processed value = (_raw + _offset) * _scale + +Where _offset and _scale are device attributes. If no _offset attribute is +present, simply assume its value is 0. + +The adis16550 driver offers data for 5 types of channels, the table below shows +the measurement units for the processed value, which are defined by the IIO +framework: + ++--------------------------------------+---------------------------+ +| Channel type | Measurement unit | ++--------------------------------------+---------------------------+ +| Acceleration on X, Y, and Z axis | Meters per Second squared | ++--------------------------------------+---------------------------+ +| Angular velocity on X, Y and Z axis | Radians per second | ++--------------------------------------+---------------------------+ +| Delta velocity on X. Y, and Z axis | Meters per Second | ++--------------------------------------+---------------------------+ +| Delta angle on X, Y, and Z axis | Radians | ++--------------------------------------+---------------------------+ +| Temperature | Millidegrees Celsius | ++--------------------------------------+---------------------------+ + +Usage examples +-------------- + +Show device name: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat name + adis16550 + +Show accelerometer channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw + 6903851 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw + 5650550 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw + 104873530 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale + 0.000000095 + +- X-axis acceleration = in_accel_x_raw * in_accel_scale = 0.655865845 m/s^2 +- Y-axis acceleration = in_accel_y_raw * in_accel_scale = 0.53680225 m/s^2 +- Z-axis acceleration = in_accel_z_raw * in_accel_scale = 9.96298535 m/s^2 + +Show gyroscope channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_x_raw + 193309 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_raw + -763676 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_z_raw + -358108 + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_scale + 0.000000003 + +- X-axis angular velocity = in_anglvel_x_raw * in_anglvel_scale = 0.000579927 rad/s +- Y-axis angular velocity = in_anglvel_y_raw * in_anglvel_scale = −0.002291028 rad/s +- Z-axis angular velocity = in_anglvel_z_raw * in_anglvel_scale = −0.001074324 rad/s + +Set calibration offset for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 5000 > in_accel_x_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 5000 + +Set calibration offset for gyroscope channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo -5000 > in_anglvel_y_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_anglvel_y_calibbias + -5000 + +Set sampling frequency: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency + 4000.000000 + + root:/sys/bus/iio/devices/iio:device0> echo 1000 > sampling_frequency + 1000.000000 + +Set bandwidth for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 100 > in_accel_filter_low_pass_3db_frequency + root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency + 100 + +Show serial number: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat serial_number + 0x000000b6 + +Show product id: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat product_id + 16550 + +Show flash count: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat flash_count + 13 + +Show firmware revision: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_revision + 1.5 + +Show firmware date: + +.. code-block:: bash + + root:/sys/kernel/debug/iio/iio:device0> cat firmware_date + 28-04-2021 + +3. Device buffers +================= + +This driver supports IIO buffers. + +The device supports retrieving the raw acceleration, gyroscope, delta velocity, +delta angle and temperature measurements using buffers. + +However, when retrieving acceleration or gyroscope data using buffers, delta +readings will not be available and vice versa. This is because the device only +allows to read either acceleration and gyroscope data or delta velocity and +delta angle data at a time and switching between these two burst data selection +modes is time consuming. + +Usage examples +-------------- + +Set device trigger in current_trigger, if not already set: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + + root:/sys/bus/iio/devices/iio:device0> echo adis16550-dev0 > trigger/current_trigger + root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger + adis16550-dev0 + +Select channels for buffer read: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_x_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_y_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_deltavelocity_z_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp0_en + +Set the number of samples to be stored in the buffer: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length + +Enable buffer readings: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable + +Obtain buffered data: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0 + ... + 0000cdf0 00 00 0d 2f 00 00 08 43 00 00 09 09 00 00 a4 5f |.../...C......._| + 0000ce00 00 00 0d 2f 00 00 07 de 00 00 08 db 00 00 a4 4b |.../...........K| + 0000ce10 00 00 0d 2f 00 00 07 58 00 00 08 a3 00 00 a4 55 |.../...X.......U| + 0000ce20 00 00 0d 2f 00 00 06 d6 00 00 08 5c 00 00 a4 62 |.../.......