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From: Tomasz Stanislawski <t.stanislaws <at> samsung.com>
Subject: [PATCH v4 0/3] TV driver for Samsung S5P platform (media part)
Newsgroups: gmane.linux.drivers.video-input-infrastructure
Date: Tuesday 24th May 2011 13:09:33 UTC (over 6 years ago)

I would like to present the 4th version of TV drivers for Samsung S5P
The most recent changes are:

1. Configuration of TV is promoted to platform level.
- setup of resources is moved to plat-s5p
- support for EXYNOS4 and S5PV210 machine.
- support for universal-c210 board
- support for Goni board

2. Runtime PM for SDO driver.

3. Moved back to dma-contig allocator.
- dma-contig is a generic interface for a device
- dma-contig use iommu if sysmmu is enabled for a platform

4. Revision of mixer's output handling
- list of to be registered outputs is kept in the mixer driver
- output is not registered if it is not avaliable

4. Bugs and other fixes:
- fixed power domain hang-up
- fixed dead-lock caused by request_module called from probe
- formatting and typos
- fixed VSYNC handling in interrupt
- hdmi: applying driver variant to select proper I2C bus

Updated RFC for TV driver:


The purpose of this RFC is to discuss the driver for a TV output interface
available in upcoming Samsung SoC. The HW is able to generate digital and
analog signals. Current version of the driver supports only digital output.

Internally the driver uses videobuf2 framework, and DMA-CONTIG memory
Not all of them are merged by now, but I decided to post the sources to
discussion driver's design.

 Hardware description

The SoC contains a few HW sub-blocks:

1. Video Processor (VP). It is used for processing of NV12 data.  An image
stored in RAM is accessed by DMA. Pixels are cropped, scaled. Additionally,
post processing operations like brightness, sharpness and contrast
could be performed. The output in YCbCr444 format is send to Mixer.

2. Mixer (MXR). The piece of hardware responsible for mixing and blending
multiple data inputs before passing it to an output device.  The MXR is
of handling up to three image layers. One is the output of VP.  Other two
images in RGB format (multiple variants are supported).  The layers are
cropped and blended with background color.  The blending factor, and
priority are controlled by MXR's registers. The output is passed either to
or SDO.

3. HDMI. The piece of HW responsible for generation of HDMI packets. It
pixel data from mixer and transforms it into data frames. The output is
to HDMIPHY interface.

4. HDMIPHY. Physical interface for HDMI. Its duties are sending HDMI
packets to
HDMI connector. Basically, it contains a PLL that produces source clock for
Mixer, VP and HDMI during streaming.

5. SDO. Generation of TV analog signal. The alternative output for the
It receives data and passes it to VideoDAC. The SDO is responsible for
generation of analog TV signal. It supports multiple standards.

6. VideoDAC. Modulator for TVOUT signal. Receives data from SDO. Converts
it to analog domain. Next, the signal is modulated to CVBS format,
and sent to Comosite Connector.

The diagram below depicts connection between all HW pieces.
NV12 data ---dma--->|   Video   |
                    | Processor |
RGB data  ---dma--->|           |
                    |   Mixer   |
RGB data  ---dma--->|           |
                          * dmux
                  +-----*   *------+
                  |                |
                  V                V
            +-----------+    +-----------+
            |    HDMI   |    |    SDO    |
            +-----------+    +-----------+
                  |                |
                  V                V
            +-----------+    +-----------+
            |  HDMIPHY  |    |  VideoDAC |
            +-----------+    +-----------+
                  |                |
                  V                V
                HDMI           Composite
             connector         connector

 Driver interface

The posted driver implements three V4L2 nodes. Every video node implements
output buffer. One of nodes corresponds to input of Video Processor. The
two nodes correspond to RGB inputs of Mixer. All nodes share the same
It is one of the Mixer's outputs: SDO or HDMI. Changing output in one layer
using S_OUTPUT would change outputs of all other video nodes. The same
happens if one try to reconfigure output i.e. by calling S_DV_PRESET.
it not possible to change or reconfigure the output while streaming. To sum
all features in posted version of driver goes as follows:

2. S_FMT, G_FMT - single and multiplanar API
  a) node named video0 supports formats NV12, NV12, NV12T (tiled version of
NV12), NV12MT (multiplane version of NV12T).
  b) nodes named graph0 and graph1 support formats RGB565, ARGB1555,
3. Buffer with USERPTR and MMAP memory.
4. Streaming and buffer control. (STREAMON, STREAMOFF, REQBUF, QBUF, DQBUF)
5. OUTPUT configurations and enumeration using VIDIOC_{ENUM/S/G}_OUTPUT.
6. DV preset control (SET, GET, ENUM). Currently modes 480P59_94,
1080P30, 1080P59_94 and 1080P60 work.
7. Analog standards using VIDIOC_S_STD.
8. Positioning layer's window on output display using S_CROP, G_GROP,
9. Positioning and cropping data in buffer using S_CROP, G_GROP, CROPCAP
buffer type OVERLAY. *

- add control of alpha blending / chroma keying via V4L2 controls
- add controls for luminance curve and sharpness in VP
- consider exporting all output functionalities to separate video node
- consider media controller framework
- fix dependency between all TV drivers
- move all subroutines for power management to PM runtime callbacks

* The need of cropping in source buffers came from problem with MFC driver
S5P. The MFC supports only width divisible by 64. If a width of a decoded
is not aligned do 64 then padding pixels are filled with zeros. This is an
green color in YCbCr colorspace. Filling it with zeros by a CPU is a waste
resources since an image can be cropped in VP. Is it possible to set crops
user data for M2M devices. V4L2 lacks such functionality of non-M2M
Therefore cropping in buffer V4L2_BUF_TYPE_VIDEO_OVERLAY was used as an

 Device Architecture

Three drivers are added in this patch.

1. HDMIPHY. It is an I2C driver for HDMIPHY interface. It exports following
callback by V4L2 subdevice:
- s_power: currently stub
- s_stream: configures and starts/stops HDMIPHY
- s_dv_preset: used to choose proper frequency of clock for other TV

2. HDMI. The auxiliary driver used to control HDMI interface. It exports
subdev in its private data for use by other drivers. The following
callbacks are
- s_power: runs HDMI hardware, regulators and clocks.
- s_stream: runs HDMIPHY and starts generation of video frames.
- enum_dv_presets
- s_dv_preset
- g_mbus_format: returns information on data format expected by on HDMI
  The driver supports an interrupt. It is used to detect plug/unplug events
kernel debugs.  The API for detection of such an events in V4L2 API is to

3. SDO. The auxiliary driver used to control analog TV. It also exports its
subdev for other drivers. The following callbacks are implemented.
- s_power: runs TV hardware, regulators and clocks.
- s_stream: runs TV clock and starts generation of video signal.
- s_std: configuration of TV standard from one of PAL/NTSC family
- g_tvnorms: used by Mixer to obtain tv standards supported by SDO
- g_mbus_format: returns information on data format expected by on SDO

5. Mixer & Video Processor driver. It is called 's5p-mixer' because of
historical reasons. It was decided combine VP and MXR drivers into one
of shared interrupt and very similar interface via V4L2 nodes. The driver
is a
realization of many-to-many relation between multiple input layers and
outputs. All shared resources are kept in struct mxr_device. It provides
utilities for management and synchronization of access to resources and
reference counting. The outputs are obtained from HDMI/SDO private data. 
layer is a single video node. Simple inheritance is applied because there
little difference between layer's types. Every layer type implements set of
ops.  There are different ops for Mixer layers and other for VP layer.

The videobuf2 framework was used for the management of buffers and
All other V4L2 ioctls are processed in layers common interface. The
was used as memory allocator for Mixer's buffers. It could be easily
with any other allocator integrated with videobuf2 framework.

 Usage summary

Follow steps below to display double-buffered animation on SDO output.
In order to use other output please use VIDIOC_S_OUTPUT.

