[PATCH net-next v2] net: dsa: mt7530: detect PHY muxing when PHY is defined on switch MDIO bus

[PATCH net-next v2] net: dsa: mt7530: detect PHY muxing when PHY is defined on switch MDIO bus

[Arınç ÜNAL via B4 Relay]

From: Arınç ÜNAL <arinc.unal@arinc9.com>

Currently, the MT7530 DSA subdriver configures the MT7530 switch to provide
direct access to switch PHYs, meaning, the switch PHYs listen on the MDIO
bus the switch listens on. The PHY muxing feature makes use of this.

This is problematic as the PHY may be attached before the switch is
initialised, in which case, the PHY will fail to be attached.

Since commit 91374ba537bd ("net: dsa: mt7530: support OF-based registration
of switch MDIO bus"), we can describe the switch PHYs on the MDIO bus of
the switch on the device tree. Extend the check to detect PHY muxing when
the PHY is defined on the MDIO bus of the switch on the device tree.

When the PHY is described this way, the switch will be initialised first,
then the switch MDIO bus will be registered. Only after these steps, the
PHY will be attached.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
---
Changes in v2:
- Address the terminology on the patch log.
- Link to v1: https://lore.kernel.org/r/20240429-b4-for-netnext-mt7530-use-switch-mdio-bus-for-phy-muxing-v1-1-1f775983e155@arinc9.com
---
 drivers/net/dsa/mt7530.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 2b9f904a98f0..6cf21c9d523b 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2483,7 +2483,8 @@ mt7530_setup(struct dsa_switch *ds)
 			if (!phy_node)
 				continue;
 
-			if (phy_node->parent == priv->dev->of_node->parent) {
+			if (phy_node->parent == priv->dev->of_node->parent ||
+			    phy_node->parent->parent == priv->dev->of_node) {
 				ret = of_get_phy_mode(mac_np, &interface);
 				if (ret && ret != -ENODEV) {
 					of_node_put(mac_np);

---
base-commit: 5c4c0edca68a5841a8d53ccd49596fe199c8334c
change-id: 20240429-b4-for-netnext-mt7530-use-switch-mdio-bus-for-phy-muxing-586269371c55

Best regards,
-- 
Arınç ÜNAL <arinc.unal@arinc9.com>



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Re: [PATCH net-next v2] net: dsa: mt7530: detect PHY muxing when PHY is defined on switch MDIO bus

[Daniel Golle]

On Tue, Apr 30, 2024 at 08:01:33AM +0300, Arınç ÜNAL via B4 Relay wrote:
> From: Arınç ÜNAL <arinc.unal@arinc9.com>
> 
> Currently, the MT7530 DSA subdriver configures the MT7530 switch to provide
> direct access to switch PHYs, meaning, the switch PHYs listen on the MDIO
> bus the switch listens on. The PHY muxing feature makes use of this.
> 
> This is problematic as the PHY may be attached before the switch is
> initialised, in which case, the PHY will fail to be attached.
> 
> Since commit 91374ba537bd ("net: dsa: mt7530: support OF-based registration
> of switch MDIO bus"), we can describe the switch PHYs on the MDIO bus of
> the switch on the device tree. Extend the check to detect PHY muxing when
> the PHY is defined on the MDIO bus of the switch on the device tree.
> 
> When the PHY is described this way, the switch will be initialised first,
> then the switch MDIO bus will be registered. Only after these steps, the
> PHY will be attached.
> 
> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>

Reviewed-by: Daniel Golle <daniel@makrotopia.org>

> ---
> Changes in v2:
> - Address the terminology on the patch log.
> - Link to v1: https://lore.kernel.org/r/20240429-b4-for-netnext-mt7530-use-switch-mdio-bus-for-phy-muxing-v1-1-1f775983e155@arinc9.com
> ---
>  drivers/net/dsa/mt7530.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 2b9f904a98f0..6cf21c9d523b 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -2483,7 +2483,8 @@ mt7530_setup(struct dsa_switch *ds)
>  			if (!phy_node)
>  				continue;
>  
> -			if (phy_node->parent == priv->dev->of_node->parent) {
> +			if (phy_node->parent == priv->dev->of_node->parent ||
> +			    phy_node->parent->parent == priv->dev->of_node) {

I had some concerns about missing check for phy_node->parent != NULL,
but it's impossible in practise. If phy_node exists, it will have a parent
node as well.