\...b| + 0000ce30 00 00 0d 2f 00 00 06 45 00 00 08 37 00 00 a4 47 |.../...E...7...G| + 0000ce40 00 00 0d 2f 00 00 05 d4 00 00 08 30 00 00 a3 fa |.../.......0....| + 0000ce50 00 00 0d 2f 00 00 05 d0 00 00 08 12 00 00 a3 d3 |.../............| + 0000ce60 00 00 0d 2f 00 00 05 dd 00 00 08 2e 00 00 a3 e9 |.../............| + 0000ce70 00 00 0d 2f 00 00 05 cc 00 00 08 51 00 00 a3 d5 |.../.......Q....| + 0000ce80 00 00 0d 2f 00 00 05 ba 00 00 08 22 00 00 a3 9a |.../......."....| + 0000ce90 00 00 0d 2f 00 00 05 9c 00 00 07 d9 00 00 a3 40 |.../...........@| + 0000cea0 00 00 0d 2f 00 00 05 68 00 00 07 94 00 00 a2 e4 |.../...h........| + 0000ceb0 00 00 0d 2f 00 00 05 25 00 00 07 8d 00 00 a2 ce |.../...%........| + ... + +See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered +data is structured. + +4. IIO Interfacing Tools +======================== + +See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO +interfacing tools. diff --git a/Documentation/iio/adxl380.rst b/Documentation/iio/adxl380.rst new file mode 100644 index 000000000000..66c8a4d4f767 --- /dev/null +++ b/Documentation/iio/adxl380.rst @@ -0,0 +1,233 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +ADXL380 driver +=============== + +This driver supports Analog Device's ADXL380/382 on SPI/I2C bus. + +1. Supported devices +==================== + +* `ADXL380 <https://www.analog.com/ADXL380>`_ +* `ADXL382 <https://www.analog.com/ADXL382>`_ + +The ADXL380/ADXL382 is a low noise density, low power, 3-axis accelerometer with +selectable measurement ranges. The ADXL380 supports the ±4 g, ±8 g, and ±16 g +ranges, and the ADXL382 supports ±15 g, ±30 g, and ±60 g ranges. + +2. Device attributes +==================== + +Accelerometer measurements are always provided. + +Temperature data are also provided. This data can be used to monitor the +internal system temperature or to improve the temperature stability of the +device via calibration. + +Each IIO device, has a device folder under ``/sys/bus/iio/devices/iio:deviceX``, +where X is the IIO index of the device. Under these folders reside a set of +device files, depending on the characteristics and features of the hardware +device in questions. These files are consistently generalized and documented in +the IIO ABI documentation. + +The following tables show the adxl380 related device files, found in the +specific device folder path ``/sys/bus/iio/devices/iio:deviceX``. + ++---------------------------------------------------+----------------------------------------------------------+ +| 3-Axis Accelerometer related device files | Description | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_scale | Scale for the accelerometer channels. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_filter_high_pass_3db_frequency | Low pass filter bandwidth. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_filter_high_pass_3db_frequency_available | Available low pass filter bandwidth configurations. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_filter_low_pass_3db_frequency | High pass filter bandwidth. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_filter_low_pass_3db_frequency_available | Available high pass filter bandwidth configurations. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x_calibbias | Calibration offset for the X-axis accelerometer channel. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_x_raw | Raw X-axis accelerometer channel value. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_y_calibbias | y-axis acceleration offset correction | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_y_raw | Raw Y-axis accelerometer channel value. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_z_calibbias | Calibration offset for the Z-axis accelerometer channel. | ++---------------------------------------------------+----------------------------------------------------------+ +| in_accel_z_raw | Raw Z-axis accelerometer channel value. | ++---------------------------------------------------+----------------------------------------------------------+ + ++----------------------------------+--------------------------------------------+ +| Temperature sensor related files | Description | ++----------------------------------+--------------------------------------------+ +| in_temp_raw | Raw temperature channel value. | ++----------------------------------+--------------------------------------------+ +| in_temp_offset | Offset for the temperature sensor channel. | ++----------------------------------+--------------------------------------------+ +| in_temp_scale | Scale for the temperature sensor channel. | ++----------------------------------+--------------------------------------------+ + ++------------------------------+----------------------------------------------+ +| Miscellaneous device files | Description | ++------------------------------+----------------------------------------------+ +| name | Name of the IIO device. | ++------------------------------+----------------------------------------------+ +| sampling_frequency | Currently selected sample rate. | ++------------------------------+----------------------------------------------+ +| sampling_frequency_available | Available sampling frequency configurations. | ++------------------------------+----------------------------------------------+ + +Channels processed values +------------------------- + +A