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

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Message-ID: <87seh6ffh1.fsf@minerva.mail-host-address-is-not-set>
Date: Mon, 01 Sep 2025 15:51:38 +0200
From: Javier Martinez Canillas <javierm@...hat.com>
To: Marcus Folkesson <marcus.folkesson@...il.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>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org, Marcus Folkesson <marcus.folkesson@...il.com>
Subject: Re: [PATCH v2 0/6] drm/st7571-i2c: add support for grayscale xrgb8888

Marcus Folkesson <marcus.folkesson@...il.com> writes:

Hello Marcus,

> 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
>

When applying I noticed that patch #5 had the following warning [0], but
I fixed it locally before pushing to drm-misc (drm-misc-next). Thanks!

[0]: CHECK: Alignment should match open parenthesis
#86: FILE: drivers/gpu/drm/drm_format_helper.c:1415:
+void drm_fb_xrgb8888_to_gray2(struct iosys_map *dst, const unsigned int *dst_pitch,
+                            const struct iosys_map *src, const struct drm_framebuffer *fb,

CHECK: Alignment should match open parenthesis
#153: FILE: include/drm/drm_format_helper.h:140:
+void drm_fb_xrgb8888_to_gray2(struct iosys_map *dst, const unsigned int *dst_pitch,
+                            const struct iosys_map *src, const struct drm_framebuffer *fb,

total: 0 errors, 0 warnings, 2 checks, 125 lines checked

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat