i2c: rcar: fix resume by always initializing registers before transfer

Resume failed because of uninitialized registers. Instead of adding a
resume callback, we simply initialize registers before every transfer.
This lightweight change is more robust and will keep us safe if we ever
need support for power domains or dynamic frequency changes.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-rcar.c

@@ -700,6 +700,8 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
 	pm_runtime_get_sync(dev);
 
+	rcar_i2c_init(priv);
+
 	ret = rcar_i2c_bus_barrier(priv);
 	if (ret < 0)
 		goto out;
@@ -860,8 +862,6 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto out_pm_put;
 
-	rcar_i2c_init(priv);
-
 	/* Don't suspend when multi-master to keep arbitration working */
 	if (of_property_read_bool(dev->of_node, "multi-master"))
 		priv->flags |= ID_P_PM_BLOCKED;