channel value can be read from its _raw attribute. The value returned is the +raw value as reported by the devices. To get the processed value of the channel, +apply the following formula: + +.. code-block:: bash + + processed value = (_raw + _offset) * _scale + +Where _offset and _scale are device attributes. If no _offset attribute is +present, simply assume its value is 0. + +The ADXL380 driver offers data for 2 types of channels, the table below shows +the measurement units for the processed value, which are defined by the IIO +framework: + ++-------------------------------------+---------------------------+ +| Channel type | Measurement unit | ++-------------------------------------+---------------------------+ +| Acceleration on X, Y, and Z axis | Meters per Second squared | ++-------------------------------------+---------------------------+ +| Temperature | Millidegrees Celsius | ++-------------------------------------+---------------------------+ + +Usage examples +-------------- + +Show device name: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat name + adxl382 + +Show accelerometer channels value: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw + -1771 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_y_raw + 282 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_z_raw + -1523 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale + 0.004903325 + +- X-axis acceleration = in_accel_x_raw * in_accel_scale = −8.683788575 m/s^2 +- Y-axis acceleration = in_accel_y_raw * in_accel_scale = 1.38273765 m/s^2 +- Z-axis acceleration = in_accel_z_raw * in_accel_scale = -7.467763975 m/s^2 + +Set calibration offset for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 0 + + root:/sys/bus/iio/devices/iio:device0> echo 50 > in_accel_x_calibbias + root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_calibbias + 50 + +Set sampling frequency: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency + 16000 + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency_available + 16000 32000 64000 + + root:/sys/bus/iio/devices/iio:device0> echo 32000 > sampling_frequency + root:/sys/bus/iio/devices/iio:device0> cat sampling_frequency + 32000 + +Set low pass filter bandwidth for accelerometer channels: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency + 32000 + root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency_available + 32000 8000 4000 2000 + + root:/sys/bus/iio/devices/iio:device0> echo 2000 > in_accel_filter_low_pass_3db_frequency + root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency + 2000 + +3. Device buffers +================= + +This driver supports IIO buffers. + +All devices support retrieving the raw acceleration and temperature measurements +using buffers. + +Usage examples +-------------- + +Select channels for buffer read: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_x_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_y_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_accel_z_en + root:/sys/bus/iio/devices/iio:device0> echo 1 > scan_elements/in_temp_en + +Set the number of samples to be stored in the buffer: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 10 > buffer/length + +Enable buffer readings: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> echo 1 > buffer/enable + +Obtain buffered data: + +.. code-block:: bash + + root:/sys/bus/iio/devices/iio:device0> hexdump -C /dev/iio\:device0 + ... + 002bc300 f7 e7 00 a8 fb c5 24 80 f7 e7 01 04 fb d6 24 80 |......$.......$.| + 002bc310 f7 f9 00 ab fb dc 24 80 f7 c3 00 b8 fb e2 24 80 |......$.......$.| + 002bc320 f7 fb 00 bb fb d1 24 80 f7 b1 00 5f fb d1 24 80 |......$...._..$.| + 002bc330 f7 c4 00 c6 fb a6 24 80 f7 a6 00 68 fb f1 24 80 |......$....h..$.| + 002bc340 f7 b8 00 a3 fb e7 24 80 f7 9a 00 b1 fb af 24 80 |......$.......$.| + 002bc350 f7 b1 00 67 fb ee 24 80 f7 96 00 be fb 92 24 80 |...g..$.......$.| + 002bc360 f7 ab 00 7a fc 1b 24 80 f7 b6 00 ae fb 76 24 80 |...z..$......v$.| + 002bc370 f7 ce 00 a3 fc 02 24 80 f7 c0 00 be fb 8b 24 80 |......$.......$.| + 002bc380 f7 c3 00 93 fb d0 24 80 f7 ce 00 d8 fb c8 24 80 |......$.......$.| + 002bc390 f7 bd 00 c0 fb 82 24 80 f8 00 00 e8 fb db 24 80 |......$.......$.| + 002bc3a0 f7 d8 00 d3 fb b4 24 80 f8 0b 00 e5 fb c3 24 80 |......$.......$.| + 002bc3b0 f7 eb 00 c8 fb 92 24 80 f7 e7 00 ea fb cb 24 80 |......$.......$.| + 002bc3c0 f7 fd 00 cb fb 94 24 80 f7 e3 00 f2 fb b8 24 80 |......$.......$.| + ... + +See ``Documentation/iio/iio_devbuf.rst`` for more information about how buffered +data is structured. + +4. IIO Interfacing Tools +======================== + +See ``Documentation/iio/iio_tools.rst`` for the description of the available IIO +interfacing tools. diff --git a/Documentation/iio/bno055.rst b/Documentation/iio/bno055.rst new file mode 100644 index 000000000000..f1111ff3fe2e --- /dev/null +++ b/Documentation/iio/bno055.rst @@ -0,0 +1,51 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +BNO055 driver +============================== + +1. Overview +=========== + +This driver supports Bosch BNO055 IMUs (on both serial and I2C busses). + +Accelerometer, magnetometer and gyroscope measures are always provided. +When "fusion_enable" sysfs attribute is set to 1, orientation (both Euler +angles and quaternion), linear velocity and gravity vector are also +provided, but some sensor