To be super extra safe, maybe doing
phy_node->parent && phy_node->parent->parent == priv->dev->of_node
would be better.

>  				ret = of_get_phy_mode(mac_np, &interface);
>  				if (ret && ret != -ENODEV) {
>  					of_node_put(mac_np);
> 
> ---
> base-commit: 5c4c0edca68a5841a8d53ccd49596fe199c8334c
> change-id: 20240429-b4-for-netnext-mt7530-use-switch-mdio-bus-for-phy-muxing-586269371c55
> 
> Best regards,
> -- 
> Arınç ÜNAL <arinc.unal@arinc9.com>
> 
> 
> 

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Re: [PATCH net-next v2] net: dsa: mt7530: detect PHY muxing when PHY is defined on switch MDIO bus

[Arınç ÜNAL]

On 06/05/2024 14:24, Daniel Golle wrote:
> On Tue, Apr 30, 2024 at 08:01:33AM +0300, Arınç ÜNAL via B4 Relay wrote:
>> From: Arınç ÜNAL <arinc.unal@arinc9.com>
>>
>> Currently, the MT7530 DSA subdriver configures the MT7530 switch to provide
>> direct access to switch PHYs, meaning, the switch PHYs listen on the MDIO
>> bus the switch listens on. The PHY muxing feature makes use of this.
>>
>> This is problematic as the PHY may be attached before the switch is
>> initialised, in which case, the PHY will fail to be attached.
>>
>> Since commit 91374ba537bd ("net: dsa: mt7530: support OF-based registration
>> of switch MDIO bus"), we can describe the switch PHYs on the MDIO bus of
>> the switch on the device tree. Extend the check to detect PHY muxing when
>> the PHY is defined on the MDIO bus of the switch on the device tree.
>>
>> When the PHY is described this way, the switch will be initialised first,
>> then the switch MDIO bus will be registered. Only after these steps, the
>> PHY will be attached.
>>
>> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
> 
> Reviewed-by: Daniel Golle <daniel@makrotopia.org>
> 
>> ---
>> Changes in v2:
>> - Address the terminology on the patch log.
>> - Link to v1: https://lore.kernel.org/r/20240429-b4-for-netnext-mt7530-use-switch-mdio-bus-for-phy-muxing-v1-1-1f775983e155@arinc9.com
>> ---
>>   drivers/net/dsa/mt7530.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
>> index 2b9f904a98f0..6cf21c9d523b 100644
>> --- a/drivers/net/dsa/mt7530.c
>> +++ b/drivers/net/dsa/mt7530.c
>> @@ -2483,7 +2483,8 @@ mt7530_setup(struct dsa_switch *ds)
>>   			if (!phy_node)
>>   				continue;
>>   
>> -			if (phy_node->parent == priv->dev->of_node->parent) {
>> +			if (phy_node->parent == priv->dev->of_node->parent ||
>> +			    phy_node->parent->parent == priv->dev->of_node) {
> 
> I had some concerns about missing check for phy_node->parent != NULL,
> but it's impossible in practise. If phy_node exists, it will have a parent
> node as well.
> 
> To be super extra safe, maybe doing
> phy_node->parent && phy_node->parent->parent == priv->dev->of_node
> would be better.

At the current state of this driver where the hardware probes on OF, I
don't see any benefit of doing this so I'm going to pass on this for now.

Arınç

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Re: [PATCH net-next v2] net: dsa: mt7530: detect PHY muxing when PHY is defined on switch MDIO bus

[patchwork-bot+netdevbpf]

Hello:

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

On Tue, 30 Apr 2024 08:01:33 +0300 you wrote:
> From: Arınç ÜNAL <arinc.unal@arinc9.com>
> 
> Currently, the MT7530 DSA subdriver configures the MT7530 switch to provide
> direct access to switch PHYs, meaning, the switch PHYs listen on the MDIO
> bus the switch listens on. The PHY muxing feature makes use of this.
> 
> This is problematic as the PHY may be attached before the switch is
> initialised, in which case, the PHY will fail to be attached.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] net: dsa: mt7530: detect PHY muxing when PHY is defined on switch MDIO bus
    https://git.kernel.org/netdev/net-next/c/d8dcf5bd6d0e

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



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