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[media] doc-rst: add documentation for fimc driver
Convert the document to rst and add it to the v4l-drivers book. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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@ -1,7 +1,9 @@
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Samsung S5P/EXYNOS4 FIMC driver
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.. include:: <isonum.txt>
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Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
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---------------------------------------------------------------------------
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The Samsung S5P/EXYNOS4 FIMC driver
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===================================
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Copyright |copy| 2012 - 2013 Samsung Electronics Co., Ltd.
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The FIMC (Fully Interactive Mobile Camera) device available in Samsung
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SoC Application Processors is an integrated camera host interface, color
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@ -12,13 +14,13 @@ slightly different capabilities, like pixel alignment constraints, rotator
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availability, LCD writeback support, etc. The driver is located at
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drivers/media/platform/exynos4-is directory.
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1. Supported SoCs
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=================
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Supported SoCs
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--------------
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S5PC100 (mem-to-mem only), S5PV210, EXYNOS4210
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2. Supported features
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=====================
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Supported features
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------------------
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- camera parallel interface capture (ITU-R.BT601/565);
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- camera serial interface capture (MIPI-CSI2);
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@ -28,12 +30,14 @@ S5PC100 (mem-to-mem only), S5PV210, EXYNOS4210
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instance to any parallel video input or any MIPI-CSI front-end);
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- runtime PM and system wide suspend/resume
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Not currently supported:
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Not currently supported
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-----------------------
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- LCD writeback input
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- per frame clock gating (mem-to-mem)
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3. Files partitioning
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=====================
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Files partitioning
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------------------
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- media device driver
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drivers/media/platform/exynos4-is/media-dev.[ch]
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@ -52,10 +56,11 @@ Not currently supported:
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drivers/media/platform/exynos4-is/fimc-reg.h
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drivers/media/platform/exynos4-is/regs-fimc.h
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4. User space interfaces
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========================
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User space interfaces
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---------------------
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4.1. Media device interface
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Media device interface
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~~~~~~~~~~~~~~~~~~~~~~
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The driver supports Media Controller API as defined at
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https://linuxtv.org/downloads/v4l-dvb-apis/media_common.html
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@ -72,7 +77,8 @@ Reconfiguration is done by enabling/disabling media links created by the driver
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during initialization. The internal device topology can be easily discovered
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through media entity and links enumeration.
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4.2. Memory-to-memory video node
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Memory-to-memory video node
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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V4L2 memory-to-memory interface at /dev/video? device node. This is standalone
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video device, it has no media pads. However please note the mem-to-mem and
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@ -80,7 +86,8 @@ capture video node operation on same FIMC instance is not allowed. The driver
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detects such cases but the applications should prevent them to avoid an
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undefined behaviour.
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4.3. Capture video node
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Capture video node
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~~~~~~~~~~~~~~~~~~
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The driver supports V4L2 Video Capture Interface as defined at:
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https://linuxtv.org/downloads/v4l-dvb-apis/devices.html
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@ -89,13 +96,15 @@ At the capture and mem-to-mem video nodes only the multi-planar API is
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supported. For more details see:
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https://linuxtv.org/downloads/v4l-dvb-apis/planar-apis.html
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4.4. Camera capture subdevs
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Camera capture subdevs
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~~~~~~~~~~~~~~~~~~~~~~
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Each FIMC instance exports a sub-device node (/dev/v4l-subdev?), a sub-device
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node is also created per each available and enabled at the platform level
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MIPI-CSI receiver device (currently up to two).
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4.5. sysfs
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sysfs
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~~~~~
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In order to enable more precise camera pipeline control through the sub-device
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API the driver creates a sysfs entry associated with "s5p-fimc-md" platform
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@ -115,15 +124,22 @@ when the last configuration steps at the video node is performed.
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For full sub-device control support (subdevs configured at user space before
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starting streaming):
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.. code-block:: none
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# echo "sub-dev" > /sys/platform/devices/s5p-fimc-md/subdev_conf_mode
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For V4L2 video node control only (subdevs configured internally by the host
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driver):
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.. code-block:: none
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# echo "vid-dev" > /sys/platform/devices/s5p-fimc-md/subdev_conf_mode
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This is a default option.
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5. Device mapping to video and subdev device nodes
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==================================================
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--------------------------------------------------
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There are associated two video device nodes with each device instance in
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hardware - video capture and mem-to-mem and additionally a subdev node for
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@ -134,14 +150,21 @@ How to find out which /dev/video? or /dev/v4l-subdev? is assigned to which
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device?
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You can either grep through the kernel log to find relevant information, i.e.
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.. code-block:: none
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# dmesg | grep -i fimc
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(note that udev, if present, might still have rearranged the video nodes),
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or retrieve the information from /dev/media? with help of the media-ctl tool:
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.. code-block:: none
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# media-ctl -p
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7. Build
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========
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--------
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If the driver is built as a loadable kernel module (CONFIG_VIDEO_SAMSUNG_S5P_FIMC=m)
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two modules are created (in addition to the core v4l2 modules): s5p-fimc.ko and
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@ -25,4 +25,5 @@ License".
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cx18
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cx88
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davinci-vpbe
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fimc
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zr364xx
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