diff options
Diffstat (limited to 'Documentation/driver-api/iio')
| -rw-r--r-- | Documentation/driver-api/iio/buffers.rst | 23 | ||||
| -rw-r--r-- | Documentation/driver-api/iio/core.rst | 38 | ||||
| -rw-r--r-- | Documentation/driver-api/iio/hw-consumer.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/iio/triggered-buffers.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/iio/triggers.rst | 4 |
5 files changed, 35 insertions, 34 deletions
diff --git a/Documentation/driver-api/iio/buffers.rst b/Documentation/driver-api/iio/buffers.rst index dd64c9c5fb1e..63f364e862d1 100644 --- a/Documentation/driver-api/iio/buffers.rst +++ b/Documentation/driver-api/iio/buffers.rst @@ -2,7 +2,7 @@ Buffers ======= -* struct :c:type:`iio_buffer` — general buffer structure +* struct iio_buffer — general buffer structure * :c:func:`iio_validate_scan_mask_onehot` — Validates that exactly one channel is selected * :c:func:`iio_buffer_get` — Grab a reference to the buffer @@ -15,8 +15,8 @@ trigger source. Multiple data channels can be read at once from IIO buffer sysfs interface ========================== An IIO buffer has an associated attributes directory under -:file:`/sys/bus/iio/iio:device{X}/buffer/*`. Here are some of the existing -attributes: +:file:`/sys/bus/iio/devices/iio:device{X}/buffer/*`. Here are some of the +existing attributes: * :file:`length`, the total number of data samples (capacity) that can be stored by the buffer. @@ -28,24 +28,26 @@ IIO buffer setup The meta information associated with a channel reading placed in a buffer is called a scan element. The important bits configuring scan elements are exposed to userspace applications via the -:file:`/sys/bus/iio/iio:device{X}/scan_elements/*` directory. This file contains -attributes of the following form: +:file:`/sys/bus/iio/devices/iio:device{X}/scan_elements/` directory. This +directory contains attributes of the following form: * :file:`enable`, used for enabling a channel. If and only if its attribute is non *zero*, then a triggered capture will contain data samples for this channel. +* :file:`index`, the scan_index of the channel. * :file:`type`, description of the scan element data storage within the buffer and hence the form in which it is read from user space. - Format is [be|le]:[s|u]bits/storagebitsXrepeat[>>shift] . + Format is [be|le]:[s|u]bits/storagebits[Xrepeat][>>shift] . + * *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. - * *shift*, if specified, is the shift that needs to be applied prior to - masking out unused bits. + buffer. * *repeat*, specifies the number of bits/storagebits repetitions. When the - repeat element is 0 or 1, then the repeat value is omitted. + 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-bits registers as follows:: @@ -122,4 +124,3 @@ More details .. kernel-doc:: include/linux/iio/buffer.h .. kernel-doc:: drivers/iio/industrialio-buffer.c :export: - diff --git a/Documentation/driver-api/iio/core.rst b/Documentation/driver-api/iio/core.rst index b0bc0c028cc5..42b580fb2989 100644 --- a/Documentation/driver-api/iio/core.rst +++ b/Documentation/driver-api/iio/core.rst @@ -10,11 +10,11 @@ applications manipulating sensors. The implementation can be found under Industrial I/O Devices ---------------------- -* struct :c:type:`iio_dev` - industrial I/O device -* :c:func:`iio_device_alloc()` - allocate an :c:type:`iio_dev` from a driver -* :c:func:`iio_device_free()` - free an :c:type:`iio_dev` from a driver -* :c:func:`iio_device_register()` - register a device with the IIO subsystem -* :c:func:`iio_device_unregister()` - unregister a device from the IIO +* struct iio_dev - industrial I/O device +* iio_device_alloc() - allocate an :c:type:`iio_dev` from a driver +* iio_device_free() - free an :c:type:`iio_dev` from a driver +* iio_device_register() - register a device with the IIO subsystem +* iio_device_unregister() - unregister a device from the IIO subsystem An IIO device usually corresponds to a single hardware sensor and it @@ -24,7 +24,7 @@ then we will show how a device driver makes use of an IIO device. There are two ways for a user space application to interact with an IIO driver. -1. :file:`/sys/bus/iio/iio:device{X}/`, this represents a hardware sensor +1. :file:`/sys/bus/iio/devices/iio:device{X}/`, this represents a hardware sensor and groups together the data channels of the same chip. 2. :file:`/dev/iio:device{X}`, character device node interface used for buffered data transfer and for events information retrieval. @@ -34,25 +34,25 @@ A typical IIO driver will register itself as an :doc:`I2C <../i2c>` or At probe: -1. Call :c:func:`iio_device_alloc()`, which allocates memory for an IIO device. +1. Call iio_device_alloc(), which allocates memory for an IIO device. 2. Initialize IIO device fields with driver specific information (e.g. device name, device channels). -3. Call :c:func:`iio_device_register()`, this registers the device with the +3. Call iio_device_register(), this registers the device with the IIO core. After this call the device is ready to accept requests from user space applications. At remove, we free the resources allocated in probe in reverse order: -1. :c:func:`iio_device_unregister()`, unregister the device from the IIO core. -2. :c:func:`iio_device_free()`, free the memory allocated for the IIO device. +1. iio_device_unregister(), unregister the device from the IIO core. +2. iio_device_free(), free the memory allocated for the IIO device. IIO device sysfs interface ========================== Attributes are sysfs files used to expose chip info and also allowing applications to set various configuration parameters. For device with -index X, attributes can be found under /sys/bus/iio/iio:deviceX/ directory. -Common attributes are: +index X, attributes can be found under /sys/bus/iio/devices/iio:deviceX/ +directory. Common attributes are: * :file:`name`, description of the physical chip. * :file:`dev`, shows the major:minor pair associated with @@ -60,13 +60,13 @@ Common attributes are: * :file:`sampling_frequency_available`, available discrete set of sampling frequency values for device. * Available standard attributes for IIO devices are described in the - :file:`Documentation/ABI/testing/sysfs-bus-iio` file in the Linux kernel + :file:Documentation/ABI/testing/sysfs-bus-iio file in the Linux kernel sources. IIO device channels =================== -struct :c:type:`iio_chan_spec` - specification of a single channel +struct iio_chan_spec - specification of a single channel An IIO device channel is a representation of a data channel. An IIO device can have one or multiple channels. For example: @@ -77,7 +77,7 @@ have one or multiple channels. For example: * an accelerometer can have up to 3 channels representing acceleration on X, Y and Z axes. -An IIO channel is described by the struct :c:type:`iio_chan_spec`. +An IIO channel is described by the struct iio_chan_spec. A thermometer driver for the temperature sensor in the example above would have to describe its channel as follows:: @@ -140,16 +140,16 @@ Here is how we can make use of the channel's modifiers:: This channel's definition will generate two separate sysfs files for raw data retrieval: -* :file:`/sys/bus/iio/iio:device{X}/in_intensity_ir_raw` -* :file:`/sys/bus/iio/iio:device{X}/in_intensity_both_raw` +* :file:`/sys/bus/iio/devices/iio:device{X}/in_intensity_ir_raw` +* :file:`/sys/bus/iio/devices/iio:device{X}/in_intensity_both_raw` one file for processed data: -* :file:`/sys/bus/iio/iio:device{X}/in_illuminance_input` +* :file:`/sys/bus/iio/devices/iio:device{X}/in_illuminance_input` and one shared sysfs file for sampling frequency: -* :file:`/sys/bus/iio/iio:device{X}/sampling_frequency`. +* :file:`/sys/bus/iio/devices/iio:device{X}/sampling_frequency`. Here is how we can make use of the channel's indexing:: diff --git a/Documentation/driver-api/iio/hw-consumer.rst b/Documentation/driver-api/iio/hw-consumer.rst index 819fb9edc005..76133a3796f2 100644 --- a/Documentation/driver-api/iio/hw-consumer.rst +++ b/Documentation/driver-api/iio/hw-consumer.rst @@ -8,7 +8,7 @@ software buffer for data. The implementation can be found under :file:`drivers/iio/buffer/hw-consumer.c` -* struct :c:type:`iio_hw_consumer` — Hardware consumer structure +* struct iio_hw_consumer — Hardware consumer structure * :c:func:`iio_hw_consumer_alloc` — Allocate IIO hardware consumer * :c:func:`iio_hw_consumer_free` — Free IIO hardware consumer * :c:func:`iio_hw_consumer_enable` — Enable IIO hardware consumer diff --git a/Documentation/driver-api/iio/triggered-buffers.rst b/Documentation/driver-api/iio/triggered-buffers.rst index 0db12660cc90..417555dbbdf4 100644 --- a/Documentation/driver-api/iio/triggered-buffers.rst +++ b/Documentation/driver-api/iio/triggered-buffers.rst @@ -10,7 +10,7 @@ IIO triggered buffer setup * :c:func:`iio_triggered_buffer_setup` — Setup triggered buffer and pollfunc * :c:func:`iio_triggered_buffer_cleanup` — Free resources allocated by :c:func:`iio_triggered_buffer_setup` -* struct :c:type:`iio_buffer_setup_ops` — buffer setup related callbacks +* struct iio_buffer_setup_ops — buffer setup related callbacks A typical triggered buffer setup looks like this:: diff --git a/Documentation/driver-api/iio/triggers.rst b/Documentation/driver-api/iio/triggers.rst index dfd7ba3eabde..288625e40672 100644 --- a/Documentation/driver-api/iio/triggers.rst +++ b/Documentation/driver-api/iio/triggers.rst @@ -2,7 +2,7 @@ Triggers ======== -* struct :c:type:`iio_trigger` — industrial I/O trigger device +* struct iio_trigger — industrial I/O trigger device * :c:func:`devm_iio_trigger_alloc` — Resource-managed iio_trigger_alloc * :c:func:`devm_iio_trigger_register` — Resource-managed iio_trigger_register iio_trigger_unregister @@ -63,7 +63,7 @@ Let's see a simple example of how to setup a trigger to be used by a driver:: IIO trigger ops =============== -* struct :c:type:`iio_trigger_ops` — operations structure for an iio_trigger. +* struct iio_trigger_ops — operations structure for an iio_trigger. Notice that a trigger has a set of operations attached: |