linux-kernel - [PATCH v2 0/6] drm/st7571-i2c: add support for grayscale xrgb8888

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Message-Id: <20250721-st7571-format-v2-0-159f4134098c@gmail.com>
Date: Mon, 21 Jul 2025 12:43:30 +0200
From: Marcus Folkesson <marcus.folkesson@...il.com>
To: 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>, 
 Javier Martinez Canillas <javierm@...hat.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 devicetree@...r.kernel.org, Marcus Folkesson <marcus.folkesson@...il.com>
Subject: [PATCH v2 0/6] drm/st7571-i2c: add support for grayscale xrgb8888

The goal with this series is to add support for 2bit grayscale with
the xrgb8888 pixel format for the st7571 display controller.

The first patch only corrects a comment of the pixel format.

The next four patches adds support for inverting pixels. This is
necessary as the connected display may or may not use the "right" (0 =>
black, 1 => white) pixel format expected by the supported formats
(R1/R2/XRGB8888).

The fifth patch adds a helper function (drm_fb_xrgb8888_to_gray2) to
convert xrgb8888 to gray2.

The last path adds support for gray2 in the st7571 driver.
Compare the mono [1] and the gray2 [2] variants of our penguin.

[1] https://www.marcusfolkesson.se/gray2.png
[2] https://www.marcusfolkesson.se/xrgb8888.png

Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
---
Changes in v2:
- Do not share code between _to_mono() and _to_gray2()
- Correct formatting (remove  "|") in the dt bindings
- Implement support for inverting pixels for st7567
- Link to v1: https://lore.kernel.org/r/20250714-st7571-format-v1-0-a27e5112baff@gmail.com

---
Marcus Folkesson (6):
      drm/st7571-i2c: correct pixel data format description
      dt-bindings: display: sitronix,st7571: add optional inverted property
      dt-bindings: display: sitronix,st7567: add optional inverted property
      drm/st7571-i2c: add support for inverted pixel format
      drm/format-helper: introduce drm_fb_xrgb8888_to_gray2()
      drm/st7571-i2c: add support for 2bit grayscale for XRGB8888

 .../bindings/display/sitronix,st7567.yaml          |   5 +
 .../bindings/display/sitronix,st7571.yaml          |   5 +
 drivers/gpu/drm/drm_format_helper.c                | 108 +++++++++++++++++++++
 drivers/gpu/drm/sitronix/st7571-i2c.c              |  41 ++++----
 include/drm/drm_format_helper.h                    |   4 +
 5 files changed, 144 insertions(+), 19 deletions(-)
---
base-commit: ca2a6abdaee43808034cdb218428d2ed85fd3db8
change-id: 20250520-st7571-format-2ce6badc48c6

Best regards,
-- 
Marcus Folkesson <marcus.folkesson@...il.com>