Re: [PATCH v2] net: stmmac: avoid repeated devm_gpiod_get_optional in mdio

[Andrew Lunn <andrew@lunn.ch>]

On Sat, Mar 28, 2026 at 11:25:20AM +0800, Liu Xiang wrote:
> During system resume, stmmac_resume() calls stmmac_mdio_reset().
> This results in repeated calls to devm_gpiod_get_optional() for the same
> GPIO. The second invocation returns an error since the GPIO descriptor has
> already been obtained.

How is this different to v1?

> @@ -386,15 +386,15 @@ int stmmac_mdio_reset(struct mii_bus *bus)
>  
>  #ifdef CONFIG_OF
>  	if (priv->device->of_node) {
> -		struct gpio_desc *reset_gpio;
>  		u32 delays[3] = { 0, 0, 0 };
>  
> -		reset_gpio = devm_gpiod_get_optional(priv->device,
> -						     "snps,reset",
> -						     GPIOD_OUT_LOW);
> -		if (IS_ERR(reset_gpio))
> -			return PTR_ERR(reset_gpio);
> -
> +		if (IS_ERR_OR_NULL(priv->reset_gpio)) {
> +			priv->reset_gpio = devm_gpiod_get_optional(priv->device,
> +								   "snps,reset",
> +								 GPIOD_OUT_LOW);
> +			if (IS_ERR(priv->reset_gpio))
> +				return PTR_ERR(priv->reset_gpio);
> +		}

In general, a driver should get the resources it needs in probe, since
probe can only be successful once. So i suggest moving this into
stmmac_mdio_register() which is the equivalent of probe. To keep the
behaviour the same, pass GPIOD_ASIS, and then here in _reset set it
low.

	Andrew