media: ov5640: Add LINK_FREQ control

Add the V4L2_CID_LINK_FREQ control to the ov5640 driver.
Make the control read-only for the moment.
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/i2c/ov5640.c

@@ -141,6 +141,24 @@ static const u32 ov5640_pixel_rates[] = {
 	[OV5640_PIXEL_RATE_48M] = 48000000,
 };
 
+/*
+ * MIPI CSI-2 link frequencies.
+ *
+ * Derived from the above defined pixel rate for bpp = (8, 16, 24) and
+ * data_lanes = (1, 2)
+ *
+ * link_freq = (pixel_rate * bpp) / (2 * data_lanes)
+ */
+static const s64 ov5640_csi2_link_freqs[] = {
+	992000000, 888000000, 768000000, 744000000, 672000000, 672000000,
+	592000000, 592000000, 576000000, 576000000, 496000000, 496000000,
+	384000000, 384000000, 384000000, 336000000, 296000000, 288000000,
+	248000000, 192000000, 192000000, 192000000, 96000000,
+};
+
+/* Link freq for default mode: UYVY 16 bpp, 2 data lanes. */
+#define OV5640_DEFAULT_LINK_FREQ	13
+
 enum ov5640_format_mux {
 	OV5640_FMT_MUX_YUV422 = 0,
 	OV5640_FMT_MUX_RGB,
@@ -258,6 +276,7 @@ struct ov5640_mode_info {
 struct ov5640_ctrls {
 	struct v4l2_ctrl_handler handler;
 	struct v4l2_ctrl *pixel_rate;
+	struct v4l2_ctrl *link_freq;
 	struct {
 		struct v4l2_ctrl *auto_exp;
 		struct v4l2_ctrl *exposure;
@@ -2855,6 +2874,12 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
 			      ov5640_pixel_rates[0], 1,
 			      ov5640_pixel_rates[mode->pixel_rate]);
 
+	ctrls->link_freq = v4l2_ctrl_new_int_menu(hdl, ops,
+					V4L2_CID_LINK_FREQ,
+					ARRAY_SIZE(ov5640_csi2_link_freqs) - 1,
+					OV5640_DEFAULT_LINK_FREQ,
+					ov5640_csi2_link_freqs);
+
 	/* Auto/manual white balance */
 	ctrls->auto_wb = v4l2_ctrl_new_std(hdl, ops,
 					   V4L2_CID_AUTO_WHITE_BALANCE,
@@ -2903,6 +2928,7 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
 	}
 
 	ctrls->pixel_rate->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+	ctrls->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
 	ctrls->gain->flags |= V4L2_CTRL_FLAG_VOLATILE;
 	ctrls->exposure->flags |= V4L2_CTRL_FLAG_VOLATILE;