Re: [PATCH] net: macb: Fix regression breaking non-MDIO fixed-link PHYs

Hi,

On Wed, Aug 15, 2018 at 3:35 AM Andrew Lunn [off-list ref] wrote:

On Tue, Aug 14, 2018 at 05:58:12PM +0200, Uwe Kleine-König wrote:

quoted

Hello Ahmad,


On Tue, Aug 14, 2018 at 04:12:40PM +0200, Ahmad Fatoum wrote:

quoted

The referenced commit broke initializing macb on the EVB-KSZ9477 eval board.
There, of_mdiobus_register was called even for the fixed-link representing
the SPI-connected switch PHY, with the result that the driver attempts to
enumerate PHYs on a non-existent MDIO bus:

I ran into a similar problem on v14.4 for davinci_mdio I had to patch
it with [1].
The cpsw has 2 phys one phy is connected to KSZ9031 and other to
ksz9897 Ethernet switch
which is treated as a fixed phy with no mdio lines because of which
mdio_read/write failed.
This didn’t happen in v4.9.x something in core has changed ?

[1]

diff --git a/drivers/net/ethernet/ti/davinci_mdio.c

b/drivers/net/ethernet/ti/davinci_mdio.c
index 3e84107..197baa6 100644

--- a/drivers/net/ethernet/ti/davinci_mdio.c
+++ b/drivers/net/ethernet/ti/davinci_mdio.c

@@ -245,6 +245,13 @@ static int davinci_mdio_read(struct mii_bus *bus,

int phy_id, int phy_reg)
        u32 reg;
        int ret;

+       if (phy_id == 2)
+               return 0;
+
        if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
                return -EINVAL;

@@ -289,6 +296,13 @@ static int davinci_mdio_write(struct mii_bus

*bus, int phy_id,
        u32 reg;
        int ret;

+       if (phy_id == 2)
+               return 0;
+
        if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
                return -EINVAL;


Cheers,
--Prabhakar Lad