linux-kernel - Re: [PATCH 0/2] drm/panel: novatek-nt35560: Fix bug and clean up

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Message-ID: <CAD=FV=V65Pa0p-ckGAHTCgkqd00M9gE2Py99QcYmaq13jOdX9g@mail.gmail.com>
Date: Fri, 25 Jul 2025 14:16:56 -0700
From: Doug Anderson <dianders@...omium.org>
To: Brigham Campbell <me@...ghamcampbell.com>
Cc: maarten.lankhorst@...ux.intel.com, mripard@...nel.org, tzimmermann@...e.de, 
	airlied@...il.com, simona@...ll.ch, linus.walleij@...aro.org, 
	neil.armstrong@...aro.org, jessica.zhang@....qualcomm.com, sam@...nborg.org, 
	skhan@...uxfoundation.org, linux-kernel-mentees@...ts.linux.dev, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] drm/panel: novatek-nt35560: Fix bug and clean up

Hi,

On Thu, Jul 24, 2025 at 1:23 PM Brigham Campbell <me@...ghamcampbell.com> wrote:
>
> This series does the following:
>  - Add mipi_dsi_dcs_read_multi() to drm_mipi_dsi.c for improved error
>    handling in drivers which use mipi_dsi_dcs_read() such as the
>    novatek-nt35560 driver.
>  - Fix a bug in nt35560_set_brightness() which causes the driver to
>    incorrectly report that it "failed to disable display backlight".
>  - Clean up novatek-nt35560 driver to use "multi" variants of MIPI
>    functions which promote cleaner code.
>
> If there's a reason that mipi_dsi_dcs_read_multi doesn't exist, I'm
> happy to drop it.

It's a _little_ weird since one would normally assume that the caller
would want to immediately act on whatever was read and to do that
they'd need to look at the error code right away.

...but then again, there are places where a driver might want to read
multiple things and then check for errors once in the end (like the
driver you're changing here does). So I'm not against it. I'm not sure
I'd expect it to be universally used, though...