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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-21 14:10:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-21 14:10:36 -0800
commitde1617578849acab8e16c9ffdce39b91fb50639d (patch)
tree913a330d92a5ce327a48531f58c78b0d72a109a7 /Documentation/driver-api
parentMerge tag 'for-linus-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs (diff)
parentmedia: v4l: async: Fix kerneldoc documentation for async functions (diff)
downloadlinux-dev-de1617578849acab8e16c9ffdce39b91fb50639d.tar.xz
linux-dev-de1617578849acab8e16c9ffdce39b91fb50639d.zip
Merge tag 'media/v5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab: - some core fixes in VB2 mem2mem support - some improvements and cleanups in V4L2 async kAPI - newer controls in V4L2 API for H-264 and HEVC codecs - allegro-dvt driver was promoted from staging - new i2c sendor drivers: imx334, ov5648, ov8865 - new automobile camera module: rdacm21 - ipu3 cio2 driver started gained support for some ACPI BIOSes - new ATSC frontend: MaxLinear mxl692 VSB tuner/demod - the SMIA/CCS driver gained more support for CSS standard - several driver fixes, updates and improvements * tag 'media/v5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (362 commits) media: v4l: async: Fix kerneldoc documentation for async functions media: i2c: max9271: Add MODULE_* macros media: i2c: Kconfig: Make MAX9271 a module media: imx334: 'ret' is uninitialized, should have been PTR_ERR() media: i2c: Add imx334 camera sensor driver media: dt-bindings: media: Add bindings for imx334 media: ov8856: Configure sensor for GRBG Bayer for all modes media: i2c: imx219: Implement V4L2_CID_LINK_FREQ control media: ov5675: fix vflip/hflip control media: ipu3-cio2: Build bridge only if ACPI is enabled media: Remove the legacy v4l2-clk API media: ov6650: Use the generic clock framework media: mt9m111: Use the generic clock framework media: ov9640: Use the generic clock framework media: pxa_camera: Drop the v4l2-clk clock register media: mach-pxa: Register the camera sensor fixed-rate clock media: i2c: imx258: get clock from device properties and enable it via runtime PM media: i2c: imx258: simplify getting state container media: i2c: imx258: add support for binding via device tree media: dt-bindings: media: imx258: add bindings for IMX258 sensor ...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/media/camera-sensor.rst20
-rw-r--r--Documentation/driver-api/media/cec-core.rst2
-rw-r--r--Documentation/driver-api/media/csi2.rst4
-rw-r--r--Documentation/driver-api/media/drivers/ccs/ccs.rst13
-rw-r--r--Documentation/driver-api/media/v4l2-clocks.rst31
-rw-r--r--Documentation/driver-api/media/v4l2-core.rst1
-rw-r--r--Documentation/driver-api/media/v4l2-subdev.rst63
7 files changed, 81 insertions, 53 deletions
diff --git a/Documentation/driver-api/media/camera-sensor.rst b/Documentation/driver-api/media/camera-sensor.rst
index ffb0cad8137a..3fc378b3b269 100644
--- a/Documentation/driver-api/media/camera-sensor.rst
+++ b/Documentation/driver-api/media/camera-sensor.rst
@@ -15,7 +15,7 @@ Camera sensors have an internal clock tree including a PLL and a number of
divisors. The clock tree is generally configured by the driver based on a few
input parameters that are specific to the hardware:: the external clock frequency
and the link frequency. The two parameters generally are obtained from system
-firmware. No other frequencies should be used in any circumstances.
+firmware. **No other frequencies should be used in any circumstances.**
The reason why the clock frequencies are so important is that the clock signals
come out of the SoC, and in many cases a specific frequency is designed to be
@@ -23,6 +23,24 @@ used in the system. Using another frequency may cause harmful effects
elsewhere. Therefore only the pre-determined frequencies are configurable by the
user.
+ACPI
+~~~~
+
+Read the "clock-frequency" _DSD property to denote the frequency. The driver can
+rely on this frequency being used.
+
+Devicetree
+~~~~~~~~~~
+
+The currently preferred way to achieve this is using "assigned-clock-rates"
+property. See Documentation/devicetree/bindings/clock/clock-bindings.txt for
+more information. The driver then gets the frequency using clk_get_rate().
+
+This approach has the drawback that there's no guarantee that the frequency
+hasn't been modified directly or indirectly by another driver, or supported by
+the board's clock tree to begin with. Changes to the Common Clock Framework API
+are required to ensure reliability.
