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The patch also adds a model for common raw sensors. Signed-off-by: Sakari Ailus Reviewed-by: Tomi Valkeinen Reviewed-by: Lad Prabhakar Reviewed-by: Mirela Rabulea Reviewed-by: Lad Prabhakar --- .../media/drivers/camera-sensor.rst | 4 + .../media/v4l/common-raw-sensor.dia | 442 ++++++++++++++++++ .../media/v4l/common-raw-sensor.svg | 134 ++++++ .../userspace-api/media/v4l/dev-subdev.rst | 2 + .../media/v4l/subdev-config-model.rst | 230 +++++++++ 5 files changed, 812 insertions(+) create mode 100644 Documentation/userspace-api/media/v4l/common-raw-sensor= .dia create mode 100644 Documentation/userspace-api/media/v4l/common-raw-sensor= .svg create mode 100644 Documentation/userspace-api/media/v4l/subdev-config-mod= el.rst diff --git a/Documentation/userspace-api/media/drivers/camera-sensor.rst b/= Documentation/userspace-api/media/drivers/camera-sensor.rst index cbbfbb0d8273..39f3f91c6733 100644 --- a/Documentation/userspace-api/media/drivers/camera-sensor.rst +++ b/Documentation/userspace-api/media/drivers/camera-sensor.rst @@ -18,6 +18,8 @@ binning functionality. The sensor drivers belong to two d= istinct classes, freely configurable and register list-based drivers, depending on how the driver configures this functionality. =20 +Also see :ref:`media_subdev_config_model_common_raw_sensor`. + Freely configurable camera sensor drivers ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ =20 @@ -118,6 +120,8 @@ values programmed by the register sequences. The defaul= t values of these controls shall be 0 (disabled). Especially these controls shall not be inv= erted, independently of the sensor's mounting rotation. =20 +.. _media_using_camera_sensor_drivers_embedded_data: + Embedded data ------------- =20 diff --git a/Documentation/userspace-api/media/v4l/common-raw-sensor.dia b/= Documentation/userspace-api/media/v4l/common-raw-sensor.dia new file mode 100644 index 000000000000..24b3f2b2a626 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/common-raw-sensor.dia @@ -0,0 +1,442 @@ + + + + + + + + + + + + + #A4# + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + #image data (1)# + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + #embedded data (n - 1)# + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + #source pad (0)# + + + + + + + + + + + + + + + + + + + + + + + + diff --git a/Documentation/userspace-api/media/v4l/common-raw-sensor.svg b/= Documentation/userspace-api/media/v4l/common-raw-sensor.svg new file mode 100644 index 000000000000..1d6055da2519 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/common-raw-sensor.svg @@ -0,0 +1,134 @@ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documen= tation/userspace-api/media/v4l/dev-subdev.rst index bb86cadfad1c..b0774b9a9b71 100644 --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst @@ -846,3 +846,5 @@ stream while it may be possible to enable and disable t= he embedded data stream. =20 The embedded data format does not need to be configured on the sensor's pa= ds as the format is dictated by the pixel data format in this case. + +.. include:: subdev-config-model.rst diff --git a/Documentation/userspace-api/media/v4l/subdev-config-model.rst = b/Documentation/userspace-api/media/v4l/subdev-config-model.rst new file mode 100644 index 000000000000..1e6c58931ea0 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/subdev-config-model.rst @@ -0,0 +1,230 @@ +.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later + +.. _media_subdev_config_model: + +Sub-device configuration models +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D + +The V4L2 specification defines a subdev API that exposes three type of +configuration elements: formats, selection rectangles and controls. The +specification contains generic information about how those configuration +elements behave, but not precisely how they apply to particular hardware +features. We leave some leeway to drivers to decide how to map selection +rectangles to device features, as long as they comply with the V4L2 +specification. This is needed as hardware features differ between devices,= so +it's the driver's responsibility to handle this mapping. + +Unfortunately, this lack of clearly