settings (e.g. low pass filtering and range) +became locked (the IMU firmware controls them). + +This driver supports also IIO buffers. + +2. Calibration +============== + +The IMU continuously performs an autocalibration procedure if (and only if) +operating in fusion mode. The magnetometer autocalibration can however be +disabled by writing 0 in the sysfs in_magn_calibration_fast_enable attribute. + +The driver provides access to autocalibration flags (i.e. you can known if +the IMU has successfully autocalibrated) and to the calibration data blob. + +The user can save this blob in a firmware file (i.e. in /lib/firmware) that +the driver looks for at probe time. If found, then the IMU is initialized +with this calibration data. This saves the user from performing the +calibration procedure every time (which consist of moving the IMU in +various way). + +The driver looks for calibration data file using two different names: first +a file whose name is suffixed with the IMU unique ID (exposed in sysfs as +serial_number) is searched for; this is useful when there is more than one +IMU instance. If this file is not found, then a "generic" calibration file +is searched for (which can be used when only one IMU is present, without +struggling with fancy names, that change on each device). + +Valid calibration file names would be e.g. + bno055-caldata-0e7c26a33541515120204a35342b04ff.dat + bno055-caldata.dat + +In non-fusion mode the IIO 'offset' attributes provide access to the +offsets from calibration data (if any), so that the user can apply them to +the accel, angvel and magn IIO attributes. In fusion mode they are not +needed (the IMU firmware internally applies those corrections) and they +read as zero. diff --git a/Documentation/iio/ep93xx_adc.rst b/Documentation/iio/ep93xx_adc.rst index 4fd8dea3f6b8..0af0e9040457 100644 --- a/Documentation/iio/ep93xx_adc.rst +++ b/Documentation/iio/ep93xx_adc.rst @@ -13,7 +13,7 @@ touchscreen/ADC module. ==================== Numbering scheme for channels 0..4 is defined in EP9301 and EP9302 datasheets. -EP9307, EP9312 and EP9312 have 3 channels more (total 8), but the numbering is +EP9307, EP9312 and EP9315 have 3 channels more (total 8), but the numbering is not defined. So the last three are numbered randomly, let's say. Assuming ep93xx_adc is IIO device0, you'd find the following entries under diff --git a/Documentation/iio/iio_adc.rst b/Documentation/iio/iio_adc.rst new file mode 100644 index 000000000000..f2f19a691907 --- /dev/null +++ b/Documentation/iio/iio_adc.rst @@ -0,0 +1,305 @@ +.. SPDX-License-Identifier: GPL-2.0-only + +========================= +IIO Abstractions for ADCs +========================= + +1. Overview +=========== + +The IIO subsystem supports many Analog to Digital Converters (ADCs). Some ADCs +have features and characteristics that are supported in specific ways by IIO +device drivers. This documentation describes common ADC features and explains +how they are supported by the IIO subsystem. + +1. ADC Channel Types +==================== + +ADCs can have distinct types of inputs, each of them measuring analog voltages +in a slightly different way. An ADC digitizes the analog input voltage over a +span that is often given by the provided voltage reference, the input type, and +the input polarity. The input range allowed to an ADC channel is needed to +determine the scale factor and offset needed to obtain the measured value in +real-world units (millivolts for voltage measurement, milliamps for current +measurement, etc.). + +Elaborate designs may have nonlinear characteristics or integrated components +(such as amplifiers and reference buffers) that might also have to be considered +to derive the allowed input range for an ADC. For clarity, the sections below +assume the input range only depends on the provided voltage references, input +type, and input polarity. + +There are three general types of ADC inputs (single-ended, differential, +pseudo-differential) and two possible polarities (unipolar, bipolar). The input +type (single-ended, differential, pseudo-differential) is one channel +characteristic, and is completely independent of the polarity (unipolar, +bipolar) aspect. A comprehensive article about ADC input types (on which this +doc is heavily based on) can be found at +https://www.analog.com/en/resources/technical-articles/sar-adc-input-types.html. + +1.1 Single-ended channels +------------------------- + +Single-ended channels digitize the analog input voltage relative to ground and +can be either unipolar or bipolar. + +1.1.1 Single-ended Unipolar Channels +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +:: + + ---------- VREF ------------- + ´ ` ´ ` _____________ + / \ / \ / | + / \ / \ --- < IN ADC | + \ / \ / \ | + `-´ `-´ \ VREF | + -------- GND (0V) ----------- +-----------+ + ^ + | + External VREF + +The input voltage to a **single-ended unipolar** channel is allowed to swing +from GND to VREF (where VREF is a voltage reference with electrical potential +higher than system ground). The maximum input voltage is also called VFS +(Voltage input Full-Scale), with VFS being determined by VREF. The voltage +reference may be provided from an external supply or derived from the chip power +source. + +A single-ended unipolar channel could be described in device tree like the +following