[patch 24/26] i2c-pasemi: Fix NACK detection

[Greg Kroah-Hartman <gregkh@suse.de>]

2.6.22-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Jean Delvare <khali@linux-fr.org>

patch be8a1f7cd4501c3b4b32543577a33aee6d2193ac in mainline.

Turns out we don't actually check the status to see if there was a
device out there to talk to, just if we had a timeout when doing so.

Add the proper check, so we don't falsly think there are devices
on the bus that are not there, etc.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/i2c/busses/i2c-pasemi.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/i2c/busses/i2c-pasemi.c
+++ b/drivers/i2c/busses/i2c-pasemi.c
@@ -51,6 +51,7 @@ struct pasemi_smbus {
 #define MRXFIFO_DATA_M	0x000000ff
 
 #define SMSTA_XEN	0x08000000
+#define SMSTA_MTN	0x00200000
 
 #define CTL_MRR		0x00000400
 #define CTL_MTR		0x00000200
@@ -98,6 +99,10 @@ static unsigned int pasemi_smb_waitready
 		status = reg_read(smbus, REG_SMSTA);
 	}
 
+	/* Got NACK? */
+	if (status & SMSTA_MTN)
+		return -ENXIO;
+
 	if (timeout < 0) {
 		dev_warn(&smbus->dev->dev, "Timeout, status 0x%08x\n", status);
 		reg_write(smbus, REG_SMSTA, status);

-- 
-
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