defined mapping in the specification h= as led +to different drivers mapping the same hardware features to different API +elements, or implementing the API elements with slightly different +behaviours. Furthermore, many drivers have implemented selection rectangle= s in +ways that do not comply with the V4L2 specification. All of this makes use= rspace +development difficult. + +Sub-device configuration models specify in detail what the user space can = expect +from a sub-device in terms of V4L2 sub-device interface support, semantics +included. + +A sub-device may implement more than one configuration model at the same +time. The implemented configuration models can be obtained from the sub-de= vice's +``V4L2_CID_CONFIG_MODEL`` control. + +.. _media_subdev_config_model_common_raw_sensor: + +Common raw camera sensor model +------------------------------ + +The common raw camera sensor model defines a set of enumeration and +configuration interfaces (formats, selections etc.) that cover the vast ma= jority +of functionality of raw camera sensors. Not all of the interfaces are +necessarily offered by all drivers. + +A sub-device complies with the common raw sensor model if the +``V4L2_CONFIG_MODEL_COMMON_RAW_SENSOR`` bit is set in the +``V4L2_CID_CONFIG_MODEL`` control of the sub-device. + +The common raw camera sensor model is aligned with +:ref:`media_using_camera_sensor_drivers`. Please refer to that regarding a= spects +not specified here. + +Each camera sensor implementing the common raw sensor model exposes a sing= le +V4L2 sub-device. The sub-device contains a single source pad (0) and two o= r more +internal pads: one or more image data internal pads (starting from 1) and +optionally an embedded data pad. + +Additionally, further internal pads may be supported for other features. U= sing +more than one image data internal pad or more than one non-image data pad +requires these pads documented separately for the given device. The indice= s of +the image data internal pads shall be lower than those of the non-image da= ta +pads. + +This is shown in :ref:`media_subdev_config_model_common_raw_sensor_subdev`. + +.. _media_subdev_config_model_common_raw_sensor_subdev: + +.. kernel-figure:: common-raw-sensor.svg + :alt: common-raw-sensor.svg + :align: center + + **Common raw sensor sub-device with n pads (n =3D=3D 2)** + +Routes +^^^^^^ + +A sub-device conforming to common raw camera sensor model implements the +following routes. + +.. flat-table:: Routes + :header-rows: 1 + + * - Sink pad/stream + - Source pad/stream + - Static (X/M(aybe)/-) + - Mandatory (X/-) + - Synopsis + * - 1/0 + - 0/0 + - X + - X + - Image data + * - 2/0 + - 0/1 + - M + - \- + - Embedded data + +Support for the embedded data stream is optional. Drivers supporting the +embedded data stream may allow disabling and enabling the route when the +streaming is disabled. + +Sensor pixel array size, cropping and binning +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The sensor's pixel array is divided into one or more areas. The areas arou= nd the +edge of the pixel array, usually one or more sides, may contain optical bl= ack +pixels, dummy pixels and other non-image pixels. The entire pixel array si= ze is +conveyed by the format on (pad, stream) pair 1/0. + +A rectangle within the pixel array contains the visible pixels. Capturing = the +non-visible pixels outside the visible pixel area may be supported by the +sensor. The visible pixel area corresponds to the ``V4L2_SEL_TGT_CROP_DEFA= ULT`` +selection target on (pad, stream) pair 1/0. + +Sensors can perform multiple operations that affect the output image size.