i2c: i2c-bfin-twi: Illegal i2c bus lock upon certain transfer scenarios.
authorMichael Hennerich <michael.hennerich@analog.com>
Wed, 13 Jun 2012 08:22:40 +0000 (16:22 +0800)
committerWolfram Sang <w.sang@pengutronix.de>
Fri, 13 Jul 2012 06:27:31 +0000 (08:27 +0200)
commit925594e03550f1825647ea5408a32bb9803d90f1
treedebca96175b8e0a36a7265c71722887633fa873c
parentd61a9095155e832287552a9e565b8756ee293c46
i2c: i2c-bfin-twi: Illegal i2c bus lock upon certain transfer scenarios.

For transfer counts > 255 bytes i2c-bfin-twi sets the data
transfer counter DCNT to 0xFF indicating unlimited transfers.
It then uses a flag iface->manual_stop to manually issue the STOP
condition, once the required amount of bytes are received.

We found that on I2C receive operation issuing the STOP condition
together with a FULL RCV FIFO (2bytes) will cause SDA and SCL be
constantly driven low.

Temporary workaround until further investigation:
Discard the RCV FIFO before issuing the STOP condition.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
drivers/i2c/busses/i2c-bfin-twi.c