[PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Arınç ÜNAL]

From: David Bauer <mail@david-bauer.net>

Currently the MDIO bus of the switches the MT7530 DSA subdriver controls
can only be registered as non-OF-based. Bring support for registering the
bus OF-based.

The subdrivers that control switches [with MDIO bus] probed on OF must
follow this logic to support all cases properly:

No switch MDIO bus defined: Populate ds->user_mii_bus, register the MDIO
bus, set the interrupts for PHYs if "interrupt-controller" is defined at
the switch node. This case should only be covered for the switches which
their dt-bindings documentation didn't document the MDIO bus from the
start. This is to keep supporting the device trees that do not describe the
MDIO bus on the device tree but the MDIO bus is being used nonetheless.

Switch MDIO bus defined: Don't populate ds->user_mii_bus, register the MDIO
bus, set the interrupts for PHYs if ["interrupt-controller" is defined at
the switch node and "interrupts" is defined at the PHY nodes under the
switch MDIO bus node].

Switch MDIO bus defined but explicitly disabled: If the device tree says
status = "disabled" for the MDIO bus, we shouldn't need an MDIO bus at all.
Instead, just exit as early as possible and do not call any MDIO API.

The use of ds->user_mii_bus is inappropriate when the MDIO bus of the
switch is described on the device tree [1], which is why we don't populate
ds->user_mii_bus in that case.

Link: https://lore.kernel.org/netdev/20231213120656.x46fyad6ls7sqyzv@skbuf/ [1]
Suggested-by: David Bauer <mail@david-bauer.net>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
---
 drivers/net/dsa/mt7530.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 391c4dbdff42..39d7e7ad7154 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
 static int
 mt7530_setup_mdio(struct mt7530_priv *priv)
 {
+	struct device_node *mnp, *np = priv->dev->of_node;
 	struct dsa_switch *ds = priv->ds;
 	struct device *dev = priv->dev;
 	struct mii_bus *bus;
 	static int idx;
-	int ret;
+	int ret = 0;
+
+	mnp = of_get_child_by_name(np, "mdio");
+
+	if (mnp && !of_device_is_available(mnp))
+		goto out;
 
 	bus = devm_mdiobus_alloc(dev);
 	if (!bus)
 		return -ENOMEM;
 
-	ds->user_mii_bus = bus;
+	if (!mnp)
+		ds->user_mii_bus = bus;
+
 	bus->priv = priv;
 	bus->name = KBUILD_MODNAME "-mii";
 	snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d", idx++);
@@ -2174,16 +2182,18 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
 	bus->parent = dev;
 	bus->phy_mask = ~ds->phys_mii_mask;
 
-	if (priv->irq)
+	if (priv->irq && !mnp)
 		mt7530_setup_mdio_irq(priv);
 
-	ret = devm_mdiobus_register(dev, bus);
+	ret = devm_of_mdiobus_register(dev, bus, mnp);
+	of_node_put(mnp);
 	if (ret) {
 		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
 		if (priv->irq)
 			mt7530_free_mdio_irq(priv);
 	}
 
+out:
 	return ret;
 }
 
-- 
2.40.1

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Arınç ÜNAL]

The author is wrong. I'll fix that with v2. I'm waiting for reviews in the
meantime.

pw-bot: cr

Arınç

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Simon Horman]

