i2c-pasemi: Fix NACK detection

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>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-pasemi.c b/drivers/i2c/busses/i2c-pasemi.c
index 79c72dfa63b7..ca18e0be4901 100644
--- 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(struct pasemi_smbus *smbus)
                 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);