01. Open video node named graph0.
02. S_FMT(type = OUTPUT, pixelformat = V4L2_PIX_FMT_RGB*, width, height,
03. REQ_BUFS(type = OUTPUT, memory = MMAP, count = 2)
04. MMAP(type = OUTPUT, index = 0)
05. MMAP(type = OUTPUT, index = 1)
06. Fill buffer 0 with data
07. QBUF(type = OUTPUT, index = 0)
08. STREAM_ON(type = OUTPUT)
09. Fill buffer 1 with data
10. QBUF(type = OUTPUT, index = 1)
11. DQBUF(type = OUTPUT)
12. QBUF(type = OUTPUT, index = 0)
13. DQBUF(type = OUTPUT)
14. Goto 09

 Patch Summary

Tomasz Stanislawski (3):
  v4l: add macro for 1080p59_54 preset
  v4l: add g_tvnorms callback to V4L2 subdev
  s5p-tv: add drivers for TV on Samsung S5P platform

 drivers/media/video/Kconfig                  |    8 +
 drivers/media/video/Makefile                 |    1 +
 drivers/media/video/s5p-tv/Kconfig           |   68 +
 drivers/media/video/s5p-tv/Makefile          |   17 +
 drivers/media/video/s5p-tv/hdmi.h            |   74 +
 drivers/media/video/s5p-tv/hdmi_drv.c        | 1008 ++++++++++++++
 drivers/media/video/s5p-tv/hdmiphy_drv.c     |  250 ++++
 drivers/media/video/s5p-tv/mixer.h           |  336 +++++
 drivers/media/video/s5p-tv/mixer_drv.c       |  488 +++++++
 drivers/media/video/s5p-tv/mixer_grp_layer.c |  180 +++
 drivers/media/video/s5p-tv/mixer_reg.c       |  566 ++++++++
 drivers/media/video/s5p-tv/mixer_reg.h       |   46 +
 drivers/media/video/s5p-tv/mixer_video.c     |  957 +++++++++++++
 drivers/media/video/s5p-tv/mixer_vp_layer.c  |  206 +++
 drivers/media/video/s5p-tv/regs-hdmi.h       | 1849
 drivers/media/video/s5p-tv/regs-sdo.h        |  453 +++++++
 drivers/media/video/s5p-tv/regs-vmx.h        |  197 +++
 drivers/media/video/s5p-tv/regs-vp.h         |  277 ++++
 drivers/media/video/s5p-tv/sdo_drv.c         |  530 ++++++++
 drivers/media/video/v4l2-common.c            |    1 +
 include/linux/videodev2.h                    |    1 +
 include/media/v4l2-subdev.h                  |    1 +
 22 files changed, 7514 insertions(+), 0 deletions(-)
 create mode 100644 drivers/media/video/s5p-tv/Kconfig
 create mode 100644 drivers/media/video/s5p-tv/Makefile
 create mode 100644 drivers/media/video/s5p-tv/hdmi.h
 create mode 100644 drivers/media/video/s5p-tv/hdmi_drv.c
 create mode 100644 drivers/media/video/s5p-tv/hdmiphy_drv.c
 create mode 100644 drivers/media/video/s5p-tv/mixer.h
 create mode 100644 drivers/media/video/s5p-tv/mixer_drv.c
 create mode 100644 drivers/media/video/s5p-tv/mixer_grp_layer.c
 create mode 100644 drivers/media/video/s5p-tv/mixer_reg.c
 create mode 100644 drivers/media/video/s5p-tv/mixer_reg.h
 create mode 100644 drivers/media/video/s5p-tv/mixer_video.c
 create mode 100644 drivers/media/video/s5p-tv/mixer_vp_layer.c
 create mode 100644 drivers/media/video/s5p-tv/regs-hdmi.h
 create mode 100644 drivers/media/video/s5p-tv/regs-sdo.h
 create mode 100644 drivers/media/video/s5p-tv/regs-vmx.h
 create mode 100644 drivers/media/video/s5p-tv/regs-vp.h
 create mode 100644 drivers/media/video/s5p-tv/sdo_drv.c

CD: 3ms