On Sat, Jan 06, 2024 at 03:21:42PM +0300, Arınç ÜNAL wrote:
> From: David Bauer <mail@david-bauer.net>
> 
> Currently the MDIO bus of the switches the MT7530 DSA subdriver controls
> can only be registered as non-OF-based. Bring support for registering the
> bus OF-based.
> 
> The subdrivers that control switches [with MDIO bus] probed on OF must
> follow this logic to support all cases properly:
> 
> No switch MDIO bus defined: Populate ds->user_mii_bus, register the MDIO
> bus, set the interrupts for PHYs if "interrupt-controller" is defined at
> the switch node. This case should only be covered for the switches which
> their dt-bindings documentation didn't document the MDIO bus from the
> start. This is to keep supporting the device trees that do not describe the
> MDIO bus on the device tree but the MDIO bus is being used nonetheless.
> 
> Switch MDIO bus defined: Don't populate ds->user_mii_bus, register the MDIO
> bus, set the interrupts for PHYs if ["interrupt-controller" is defined at
> the switch node and "interrupts" is defined at the PHY nodes under the
> switch MDIO bus node].
> 
> Switch MDIO bus defined but explicitly disabled: If the device tree says
> status = "disabled" for the MDIO bus, we shouldn't need an MDIO bus at all.
> Instead, just exit as early as possible and do not call any MDIO API.
> 
> The use of ds->user_mii_bus is inappropriate when the MDIO bus of the
> switch is described on the device tree [1], which is why we don't populate
> ds->user_mii_bus in that case.
> 
> Link: https://lore.kernel.org/netdev/20231213120656.x46fyad6ls7sqyzv@skbuf/ [1]
> Suggested-by: David Bauer <mail@david-bauer.net>
> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
> ---
>  drivers/net/dsa/mt7530.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 391c4dbdff42..39d7e7ad7154 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
>  static int
>  mt7530_setup_mdio(struct mt7530_priv *priv)
>  {
> +	struct device_node *mnp, *np = priv->dev->of_node;
>  	struct dsa_switch *ds = priv->ds;
>  	struct device *dev = priv->dev;
>  	struct mii_bus *bus;
>  	static int idx;
> -	int ret;
> +	int ret = 0;
> +
> +	mnp = of_get_child_by_name(np, "mdio");
> +
> +	if (mnp && !of_device_is_available(mnp))
> +		goto out;

nit: I think it would easier on the eyes to simply

		return 0;

>  
>  	bus = devm_mdiobus_alloc(dev);
>  	if (!bus)
>  		return -ENOMEM;
>  
> -	ds->user_mii_bus = bus;
> +	if (!mnp)
> +		ds->user_mii_bus = bus;
> +
>  	bus->priv = priv;
>  	bus->name = KBUILD_MODNAME "-mii";
>  	snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d", idx++);
> @@ -2174,16 +2182,18 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
>  	bus->parent = dev;
>  	bus->phy_mask = ~ds->phys_mii_mask;
>  
> -	if (priv->irq)
> +	if (priv->irq && !mnp)
>  		mt7530_setup_mdio_irq(priv);
>  
> -	ret = devm_mdiobus_register(dev, bus);
> +	ret = devm_of_mdiobus_register(dev, bus, mnp);
> +	of_node_put(mnp);
>  	if (ret) {
>  		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
>  		if (priv->irq)
>  			mt7530_free_mdio_irq(priv);
>  	}
>  
> +out:
>  	return ret;
>  }
>  
> -- 
> 2.40.1
> 

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Arınç ÜNAL]

