On Tue, 21 Sep 2021, Marek Vasut wrote:

> The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper
> in backlight.c") says that gpio-backlight uses brightness as power state.
> This has been fixed since in ec665b756e6f7 ("backlight: gpio-backlight:
> Correct initial power state handling") and other backlight drivers do not
> require this workaround. Drop the workaround.
> 
> This fixes the case where e.g. pwm-backlight can perfectly well be set to
> brightness 0 on boot in DT, which without this patch leads to the display
> brightness to be max instead of off.
> 
> Fixes: c2adda27d202f ("video: backlight: Add of_find_backlight helper in 
> backlight.c")
> Acked-by: Noralf Trønnes <nor...@tronnes.org>
> Reviewed-by: Daniel Thompson <daniel.thomp...@linaro.org>
> Cc: <sta...@vger.kernel.org> # 5.4+
> Cc: <sta...@vger.kernel.org> # 4.19.x: ec665b756e6f7: backlight: 
> gpio-backlight: Correct initial power state handling
> Signed-off-by: Marek Vasut <ma...@denx.de>
> Cc: Daniel Thompson <daniel.thomp...@linaro.org>
> Cc: Lee Jones <lee.jo...@linaro.org>
> Cc: Meghana Madhyastha <meghana.madhyas...@gmail.com>
> Cc: Noralf Trønnes <nor...@tronnes.org>
> Cc: Sean Paul <seanp...@chromium.org>
> Cc: Thierry Reding <tred...@nvidia.com>
> ---
> V2: Add AB/RB, CC stable
> ---
>  drivers/video/backlight/backlight.c | 6 ------
>  1 file changed, 6 deletions(-)

Applied with some changes to the sign-off block, thanks.

> diff --git a/drivers/video/backlight/backlight.c 
> b/drivers/video/backlight/backlight.c
> index 537fe1b376ad7..fc990e576340b 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -688,12 +688,6 @@ static struct backlight_device *of_find_backlight(struct 
> device *dev)
>                       of_node_put(np);
>                       if (!bd)
>                               return ERR_PTR(-EPROBE_DEFER);
> -                     /*
> -                      * Note: gpio_backlight uses brightness as
> -                      * power state during probe
> -                      */
> -                     if (!bd->props.brightness)
> -                             bd->props.brightness = bd->props.max_brightness;
>               }
>       }
>  

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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