media: imx335: Support 2 or 4 lane operation modes

The IMX335 can support both 2 and 4 lane configurations.
Extend the driver to configure the lane mode accordingly.
Update the pixel rate depending on the number of lanes in use.
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Tommaso Merciai <tomm.merciai@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: fixup missing : in @lane_mode kerneldoc line]

drivers/media/i2c/imx335.c

@@ -21,6 +21,11 @@
 #define IMX335_MODE_STANDBY	0x01
 #define IMX335_MODE_STREAMING	0x00
 
+/* Data Lanes */
+#define IMX335_LANEMODE		0x3a01
+#define IMX335_2LANE		1
+#define IMX335_4LANE		3
+
 /* Lines per frame */
 #define IMX335_REG_LPFR		0x3030
 
@@ -147,6 +152,7 @@ struct imx335_mode {
  * @exp_ctrl: Pointer to exposure control
  * @again_ctrl: Pointer to analog gain control
  * @vblank: Vertical blanking in lines
+ * @lane_mode: Mode for number of connected data lanes
  * @cur_mode: Pointer to current selected sensor mode
  * @mutex: Mutex for serializing sensor controls
  * @link_freq_bitmap: Menu bitmap for link_freq_ctrl
@@ -171,6 +177,7 @@ struct imx335 {
 		struct v4l2_ctrl *again_ctrl;
 	};
 	u32 vblank;
+	u32 lane_mode;
 	const struct imx335_mode *cur_mode;
 	struct mutex mutex;
 	unsigned long link_freq_bitmap;
@@ -936,6 +943,11 @@ static int imx335_start_streaming(struct imx335 *imx335)
 		return ret;
 	}
 
+	/* Configure lanes */
+	ret = imx335_write_reg(imx335, IMX335_LANEMODE, 1, imx335->lane_mode);
+	if (ret)
+		return ret;
+
 	/* Setup handler will write actual exposure and gain */
 	ret =  __v4l2_ctrl_handler_setup(imx335->sd.ctrl_handler);
 	if (ret) {
@@ -1096,7 +1108,14 @@ static int imx335_parse_hw_config(struct imx335 *imx335)
 	if (ret)
 		return ret;
 
-	if (bus_cfg.bus.mipi_csi2.num_data_lanes != IMX335_NUM_DATA_LANES) {
+	switch (bus_cfg.bus.mipi_csi2.num_data_lanes) {
+	case 2:
+		imx335->lane_mode = IMX335_2LANE;
+		break;
+	case 4:
+		imx335->lane_mode = IMX335_4LANE;
+		break;
+	default:
 		dev_err(imx335->dev,
 			"number of CSI2 data lanes %d is not supported\n",
 			bus_cfg.bus.mipi_csi2.num_data_lanes);