i2c: sh_mobile: make sure to not accidently trigger STOP

The datasheet was a bit vague, but after consultation with HW designers,
we came to the conclusion that we should set the SCP bit always when
dealing only with the ICE bit. A set SCP bit is ignored, and thus fine,
a cleared one may trigger STOP on the bus.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-sh_mobile.c

@@ -604,10 +604,10 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
 
 	if (do_init) {
 		/* Initialize channel registers */
-		iic_wr(pd, ICCR, 0);
+		iic_wr(pd, ICCR, ICCR_SCP);
 
 		/* Enable channel and configure rx ack */
-		iic_wr(pd, ICCR, ICCR_ICE);
+		iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
 
 		/* Set the clock */
 		iic_wr(pd, ICCL, pd->iccl & 0xff);
@@ -723,7 +723,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
 	}
 
 	/* Disable channel */
-	iic_wr(pd, ICCR, 0);
+	iic_wr(pd, ICCR, ICCR_SCP);
 
 	/* Disable clock and mark device as idle */
 	pm_runtime_put_sync(pd->dev);