[PATCH v3 0/5] Add support for PinePhone LCD panel

From: Ondrej Jirman
Date: Wed May 13 2020 - 17:25:07 EST


This patchset adds support for the LCD panel of PinePhone.

The first 3 patches are for the panel itself, and the last 2 patches are
for enabling it on PinePhone.

I've tested this on PinePhone 1.0 and 1.2.

Please take a look.

thank you and regards,
Ondrej Jirman


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 (4):
dt-bindings: vendor-prefixes: Add Xingbangda
dt-bindings: panel: Add binding for Xingbangda XBD599 panel
drm: panel: Add Xingbangda XBD599 panel (ST7703 controller)
arm64: dts: sun50i-a64-pinephone: Enable LCD support on PinePhone

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

.../display/panel/sitronix,st7703.yaml | 63 +++
.../devicetree/bindings/vendor-prefixes.yaml | 2 +
.../allwinner/sun50i-a64-pinephone-1.1.dts | 19 +
.../dts/allwinner/sun50i-a64-pinephone.dtsi | 54 +++
drivers/gpu/drm/panel/Kconfig | 10 +
drivers/gpu/drm/panel/Makefile | 1 +
drivers/gpu/drm/panel/panel-sitronix-st7703.c | 386 ++++++++++++++++++
7 files changed, 535 insertions(+)
create mode 100644 Documentation/devicetree/bindings/display/panel/sitronix,st7703.yaml
create mode 100644 drivers/gpu/drm/panel/panel-sitronix-st7703.c

--
2.26.2