From 6436cbcd735a11fc93bf3353c68914bc545e6d1e Mon Sep 17 00:00:00 2001 From: Giuseppe Cavallaro <peppe.cavallaro@st.com> Date: Thu, 20 Nov 2008 20:43:18 -0800 Subject: [PATCH] phy: fix phy_id detection also for broken hardware. This patch fixes the case when the phy_ids is mostly Fs and in some case 0x0 due to broken hardware. Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> Signed-off-by: David S. Miller <davem@davemloft.net> --- drivers/net/phy/phy_device.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 55bc24b234e3..25acbbde4a60 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -227,8 +227,17 @@ struct phy_device * get_phy_device(struct mii_bus *bus, int addr) if (r) return ERR_PTR(r); - /* If the phy_id is all Fs or all 0s, there is no device there */ - if ((0xffff == phy_id) || (0x00 == phy_id)) + /* If the phy_id is mostly Fs, there is no device there */ + if ((phy_id & 0x1fffffff) == 0x1fffffff) + return NULL; + + /* + * Broken hardware is sometimes missing the pull down resistor on the + * MDIO line, which results in reads to non-existent devices returning + * 0 rather than 0xffff. Catch this here and treat 0 as a non-existent + * device as well. + */ + if (phy_id == 0) return NULL; dev = phy_device_create(bus, addr, phy_id); -- GitLab