i2c-pasemi: Fix NACK detection

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>

diff --git a/drivers/i2c/busses/i2c-pasemi.c b/drivers/i2c/busses/i2c-pasemi.c
index 58e32714afb5b881068c9ca096d8ec271a448cd7..dcf5dec59fd57b88c46e3f81829e698aa337e655 100644 (file)
--- 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);