example:: + + adc@0 { + ... + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { + reg = <0>; + }; + }; + +One is always allowed to include ADC channel nodes in the device tree. Though, +if the device has a uniform set of inputs (e.g. all inputs are single-ended), +then declaring the channel nodes is optional. + +One caveat for devices that support mixed single-ended and differential channels +is that single-ended channel nodes also need to provide a ``single-channel`` +property when ``reg`` is an arbitrary number that doesn't match the input pin +number. + +See ``Documentation/devicetree/bindings/iio/adc/adc.yaml`` for the complete +documentation of ADC specific device tree properties. + + +1.1.2 Single-ended Bipolar Channels +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +:: + + ---------- +VREF ------------ + ´ ` ´ ` _____________________ + / \ / \ / | + / \ / \ --- < IN ADC | + \ / \ / \ | + `-´ `-´ \ +VREF -VREF | + ---------- -VREF ------------ +-------------------+ + ^ ^ + | | + External +VREF ------+ External -VREF + +For a **single-ended bipolar** channel, the analog voltage input can go from +-VREF to +VREF (where -VREF is the voltage reference that has the lower +electrical potential while +VREF is the reference with the higher one). Some ADC +chips derive the lower reference from +VREF, others get it from a separate +input. Often, +VREF and -VREF are symmetric but they don't need to be so. When +-VREF is lower than system ground, these inputs are also called single-ended +true bipolar. Also, while there is a relevant difference between bipolar and +true bipolar from the electrical perspective, IIO makes no explicit distinction +between them. + +Here's an example device tree description of a single-ended bipolar channel:: + + adc@0 { + ... + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { + reg = <0>; + bipolar; + }; + }; + +1.2 Differential channels +------------------------- + +A differential voltage measurement digitizes the voltage level at the positive +input (IN+) relative to the negative input (IN-) over the -VREF to +VREF span. +In other words, a differential channel measures the potential difference between +IN+ and IN-, which is often denoted by the IN+ - IN- formula. + +1.2.1 Differential Bipolar Channels +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +:: + + -------- +VREF ------ +-------------------+ + ´ ` ´ ` / | + / \ / \ / --- < IN+ | + `-´ `-´ | | + -------- -VREF ------ | | + | ADC | + -------- +VREF ------ | | + ´ ` ´ ` | | + \ / \ / \ --- < IN- | + `-´ `-´ \ +VREF -VREF | + -------- -VREF ------ +-------------------+ + ^ ^ + | +---- External -VREF + External +VREF + +The analog signals to **differential bipolar** inputs are also allowed to swing +from -VREF to +VREF. The bipolar part of the name means that the resulting value +of the difference (IN+ - IN-) can be positive or negative. If -VREF is below +system GND, these are also called differential true bipolar inputs. + +Device tree example of a differential bipolar channel:: + + adc@0 { + ... + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { + reg = <0>; + bipolar; + diff-channels = <0 1>; + }; + }; + +In the ADC driver, ``differential = 1`` is set into ``struct iio_chan_spec`` for +the channel. Even though, there are three general input types, ``differential`` +is only used to distinguish between differential and non-differential (either +single-ended or pseudo-differential) input types. See +``include/linux/iio/iio.h`` for more information. + +1.2.2 Differential Unipolar Channels +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +For **differential unipolar** channels, the analog voltage at the positive input +must also be higher than the voltage at the negative input. Thus, the actual +input range allowed to a differential unipolar channel is IN- to +VREF. Because +IN+ is allowed to swing with the measured analog signal and the input setup must +guarantee IN+ will not go below IN- (nor IN- will raise above IN+), most +differential unipolar channel setups have IN- fixed to a known voltage that does +not fall within the voltage range expected for the measured signal. That leads +to a setup that is equivalent to a pseudo-differential channel. Thus, +differential unipolar setups can often be supported as pseudo-differential +unipolar channels. + +1.3 Pseudo-differential Channels +-------------------------------- + +There is a third ADC input type which is called pseudo-differential or +single-ended to differential configuration. A pseudo-differential channel is +similar to a differential channel in that it also measures IN+ relative to IN-. +However, unlike bipolar differential channels, the negative input is limited to +a narrow voltage range (taken as a constant voltage) while only IN+ is allowed +to swing. A pseudo-differential channel can be made out from a differential pair +of inputs by restricting the negative input to a known voltage while allowing +only the positive input to swing. Sometimes, the input provided to IN- is called +common-mode voltage. Besides, some parts have a COM pin that allows single-ended +inputs to be referenced to a common-mode voltage, making them +pseudo-differential channels. Often, the common mode input voltage can be +described in the device tree as a voltage regulator (e.g. ``com-supply``) since +it is basically a constant