Re: [PATCH v4] net: stmmac: avoid repeated devm_gpiod_get_optional in mdio reset on resume

[Andrew Lunn <andrew@lunn.ch>]

On Fri, May 15, 2026 at 02:56:52PM +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.
> 
> Fixes: 7c86f20d15b7c113 ("net: stmmac: use GPIO descriptors in stmmac_mdio_reset")
> Suggested-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Liu Xiang <liu.xiang@zlingsmart.com>
> ---

Under the --- you should include the history of the patch. This is
version 4. How does it differ to v1, v2, v3.

> +	priv->reset_gpio = devm_gpiod_get_optional(priv->device,
> +						   "snps,reset",
> +						   GPIOD_ASIS);
> +	if (IS_ERR(priv->reset_gpio)) {
> +		priv->reset_gpio = NULL;
> +		dev_warn(dev, "No reset GPIO found\n");
> +	}

Please read the documentation for devm_gpiod_get_optional().

There are three different cases:

1) A GPIO is returned
2) No GPIO is found in DT, which since it is optional, is O.K.
3) A real error happened, which should fail the probe.

Also, see what happens when you pass NULL to any gpiod_ method.

    Andrew

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