From c4ae05b976b2a67fb24f35d21731b4da2c235bbf Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Tue, 17 Jul 2018 11:00:05 +0200 Subject: [PATCH] i2c: recovery: make pin init look like STOP When we initialize the pins, make sure it looks like STOP by dividing the delay into halves. It shouldn't matter because SDA is expected to be held low by a device, but for super-safety, let's do it. Signed-off-by: Wolfram Sang Reviewed-by: Ulrich Hecht Reviewed-by: Peter Rosin Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-base.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 57538d7..02d6f27 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -190,10 +190,17 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) if (bri->prepare_recovery) bri->prepare_recovery(adap); + /* + * If we can set SDA, we will always create a STOP to ensure additional + * pulses will do no harm. This is achieved by letting SDA follow SCL + * half a cycle later. Check the 'incomplete_write_byte' fault injector + * for details. + */ bri->set_scl(adap, scl); + ndelay(RECOVERY_NDELAY / 2); if (bri->set_sda) - bri->set_sda(adap, 1); - ndelay(RECOVERY_NDELAY); + bri->set_sda(adap, scl); + ndelay(RECOVERY_NDELAY / 2); /* * By this time SCL is high, as we need to give 9 falling-rising edges @@ -211,13 +218,7 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) scl = !scl; bri->set_scl(adap, scl); - - /* - * If we can set SDA, we will always create STOP here to ensure - * the additional pulses will do no harm. This is achieved by - * letting SDA follow SCL half a cycle later. Check the - * 'incomplete_write_byte' fault injector for details. - */ + /* Creating STOP again, see above */ ndelay(RECOVERY_NDELAY / 2); if (bri->set_sda) bri->set_sda(adap, scl); -- 2.7.4