linux-kernel - Re: [PATCH v8 0/5] auxdisplay: add support for TI LP5812 4x3 Matrix LED driver

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Message-Id: <20250428163718.15918-1-trannamatk@gmail.com>
Date: Mon, 28 Apr 2025 23:37:18 +0700
From: Nam Tran <trannamatk@...il.com>
To: andy@...nel.org
Cc: geert@...ux-m68k.org,
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Subject: Re: [PATCH v8 0/5] auxdisplay: add support for TI LP5812 4x3 Matrix LED driver

On Sun, 27 Apr 2025 Andy Shevchenko wrote:

> On Sun, Apr 27, 2025 at 11:25 AM Nam Tran <trannamatk@...il.com> wrote:
> >
> > This patch series adds support for the TI/National Semiconductor LP5812
> > 4x3 matrix RGB LED driver. The driver supports features such as autonomous
> > animation and time-cross-multiplexing (TCM) for dynamic LED effects.
> >
> > Signed-off-by: Nam Tran <trannamatk@...il.com>
> > ---
> > Changes in v8:
> > - Move driver to drivers/auxdisplay/ instead of drivers/leds/.
> > - Rename files from leds-lp5812.c/.h to lp5812.c/.h.
> > - Move ti,lp5812.yaml binding to auxdisplay/ directory,
> >   and update the title and $id to match new path.
> > - No functional changes to the binding itself (keep Reviewed-by).
> > - Update commit messages and patch titles to reflect the move.
> > - Link to v7: https://lore.kernel.org/linux-leds/20250422190121.46839-1-trannamatk@gmail.com/
> 
> Out of sudden without discussing with auxdisplay maintainers/reviewers?
> Thanks, no.
> Please, put into the cover letter the meaningful summary of what's
> going on and why this becomes an auxdisplay issue. Brief review of the
> bindings sounds more likely like LEDS or PWM subsystems.

Apologies for moving the driver to auxdisplay without prior discussion with you
and the other auxdisplay maintainers.

The decision to move it was based on advice from Lee Jones (LED subsystem co-maintainer).
He reviewed the v7 series while it was still under drivers/leds/, and explicitly recommended
that I move it to drivers/auxdisplay/.
Reference: https://lore.kernel.org/linux-leds/20250425101112.GB1567507@google.com/

Here’s a brief summary of why LP5812 fits better in auxdisplay than in LEDS or PWM subsystems:
- 4 outputs drive 12 LEDs (4 RGB) using time-cross-multiplexing (TCM).
- An autonomous animation engine creates complex visual effects without CPU intervention.
- Supports analog current control, PWM dimming up to 24kHz, de-ghosting, and phase shifting,
  all targeting dynamic visual outputs rather than static LED states.

I will prepare a v9 with an updated cover letter summarizing this background.
I am also happy to make further adjustments based on your and other auxdisplay maintainers’ guidance.

Thanks for reviewing and helping me through the submission process.

Best regards,
Nam Tran