[RFC PATCH 0/4] Common Display Framework-TF

[Tomasz Figa]

Hi,

After pretty long time of trying to adapt Exynos-specific DSI display support
to Common Display Framework I'm ready to show some preliminary RFC patches.
This series shows some ideas for CDF that came to my mind during my work,
some changes based on comments received by Tomi's edition of CDF and also
preliminarys version of Exynos DSI (video source part only, still with some
FIXMEs) and Samsung S6E8AX0 DSI panel drivers.

It is heavily based on Tomi's work which can be found here:
http://thread.gmane.org/gmane.comp.video.dri.devel/78227

The code might be a bit hacky in places, as I wanted to get it to a kind
of complete and working state first. However I hope that some of the ideas
might useful for further works.

So, here comes the TF edition of Common Clock Framework.
--------------------------------------------------------

Changes done to Tomi's edition of CDF:

 - Replaced set_operation_mode, set_pixel_format and set_size video source
   operations with get_params display entity operation, as it was originally
   in Laurent's version.

   We have discussed this matter on the mailing list
   and decided that it would be better to have the source ask the sink for
   its parameter structure and do whatever appropriate with it.

 - Defined a preliminary set of DSI bus parameters.

   Following parameters are defined:

   1. Pixel format used for video data transmission.
   2. Mode flags (several bit flags ORed together):
     a) DSI_MODE_VIDEO - entity uses video mode (as opposed to command mode),
        following DSI_MODE_VIDEO_* flags are relevant only if this flag is set.
        b) DSI_MODE_VIDEO_BURST - entity uses burst transfer for video data
        c) DSI_MODE_VIDEO_SYNC_PULSE - entity uses sync pulses (as opposed
           to sync events)
        d) DSI_MODE_VIDEO_AUTO_VERT - entity uses automatic video mode
           detection
        e) DSI_MODE_VIDEO_HSE - entity needs horizontal sync end packets
        f) DSI_MODE_VIDEO_HFP - entity needs horizontal front porch area
        g) DSI_MODE_VIDEO_HBP - entity needs horizontal back porch area
        h) DSI_MODE_VIDEO_HSA - entity needs horizontal sync active area
     i) DSI_MODE_VSYNC_FLUSH - vertical sync pulse flushes video data
     j) DSI_MODE_EOT_PACKET - entity needs EoT packets
   3. Bit (serial) clock frequency in HS mode.
   4. Escape mode clock frequency.
   5. Mask of used data lanes (each bit represents single lane).
   6. Command allow area in video mode - amount of lines after transmitting
      video data when generic commands are accepted.

   Feel free to suggest anything missing or wrong, as the list of
   parameters is based merely on what was used in original Exynos MIPI
   DSIM driver.

 - Redesigned source-entity matching.

   Now each source has name string and integer id and each entity has
   source name and source id. In addition, they can have of_node specified,
   which is used for Device Tree-based matching.

   The matching procedure is as follows:

   1. Matching takes place when display entity registers.
     a) If there is of_node specified for the entity then "video-source"
        phandle of this node is being parsed and list of registered sources
        is traversed in search of a source with of_node received from
        parsing the phandle.
     b) Otherwise the matching key is a pair of source name and id.
   2. If no matching source is found, display_entity_register returns
      -EPROBE_DEFER error which causes the entity driver to defer its
      probe until the source registers.
   3. Otherwise an optional bind operation of video source is called,
      sink field of source and source field of entity are set and the
      matching ends successfully.

 - Some initial concept of source-entity cross-locking.

   Only video source is protected at the moment, as I still have to think
   a bit about locking the entity in a way where removing it by user request
   is still possible.

 - Dropped any panels and chips that I can't test.

   They are irrelevant for this series, so there is no point in including them.

 - Added Exynos DSI video source driver.

   This is a new driver for the DSI controller found in Exynos SoCs. It still
   needs some work, but in current state can be considered an example of DSI
   video source implementation for my version of CDF.

 - Added Samsung S6E8AX0 DSI panel driver.

   This is the old Exynos-specific driver, just migrated to CDF and with
   some hacks to provide control over entity state to userspace using
   lcd device. However it can be used to demonstrate video source ops in use.

Feel free to comment as much as you can.

Tomasz Figa (4):
  video: add display-core
  video: add makefile & kconfig
  video: display: Add exynos-dsi video source driver
  video: display: Add Samsung s6e8ax0 display panel driver

 drivers/video/Kconfig                     |    1 +
 drivers/video/Makefile                    |    1 +
 drivers/video/display/Kconfig             |   16 +
 drivers/video/display/Makefile            |    3 +
 drivers/video/display/display-core.c      |  295 +++++++
 drivers/video/display/panel-s6e8ax0.c     | 1027 ++++++++++++++++++++++
 drivers/video/display/source-exynos_dsi.c | 1313 +++++++++++++++++++++++++++++
 include/video/display.h                   |  230 +++++
 include/video/exynos_dsi.h                |   41 +
 include/video/panel-s6e8ax0.h             |   41 +
 10 files changed, 2968 insertions(+)
 create mode 100644 drivers/video/display/Kconfig
 create mode 100644 drivers/video/display/Makefile
 create mode 100644 drivers/video/display/display-core.c
 create mode 100644 drivers/video/display/panel-s6e8ax0.c
 create mode 100644 drivers/video/display/source-exynos_dsi.c
 create mode 100644 include/video/display.h
 create mode 100644 include/video/exynos_dsi.h
 create mode 100644 include/video/panel-s6e8ax0.h

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1.8.1