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authorDaniel Kurtz <djkurtz@chromium.org>2012-07-24 16:13:58 +0400
committerJean Delvare <khali@endymion.delvare>2012-07-24 16:13:58 +0400
commit70a1cc1952355404a5746c88757f5a444df52b04 (patch)
treeb97d76988c4ac5781faf3edd8bde4021eadc1ad1
parent0ba8b8bfd56533f0b9af7513c6ebbc10c79ae052 (diff)
downloadlinux-70a1cc1952355404a5746c88757f5a444df52b04.tar.xz
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>
-rw-r--r--drivers/i2c/busses/i2c-i801.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 05f394938b82..40a50f780972 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/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);