Re: [PATCH V4] leds: rgb: leds-group-multicolor: Implement default-intensity

[Lee Jones <lee@kernel.org>]

On Thu, 13 Aug 2026, sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] The `default-intensity` property read from individual monochromatic LED nodes is applied to the multicolor group without rescaling, causing incorrect brightness calculations.

Please review, explain or fix the Sashiko review(s).

If this is a set, this request includes the other patches too.

> --
> 
> --- Patch [1]: [PATCH V4] leds: rgb: leds-group-multicolor: Implement default-intensity ---
> commit 13399f1aaceaf09afa7e252e35000d7d61ab1925
> Author: Stefan Wahren <wahrenst@gmx.net>
> 
> leds: rgb: leds-group-multicolor: Implement default-intensity
> 
> This commit introduces support for the default-intensity property during
> boot for LED multicolor groups. If the property is missing, the code falls
> back to the previous behavior of configuring the sub-LED intensity to its
> maximum.
> 
> > diff --git a/drivers/leds/rgb/leds-group-multicolor.c b/drivers/leds/rgb/leds-group-multicolor.c
> > --- a/drivers/leds/rgb/leds-group-multicolor.c
> > +++ b/drivers/leds/rgb/leds-group-multicolor.c
> > @@ -108,8 +108,10 @@ static int leds_gmc_probe(struct platform_device *pdev)
> >  
> >  		subled[i].color_index = led_cdev->color;
> >  
> > -		/* Configure the LED intensity to its maximum */
> > -		subled[i].intensity = max_brightness;
> > +		ret = device_property_read_u32(led_cdev->dev, "default-intensity",
> > +					       &subled[i].intensity);
> > +		if (ret || subled[i].intensity > max_brightness)
> > +			subled[i].intensity = max_brightness;
> 
> [Severity: Medium]
> Does this logic properly scale the intensity when the individual LEDs in the
> group have different maximum brightness values?
> 
> If a multicolor group consists of LEDs with vastly different maximum brightness
> capabilities (like a GPIO LED maxing at 1 and a PWM LED maxing at 255), the
> overall group max_brightness will evaluate to 255.
> 
> When reading the default-intensity from the device tree, the value is typically
> specified on the scale of the individual sub-LED's max brightness. If this
> value is assigned directly to subled[i].intensity without being scaled up to
> the group's max_brightness, the sub-LED might be initialized with only a tiny
> fraction of its intended intensity, often resulting in the LED being completely
> unlit instead of at the requested intensity.
> 
> >  	}
> >  
> >  	/* Initialise the multicolor's LED class device */
> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260813091428.9072-1-wahrenst@gmx.net?part=1

-- 
Lee Jones