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i2c: generic recovery: check SCL before SDA

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Move the check for a stuck SCL before the check for a high SDA.
This prevent false positives in the specific case that SDA is fine
and SCL is stuck, which previously returned 0.

Also check SDA again after the loop, if we can.
Together, these changes should lead to a lot more failed
recoveries being caught and returning error codes.

Signed-off-by: Claudio Foellmi <claudio.foellmi@ergon.ch>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Claudio Foellmi 2017-10-05 14:44:14 +02:00 committed by Wolfram Sang
parent 3ded0512e9
commit 1f35b86536
1 changed files with 7 additions and 3 deletions
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10
drivers/i2c/i2c-core-base.c
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@ -205,9 +205,6 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
*/
while (i++ < RECOVERY_CLK_CNT * 2) {
if (val) {
/* Break if SDA is high */
if (bri->get_sda && bri->get_sda(adap))
break;
/* SCL shouldn't be low here */
if (!bri->get_scl(adap)) {
dev_err(&adap->dev,
@ -215,6 +212,9 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
ret = -EBUSY;
break;
}
/* Break if SDA is high */
if (bri->get_sda && bri->get_sda(adap))
break;
}
val = !val;
@ -222,6 +222,10 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
ndelay(RECOVERY_NDELAY);
}
/* check if recovery actually succeeded */
if (bri->get_sda && !bri->get_sda(adap))
ret = -EBUSY;
if (bri->unprepare_recovery)
bri->unprepare_recovery(adap);