Re: [PATCH] drm/bridge: anx7625: Check GPIO description to avoid crash

On Thu, Nov 18, 2021 at 11:11 AM Xin Ji xji@analogixsemi.com wrote:

@@ -1098,9 +1098,18 @@ static void anx7625_init_gpio(struct anx7625_data *platform) /* Gpio for chip power enable */ platform->pdata.gpio_p_on = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);

•   if (IS_ERR(platform->pdata.gpio_p_on)) {
  

•           DRM_DEV_DEBUG_DRIVER(dev, "no enable gpio found\n");
  

•           platform->pdata.gpio_p_on = NULL;
  

•   }
  

•   /* Gpio for chip reset */
    platform->pdata.gpio_reset =
            devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
  

•   if (IS_ERR(platform->pdata.gpio_reset)) {
  

•           DRM_DEV_DEBUG_DRIVER(dev, "no reset gpio found\n");
  

•           platform->pdata.gpio_p_on = NULL;
  

•   }
  
    if (platform->pdata.gpio_p_on && platform->pdata.gpio_reset) {
            platform->pdata.low_power_mode = 1;
  

devm_gpiod_get_optional() is possible to return NULL (see https://elixir.bootlin.com/linux/v5.15.2/source/drivers/gpio/gpiolib-devres....). Thus, we should use IS_ERR_OR_NULL for checking the return value.

The cases here would work fine except it will skip to print some informative messages.

Acked-by: Tzung-Bi Shih tzungbi@google.com