On 7.01.2024 22:52, Simon Horman wrote:
> On Sat, Jan 06, 2024 at 03:21:42PM +0300, Arınç ÜNAL wrote:
>> From: David Bauer <mail@david-bauer.net>
>>
>> Currently the MDIO bus of the switches the MT7530 DSA subdriver controls
>> can only be registered as non-OF-based. Bring support for registering the
>> bus OF-based.
>>
>> The subdrivers that control switches [with MDIO bus] probed on OF must
>> follow this logic to support all cases properly:
>>
>> No switch MDIO bus defined: Populate ds->user_mii_bus, register the MDIO
>> bus, set the interrupts for PHYs if "interrupt-controller" is defined at
>> the switch node. This case should only be covered for the switches which
>> their dt-bindings documentation didn't document the MDIO bus from the
>> start. This is to keep supporting the device trees that do not describe the
>> MDIO bus on the device tree but the MDIO bus is being used nonetheless.
>>
>> Switch MDIO bus defined: Don't populate ds->user_mii_bus, register the MDIO
>> bus, set the interrupts for PHYs if ["interrupt-controller" is defined at
>> the switch node and "interrupts" is defined at the PHY nodes under the
>> switch MDIO bus node].
>>
>> Switch MDIO bus defined but explicitly disabled: If the device tree says
>> status = "disabled" for the MDIO bus, we shouldn't need an MDIO bus at all.
>> Instead, just exit as early as possible and do not call any MDIO API.
>>
>> The use of ds->user_mii_bus is inappropriate when the MDIO bus of the
>> switch is described on the device tree [1], which is why we don't populate
>> ds->user_mii_bus in that case.
>>
>> Link: https://lore.kernel.org/netdev/20231213120656.x46fyad6ls7sqyzv@skbuf/ [1]
>> Suggested-by: David Bauer <mail@david-bauer.net>
>> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
>> ---
>>   drivers/net/dsa/mt7530.c | 18 ++++++++++++++----
>>   1 file changed, 14 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
>> index 391c4dbdff42..39d7e7ad7154 100644
>> --- a/drivers/net/dsa/mt7530.c
>> +++ b/drivers/net/dsa/mt7530.c
>> @@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
>>   static int
>>   mt7530_setup_mdio(struct mt7530_priv *priv)
>>   {
>> +	struct device_node *mnp, *np = priv->dev->of_node;
>>   	struct dsa_switch *ds = priv->ds;
>>   	struct device *dev = priv->dev;
>>   	struct mii_bus *bus;
>>   	static int idx;
>> -	int ret;
>> +	int ret = 0;
>> +
>> +	mnp = of_get_child_by_name(np, "mdio");
>> +
>> +	if (mnp && !of_device_is_available(mnp))
>> +		goto out;
> 
> nit: I think it would easier on the eyes to simply
> 
> 		return 0;

Will do.

Thanks.
Arınç

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Vladimir Oltean]

On Mon, Jan 08, 2024 at 01:22:18PM +0300, Arınç ÜNAL wrote:
> > > diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> > > index 391c4dbdff42..39d7e7ad7154 100644
> > > --- a/drivers/net/dsa/mt7530.c
> > > +++ b/drivers/net/dsa/mt7530.c
> > > @@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
> > >   static int
> > >   mt7530_setup_mdio(struct mt7530_priv *priv)
> > >   {
> > > +	struct device_node *mnp, *np = priv->dev->of_node;
> > >   	struct dsa_switch *ds = priv->ds;
> > >   	struct device *dev = priv->dev;
> > >   	struct mii_bus *bus;
> > >   	static int idx;
> > > -	int ret;
> > > +	int ret = 0;
> > > +
> > > +	mnp = of_get_child_by_name(np, "mdio");
> > > +
> > > +	if (mnp && !of_device_is_available(mnp))
> > > +		goto out;
> > 
> > nit: I think it would easier on the eyes to simply
> > 
> > 		return 0;

Actually "return 0" leaks "mnp". An of_node_put() is needed.

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Simon Horman]

On Mon, Jan 08, 2024 at 01:00:00PM +0200, Vladimir Oltean wrote:
> On Mon, Jan 08, 2024 at 01:22:18PM +0300, Arınç ÜNAL wrote:
> > > > diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> > > > index 391c4dbdff42..39d7e7ad7154 100644
> > > > --- a/drivers/net/dsa/mt7530.c
> > > > +++ b/drivers/net/dsa/mt7530.c
> > > > @@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
> > > >   static int
> > > >   mt7530_setup_mdio(struct mt7530_priv *priv)
> > > >   {
> > > > +	struct device_node *mnp, *np = priv->dev->of_node;
> > > >   	struct dsa_switch *ds = priv->ds;
> > > >   	struct device *dev = priv->dev;
> > > >   	struct mii_bus *bus;
> > > >   	static int idx;
> > > > -	int ret;
> > > > +	int ret = 0;
> > > > +
> > > > +	mnp = of_get_child_by_name(np, "mdio");
> > > > +
> > > > +	if (mnp && !of_device_is_available(mnp))
> > > > +		goto out;
> > > 
> > > nit: I think it would easier on the eyes to simply
> > > 
> > > 		return 0;
> 
> Actually "return 0" leaks "mnp". An of_node_put() is needed.

Yes, sorry for not noticing that.

