[PATCH v2] backlight: gpio_backlight: Drop output gpio direction check for initial power state

Daniel Thompson daniel.thompson at linaro.org
Fri Jul 21 08:42:51 UTC 2023


On Fri, Jul 21, 2023 at 07:31:37AM +0000, Ying Liu wrote:
> If gpio pin is in input state but backlight is currently off due to
> default pull downs, then initial power state is set to FB_BLANK_UNBLANK
> in DT boot mode with phandle link and the backlight is effectively
> turned on in gpio_backlight_probe(), which is undesirable according to
> patch description of commit ec665b756e6f ("backlight: gpio-backlight:
> Correct initial power state handling").
>
> Quote:
> ---
> If in DT boot we have phandle link then leave the GPIO in a state which the
> bootloader left it and let the user of the backlight to configure it further.
> ---
>
> So, let's drop output gpio direction check and only check gpio value to set
> the initial power state.
>
> Signed-off-by: Liu Ying <victor.liu at nxp.com>

Based on the discussion for v1 about 706dc68102bc ("backlight: gpio:
Explicitly set the direction of the GPIO"), I think there should
be a Fixes: tag here.


Daniel.


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