linux-kernel - [PATCH v2 0/4] Add support for OLED panel used on Snapdragon Lenovo T14s Gen6

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Message-Id: <20250325-wip-obbardc-qcom-t14s-oled-panel-v2-0-e9bc7c9d30cc@linaro.org>
Date: Tue, 25 Mar 2025 19:21:25 +0000
From: Christopher Obbard <christopher.obbard@...aro.org>
To: Douglas Anderson <dianders@...omium.org>, 
 Neil Armstrong <neil.armstrong@...aro.org>, 
 Jessica Zhang <quic_jesszhan@...cinc.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>, 
 Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 linux-arm-msm@...r.kernel.org, Johan Hovold <johan@...nel.org>, 
 Rui Miguel Silva <rui.silva@...aro.org>, Abel Vesa <abel.vesa@...aro.org>, 
 devicetree@...r.kernel.org, 
 Christopher Obbard <christopher.obbard@...aro.org>
Subject: [PATCH v2 0/4] Add support for OLED panel used on Snapdragon
 Lenovo T14s Gen6

The Snapdragon Lenovo T14s Gen6 can be bought with a number of different
panels. This patch series adds support for the OLED model which has a
Samsung ATNA40YK20 panel.

The first patch documents the panel in the existing driver.

The second patch adds the missing HPD gpio to the T14s devicetree. I
think that this patch could be split into two; one patch for the pinctrl
addition and one patch for adding the hpd-gpio property to the T14s
panel. But that can come in V3.

The third patch adds the eDP panel to the T14s OLED devicetree.

The fourth (and final) patch works around a problem when reading the
eDP panel's maximum backlight value. Without this patch, the maximum
brightness is detected as 0, thus meaning the backlight is never enabled.
I expect this patch to need a few rounds of rework/testing on other
devices!

The raw EDID of the panel is:

00 ff ff ff ff ff ff 00 4c 83 9f 41 00 00 00 00
00 21 01 04 b5 1e 13 78 02 0c f1 ae 52 3c b9 23
0c 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 ca fe 40 64 b0 08 18 70 20 08
88 00 2e bd 10 00 00 1b ca fe 40 64 b0 08 38 77
08 20 88 00 2e bd 10 00 00 1b 00 00 00 fe 00 53
44 43 20 20 20 20 20 20 20 20 20 20 00 00 00 fe
00 41 54 4e 41 34 30 59 4b 32 30 2d 30 20 01 cf
02 03 0f 00 e3 05 80 00 e6 06 05 01 74 60 07 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 b7

Signed-off-by: Christopher Obbard <christopher.obbard@...aro.org>
---
Changes in v2:
- Use the existing atna33xc20 driver rather than panel-edp.
- Add eDP panel into OLED devicetree.
- Add patch to read the correct maximum brightness from the eDP panel.
- Link to v1: https://lore.kernel.org/r/20250320-wip-obbardc-qcom-t14s-oled-panel-v1-1-05bc4bdcd82a@linaro.org

---
Christopher Obbard (4):
      dt-bindings: display: panel: samsung,atna40yk20: document ATNA40YK20
      arm64: dts: qcom: x1e78100-t14s: add hpd gpio to LCD panel
      arm64: dts: qcom: x1e78100-t14s-oled: add eDP panel
      drm/dp: fallback to maximum when PWM bit count is zero

 .../bindings/display/panel/samsung,atna33xc20.yaml |  2 +
 .../qcom/x1e78100-lenovo-thinkpad-t14s-oled.dts    | 10 +++++
 .../dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi    | 11 +++++
 drivers/gpu/drm/display/drm_dp_helper.c            | 51 ++++++++++++++--------
 4 files changed, 57 insertions(+), 17 deletions(-)
---
base-commit: b6ae34803e82511009e2b78dc4fd154330ecdc2d
change-id: 20250320-wip-obbardc-qcom-t14s-oled-panel-b74fed21d600

Best regards,
-- 
Christopher Obbard <christopher.obbard@...aro.org>