i2c: rcar: refactor setup of a msg

BugLink: https://bugs.launchpad.net/bugs/1776177

commit b9d0684c upstream.

We want to reuse this function later.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/i2c/busses/i2c-rcar.c

@@ -107,6 +107,7 @@ struct rcar_i2c_priv {
 	void __iomem *io;
 	struct i2c_adapter adap;
 	struct i2c_msg *msg;
+	int msgs_left;
 	struct clk *clk;
 
 	wait_queue_head_t wait;
@@ -255,6 +256,11 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
 {
 	int read = !!rcar_i2c_is_recv(priv);
 
+	priv->pos = 0;
+	priv->flags = 0;
+	if (priv->msgs_left == 1)
+		rcar_i2c_flags_set(priv, ID_LAST_MSG);
+
 	rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | read);
 	rcar_i2c_write(priv, ICMSR, 0);
 	rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
@@ -500,10 +506,7 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
 		/* init each data */
 		priv->msg = &msgs[i];
-		priv->pos	= 0;
-		priv->flags	= 0;
-		if (i == num - 1)
-			rcar_i2c_flags_set(priv, ID_LAST_MSG);
+		priv->msgs_left = num - i;
 
 		rcar_i2c_prepare_msg(priv);