+
Frame size
----------
diff --git a/Documentation/driver-api/media/cec-core.rst b/Documentation/driver-api/media/cec-core.rst
index a26dc87eee8f..56345eae9a26 100644
--- a/Documentation/driver-api/media/cec-core.rst
+++ b/Documentation/driver-api/media/cec-core.rst
@@ -26,7 +26,7 @@ It is documented in the HDMI 1.4 specification with the new 2.0 bits documented
in the HDMI 2.0 specification. But for most of the features the freely available
HDMI 1.3a specification is sufficient:
-http://www.microprocessor.org/HDMISpecification13a.pdf
+https://www.hdmi.org/spec/index
CEC Adapter Interface
diff --git a/Documentation/driver-api/media/csi2.rst b/Documentation/driver-api/media/csi2.rst
index e3bbc6baf0f0..11c52b0be8b8 100644
--- a/Documentation/driver-api/media/csi2.rst
+++ b/Documentation/driver-api/media/csi2.rst
@@ -35,7 +35,7 @@ ability to start and stop the stream.
The value of the V4L2_CID_PIXEL_RATE is calculated as follows::
- pixel_rate = link_freq * 2 * nr_of_lanes / bits_per_sample
+ pixel_rate = link_freq * 2 * nr_of_lanes * 16 / k / bits_per_sample
where
@@ -53,6 +53,8 @@ where
- Two bits are transferred per clock cycle per lane.
* - bits_per_sample
- Number of bits per sample.
+ * - k
+ - 16 for D-PHY and 7 for C-PHY
The transmitter drivers must, if possible, configure the CSI-2
transmitter to *LP-11 mode* whenever the transmitter is powered on but
diff --git a/Documentation/driver-api/media/drivers/ccs/ccs.rst b/Documentation/driver-api/media/drivers/ccs/ccs.rst
index f49e971f2d92..b461c8aa2a16 100644
--- a/Documentation/driver-api/media/drivers/ccs/ccs.rst
+++ b/Documentation/driver-api/media/drivers/ccs/ccs.rst
@@ -79,4 +79,17 @@ definitions:
-l drivers/media/i2c/ccs/ccs-limits.c \
-c Documentation/driver-api/media/drivers/ccs/ccs-regs.asc
+CCS PLL calculator
+==================
+
+The CCS PLL calculator is used to compute the PLL configuration, given sensor's
+capabilities as well as board configuration and user specified configuration. As
+the configuration space that encompasses all these configurations is vast, the
+PLL calculator isn't entirely trivial. Yet it is relatively simple to use for a
+driver.
+
+The PLL model implemented by the PLL calculator corresponds to MIPI CCS 1.1.
+
+.. kernel-doc:: drivers/media/i2c/ccs-pll.h
+
**Copyright** |copy| 2020 Intel Corporation
diff --git a/Documentation/driver-api/media/v4l2-clocks.rst b/Documentation/driver-api/media/v4l2-clocks.rst
deleted file mode 100644
index 5c22eecab7ba..000000000000
--- a/Documentation/driver-api/media/v4l2-clocks.rst
+++ /dev/null
@@ -1,31 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0
-
-V4L2 clocks
------------
-
-.. attention::
-
- This is a temporary API and it shall be replaced by the generic
- clock API, when the latter becomes widely available.
-
-Many subdevices, like camera sensors, TV decoders and encoders, need a clock
-signal to be supplied by the system. Often this clock is supplied by the
-respective bridge device. The Linux kernel provides a Common Clock Framework for
-this purpose. However, it is not (yet) available on all architectures. Besides,
-the nature of the multi-functional (clock, data + synchronisation, I2C control)
-connection of subdevices to the system might impose special requirements on the
-clock API usage. E.g. V4L2 has to support clock provider driver unregistration
-while a subdevice driver is holding a reference to the clock. For these reasons
-a V4L2 clock helper API has been developed and is provided to bridge and
-subdevice drivers.
-
-The API consists of two parts: two functions to register and unregister a V4L2
-clock source: v4l2_clk_register() and v4l2_clk_unregister() and calls to control
-a clock object, similar to the respective generic clock API calls:
-v4l2_clk_get(), v4l2_clk_put(), v4l2_clk_enable(), v4l2_clk_disable(),
-v4l2_clk_get_rate(), and v4l2_clk_set_rate(). Clock suppliers have to provide
-clock operations that will be called when clock users invoke respective API
-methods.
