[PATCH] spi: bcm2835: Do not call gpiod_put() on invalid descriptor

[Bartosz Golaszewski]

On Wed, Apr 2, 2025 at 12:43 AM Florian Fainelli
<florian.fainelli at broadcom.com> wrote:
>
> If we are unable to lookup the chip-select GPIO, the error path will
> call bcm2835_spi_cleanup() which unconditionally calls gpiod_put() on
> the cs->gpio variable which we just determined was invalid.
>
> Fixes: 21f252cd29f0 ("spi: bcm2835: reduce the abuse of the GPIO API")
> Signed-off-by: Florian Fainelli <florian.fainelli at broadcom.com>
> ---
>  drivers/spi/spi-bcm2835.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
> index e1b9b1235787..a5d621b94d5e 100644
> --- a/drivers/spi/spi-bcm2835.c
> +++ b/drivers/spi/spi-bcm2835.c
> @@ -1162,7 +1162,8 @@ static void bcm2835_spi_cleanup(struct spi_device *spi)
>                                  sizeof(u32),
>                                  DMA_TO_DEVICE);
>
> -       gpiod_put(bs->cs_gpio);
> +       if (!IS_ERR(bs->cs_gpio))
> +               gpiod_put(bs->cs_gpio);
>         spi_set_csgpiod(spi, 0, NULL);
>
>         kfree(target);
> --
> 2.34.1
>
>

We could also just set it to NULL on error in bcm2835_spi_setup() but
I'm fine either way.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski at linaro.org>