The driver didn't work well with at24 driver. NACKS are lost.
Errors are lost in isr due to the local variable err. Also we didn't wait for
bus free in omap_i2c_xfer_msg.
Fix issues and get other improvements from linux kernel
Tested on OMAP4 and AM335x
Signed-off-by: Jan Weitzel <j.weitzel@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>