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Commit 70a1cc19 authored by Daniel Kurtz's avatar Daniel Kurtz Committed by Jean Delvare
Browse files

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: default avatarDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 0ba8b8bf

drivers/i2c/busses/i2c-i801.c

+6 −4
Original line number Diff line number Diff line
@@ -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);