1 files changed, 20 insertions, 4 deletions

diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 260c5d70b0b4..35812823787b 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -357,10 +357,26 @@ static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
                         count--;
                         temp++;
                         wrcount++;
-                } else { /* arbitration or no acknowledge */
-                        dev_err(&i2c_adap->dev, "sendbytes: error - bailout.\n");
-                        return (retval<0)? retval : -EFAULT;
-                                /* got a better one ?? */
+
+                /* A slave NAKing the master means the slave didn't like
+                 * something about the data it saw.  For example, maybe
+                 * the SMBus PEC was wrong.
+                 */
+                } else if (retval == 0) {
+                        dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n");
+                        return -EIO;
+
+                /* Timeout; or (someday) lost arbitration
+                 *
+                 * FIXME Lost ARB implies retrying the transaction from
+                 * the first message, after the "winning" master issues
+                 * its STOP.  As a rule, upper layer code has no reason
+                 * to know or care about this ... it is *NOT* an error.
+                 */
+                } else {
+                        dev_err(&i2c_adap->dev, "sendbytes: error %d\n",
+                                        retval);
+                        return retval;
                 }
         }
         return wrcount;