Patchwork phy: fix phy_id detection also for broken hardware.

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Submitter Giuseppe CAVALLARO
Date Nov. 20, 2008, 3:57 p.m.
Message ID <1227196656-4361-1-git-send-email-peppe.cavallaro@st.com>
Download mbox | patch
Permalink /patch/9838/
State Accepted
Delegated to: David Miller
Headers show

Comments

Giuseppe CAVALLARO - Nov. 20, 2008, 3:57 p.m.
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>
---
 drivers/net/phy/phy_device.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)
David Miller - Nov. 21, 2008, 4:43 a.m.
From: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
Date: Thu, 20 Nov 2008 16:57:36 +0100

> 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>

Applied, thanks.
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Patch

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8fb1fac..effa489 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);