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Arınç ÜNAL]

On 8.01.2024 14:00, Vladimir Oltean wrote:
> On Mon, Jan 08, 2024 at 01:22:18PM +0300, Arınç ÜNAL wrote:
>>>> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
>>>> index 391c4dbdff42..39d7e7ad7154 100644
>>>> --- a/drivers/net/dsa/mt7530.c
>>>> +++ b/drivers/net/dsa/mt7530.c
>>>> @@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
>>>>    static int
>>>>    mt7530_setup_mdio(struct mt7530_priv *priv)
>>>>    {
>>>> +	struct device_node *mnp, *np = priv->dev->of_node;
>>>>    	struct dsa_switch *ds = priv->ds;
>>>>    	struct device *dev = priv->dev;
>>>>    	struct mii_bus *bus;
>>>>    	static int idx;
>>>> -	int ret;
>>>> +	int ret = 0;
>>>> +
>>>> +	mnp = of_get_child_by_name(np, "mdio");
>>>> +
>>>> +	if (mnp && !of_device_is_available(mnp))
>>>> +		goto out;
>>>
>>> nit: I think it would easier on the eyes to simply
>>>
>>> 		return 0;
> 
> Actually "return 0" leaks "mnp". An of_node_put() is needed.

I realised that I also miss these:

- run of_node_put(mnp) if bus = devm_mdiobus_alloc(dev) fails
- don't run mt7530_free_mdio_irq if MDIO bus is described on OF

Please let me know if this addresses everything:

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 391c4dbdff42..cf2ff7680c15 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2146,24 +2146,40 @@ mt7530_free_irq_common(struct mt7530_priv *priv)
  static void
  mt7530_free_irq(struct mt7530_priv *priv)
  {
-	mt7530_free_mdio_irq(priv);
+	struct device_node *mnp, *np = priv->dev->of_node;
+
+	mnp = of_get_child_by_name(np, "mdio");
+	if (!mnp)
+		mt7530_free_mdio_irq(priv);
+	of_node_put(mnp);
+
  	mt7530_free_irq_common(priv);
  }
  
  static int
  mt7530_setup_mdio(struct mt7530_priv *priv)
  {
+	struct device_node *mnp, *np = priv->dev->of_node;
  	struct dsa_switch *ds = priv->ds;
  	struct device *dev = priv->dev;
  	struct mii_bus *bus;
  	static int idx;
-	int ret;
+	int ret = 0;
+
+	mnp = of_get_child_by_name(np, "mdio");
+
+	if (mnp && !of_device_is_available(mnp))
+		goto out;
  
  	bus = devm_mdiobus_alloc(dev);
-	if (!bus)
-		return -ENOMEM;
+	if (!bus) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (!mnp)
+		ds->user_mii_bus = bus;
  
-	ds->user_mii_bus = bus;
  	bus->priv = priv;
  	bus->name = KBUILD_MODNAME "-mii";
  	snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d", idx++);
@@ -2174,16 +2190,18 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
  	bus->parent = dev;
  	bus->phy_mask = ~ds->phys_mii_mask;
  
-	if (priv->irq)
+	if (priv->irq && !mnp)
  		mt7530_setup_mdio_irq(priv);
  
-	ret = devm_mdiobus_register(dev, bus);
+	ret = devm_of_mdiobus_register(dev, bus, mnp);
  	if (ret) {
  		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
-		if (priv->irq)
+		if (priv->irq && !mnp)
  			mt7530_free_mdio_irq(priv);
  	}
  
+out:
+	of_node_put(mnp);
  	return ret;
  }
  

Arınç

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Vladimir Oltean]

