Re: [PATCH] gpiolib: of: don't mark hog nodes OF_POPULATED before a chip is found

[Daniel Drake]

On 15/08/2026 21:44, Abdurrahman Hussain wrote:
> When a gpio-hog node is attached by a device-tree overlay before its
> parent GPIO chip has been registered, of_gpio_notify() sets
> OF_POPULATED on the node via of_node_test_and_set_flag() and only then
> discovers that there is no gpio_device for the parent, returning
> NOTIFY_DONE without clearing the flag.
>
> Since gpiochip_hog_lines() skips any hog child whose of_node carries
> OF_POPULATED, the leaked flag makes the hog silently ignored when the
> chip is registered later. Applying an overlay containing both a GPIO
> controller node and its hog children - and populating devices only
> after the overlay apply completes - hits this on every boot; the hog
> is only applied if the chip driver is unbound (which clears the flag
> in the remove path) and rebound.
>
> Look up the parent gpio_device before claiming the node so that a hog
> attached ahead of its chip stays unclaimed and is picked up normally
> by gpiochip_hog_lines() at registration time.
>
> Signed-off-by: Abdurrahman Hussain <abdurrahman@xxxxxxxxxx>
> Fixes: a23226b7c1f6 ("gpiolib: handle gpio-hogs only once")
> Cc: stable@xxxxxxxxxxxxxxx
Looks correct, and this is consistent with OF_POPULATED handling in 
of_i2c_notify() and of_spi_notify().

Reviewed-by: Daniel Drake <dan@xxxxxxxxxxxxxxx>