[PATCH 0/2] Add SPI display support for UNIHIKER M10 V1.2

[Miotsuki Mizuno <founder@crepuse.com>]

Describe the onboard 240x320 RGB565 display with panel-mipi-dbi.
The series adds the panel compatible and enables SPI2, GPIO reset/D-C
and the PWM1 backlight. It uses the existing DRM and SPI drivers.

This series is based on the separate board I2C2 preparation commit.
The prerequisite board patch was submitted separately:
https://lore.kernel.org/r/20261010232831.26908-1-founder@crepuse.com
It does not depend on the pending NS2009 driver or binding.

The 132-byte initialization firmware is available from:
https://github.com/mio-tsuki/panel-mipi-dbi-firmware/releases/tag/v1.0.0
Required filename: dfrobot,unihiker-m10-display.bin
SHA256: 50412ae6d29c5bbfb7fac585528a761fb249d7944011a1b19c5e0f80a0418e5f
The test kernel embeds it with CONFIG_EXTRA_FIRMWARE. Public release
does not imply linux-firmware acceptance.

The nominal active area is 43.2 x 57.6 mm, represented as 43 x 58 mm.
The published V1.3 schematic is not used as evidence for V1.2 supply
connections; optional power/io supply properties are omitted.

SPI2 input is assigned 100 MHz. Active transfer register readback
showed BAUDR=2, corresponding to 50 MHz. No oscilloscope measurement
is claimed. GPIO_ACTIVE_HIGH reset matches the existing DRM helper
and leaves the physical reset pin HIGH after initialization.

Built against Rockchip v7.4-armsoc/dts64, commit
ae965b9856f033145e292b0c29082a26bcc45efd. Target DTS/schema, binding
examples and strict checkpatch checks passed. 
The exact display DTS booted through normal U-Boot three times in this
retest with the original test kernel, without pstore instrumentation,
clk_ignore_unused or regulator_ignore_unused. Physical corner patterns
were confirmed; full and partial updates and five DRM disable/enable
cycles completed. The exact display/touch combination also booted and
its physical output was confirmed.

Earlier boots reset during early userspace; one partial USB log recorded
an instruction abort. This was not reproduced in the latest retest.
The resets may have resulted from accidental contact with a loose
jumper wire during reboot. The cause has not been established, and no
software fix is claimed.
Exact-DTS cold boot and deep suspend/resume have not been tested.

Mizuno Miotsuki (2):
  dt-bindings: display: panel-mipi-dbi-spi: Add UNIHIKER M10 display
  arm64: dts: rockchip: Enable display on UNIHIKER M10 V1.2

 .../display/panel/panel-mipi-dbi-spi.yaml     |  1 +
 .../dts/rockchip/rk3308-unihiker-m10-v1.2.dts | 53 +++++++++++++++++++
 2 files changed, 54 insertions(+)


base-commit: f4f7ecd2e0e8debcbab4789717cc79d570d665e3
-- 
2.56.0