Enable brightness control for the Lenovo ThinkPad T14s Gen 7 (Mahua,
X2 Elite) eDP panel.

 - Add qcom,pmk8850-pwm to the LPG binding and driver; PMK8850 reuses
   the PMK8550 two-channel 0xe800/0xe900 layout.
 - Describe the PWM node in pmk8850.dtsi, left disabled.
 - Switch the Mahua T14s LCD overlay to a pwm-backlight.

Based on next-20261012. Tested on Lenovo ThinkPad T14s Gen 7.

Srinivas Kandagatla (4):
  dt-bindings: leds: qcom-lpg: add qcom,pmk8850-pwm compatible
  leds: rgb: qcom-lpg: add qcom,pmk8850-pwm compatible
  arm64: dts: qcom: pmk8850: add PWM node
  arm64: dts: qcom: mahua-t14s: wire backlight through pmk8850 pwm

 .../bindings/leds/leds-qcom-lpg.yaml          |  2 ++
 .../mahua-lenovo-thinkpad-t14s-gen7-lcd.dts   | 26 ++++++++++++++++----
 arch/arm64/boot/dts/qcom/pmk8850.dtsi         | 10 +++++++++
 drivers/leds/rgb/leds-qcom-lpg.c              |  1 +
 4 files changed, 35 insertions(+), 4 deletions(-)


base-commit: f53c44783aacd8920469531e7c45f9f70afd291b
-- 
2.53.0

Tested on a Lenovo ThinkPad T14s Gen 7 (22A7000VUS, BOE NE140WUM-N41 panel)
with linux-next next-20261015 plus this series: the backlight device
/sys/class/backlight/backlight is registered with max_brightness 4095 and
the brightness keys work.

Tested-by: Luke Macken <luke@phorex.org>

Two observations: the panel's DPCD advertises PWM-pin brightness control
only (0x701 = 0x83, 0x702 = 0x95, no AUX_SET_CAP), and the firmware leaves
the PMK8850 PWM channel at 0xe800 enabled with GPIO5 in func3, so the LPG
path matches what the hardware is set up for.