Commit 02a6efca authored Apr 24, 2018 by Alexandre Belloni Committed by David S. Miller Apr 25, 2018

net: phy: allow scanning busses with missing phys



Some MDIO busses will error out when trying to read a phy address with no
phy present at that address. In that case, probing the bus will fail
because __mdiobus_register() is scanning the bus for all possible phys
addresses.

In case MII_PHYSID1 returns -EIO or -ENODEV, consider there is no phy at
this address and set the phy ID to 0xffffffff which is then properly
handled in get_phy_device().

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3be4aaf4

drivers/net/phy/phy_device.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -535,8 +535,17 @@ static int get_phy_id(struct mii_bus bus, int addr, u32 phy_id,

		/* Grab the bits from PHYIR1, and put them in the upper half */
		phy_reg = mdiobus_read(bus, addr, MII_PHYSID1);
		if (phy_reg < 0)
		if (phy_reg < 0) {
		/* if there is no device, return without an error so scanning
		* the bus works properly
		*/
		if (phy_reg == -EIO \|\| phy_reg == -ENODEV) {
		*phy_id = 0xffffffff;
		return 0;
		}

		return -EIO;
		}

		*phy_id = (phy_reg & 0xffff) << 16;

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