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From c6eac988444567bfb55644206d8a55f7e78b1df9 Mon Sep 17 00:00:00 2001
From: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date: Tue, 24 Apr 2018 18:09:04 +0200
Subject: [PATCH 023/211] 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>
(cherry picked from commit 02a6efcab675fe32815d824837784c3f42a7d892)
Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
---
drivers/net/phy/phy_device.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index eff5327..64e5ed9 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -536,8 +536,17 @@ 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;
--
2.7.4
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