i2c-i801: Check and return errors during byte-by-byte transfers

If an error is detected in the polling loop, abort the transaction and
return an error code.

 * DEV_ERR is set if the device does not respond with an acknowledge, and
the SMBus controller times out (minimum 25ms).
 * BUS_ERR is set if a bus arbitration collision is detected.  In other
words, when the SMBus controller tries to generate a START condition, but
detects that the SMBDATA is being held low, usually by another SMBus/I2C
master.
 * FAILED is only set if a transaction is stopped by software (using
the SMBHSTCNT KILL bit).
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-i801.c

@@ -131,9 +131,11 @@
 #define SMBHSTSTS_INTR		0x02
 #define SMBHSTSTS_HOST_BUSY	0x01
 
-#define STATUS_FLAGS		(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_FAILED | \
-				 SMBHSTSTS_BUS_ERR | SMBHSTSTS_DEV_ERR | \
-				 SMBHSTSTS_INTR)
+#define STATUS_ERROR_FLAGS	(SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
+				 SMBHSTSTS_DEV_ERR)
+
+#define STATUS_FLAGS		(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \
+				 STATUS_ERROR_FLAGS)
 
 /* Older devices have their ID defined in <linux/pci_ids.h> */
 #define PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS	0x1c22
@@ -384,7 +386,7 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 		do {
 			usleep_range(250, 500);
 			status = inb_p(SMBHSTSTS(priv));
-		} while ((!(status & SMBHSTSTS_BYTE_DONE))
+		} while (!(status & (SMBHSTSTS_BYTE_DONE | STATUS_ERROR_FLAGS))
 			 && (timeout++ < MAX_RETRIES));
 
 		result = i801_check_post(priv, status, timeout > MAX_RETRIES);