media: i2c: ov772x: Add support for BT.656 mode

Add support to read the bus-type for V4L2_MBUS_BT656 and enable BT.656
mode in the sensor if needed.

For backward compatibility with older DTS where the bus-type property was
not mandatory, assume V4L2_MBUS_PARALLEL as it was the only supported bus
at the time. v4l2_fwnode_endpoint_alloc_parse() will not fail if
'bus-type' is not specified.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ov772x.c

@@ -583,6 +583,14 @@ static int ov772x_s_stream(struct v4l2_subdev *sd, int enable)
 	if (priv->streaming == enable)
 		goto done;
 
+	if (priv->bus_type == V4L2_MBUS_BT656) {
+		ret = regmap_update_bits(priv->regmap, COM7, ITU656_ON_OFF,
+					 enable ?
+					 ITU656_ON_OFF : ~ITU656_ON_OFF);
+		if (ret)
+			goto done;
+	}
+
 	ret = regmap_update_bits(priv->regmap, COM2, SOFT_SLEEP_MODE,
 				 enable ? 0 : SOFT_SLEEP_MODE);
 	if (ret)
@@ -1365,9 +1373,21 @@ static int ov772x_parse_dt(struct i2c_client *client,
 		return -EINVAL;
 	}
 
+	/*
+	 * For backward compatibility with older DTS where the
+	 * bus-type property was not mandatory, assume
+	 * V4L2_MBUS_PARALLEL as it was the only supported bus at the
+	 * time. v4l2_fwnode_endpoint_alloc_parse() will not fail if
+	 * 'bus-type' is not specified.
+	 */
 	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
-	if (ret)
-		goto error_fwnode_put;
+	if (ret) {
+		bus_cfg = (struct v4l2_fwnode_endpoint)
+			  { .bus_type = V4L2_MBUS_BT656 };
+		ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
+		if (ret)
+			goto error_fwnode_put;
+	}
 
 	priv->bus_type = bus_cfg.bus_type;
 	v4l2_fwnode_endpoint_free(&bus_cfg);