media: i2c: imx219: Implement V4L2_CID_LINK_FREQ control

This control is needed for imx219 driver, as the link frequency
is independent from the pixel rate in this case, and can't be
calculated from the pixel rate.
Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/imx219.c

@@ -390,6 +390,10 @@ static const struct imx219_reg raw10_framefmt_regs[] = {
 	{0x0309, 0x0a},
 };
 
+static const s64 imx219_link_freq_menu[] = {
+	IMX219_DEFAULT_LINK_FREQ,
+};
+
 static const char * const imx219_test_pattern_menu[] = {
 	"Disabled",
 	"Color Bars",
@@ -547,6 +551,7 @@ struct imx219 {
 	struct v4l2_ctrl_handler ctrl_handler;
 	/* V4L2 Controls */
 	struct v4l2_ctrl *pixel_rate;
+	struct v4l2_ctrl *link_freq;
 	struct v4l2_ctrl *exposure;
 	struct v4l2_ctrl *vflip;
 	struct v4l2_ctrl *hflip;
@@ -1269,7 +1274,7 @@ static int imx219_init_controls(struct imx219 *imx219)
 	int i, ret;
 
 	ctrl_hdlr = &imx219->ctrl_handler;
-	ret = v4l2_ctrl_handler_init(ctrl_hdlr, 11);
+	ret = v4l2_ctrl_handler_init(ctrl_hdlr, 12);
 	if (ret)
 		return ret;
 
@@ -1283,6 +1288,14 @@ static int imx219_init_controls(struct imx219 *imx219)
 					       IMX219_PIXEL_RATE, 1,
 					       IMX219_PIXEL_RATE);
 
+	imx219->link_freq =
+		v4l2_ctrl_new_int_menu(ctrl_hdlr, &imx219_ctrl_ops,
+				       V4L2_CID_LINK_FREQ,
+				       ARRAY_SIZE(imx219_link_freq_menu) - 1, 0,
+				       imx219_link_freq_menu);
+	if (imx219->link_freq)
+		imx219->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+
 	/* Initial vblank/hblank/exposure parameters based on current mode */
 	imx219->vblank = v4l2_ctrl_new_std(ctrl_hdlr, &imx219_ctrl_ops,
 					   V4L2_CID_VBLANK, IMX219_VBLANK_MIN,