Re: [PATCH net-next v2 1/2] net: dsa: mt7530-mdio: read PHY address of switch from device tree

From: Arınç ÜNAL
Date: Tue Apr 16 2024 - 04:33:12 EST


On 15/04/2024 18:30, Florian Fainelli wrote:


On 4/13/2024 11:07 PM, Arınç ÜNAL via B4 Relay wrote:
From: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>

Read the PHY address the switch listens on from the reg property of the
switch node on the device tree. This change brings support for MT7530
switches on boards with such bootstrapping configuration where the switch
listens on a different PHY address than the hardcoded PHY address on the
driver, 31.

As described on the "MT7621 Programming Guide v0.4" document, the MT7530
switch and its PHYs can be configured to listen on the range of 7-12,
15-20, 23-28, and 31 and 0-4 PHY addresses.

There are operations where the switch PHY registers are used. For the PHY
address of the control PHY, transform the MT753X_CTRL_PHY_ADDR constant
into a macro and use it. The PHY address for the control PHY is 0 when the
switch listens on 31. In any other case, it is one greater than the PHY
address the switch listens on.

Reviewed-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
Tested-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>

Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>

I would go a step further and name phy_addr switch_mdio_addr, or something along those lines to clearly denote this is not a per-port PHY address neither a proper PHY device, but we've already had a similar discussion before about spelling this out clearly as a "pseudo PHY"....

I am fine with calling the switch operating on an MDIO bus a psuedo-PHY.
But I don't believe this grants making up names on our own instead of using
the name described in IEEE Std 802.3-2022. The switch listens on a PHY
address on the MDIO bus. The description for the phy_addr member of the
mt753x_info structure clearly explains that so I don't see a reason to
change the variable name.

Arınç