If we can't read SDA to bail out early and toggle too many pulses, slaves may misunderstand these pulses. In the worst case, as a write operation. To avoid that and if we can write SDA, try to send STOP to avoid the misinterpretation. Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> --- drivers/i2c/i2c-core-base.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 31d16ada6e7d..2cb4129c9585 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -198,7 +198,16 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) val = !val; bri->set_scl(adap, val); - ndelay(RECOVERY_NDELAY); + + /* + * If we can't read SDA, we don't know when to bail out early. + * So, always create STOP then to ensure the additional pulses + * will do no harm. + */ + ndelay(RECOVERY_NDELAY / 2); + if (!bri->get_sda && bri->set_sda) + bri->set_sda(adap, val); + ndelay(RECOVERY_NDELAY / 2); } /* check if recovery actually succeeded */ -- 2.11.0
