media: ov5670: Fix incorrect frame timing reported to user

Previously, pixel-rate/(pixels-per-line * lines-per-frame) was
yielding incorrect frame timing for the user.

OV sensor is using internal timing and this requires
conversion (internal timing -> PPL) for correct HBLANK calculation.

Now, change pixels-per-line domain from internal sensor clock to
pixels domain. Set HBLANK read-only because fixed PPL is used for all
resolutions. And, use more accurate link-frequency 422.4MHz instead of
rounding down to 420MHz.

Signed-off-by: Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/i2c/ov5670.c

@@ -37,7 +37,13 @@
 
 /* horizontal-timings from sensor */
 #define OV5670_REG_HTS			0x380c
-#define OV5670_DEF_PPL			3360	/* Default pixels per line */
+
+/*
+ * Pixels-per-line(PPL) = Time-per-line * pixel-rate
+ * In OV5670, Time-per-line = HTS/SCLK.
+ * HTS is fixed for all resolutions, not recommended to change.
+ */
+#define OV5670_FIXED_PPL		2724	/* Pixels per line */
 
 /* Exposure controls from sensor */
 #define OV5670_REG_EXPOSURE		0x3500
@@ -1705,12 +1711,12 @@ static const char * const ov5670_test_pattern_menu[] = {
 };
 
 /* Supported link frequencies */
-#define OV5670_LINK_FREQ_420MHZ		420000000
-#define OV5670_LINK_FREQ_420MHZ_INDEX	0
+#define OV5670_LINK_FREQ_422MHZ		422400000
+#define OV5670_LINK_FREQ_422MHZ_INDEX	0
 static const struct ov5670_link_freq_config link_freq_configs[] = {
 	{
 		/* pixel_rate = link_freq * 2 * nr_of_lanes / bits_per_sample */
-		.pixel_rate = (OV5670_LINK_FREQ_420MHZ * 2 * 2) / 10,
+		.pixel_rate = (OV5670_LINK_FREQ_422MHZ * 2 * 2) / 10,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mipi_data_rate_840mbps),
 			.regs = mipi_data_rate_840mbps,
@@ -1719,7 +1725,7 @@ static const struct ov5670_link_freq_config link_freq_configs[] = {
 };
 
 static const s64 link_freq_menu_items[] = {
-	OV5670_LINK_FREQ_420MHZ
+	OV5670_LINK_FREQ_422MHZ
 };
 
 /*
@@ -1736,7 +1742,7 @@ static const struct ov5670_mode supported_modes[] = {
 			.num_of_regs = ARRAY_SIZE(mode_2592x1944_regs),
 			.regs = mode_2592x1944_regs,
 		},
-		.link_freq_index = OV5670_LINK_FREQ_420MHZ_INDEX,
+		.link_freq_index = OV5670_LINK_FREQ_422MHZ_INDEX,
 	},
 	{
 		.width = 1296,
@@ -1746,7 +1752,7 @@ static const struct ov5670_mode supported_modes[] = {
 			.num_of_regs = ARRAY_SIZE(mode_1296x972_regs),
 			.regs = mode_1296x972_regs,
 		},
-		.link_freq_index = OV5670_LINK_FREQ_420MHZ_INDEX,
+		.link_freq_index = OV5670_LINK_FREQ_422MHZ_INDEX,
 	},
 	{
 		.width = 648,
@@ -1756,7 +1762,7 @@ static const struct ov5670_mode supported_modes[] = {
 			.num_of_regs = ARRAY_SIZE(mode_648x486_regs),
 			.regs = mode_648x486_regs,
 		},
-		.link_freq_index = OV5670_LINK_FREQ_420MHZ_INDEX,
+		.link_freq_index = OV5670_LINK_FREQ_422MHZ_INDEX,
 	},
 	{
 		.width = 2560,
@@ -1766,7 +1772,7 @@ static const struct ov5670_mode supported_modes[] = {
 			.num_of_regs = ARRAY_SIZE(mode_2560x1440_regs),
 			.regs = mode_2560x1440_regs,
 		},
-		.link_freq_index = OV5670_LINK_FREQ_420MHZ_INDEX,
+		.link_freq_index = OV5670_LINK_FREQ_422MHZ_INDEX,
 	},
 	{
 		.width = 1280,
@@ -1776,7 +1782,7 @@ static const struct ov5670_mode supported_modes[] = {
 			.num_of_regs = ARRAY_SIZE(mode_1280x720_regs),
 			.regs = mode_1280x720_regs,
 		},
-		.link_freq_index = OV5670_LINK_FREQ_420MHZ_INDEX,
+		.link_freq_index = OV5670_LINK_FREQ_422MHZ_INDEX,
 	},
 	{
 		.width = 640,
@@ -1786,7 +1792,7 @@ static const struct ov5670_mode supported_modes[] = {
 			.num_of_regs = ARRAY_SIZE(mode_640x360_regs),
 			.regs = mode_640x360_regs,
 		},
-		.link_freq_index = OV5670_LINK_FREQ_420MHZ_INDEX,
+		.link_freq_index = OV5670_LINK_FREQ_422MHZ_INDEX,
 	}
 };
 
@@ -2016,13 +2022,6 @@ static int ov5670_set_ctrl(struct v4l2_ctrl *ctrl)
 				       OV5670_REG_VALUE_16BIT,
 				       ov5670->cur_mode->height + ctrl->val);
 		break;
-	case V4L2_CID_HBLANK:
-		/* Update HTS that meets expected horizontal blanking */
-		ret = ov5670_write_reg(ov5670, OV5670_REG_HTS,
-				       OV5670_REG_VALUE_16BIT,
-				       (ov5670->cur_mode->width +
-					ctrl->val) / 2);
-		break;
 	case V4L2_CID_TEST_PATTERN:
 		ret = ov5670_enable_test_pattern(ov5670, ctrl->val);
 		break;
@@ -2078,9 +2077,11 @@ static int ov5670_init_controls(struct ov5670 *ov5670)
 
 	ov5670->hblank = v4l2_ctrl_new_std(
 				ctrl_hdlr, &ov5670_ctrl_ops, V4L2_CID_HBLANK,
-				OV5670_DEF_PPL - ov5670->cur_mode->width,
-				OV5670_DEF_PPL - ov5670->cur_mode->width, 1,
-				OV5670_DEF_PPL - ov5670->cur_mode->width);
+				OV5670_FIXED_PPL - ov5670->cur_mode->width,
+				OV5670_FIXED_PPL - ov5670->cur_mode->width, 1,
+				OV5670_FIXED_PPL - ov5670->cur_mode->width);
+	if (ov5670->hblank)
+		ov5670->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
 
 	/* Get min, max, step, default from sensor */
 	v4l2_ctrl_new_std(ctrl_hdlr, &ov5670_ctrl_ops, V4L2_CID_ANALOGUE_GAIN,
@@ -2247,7 +2248,7 @@ static int ov5670_set_pad_format(struct v4l2_subdev *sd,
 			OV5670_VTS_MAX - ov5670->cur_mode->height, 1,
 			vblank_def);
 		__v4l2_ctrl_s_ctrl(ov5670->vblank, vblank_def);
-		h_blank = OV5670_DEF_PPL - ov5670->cur_mode->width;
+		h_blank = OV5670_FIXED_PPL - ov5670->cur_mode->width;
 		__v4l2_ctrl_modify_range(ov5670->hblank, h_blank, h_blank, 1,
 					 h_blank);
 	}