[PATCH v8 0/2] Add support for PinePhone LCD panel

[Ondrej Jirman <megous@megous.com>]

This patchset adds support for the LCD panel of PinePhone.

I've tested this on PinePhone 1.0 and 1.2.

Please take a look.

thank you and regards,
  Ondrej Jirman

Changes in v8:
- Drop goodix,gt911 fallback compatible (Icenowy)
- Drop address/size-cells from &dsi node (Maxime)
- Drop already applied patches
- v7->v8 diff: https://megous.com/dl/tmp/v7-v8.patch

Changes in v7:
- Removed mode.vrefresh, rebased onto next-20200701
- v6->v7 diff: https://megous.com/dl/tmp/v6-v7.patch

Changes in v6:
- Fixed spacing in yaml
- Fixed wrong vccio->iovcc supply name in the bindings doc
- I noticed that the original driver uses a delay of 20ms in the init
  function to achieve a combined total of 120ms required from post-reset
  to display_on. I've added a similar delay to xbd599_init, so that
  xbd599 panel also has the right timing. (patch 9)
- v5->v6 diff: https://megous.com/dl/tmp/v5-v6.patch
- Added review/ack tags
- Learned to run dt_binding_check by myself ;)

Changes in v5:
- rewritten on top of rocktech-jh057n00900 driver
- rocktech-jh057n00900 renamed to st7703 (controller name)
- converted rocktech-jh057n00900 bindings to yaml and extended for xbd599

Changes in v4:
- use ->type from the mode instead of hardcoding (Samuel)
- move init_sequence to ->prepare (Samuel)
- move anti-flicker delay to ->enable, explain it (Samuel)
- add enter_sleep after display_off (Samuel)
- drop ->disable (move code to ->unprepare)
- add ID bytes dumping (Linus)
  (I can't test it since allwinner DSI driver has a broken
   dcs_read function, and I didn't manage to fix it.)
- document magic bytes (Linus)
- assert reset during powerup
- cleanup powerup timings according to the datasheet

Changes in v3:
- Panel driver renamed to the name of the LCD controller
- Re-organize the driver slightly to more easily support more panels
  based on the same controller.
- Add patch to enable the touchscreen to complete the LCD support
  on PinePhone.
- Dropped the "DSI fix" patch (the driver seems to work for me without it)
- Improved brightness levels handling:
  - PinePhone 1.0 uses default levels generated by the driver
  - On PinePhone 1.1 duty cycles < 20% lead to black screen, so
    default levels can't be used. Martijn Braam came up with a
    list of duty cycle values that lead to perception of linear
    brigtness level <-> light intensity on PinePhone 1.1
- There was some feedback on v2 about this being similar to st7701.
  It's only similar in name. Most of the "user commands" are different,
  so I opted to keep this in a new driver instead of creating st770x.
  
  Anyone who likes to check the differences, here are datasheets:

  - https://megous.com/dl/tmp/ST7703_DS_v01_20160128.pdf
  - https://megous.com/dl/tmp/ST7701.pdf

Changes in v2:
- DT Example fix.
- DT Format fix.
- Raised copyright info to 2020.
- Sort panel operation functions.
- Sort inclusion.


-- For phone owners: --

There's an open question on how to set the backlight brightness values
on post 1.0 revision phone, since lower duty cycles (< 10-20%) lead
to backlight being black. It would be nice if more people can test
the various backlight levels on 1.1 and 1.2 revision with this change
in dts:

       brightness-levels = <0 1000>;
       num-interpolated-steps = <1000>;

and report at what brightness level the backlight turns on. So far it
seems this has a wide range. Lowest useable duty cycle for me is ~7%
on 1.2 and for Martijn ~20% on 1.1.

Icenowy Zheng (1):
  arm64: dts: sun50i-a64-pinephone: Enable LCD support on PinePhone

Ondrej Jirman (1):
  arm64: dts: sun50i-a64-pinephone: Add touchscreen support

 .../allwinner/sun50i-a64-pinephone-1.1.dts    | 19 +++++++
 .../dts/allwinner/sun50i-a64-pinephone.dtsi   | 52 +++++++++++++++++++
 2 files changed, 71 insertions(+)

-- 
2.27.0