= First +of these is the analogue crop. Analogue crop limits the area of the pixel = array +which the sensor will read, affecting sensor timing as well. The granulari= ty of +the analogue crop configuration varies greatly across sensors: some sensors +support only a few different analogue crop configurations whereas others m= ay +support anything divisible by a given number of pixels. The analogue crop +configuration corresponds to the ``V4L2_SEL_TGT_CROP`` selection target on= (pad, +stream) pair 1/0. The default analogue crop rectangle corresponds to the v= isible +pixel area. + +In the next step, binning is performed on the image data read from camera +sensor's pixel array, as determined by the analogue crop configuration. En= abling +binning will effectively result in an image smaller than the original by g= iven +binning factors horizontally and vertically. Typical values are 1/2 and 1/= 3 but +others may well be supported by the hardware as well. + +Sub-sampling follows binning. Sub-sampling, like binning, reduces the size= of +the image by including only a subset of samples read from the sensor's pix= el +matrix, typically every n'th pixel horizontally and vertically, taking the +sensor's color pattern into account. Sub-sampling is generally configurable +separately horizontally and vertically. + +Binning and sub-sampling are configured using the ``V4L2_SEL_TGT_COMPOSE`` +rectangle, relative to the analogue crop rectangle, on (pad, stream) pair +1/0. The driver implementation determines how to configure binning and +sub-sampling to achieve the desired size. + +The digital crop operation takes place after binning and sub-sampling. It = is +configured by setting the ``V4L2_SEL_TGT_CROP`` rectangle on (pad, stream)= pair +0/0. The resulting image size is further output by the sensor. + +The sensor's output mbus code is configured by setting the format on the (= pad, +stream) pair 0/0. When setting the format, always use the same width and h= eight +as for the digital crop setting. + +Drivers may only support some or even none of these configurations, in whi= ch +case they do not expose the corresponding selection rectangles. If any sel= ection +targets are omitted, the further selection rectangle or format is instead +related to the previous implemented selection rectangle. For instance, if = the +sensor supports binning but not analogue crop, then the binning configurat= ion +(``V4L2_SEL_TGT_COMPOSE`` selection target) is done in relation to the vis= ible +pixel area (``V4L2_SEL_TGT_CROP_DEFAULT`` selection target). + +Also refer to :ref:`Selection targets `. + +.. flat-table:: Selection targets on pads + :header-rows: 1 + + * - Pad/Stream + - Selection target/format + - Mandatory (X/-) + - Modifiable (X/-) + - Synopsis + * - 1/0 + - Format + - X + - \- + - Image data format. The width and the height fields indicates the f= ull + size of the pixel array, including non-visible pixels. The media b= us + code of this format reflects the native pixel depth of the sensor. + * - 1/0 + - ``V4L2_SEL_TGT_CROP_DEFAULT`` + - X + - \ + - The visible pixel area. This rectangle is relative to the format o= n the + same (pad, stream). + * - 1/0 + - ``V4L2_SEL_TGT_CROP`` + - \- + - X + - Analogue crop. Analogue crop typically has a coarse granularity. T= his + rectangle is relative to the format on the same (pad, stream). + * - 1/0 + - ``V4L2_SEL_TGT_COMPOSE`` + - \- + - X + - Binning and sub-sampling. This rectangle is relative to the + ``V4L2_SEL_TGT_CROP`` rectangle on the same (pad, stream). The + combination of binning and sub-sampling is configured using this + selection target. + * - 2/0 + - Format + - X + - \- + - Embedded data format. + * - 0/0 + - ``V4L2_SEL_TGT_CROP`` + - \- + - X + - Digital crop. This rectangle is relative to the ``V4L2_SEL_TGT_COM= POSE`` + rectangle on (pad, stream) pair 1/0. + * - 0/0 + - Format + - X + - X + - Image data source format. Always assign the width and height field= s of + the format to the same values than for the ``V4L2_SEL_TGT_CROP`` + rectangle on (pad, stream) pair 0/0. The media bus code reflects t= he + pixel data output of the sensor. + * - 0/1 + - Format + - X + - \- + - Embedded data source format. + +Embedded data +^^^^^^^^^^^^^ + +The embedded data stream is produced by the sensor when the corresponding = route +is enabled. The embedded data route may also be immutable or not exist at = all, +in case the sensor (or the driver) does not support it. + +Generally the sensor embedded data width is determined by the width of the= image +data whereas the number of lines are constant for the embedded data. The u= ser +space may obtain the size of the embedded data once the image data size on= the +source pad has been configured. + +Also see :ref:`media_using_camera_sensor_drivers_embedded_data`. --=20 2.47.2