voltage source. + +1.3.1 Pseudo-differential Unipolar Channels +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +:: + + -------- +VREF ------ +-------------------+ + ´ ` ´ ` / | + / \ / \ / --- < IN+ | + `-´ `-´ | | + --------- IN- ------- | ADC | + | | + Common-mode voltage --> --- < IN- | + \ +VREF -VREF | + +-------------------+ + ^ ^ + | +---- External -VREF + External +VREF + +A **pseudo-differential unipolar** input has the limitations a differential +unipolar channel would have, meaning the analog voltage to the positive input +IN+ must stay within IN- to +VREF. The fixed voltage to IN- is often called +common-mode voltage and it must be within -VREF to +VREF as would be expected +from the signal to any differential channel negative input. + +The voltage measured from IN+ is relative to IN- but, unlike differential +channels, pseudo-differential setups are intended to gauge single-ended input +signals. To enable applications to calculate IN+ voltage with respect to system +ground, the IIO channel may provide an ``_offset`` sysfs attribute to be added +to ADC output when converting raw data to voltage units. In many setups, the +common-mode voltage input is at GND level and the ``_offset`` attribute is +omitted due to being always zero. + +Device tree example for pseudo-differential unipolar channel:: + + adc@0 { + ... + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { + reg = <0>; + single-channel = <0>; + common-mode-channel = <1>; + }; + }; + +Do not set ``differential`` in the channel ``iio_chan_spec`` struct of +pseudo-differential channels. + +1.3.2 Pseudo-differential Bipolar Channels +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +:: + + -------- +VREF ------ +-------------------+ + ´ ` ´ ` / | + / \ / \ / --- < IN+ | + `-´ `-´ | | + -------- -VREF ------ | ADC | + | | + Common-mode voltage --> --- < IN- | + \ +VREF -VREF | + +-------------------+ + ^ ^ + | +---- External -VREF + External +VREF + +A **pseudo-differential bipolar** input is not limited by the level at IN- but +it will be limited to -VREF or to GND on the lower end of the input range +depending on the particular ADC. Similar to their unipolar counter parts, +pseudo-differential bipolar channels ought to declare an ``_offset`` attribute +to enable the conversion of raw ADC data to voltage units. For the setup with +IN- connected to GND, ``_offset`` is often omitted. + +Device tree example for pseudo-differential bipolar channel:: + + adc@0 { + ... + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { + reg = <0>; + bipolar; + single-channel = <0>; + common-mode-channel = <1>; + }; + }; diff --git a/Documentation/iio/iio_configfs.rst b/Documentation/iio/iio_configfs.rst index 6e38cbbd2981..b276397af797 100644 --- a/Documentation/iio/iio_configfs.rst +++ b/Documentation/iio/iio_configfs.rst @@ -53,7 +53,7 @@ kernel module following the interface in include/linux/iio/sw_trigger.h:: */ } - static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt) + static int iio_trig_sample_remove(struct iio_sw_trigger *swt) { /* * This undoes the actions in iio_trig_sample_probe @@ -71,7 +71,7 @@ kernel module following the interface in include/linux/iio/sw_trigger.h:: .ops = &iio_trig_sample_ops, }; -module_iio_sw_trigger_driver(iio_trig_sample); + module_iio_sw_trigger_driver(iio_trig_sample); Each trigger type has its own directory under /config/iio/triggers. Loading iio-trig-sample module will create 'trig-sample' trigger type directory @@ -99,3 +99,4 @@ Each trigger can have one or more attributes specific to the trigger type. "hrtimer" trigger type doesn't have any configurable attribute from /config dir. It does introduce the sampling_frequency attribute to trigger directory. +That attribute sets the polling frequency in Hz, with mHz precision. diff --git a/Documentation/iio/iio_devbuf.rst b/Documentation/iio/iio_devbuf.rst new file mode 100644 index 000000000000..dca1f0200b0d --- /dev/null +++ b/Documentation/iio/iio_devbuf.rst @@ -0,0 +1,152 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================= +Industrial IIO device buffers +============================= + +1. Overview +=========== + +The Industrial I/O core offers a way for continuous data capture based on a +trigger source. Multiple data channels can be read at once from +``/dev/iio:deviceX`` character device node, thus reducing the CPU load. + +Devices with buffer support feature an additional sub-directory in the +``/sys/bus/iio/devices/iio:deviceX/`` directory hierarchy, called bufferY, where +Y defaults to 0, for devices with a single buffer. + +2. Buffer attributes +==================== + +An IIO buffer has an associated attributes directory under +``/sys/bus/iio/iio:deviceX/bufferY/``. The attributes are described below. + +``length`` +---------- + +Read / Write attribute which states the total number of data samples (capacity) +that can be stored by the buffer. + +``enable`` +---------- + +Read / Write attribute which starts / stops the buffer capture. This file should +be written last, after length and selection of scan elements. Writing a non-zero +value may result in an error, such as EINVAL, if, for example, an unsupported +combination of channels is given. + +``watermark`` +------------- + +Read / Write positive integer attribute specifying the maximum number of scan +elements to wait for. + +Poll