-
-It is expected that once the CCF becomes available on all relevant
-architectures this API will be removed.
diff --git a/Documentation/driver-api/media/v4l2-core.rst b/Documentation/driver-api/media/v4l2-core.rst
index 0dcad7a23141..1a8c4a5f256b 100644
--- a/Documentation/driver-api/media/v4l2-core.rst
+++ b/Documentation/driver-api/media/v4l2-core.rst
@@ -15,7 +15,6 @@ Video4Linux devices
v4l2-controls
v4l2-videobuf
v4l2-videobuf2
- v4l2-clocks
v4l2-dv-timings
v4l2-flash-led-class
v4l2-mc
diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst
index bb5b1a7cdfd9..8b53da2f9c74 100644
--- a/Documentation/driver-api/media/v4l2-subdev.rst
+++ b/Documentation/driver-api/media/v4l2-subdev.rst
@@ -122,15 +122,12 @@ Don't forget to cleanup the media entity before the sub-device is destroyed:
media_entity_cleanup(&sd->entity);
-If the subdev driver intends to process video and integrate with the media
-framework, it must implement format related functionality using
-:c:type:`v4l2_subdev_pad_ops` instead of :c:type:`v4l2_subdev_video_ops`.
-
-In that case, the subdev driver may set the link_validate field to provide
-its own link validation function. The link validation function is called for
-every link in the pipeline where both of the ends of the links are V4L2
-sub-devices. The driver is still responsible for validating the correctness
-of the format configuration between sub-devices and video nodes.
+If a sub-device driver implements sink pads, the subdev driver may set the
+link_validate field in :c:type:`v4l2_subdev_pad_ops` to provide its own link
+validation function. For every link in the pipeline, the link_validate pad
+operation of the sink end of the link is called. In both cases the driver is
+still responsible for validating the correctness of the format configuration
+between sub-devices and video nodes.
If link_validate op is not set, the default function
:c:func:`v4l2_subdev_link_validate_default` is used instead. This function
@@ -200,15 +197,45 @@ unregister the notifier the driver has to call
takes two arguments: a pointer to struct :c:type:`v4l2_device` and a
pointer to struct :c:type:`v4l2_async_notifier`.
-Before registering the notifier, bridge drivers must do two things:
-first, the notifier must be initialized using the
-:c:func:`v4l2_async_notifier_init`. Second, bridge drivers can then
-begin to form a list of subdevice descriptors that the bridge device
-needs for its operation. Subdevice descriptors are added to the notifier
-using the :c:func:`v4l2_async_notifier_add_subdev` call. This function
-takes two arguments: a pointer to struct :c:type:`v4l2_async_notifier`,
-and a pointer to the subdevice descripter, which is of type struct
-:c:type:`v4l2_async_subdev`.
+Before registering the notifier, bridge drivers must do two things: first, the
+notifier must be initialized using the :c:func:`v4l2_async_notifier_init`.
+Second, bridge drivers can then begin to form a list of subdevice descriptors
+that the bridge device needs for its operation. Several functions are available
+to add subdevice descriptors to a notifier, depending on the type of device and
+the needs of the driver.
+
+:c:func:`v4l2_async_notifier_add_fwnode_remote_subdev` and
+:c:func:`v4l2_async_notifier_add_i2c_subdev` are for bridge and ISP drivers for
+registering their async sub-devices with the notifier.
+
+:c:func:`v4l2_async_register_subdev_sensor_common` is a helper function for
+sensor drivers registering their own async sub-device, but it also registers a
+notifier and further registers async sub-devices for lens and flash devices
+found in firmware. The notifier for the sub-device is unregistered with the
+async sub-device.
+
+These functions allocate an async sub-device descriptor which is of type struct
+:c:type:`v4l2_async_subdev` embedded in a driver-specific struct. The &struct
+:c:type:`v4l2_async_subdev` shall be the first member of this struct:
+
+.. code-block:: c
+
+ struct my_async_subdev {
+ struct v4l2_async_subdev asd;
+ ...
+ };
+
+ struct my_async_subdev *my_asd;
+ struct fwnode_handle *ep;
+
+ ...
+
+ my_asd = v4l2_async_notifier_add_fwnode_remote_subdev(&notifier, ep,
+ struct my_async_subdev);
+ fwnode_handle_put(ep);
+
+ if (IS_ERR(asd))
+ return PTR_ERR(asd);
The V4L2 core will then use these descriptors to match asynchronously
registered subdevices to them. If a match is detected the ``.bound()``