On Mon, Jan 08, 2024 at 03:14:45PM +0300, Arınç ÜNAL wrote:
> I realised that I also miss these:
> 
> - run of_node_put(mnp) if bus = devm_mdiobus_alloc(dev) fails
> - don't run mt7530_free_mdio_irq if MDIO bus is described on OF
> 
> Please let me know if this addresses everything:
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 391c4dbdff42..cf2ff7680c15 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -2146,24 +2146,40 @@ mt7530_free_irq_common(struct mt7530_priv *priv)
>  static void
>  mt7530_free_irq(struct mt7530_priv *priv)
>  {
> -	mt7530_free_mdio_irq(priv);
> +	struct device_node *mnp, *np = priv->dev->of_node;
> +
> +	mnp = of_get_child_by_name(np, "mdio");
> +	if (!mnp)
> +		mt7530_free_mdio_irq(priv);
> +	of_node_put(mnp);
> +
>  	mt7530_free_irq_common(priv);
>  }
>  static int
>  mt7530_setup_mdio(struct mt7530_priv *priv)
>  {
> +	struct device_node *mnp, *np = priv->dev->of_node;
>  	struct dsa_switch *ds = priv->ds;
>  	struct device *dev = priv->dev;
>  	struct mii_bus *bus;
>  	static int idx;
> -	int ret;
> +	int ret = 0;
> +
> +	mnp = of_get_child_by_name(np, "mdio");
> +
> +	if (mnp && !of_device_is_available(mnp))
> +		goto out;
>  	bus = devm_mdiobus_alloc(dev);
> -	if (!bus)
> -		return -ENOMEM;
> +	if (!bus) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	if (!mnp)
> +		ds->user_mii_bus = bus;
> -	ds->user_mii_bus = bus;
>  	bus->priv = priv;
>  	bus->name = KBUILD_MODNAME "-mii";
>  	snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d", idx++);
> @@ -2174,16 +2190,18 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
>  	bus->parent = dev;
>  	bus->phy_mask = ~ds->phys_mii_mask;
> -	if (priv->irq)
> +	if (priv->irq && !mnp)
>  		mt7530_setup_mdio_irq(priv);
> -	ret = devm_mdiobus_register(dev, bus);
> +	ret = devm_of_mdiobus_register(dev, bus, mnp);
>  	if (ret) {
>  		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
> -		if (priv->irq)
> +		if (priv->irq && !mnp)
>  			mt7530_free_mdio_irq(priv);
>  	}
> +out:
> +	of_node_put(mnp);
>  	return ret;
>  }

Looks ok.

Please note that net-next has now closed. Sorry that I couldn't bring
myself to review more during the weekend and the holidays.
https://lore.kernel.org/netdev/20240107172221.733a7a44@kernel.org/

[PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Arınç ÜNAL]

Currently the MDIO bus of the switches the MT7530 DSA subdriver controls
can only be registered as non-OF-based. Bring support for registering the
bus OF-based.

The subdrivers that control switches [with MDIO bus] probed on OF must
follow this logic to support all cases properly:

No switch MDIO bus defined: Populate ds->user_mii_bus, register the MDIO
bus, set the interrupts for PHYs if "interrupt-controller" is defined at
the switch node. This case should only be covered for the switches which
their dt-bindings documentation didn't document the MDIO bus from the
start. This is to keep supporting the device trees that do not describe the
MDIO bus on the device tree but the MDIO bus is being used nonetheless.

Switch MDIO bus defined: Don't populate ds->user_mii_bus, register the MDIO
bus, set the interrupts for PHYs if ["interrupt-controller" is defined at
the switch node and "interrupts" is defined at the PHY nodes under the
switch MDIO bus node].

Switch MDIO bus defined but explicitly disabled: If the device tree says
status = "disabled" for the MDIO bus, we shouldn't need an MDIO bus at all.
Instead, just exit as early as possible and do not call any MDIO API.

The use of ds->user_mii_bus is inappropriate when the MDIO bus of the
switch is described on the device tree [1], which is why we don't populate
ds->user_mii_bus in that case.