will block until the watermark is reached. + +Blocking read will wait until the minimum between the requested read amount or +the low watermark is available. + +Non-blocking read will retrieve the available samples from the buffer even if +there are less samples than the watermark level. This allows the application to +block on poll with a timeout and read the available samples after the timeout +expires and thus have a maximum delay guarantee. + +Data available +-------------- + +Read-only attribute indicating the bytes of data available in the buffer. In the +case of an output buffer, this indicates the amount of empty space available to +write data to. In the case of an input buffer, this indicates the amount of data +available for reading. + +Scan elements +------------- + +The meta information associated with a channel data placed in a buffer is called +a scan element. The scan elements attributes are presented below. + +**_en** + +Read / Write attribute used for enabling a channel. If and only if its value +is non-zero, then a triggered capture will contain data samples for this +channel. + +**_index** + +Read-only unsigned integer attribute specifying the position of the channel in +the buffer. Note these are not dependent on what is enabled and may not be +contiguous. Thus for userspace to establish the full layout these must be used +in conjunction with all _en attributes to establish which channels are present, +and the relevant _type attributes to establish the data storage format. + +**_type** + +Read-only attribute containing the description of the scan element data storage +within the buffer and hence the form in which it is read from userspace. Format +is [be|le]:[s|u]bits/storagebits[Xrepeat][>>shift], where: + +- **be** or **le** specifies big or little-endian. +- **s** or **u** specifies if signed (2's complement) or unsigned. +- **bits** is the number of valid data bits. +- **storagebits** is the number of bits (after padding) that it occupies in the + buffer. +- **repeat** specifies the number of bits/storagebits repetitions. When the + repeat element is 0 or 1, then the repeat value is omitted. +- **shift** if specified, is the shift that needs to be applied prior to + masking out unused bits. + +For example, a driver for a 3-axis accelerometer with 12-bit resolution where +data is stored in two 8-bit registers is as follows:: + + 7 6 5 4 3 2 1 0 + +---+---+---+---+---+---+---+---+ + |D3 |D2 |D1 |D0 | X | X | X | X | (LOW byte, address 0x06) + +---+---+---+---+---+---+---+---+ + + 7 6 5 4 3 2 1 0 + +---+---+---+---+---+---+---+---+ + |D11|D10|D9 |D8 |D7 |D6 |D5 |D4 | (HIGH byte, address 0x07) + +---+---+---+---+---+---+---+---+ + +will have the following scan element type for each axis: + +.. code-block:: bash + + $ cat /sys/bus/iio/devices/iio:device0/buffer0/in_accel_y_type + le:s12/16>>4 + +A userspace application will interpret data samples read from the buffer as +two-byte little-endian signed data, that needs a 4 bits right shift before +masking out the 12 valid bits of data. + +It is also worth mentioning that the data in the buffer will be naturally +aligned, so the userspace application has to handle the buffers accordingly. + +Take for example, a driver with four channels with the following description: +- channel0: index: 0, type: be:u16/16>>0 +- channel1: index: 1, type: be:u32/32>>0 +- channel2: index: 2, type: be:u32/32>>0 +- channel3: index: 3, type: be:u64/64>>0 + +If all channels are enabled, the data will be aligned in the buffer as follows:: + + 0-1 2 3 4-7 8-11 12 13 14 15 16-23 -> buffer byte number + +-----+---+---+-----+-----+---+---+---+---+-----+ + |CHN_0|PAD|PAD|CHN_1|CHN_2|PAD|PAD|PAD|PAD|CHN_3| -> buffer content + +-----+---+---+-----+-----+---+---+---+---+-----+ + +If only channel0 and channel3 are enabled, the data will be aligned in the +buffer as follows:: + + 0-1 2 3 4 5 6 7 8-15 -> buffer byte number + +-----+---+---+---+---+---+---+-----+ + |CHN_0|PAD|PAD|PAD|PAD|PAD|PAD|CHN_3| -> buffer content + +-----+---+---+---+---+---+---+-----+ + +Typically the buffered data is found in raw format (unscaled with no offset +applied), however there are corner cases in which the buffered data may be found +in a processed form. Please note that these corner cases are not addressed by +this documentation. + +Please see Documentation/ABI/testing/sysfs-bus-iio for a complete +description of the attributes. diff --git a/Documentation/iio/iio_dmabuf_api.rst b/Documentation/iio/iio_dmabuf_api.rst new file mode 100644 index 000000000000..2836cadbd495 --- /dev/null +++ b/Documentation/iio/iio_dmabuf_api.rst @@ -0,0 +1,54 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +High-speed DMABUF interface for IIO +=================================== + +1. Overview +=========== + +The Industrial I/O subsystem supports access to buffers through a +file-based interface, with read() and write() access calls through the +IIO device's dev node. + +It additionally supports a DMABUF based interface, where the userspace +can attach DMABUF objects (externally created) to an IIO buffer, and +subsequently use them for data transfers. + +A userspace application can then use this interface to share DMABUF +objects between several interfaces, allowing it to transfer data in a +zero-copy fashion, for instance between IIO and the USB stack. + +The userspace