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i2c: recovery: make pin init look like STOP

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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 <wsa+renesas@sang-engineering.com>
Reviewed-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2018-07-17 11:00:05 +02:00 committed by Wolfram Sang
parent ea3cfbd896
commit c4ae05b976
1 changed files with 10 additions and 9 deletions
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19
drivers/i2c/i2c-core-base.c
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@ -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);