Link: https://lore.kernel.org/netdev/20231213120656.x46fyad6ls7sqyzv@skbuf/ [1]
Suggested-by: David Bauer <mail@david-bauer.net>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
---
 drivers/net/dsa/mt7530.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 391c4dbdff42..cf2ff7680c15 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2146,24 +2146,40 @@ mt7530_free_irq_common(struct mt7530_priv *priv)
 static void
 mt7530_free_irq(struct mt7530_priv *priv)
 {
-	mt7530_free_mdio_irq(priv);
+	struct device_node *mnp, *np = priv->dev->of_node;
+
+	mnp = of_get_child_by_name(np, "mdio");
+	if (!mnp)
+		mt7530_free_mdio_irq(priv);
+	of_node_put(mnp);
+
 	mt7530_free_irq_common(priv);
 }
 
 static int
 mt7530_setup_mdio(struct mt7530_priv *priv)
 {
+	struct device_node *mnp, *np = priv->dev->of_node;
 	struct dsa_switch *ds = priv->ds;
 	struct device *dev = priv->dev;
 	struct mii_bus *bus;
 	static int idx;
-	int ret;
+	int ret = 0;
+
+	mnp = of_get_child_by_name(np, "mdio");
+
+	if (mnp && !of_device_is_available(mnp))
+		goto out;
 
 	bus = devm_mdiobus_alloc(dev);
-	if (!bus)
-		return -ENOMEM;
+	if (!bus) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (!mnp)
+		ds->user_mii_bus = bus;
 
-	ds->user_mii_bus = bus;
 	bus->priv = priv;
 	bus->name = KBUILD_MODNAME "-mii";
 	snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d", idx++);
@@ -2174,16 +2190,18 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
 	bus->parent = dev;
 	bus->phy_mask = ~ds->phys_mii_mask;
 
-	if (priv->irq)
+	if (priv->irq && !mnp)
 		mt7530_setup_mdio_irq(priv);
 
-	ret = devm_mdiobus_register(dev, bus);
+	ret = devm_of_mdiobus_register(dev, bus, mnp);
 	if (ret) {
 		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
-		if (priv->irq)
+		if (priv->irq && !mnp)
 			mt7530_free_mdio_irq(priv);
 	}
 
+out:
+	of_node_put(mnp);
 	return ret;
 }
 
-- 
2.40.1

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Vladimir Oltean]

On Mon, Jan 22, 2024 at 08:34:31AM +0300, Arınç ÜNAL wrote:
> Currently the MDIO bus of the switches the MT7530 DSA subdriver controls
> can only be registered as non-OF-based. Bring support for registering the
> bus OF-based.
> 
> The subdrivers that control switches [with MDIO bus] probed on OF must
> follow this logic to support all cases properly:
> 
> No switch MDIO bus defined: Populate ds->user_mii_bus, register the MDIO
> bus, set the interrupts for PHYs if "interrupt-controller" is defined at
> the switch node. This case should only be covered for the switches which
> their dt-bindings documentation didn't document the MDIO bus from the
> start. This is to keep supporting the device trees that do not describe the
> MDIO bus on the device tree but the MDIO bus is being used nonetheless.
> 
> Switch MDIO bus defined: Don't populate ds->user_mii_bus, register the MDIO
> bus, set the interrupts for PHYs if ["interrupt-controller" is defined at
> the switch node and "interrupts" is defined at the PHY nodes under the
> switch MDIO bus node].
> 
> Switch MDIO bus defined but explicitly disabled: If the device tree says
> status = "disabled" for the MDIO bus, we shouldn't need an MDIO bus at all.
> Instead, just exit as early as possible and do not call any MDIO API.
> 
> The use of ds->user_mii_bus is inappropriate when the MDIO bus of the
> switch is described on the device tree [1], which is why we don't populate
> ds->user_mii_bus in that case.
> 
> Link: https://lore.kernel.org/netdev/20231213120656.x46fyad6ls7sqyzv@skbuf/ [1]
> Suggested-by: David Bauer <mail@david-bauer.net>
> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Mon, 22 Jan 2024 08:34:31 +0300 you wrote:
> Currently the MDIO bus of the switches the MT7530 DSA subdriver controls
> can only be registered as non-OF-based. Bring support for registering the
> bus OF-based.
> 
> The subdrivers that control switches [with MDIO bus] probed on OF must
> follow this logic to support all cases properly:
> 
> [...]

Here is the summary with links:
  - [net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus
    https://git.kernel.org/netdev/net-next/c/91374ba537bd

You are awesome, thank you!
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