[PATCH v2] net: airoha_eth: fix mt7531 mdio related initialization bug

[Jerome Forissier]

Hi Mikhail,

On 01/06/2026 23:35, Mikhail Kshevetskiy wrote:
> Private data isn't ready during bind time. The call of dev_get_priv()
> function will return NULL. Thus we can't save mdio device pointer and
> use it later during probe.
> 
> To solve an issue, we will move the mdio initialization to the probe
> function.
> 
> Fixes: 96d9e7c46425 ("net: airoha: use mt7531 mdio for GDM1")
> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> ---
> 
> Changes v2:
>  * small refactoring
> 
> ---
>  drivers/net/airoha_eth.c | 51 ++++++++++++++++++++++++++--------------
>  1 file changed, 33 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/net/airoha_eth.c b/drivers/net/airoha_eth.c
> index 84ee9b2ad76..0a1bcb87104 100644
> --- a/drivers/net/airoha_eth.c
> +++ b/drivers/net/airoha_eth.c
> @@ -365,6 +365,8 @@ static const char * const en7581_xsi_rsts_names[] = {
>  	"xfp-mac",
>  };
>  
> +static struct udevice *airoha_switch_mdio_init(struct udevice *dev);

I think this forward declaration is best avoided by moving the function up
in the file.

Thanks,
-- 
Jerome

> +
>  static u32 airoha_rr(void __iomem *base, u32 offset)
>  {
>  	return readl(base + offset);
> @@ -850,6 +852,7 @@ static int airoha_eth_probe(struct udevice *dev)
>  	struct airoha_eth_soc_data *data = (void *)dev_get_driver_data(dev);
>  	struct airoha_eth *eth = dev_get_priv(dev);
>  	struct regmap *scu_regmap;
> +	struct udevice *mdio_dev;
>  	ofnode node;
>  	int i, ret;
>  
> @@ -908,10 +911,9 @@ static int airoha_eth_probe(struct udevice *dev)
>  	if (ret)
>  		return ret;
>  
> -	if (eth->switch_mdio_dev) {
> -		if (!device_probe(eth->switch_mdio_dev))
> -			debug("Warning: failed to probe airoha switch mdio\n");
> -	}
> +	mdio_dev = airoha_switch_mdio_init(dev);
> +	if (!IS_ERR_OR_NULL(mdio_dev))
> +		eth->switch_mdio_dev = mdio_dev;
>  
>  	ofnode_for_each_subnode(node, dev_ofnode(dev)) {
>  		if (!ofnode_device_is_compatible(node, "airoha,eth-mac"))
> @@ -1202,39 +1204,52 @@ static int arht_eth_write_hwaddr(struct udevice *dev)
>  
>  static int airoha_eth_bind(struct udevice *dev)
>  {
> -	struct airoha_eth_soc_data *data = (void *)dev_get_driver_data(dev);
> -	struct airoha_eth *eth = dev_get_priv(dev);
> -	ofnode switch_node, mdio_node;
> -	int ret;
> -
>  	/*
>  	 * Force Probe as we set the Main ETH driver as misc
>  	 * to register multiple eth port for each GDM
>  	 */
>  	dev_or_flags(dev, DM_FLAG_PROBE_AFTER_BIND);
>  
> +	return 0;
> +}
> +
> +static struct udevice *airoha_switch_mdio_init(struct udevice *dev)
> +{
> +	struct airoha_eth_soc_data *data = (void *)dev_get_driver_data(dev);
> +	ofnode switch_node, mdio_node;
> +	struct udevice *mdio_dev;
> +	int ret;
> +
>  	if (!CONFIG_IS_ENABLED(MDIO_MT7531_MMIO))
> -		return 0;
> +		return NULL;
>  
>  	switch_node = ofnode_by_compatible(ofnode_null(),
>  					   data->switch_compatible);
>  	if (!ofnode_valid(switch_node)) {
> -		debug("Warning: missing switch node\n");
> -		return 0;
> +		debug("Warning: missing airoha switch node\n");
> +		return ERR_PTR(-EINVAL);
>  	}
>  
>  	mdio_node = ofnode_find_subnode(switch_node, "mdio");
>  	if (!ofnode_valid(mdio_node)) {
> -		debug("Warning: missing mdio node\n");
> -		return 0;
> +		debug("Warning: missing airoha switch mdio subnode\n");
> +		return ERR_PTR(-EINVAL);
>  	}
>  
>  	ret = device_bind_driver_to_node(dev, "mt7531-mdio-mmio", "mt7531-mdio",
> -					 mdio_node, &eth->switch_mdio_dev);
> -	if (ret)
> -		debug("Warning: failed to bind mdio controller\n");
> +					 mdio_node, &mdio_dev);
> +	if (ret) {
> +		debug("Warning: failed to bind airoha switch mdio\n");
> +		return ERR_PTR(ret);
> +	}
>  
> -	return 0;
> +	ret = device_probe(mdio_dev);
> +	if (ret) {
> +		debug("Warning: failed to probe airoha switch mdio\n");
> +		return ERR_PTR(ret);
> +	}
> +
> +	return mdio_dev;
>  }
>  
>  static const struct airoha_eth_soc_data en7523_data = {