Re: [PATCH 1/1] leds: Introduce the multi_max_intensity sysfs attribute

[Jacek Anaszewski <jacek.anaszewski@gmail.com>]

Hi Armin,

Thanks for the update.

On 3/24/26 9:27 PM, Armin Wolf wrote:
> Some multicolor LEDs support global brightness control in hardware,
> meaning that the maximum intensity of the color components is not
> connected to the maximum global brightness. Such LEDs cannot be
> described properly by the current multicolor LED class interface,
> because it assumes that the maximum intensity of each color component
> is described by the maximum global brightness of the LED.
> 
> Fix this by introducing a new sysfs attribute called
> "multi_max_intensity" holding the maximum intensity values for the
> color components of a multicolor LED class device. Drivers can use
> the new max_intensity field inside struct mc_subled to tell the
> multicolor LED class code about those values. Intensity values written
> by userspace applications will be limited to this maximum value.
> 
> Drivers for multicolor LEDs that do not support global brightness
> control in hardware might still want to use the maximum global LED
> brightness supplied via devicetree as the maximum intensity of each
> individual color component. Such drivers should set max_intensity
> to 0 so that the multicolor LED core can act accordingly.
> 
> The lp50xx and ncp5623 LED drivers already use hardware-based control
> for the global LED brightness. Modify those drivers to correctly
> initalize .max_intensity to avoid being limited to the maximum global
> brightness supplied via devicetree.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
>   .../ABI/testing/sysfs-class-led-multicolor    | 19 ++++++--
>   Documentation/leds/leds-class-multicolor.rst  | 21 ++++++++-
>   drivers/leds/led-class-multicolor.c           | 47 ++++++++++++++++++-
>   drivers/leds/leds-lp50xx.c                    |  1 +
>   drivers/leds/rgb/leds-ncp5623.c               |  4 +-
>   include/linux/led-class-multicolor.h          | 30 +++++++++++-
>   6 files changed, 113 insertions(+), 9 deletions(-)
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

-- 
Best regards,
Jacek Anaszewski