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

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Message-ID: <20250513085057.GB2936510@google.com>
Date: Tue, 13 May 2025 09:50:57 +0100
From: Lee Jones <lee@...nel.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Nam Tran <trannamatk@...il.com>, andy@...nel.org, pavel@....cz,
	robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
	christophe.jaillet@...adoo.fr, corbet@....net,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org, florian.fainelli@...adcom.com,
	bcm-kernel-feedback-list@...adcom.com,
	linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v8 0/5] auxdisplay: add support for TI LP5812 4x3 Matrix
 LED driver

On Tue, 13 May 2025, Geert Uytterhoeven wrote:

> Hi Nam,
> 
> On Mon, 12 May 2025 at 19:38, Nam Tran <trannamatk@...il.com> wrote:
> > On Mon, 12 May 2025 Andy Shevchenko wrote:
> > > On Sat, May 10, 2025 at 02:48:02PM +0700, Nam Tran wrote:
> > > > On Thu, 8 May 2025 Lee Jones wrote:
> > > > > On Thu, 08 May 2025, Andy Shevchenko wrote:
> > > > > > On Thu, May 8, 2025 at 5:27 PM Nam Tran <trannamatk@...il.com> wrote:
> > > > > > > On Thu, 8 May 2025 Lee Jones wrote:
> > > > > > > > On Thu, 08 May 2025, Andy Shevchenko wrote:
> >
> > ...
> >
> > > > I think setting PWM also same as brightness_set API. However, there are
> > > > many PWM config for a LED and it is one of other config to make autonomous mode work.
> > > > Therefore, standard led API can use in some use cases only.
> > > >
> > > > Please see the link below for a better visualization of how to configure the LP5812.
> > > > https://dev.ti.com/gallery/view/LED/LP581x/ver/0.10.0/
> > >
> > > To me it sounds like you should start from the small steps, i.e. do not
> > > implement everything at once. And starting point of the 4 RGB LEDs sounds
> > > the best approach to me. Then, if needed, you can always move on with
> > > fancy features of this hardware on top of the existing code.
> >
> > Thanks for the suggestion.
> > I understand your point and agree that starting with standard LED APIs is the preferred approach.
> 
> i.e. a drivers/leds/ driver.
> 
> > However, the LP5812 hardware offers more advanced features, and I’d like to support end users all
> > features as shown in the link: https://dev.ti.com/gallery/view/LED/LP581x/ver/0.10.0/.
> > It is easy for end user to investigate and use driver.
> >
> > If I want to keep the current driver interface to meet this expectation, would it be acceptable
> > to move it to the misc subsystem to better support the hardware?
> 
> I guess you can add custom sysfs controls for the advanced features
> on top of the drivers/leds/ driver?

Yes, exactly that.

-- 
Lee Jones [李琼斯]