[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>
This commit is contained in:
Mauro Carvalho Chehab 2016-07-17 17:57:31 -03:00
parent e0f104538c
commit f0726e4275
2 changed files with 60 additions and 36 deletions

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@ -1,7 +1,9 @@
Samsung S5P/EXYNOS4 FIMC driver
.. include:: <isonum.txt>
Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
---------------------------------------------------------------------------
The Samsung S5P/EXYNOS4 FIMC driver
===================================
Copyright |copy| 2012 - 2013 Samsung Electronics Co., Ltd.
The FIMC (Fully Interactive Mobile Camera) device available in Samsung
SoC Application Processors is an integrated camera host interface, color
@ -12,50 +14,53 @@ slightly different capabilities, like pixel alignment constraints, rotator
availability, LCD writeback support, etc. The driver is located at
drivers/media/platform/exynos4-is directory.
1. Supported SoCs
=================
Supported SoCs
--------------
S5PC100 (mem-to-mem only), S5PV210, EXYNOS4210
2. Supported features
=====================
Supported features
------------------
- camera parallel interface capture (ITU-R.BT601/565);
- camera serial interface capture (MIPI-CSI2);
- memory-to-memory processing (color space conversion, scaling, mirror
and rotation);
- dynamic pipeline re-configuration at runtime (re-attachment of any FIMC
instance to any parallel video input or any MIPI-CSI front-end);
- runtime PM and system wide suspend/resume
- camera parallel interface capture (ITU-R.BT601/565);
- camera serial interface capture (MIPI-CSI2);
- memory-to-memory processing (color space conversion, scaling, mirror
and rotation);
- dynamic pipeline re-configuration at runtime (re-attachment of any FIMC
instance to any parallel video input or any MIPI-CSI front-end);
- runtime PM and system wide suspend/resume
Not currently supported:
- LCD writeback input
- per frame clock gating (mem-to-mem)
Not currently supported
-----------------------
3. Files partitioning
=====================
- LCD writeback input
- per frame clock gating (mem-to-mem)
Files partitioning
------------------
- media device driver
drivers/media/platform/exynos4-is/media-dev.[ch]
- camera capture video device driver
- camera capture video device driver
drivers/media/platform/exynos4-is/fimc-capture.c
- MIPI-CSI2 receiver subdev
- MIPI-CSI2 receiver subdev
drivers/media/platform/exynos4-is/mipi-csis.[ch]
- video post-processor (mem-to-mem)
- video post-processor (mem-to-mem)
drivers/media/platform/exynos4-is/fimc-core.c
- common files
- common files
drivers/media/platform/exynos4-is/fimc-core.h
drivers/media/platform/exynos4-is/fimc-reg.h
drivers/media/platform/exynos4-is/regs-fimc.h
4. User space interfaces
========================
User space interfaces
---------------------
4.1. Media device interface
Media device interface
~~~~~~~~~~~~~~~~~~~~~~
The driver supports Media Controller API as defined at
https://linuxtv.org/downloads/v4l-dvb-apis/media_common.html
@ -72,7 +77,8 @@ Reconfiguration is done by enabling/disabling media links created by the driver
during initialization. The internal device topology can be easily discovered
through media entity and links enumeration.
4.2. Memory-to-memory video node
Memory-to-memory video node
~~~~~~~~~~~~~~~~~~~~~~~~~~~
V4L2 memory-to-memory interface at /dev/video? device node. This is standalone
video device, it has no media pads. However please note the mem-to-mem and
@ -80,7 +86,8 @@ capture video node operation on same FIMC instance is not allowed. The driver
detects such cases but the applications should prevent them to avoid an
undefined behaviour.
4.3. Capture video node
Capture video node
~~~~~~~~~~~~~~~~~~
The driver supports V4L2 Video Capture Interface as defined at:
https://linuxtv.org/downloads/v4l-dvb-apis/devices.html
@ -89,13 +96,15 @@ At the capture and mem-to-mem video nodes only the multi-planar API is
supported. For more details see:
https://linuxtv.org/downloads/v4l-dvb-apis/planar-apis.html
4.4. Camera capture subdevs
Camera capture subdevs
~~~~~~~~~~~~~~~~~~~~~~
Each FIMC instance exports a sub-device node (/dev/v4l-subdev?), a sub-device
node is also created per each available and enabled at the platform level
MIPI-CSI receiver device (currently up to two).
4.5. sysfs
sysfs
~~~~~
In order to enable more precise camera pipeline control through the sub-device
API the driver creates a sysfs entry associated with "s5p-fimc-md" platform
@ -115,15 +124,22 @@ when the last configuration steps at the video node is performed.
For full sub-device control support (subdevs configured at user space before
starting streaming):
# echo "sub-dev" > /sys/platform/devices/s5p-fimc-md/subdev_conf_mode
.. code-block:: none
# echo "sub-dev" > /sys/platform/devices/s5p-fimc-md/subdev_conf_mode
For V4L2 video node control only (subdevs configured internally by the host
driver):
# echo "vid-dev" > /sys/platform/devices/s5p-fimc-md/subdev_conf_mode
.. code-block:: none
# echo "vid-dev" > /sys/platform/devices/s5p-fimc-md/subdev_conf_mode
This is a default option.
5. Device mapping to video and subdev device nodes
==================================================
--------------------------------------------------
There are associated two video device nodes with each device instance in
hardware - video capture and mem-to-mem and additionally a subdev node for
@ -134,14 +150,21 @@ How to find out which /dev/video? or /dev/v4l-subdev? is assigned to which
device?
You can either grep through the kernel log to find relevant information, i.e.
# dmesg | grep -i fimc
.. code-block:: none
# dmesg | grep -i fimc
(note that udev, if present, might still have rearranged the video nodes),
or retrieve the information from /dev/media? with help of the media-ctl tool:
# media-ctl -p
.. code-block:: none
# media-ctl -p
7. Build
========
--------
If the driver is built as a loadable kernel module (CONFIG_VIDEO_SAMSUNG_S5P_FIMC=m)
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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