On Mon, 15 Nov 2021, Marijn Suijten wrote:
> The hardware is capable of controlling any non-contiguous sequence of
> LEDs specified in the DT using qcom,enabled-strings as u32
> array, and this also follows from the DT-bindings documentation. The
> numbers specified in this array represent indices of the LED strings
> that are to be enabled and disabled.
>
> Its value is appropriately used to setup and enable string modules, but
> completely disregarded in the set_brightness paths which only iterate
> over the number of strings linearly.
> Take an example where only string 2 is enabled with
> qcom,enabled_strings=<2>: this string is appropriately enabled but
> subsequent brightness changes would have only touched the zero'th
> brightness register because num_strings is 1 here. This is simply
> addressed by looking up the string for this index in the enabled_strings
> array just like the other codepaths that iterate over num_strings.
>
> Likewise enabled_strings is now also used in the autodetection path for
> consistent behaviour: when a list of strings is specified in DT only
> those strings will be probed for autodetection, analogous to how the
> number of strings that need to be probed is already bound by
> qcom,num-strings. After all autodetection uses the set_brightness
> helpers to set an initial value, which could otherwise end up changing
> brightness on a different set of strings.
>
> Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3")
> Fixes: 03b2b5e86986 ("backlight: qcom-wled: Add support for WLED4 peripheral")
> Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx>
> Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> ---
> drivers/video/backlight/qcom-wled.c | 22 ++++++++++++----------
> 1 file changed, 12 insertions(+), 10 deletions(-)
Applied, thanks.
--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