application can also memory-map the DMABUF objects, and +access the sample data directly. The advantage of doing this vs. the +read() interface is that it avoids an extra copy of the data between the +kernel and userspace. This is particularly useful for high-speed devices +which produce several megabytes or even gigabytes of data per second. +It does however increase the userspace-kernelspace synchronization +overhead, as the DMA_BUF_SYNC_START and DMA_BUF_SYNC_END IOCTLs have to +be used for data integrity. + +2. User API +=========== + +As part of this interface, three new IOCTLs have been added. These three +IOCTLs have to be performed on the IIO buffer's file descriptor, which +can be obtained using the IIO_BUFFER_GET_FD_IOCTL() ioctl. + + ``IIO_BUFFER_DMABUF_ATTACH_IOCTL(int fd)`` + Attach the DMABUF object, identified by its file descriptor, to the + IIO buffer. Returns zero on success, and a negative errno value on + error. + + ``IIO_BUFFER_DMABUF_DETACH_IOCTL(int fd)`` + Detach the given DMABUF object, identified by its file descriptor, + from the IIO buffer. Returns zero on success, and a negative errno + value on error. + + Note that closing the IIO buffer's file descriptor will + automatically detach all previously attached DMABUF objects. + + ``IIO_BUFFER_DMABUF_ENQUEUE_IOCTL(struct iio_dmabuf *iio_dmabuf)`` + Enqueue a previously attached DMABUF object to the buffer queue. + Enqueued DMABUFs will be read from (if output buffer) or written to + (if input buffer) as long as the buffer is enabled. diff --git a/Documentation/iio/iio_tools.rst b/Documentation/iio/iio_tools.rst new file mode 100644 index 000000000000..cc691c7f6365 --- /dev/null +++ b/Documentation/iio/iio_tools.rst @@ -0,0 +1,27 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +IIO Interfacing Tools +===================== + +1. Linux Kernel Tools +===================== + +Linux Kernel provides some userspace tools that can be used to retrieve data +from IIO sysfs: + +* lsiio: example application that provides a list of IIO devices and triggers +* iio_event_monitor: example application that reads events from an IIO device + and prints them +* iio_generic_buffer: example application that reads data from buffer +* iio_utils: set of APIs, typically used to access sysfs files. + +2. LibIIO +========= + +LibIIO is a C/C++ library that provides generic access to IIO devices. The +library abstracts the low-level details of the hardware, and provides a simple +yet complete programming interface that can be used for advanced projects. + +For more information about LibIIO, please see: +https://github.com/analogdevicesinc/libiio diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst index 58b7a4ebac51..2d6afc5a8ed5 100644 --- a/Documentation/iio/index.rst +++ b/Documentation/iio/index.rst @@ -7,6 +7,31 @@ Industrial I/O .. toctree:: :maxdepth: 1 + iio_adc iio_configfs + iio_devbuf + iio_dmabuf_api + iio_tools +Industrial I/O Kernel Drivers +============================= + +.. toctree:: + :maxdepth: 1 + + ad3552r + ad4000 + ad4030 + ad4695 + ad7191 + ad7380 + ad7606 + ad7625 + ad7944 + adis16475 + adis16480 + adis16550 + adxl380 + bno055 ep93xx_adc + opt4060 diff --git a/Documentation/iio/opt4060.rst b/Documentation/iio/opt4060.rst new file mode 100644 index 000000000000..eb155089b6d2 --- /dev/null +++ b/Documentation/iio/opt4060.rst @@ -0,0 +1,61 @@ +============================== +OPT4060 driver +============================== + +1. Overview +============================= + +This driver supports the Texas Instrument RGBW high resolution color sensor over +I2C. +https://www.ti.com/lit/gpn/opt4060 + +The driver supports: +- Raw values for red, green, blue and clear. +- Illuminance values. +- Scaled color values for red, green and blue. +- IIO events for thresholds. +- IIO triggered buffer using both its own data ready trigger and triggers from +other drivers. + +2. Illuminance calculation +============================= + +Illuminance is calculated using the wide spectrum green channel. + +lux = GREEN_RAW x 2.15e-3 + +The value is accessed from: +/sys/bus/iio/devices/iio:deviceX/in_illuminance_input + +See section 8.4.5.2 in the data sheet for additional details. + +3. Color scale values +============================= + +The sensor has different sensitivity for the different color components and +compensating factors are exposed from the driver. + +The values are accessed from: +/sys/bus/iio/devices/iio:deviceX/in_intensity_red_scale +/sys/bus/iio/devices/iio:deviceX/in_intensity_green_scale +/sys/bus/iio/devices/iio:deviceX/in_intensity_blue_scale + +A userspace application can multiply the raw values with the scale values so +that for a particular test light source, typically white, the measurement +intensity is the same across the different color channels. This is calculated +in the following way: + +R = RED_RAW x SCALE_RED(2.4) +G = GREEN_RAW x SCALE_GREEN(1.0) +B = BLUE_RAW x SCALE_BLUE(1.3) + +The data sheet suggests using the scaled values to normalize the scaled R, G +and B values. This is useful to get a value for the ratio between colors +independent of light intensity. A userspace application can do this in the +following way: + +R_NORMALIZED = R / (R + G + B) +G_NORMALIZED = G / (R + G + B) +B_NORMALIZED = B / (R + G + B) + +See section 8.4.5.2 in the data sheet for additional details. |