From 36641b045c839797739f9863e86e4dae2370e24f Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 11 Jun 2021 23:05:24 +0300 Subject: net: pcs: xpcs: also ignore phy id if it's all ones xpcs_get_id() searches multiple MMDs for a known PHY ID, starting with MDIO_MMD_PCS (3). However not all integrators might have implemented that MMD on their MDIO bus. For example, the NXP SJA1105 and SJA1110 switches only implement vendor-specific MMD 1 and 2. When there is nothing on an MDIO bus at a certain address, traditionally the bus returns 0xffff, which means that the bus remained in its default pull-up state for the duration of the MDIO transaction. The 0xffff value is widely used in drivers/net/phy/phy_device.c (see get_phy_c22_id for example) to denote a missing device. So it makes sense for the xpcs to ignore this value as well, and continue its search, eventually finding the proper PHY ID in the vendor-specific MMDs. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- drivers/net/pcs/pcs-xpcs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/net/pcs') diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c index 743b53734eeb..ecf5011977d3 100644 --- a/drivers/net/pcs/pcs-xpcs.c +++ b/drivers/net/pcs/pcs-xpcs.c @@ -965,8 +965,10 @@ static u32 xpcs_get_id(struct dw_xpcs *xpcs) if (ret < 0) return 0xffffffff; - /* If Device IDs are not all zeros, we found C73 AN-type device */ - if (id | ret) + /* If Device IDs are not all zeros or all ones, + * we found C73 AN-type device + */ + if ((id | ret) && (id | ret) != 0xffffffff) return id | ret; /* Next, search C37 PCS using Vendor-Specific MII MMD */ -- cgit