[RFC PATCH 0/7] sun8i H3 HDMI glue driver for DW HDMI

[Jernej Skrabec]

This patch series adds a HDMI glue driver for Allwinner H3 SoC. For now, only
video and CEC functionality is supported. Audio needs more tweaks.

Series is based on the H3 DE2 patch series available on mailing list:
http://lists.infradead.org/pipermail/linux-arm-kernel/2017-August/522697.html
(ignore patches marked with [NOT FOR REVIEW NOW] tag)

Patch 1 adds support for polling plug detection since custom PHY used here
doesn't support HPD interrupt.

Patch 2 enables overflow workaround for v1.32a. This HDMI controller exhibits
same issues as HDMI controller used in iMX6 SoCs.

Patch 3 adds CLK_SET_RATE_PARENT to hdmi clock.

Patch 4 adds dt bindings documentation.

Patch 5 adds actual H3 HDMI glue driver.

Patch 6 and 7 add HDMI node to DT and enable it where needed.

Allwinner used DW HDMI controller in a non standard way:
- register offsets obfuscation layer, which can fortunately be turned off
- register read lock, which has to be disabled by magic number
- custom PHY, which have to be initialized before DW HDMI controller
- non standard clocks
- no HPD interrupt

Because of that, I have two questions:
- Since HPD have to be polled, is it enough just to enable poll mode? I'm
  mainly concerned about invalidating CEC address here.
- PHY has to be initialized before DW HDMI controller to disable offset
  obfuscation and read lock among other things. This means that all clocks have
  to be enabled in glue driver. This poses a problem, since when using
  component model, dw-hdmi bridge uses drvdata for it's own private data and
  prevents glue layer to pass a pointer to unbind function, where clocks should
  be disabled. I noticed same issue in meson DW HDMI glue driver, where clocks
  are also not disabled when unbind callback is called. I noticed that when H3
  SoC is shutdown, HDMI output is still enabled and lastest image is shown on
  monitor until it is unplugged from power supply. Is there any simple solution
  to this?

Chen-Yu,
TL Lim was unable to obtain any answer from Allwinner about HDMI clocks. I think
it is safe to assume that divider in HDMI clock doesn't have any effect.

Branch based on linux-next from 1. September with integrated patches is
available here:
https://github.com/jernejsk/linux-1/tree/h3_hdmi_rfc

Some additonal info about H3 HDMI:
https://linux-sunxi.org/DWC_HDMI_Controller

Thanks to Jens Kuske, who figured out that it is actually DW HDMI controller
and mapped scrambled register offsets to original ones.

Icenowy Zheng (1):
  ARM: sun8i: h3: Add DesignWare HDMI controller node

Jernej Skrabec (6):
  drm: bridge: Enable polling hpd event in dw_hdmi
  drm: bridge: Enable workaround in dw_hdmi for v1.32a
  clk: sunxi: Add CLK_SET_RATE_PARENT flag for H3 HDMI clock
  dt-bindings: Document Allwinner DWC HDMI TX node
  drm: sun4i: Add a glue for the DesignWare HDMI controller in H3
  ARM: sun8i: h3: Enable HDMI output on H3 boards

 .../bindings/display/sunxi/sun4i-drm.txt           | 158 ++++++-
 arch/arm/boot/dts/sun8i-h3-bananapi-m2-plus.dts    |  33 ++
 arch/arm/boot/dts/sun8i-h3-beelink-x2.dts          |  33 ++
 arch/arm/boot/dts/sun8i-h3-nanopi-m1.dts           |  33 ++
 arch/arm/boot/dts/sun8i-h3-orangepi-2.dts          |  33 ++
 arch/arm/boot/dts/sun8i-h3-orangepi-lite.dts       |  33 ++
 arch/arm/boot/dts/sun8i-h3-orangepi-one.dts        |  33 ++
 arch/arm/boot/dts/sun8i-h3-orangepi-pc.dts         |  33 ++
 arch/arm/boot/dts/sun8i-h3.dtsi                    |   5 +
 arch/arm/boot/dts/sunxi-h3-h5.dtsi                 |  36 ++
 drivers/clk/sunxi-ng/ccu-sun8i-h3.c                |   2 +-
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c          |  14 +-
 drivers/gpu/drm/sun4i/Kconfig                      |   9 +
 drivers/gpu/drm/sun4i/Makefile                     |   1 +
 drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c              | 500 +++++++++++++++++++++
 15 files changed, 950 insertions(+), 6 deletions(-)
 create mode 100644 drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c

-- 
2.14.1