linux-kernel - Re: [PATCH v3 2/3] leds: add support for TI LP5860 LED driver chip

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Message-ID: <20251009124427.GC2796410@google.com>
Date: Thu, 9 Oct 2025 13:44:27 +0100
From: Lee Jones <lee@...nel.org>
To: Steffen Trumtrar <s.trumtrar@...gutronix.de>
Cc: Pavel Machek <pavel@....cz>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Steffen Trumtrar <kernel@...gutronix.de>,
	Pavel Machek <pavel@...nel.org>, Mark Brown <broonie@...nel.org>,
	linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
	linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] leds: add support for TI LP5860 LED driver chip

On Tue, 30 Sep 2025, Steffen Trumtrar wrote:

> 
> Hi,
> 
> On 2025-09-16 at 16:34 +01, Lee Jones <lee@...nel.org> wrote:
> 
> > > +#include <linux/gpio.h>
> > > +#include <linux/led-class-multicolor.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of_gpio.h>
> > > +#include <linux/of_platform.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +#include <linux/platform_data/leds-lp5860.h>
> > > +
> > > +static struct lp5860_led *mcled_cdev_to_led(struct led_classdev_mc *mc_cdev)
> > > +{
> > > +	return container_of(mc_cdev, struct lp5860_led, mc_cdev);
> > > +}
> > > +
> > > +LP5860_SHOW_MODE(r_global_brightness_set, LP5860_REG_R_CURRENT_SET, LP5860_CC_GROUP_MASK, 0)
> > > +LP5860_STORE_MODE(r_global_brightness_set, LP5860_REG_R_CURRENT_SET, LP5860_CC_GROUP_MASK, 0)
> > > +DEVICE_ATTR_RW(r_global_brightness_set);
> > 
> > How is this different to /sys/class/leds/<led>/multi_intensity?
> > 
> > # echo 43 226 138 > /sys/class/leds/multicolor:status/multi_intensity
> > red -
> >     intensity = 138
> >     max_brightness = 255
> > green -
> >     intensity = 43
> >     max_brightness = 255
> > blue -
> >     intensity = 226
> >     max_brightness = 255
> > 
> 
> the LP5860 has a register for setting the maximal brightness that holds for all LEDs in the matrix. multi_intensity and max_brightness is only for that one multicolor LED, right? And I can only manipulate the max_brightness of that one multicolor LED instance.
> If I'm wrong, I'd be happy to not have to add the sysfs files.

Does group_multicolor help?  Or can it be expanded for future similar use-cases?

-- 
Lee Jones [李琼斯]