[PATCH RESEND v3] net: airoha_eth: fix mt7531 mdio related initialization bug

[Jerome Forissier]

On 16/06/2026 16:54, Tom Rini wrote:
> On Tue, Jun 16, 2026 at 08:38:45AM +0300, 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 mt7531 mdio device binding to the probing
>> function of 'airoha-eth' driver.
>>
>> All GDM ports (except of GDM1) are connected directly to their PHYs, so
>> corresponding mdio bus will be automatically probed during PHY setup.
>>
>> GDM1 ports differ from other GDM ports. It connected to the airoha switch
>> device. The mt7531 mdio bus is used to manage link state of airoha switch
>> device ports (LAN ports 1-4 corresponds to PHYs 0x09-0x0C). Therefore,
>> manual probing of mt7531 mdio bus is required to be able set/query states
>> of corresponding LAN ports.
>>
>> Fixes: 96d9e7c46425 ("net: airoha: use mt7531 mdio for GDM1")
>> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> 
> This is fixing something introduced for the upcoming release, Jerome do
> you want to take it (or have feedback on it?) or should I? Thanks!

LGTM. I have it in my patchwork queue already so I'll take it. It will be
in my next PR to you for master.

Thanks!
-- 
Jerome

> 
>> ---
>> Changes v2:
>>  * small refactoring
>>
>> Changes v3:
>>  * Move mt7531 mdio bus initialization function before it's first usage.
>>  * Probe mt7531 mdio bus for GDM1 port, but not for other GDM port.
>>  * Add an explanation why mt7531 mdio bus must be probed for GDM1 only
>> ---
>>  drivers/net/airoha_eth.c | 78 ++++++++++++++++++++++++----------------
>>  1 file changed, 48 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/net/airoha_eth.c b/drivers/net/airoha_eth.c
>> index 84ee9b2ad76..e5d39b95cc5 100644
>> --- a/drivers/net/airoha_eth.c
>> +++ b/drivers/net/airoha_eth.c
>> @@ -845,11 +845,45 @@ static int airoha_alloc_gdm_port(struct udevice *dev, ofnode node)
>>  					    (ulong)eth, node, &gdm_dev);
>>  }
>>  
>> +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 NULL;
>> +
>> +	switch_node = ofnode_by_compatible(ofnode_null(),
>> +					   data->switch_compatible);
>> +	if (!ofnode_valid(switch_node)) {
>> +		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 airoha switch mdio subnode\n");
>> +		return ERR_PTR(-EINVAL);
>> +	}
>> +
>> +	ret = device_bind_driver_to_node(dev, "mt7531-mdio-mmio", "mt7531-mdio",
>> +					 mdio_node, &mdio_dev);
>> +	if (ret) {
>> +		debug("Warning: failed to bind airoha switch mdio\n");
>> +		return ERR_PTR(ret);
>> +	}
>> +
>> +	return mdio_dev;
>> +}
>> +
>>  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 +942,10 @@ 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");
>> -	}
>> +	/* Airoha switch mdio PHYs maybe used by several GDM devices */
>> +	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"))
>> @@ -957,6 +991,16 @@ static int airoha_eth_port_probe(struct udevice *dev)
>>  #else
>>  		return -EINVAL;
>>  #endif
>> +	} else {
>> +		/*
>> +		 * GDM1 device connected to airoha switch. Probe airoha switch
>> +		 * mdio to be able set/query states of corresponding LAN ports.
>> +		 */
>> +		ret = device_probe(eth->switch_mdio_dev);
>> +		if (ret) {
>> +			debug("Warning: failed to probe airoha switch mdio\n");
>> +			eth->switch_mdio_dev = NULL;
>> +		}
>>  	}
>>  
>>  	return 0;
>> @@ -1202,38 +1246,12 @@ 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);
>>  
>> -	if (!CONFIG_IS_ENABLED(MDIO_MT7531_MMIO))
>> -		return 0;
>> -
>> -	switch_node = ofnode_by_compatible(ofnode_null(),
>> -					   data->switch_compatible);
>> -	if (!ofnode_valid(switch_node)) {
>> -		debug("Warning: missing switch node\n");
>> -		return 0;
>> -	}
>> -
>> -	mdio_node = ofnode_find_subnode(switch_node, "mdio");
>> -	if (!ofnode_valid(mdio_node)) {
>> -		debug("Warning: missing mdio node\n");
>> -		return 0;
>> -	}
>> -
>> -	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");
>> -
>>  	return 0;
>>  }
>>  
>> -- 
>> 2.53.0
>>
>