Currently, the i2c-algo-pca driver does nothing if the chip enters state
0x30 (Data byte in I2CDAT has been transmitted; NOT ACK has been
received).  Thus, the i2c bus connected to the controller gets stuck
afterwards.

I have seen this kind of error on a custom board in certain load
situations most probably caused by interference or noise.

A possible reaction is to let the controller generate a STOP condition.
This is documented in the PCA9564 data sheet (2006-09-01) and the same
is done for other NACK states as well.

Further, state 0x38 isn't handled completely, either. Try to do another
START in this case like the data sheet says. As this couldn't be tested,
I've added a comment to try to reset the chip if the START doesn't help
as suggested by Wolfram Sang.
Signed-off-by: Enrik Berkhan <Enrik.Berkhan@ge.com>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>