[PATCH 09/13] media: imx355: Remove redundant fll_min, and implement fixed offset

[Dave Stevenson]

fll_min (Frame Length Lines) is set to the same value as fll_def
for all modes, which makes it redundant.

The actual value is also erroneous as sensor works in all the
defined modes with FLL set at the mode height + 20 lines, so
set the vblank control minimum to 20 rather than varying it.
This also improves the maximum frame rate achievable.

Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
---
 drivers/media/i2c/imx355.c | 27 +++++----------------------
 1 file changed, 5 insertions(+), 22 deletions(-)

diff --git a/drivers/media/i2c/imx355.c b/drivers/media/i2c/imx355.c
index 12005bc40f36..5a3bfcd0f51c 100644
--- a/drivers/media/i2c/imx355.c
+++ b/drivers/media/i2c/imx355.c
@@ -33,6 +33,8 @@
 /* V_TIMING internal */
 #define IMX355_REG_FLL			0x0340
 #define IMX355_FLL_MAX			0xffff
+/* Number of lines above frame height that are required. */
+#define IMX355_FLL_OFFSET		20
 
 #define IMX355_REG_LLP			0x0342
 #define IMX355_LLP_MAX			0xffff
@@ -105,7 +107,6 @@ struct imx355_mode {
 
 	/* V-timing */
 	u32 fll_def;
-	u32 fll_min;
 
 	/* H-timing */
 	u32 llp;
@@ -360,7 +361,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 3280,
 		.height = 2464,
 		.fll_def = 2615,
-		.fll_min = 2615,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_3280x2464_regs),
@@ -376,7 +376,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 3268,
 		.height = 2448,
 		.fll_def = 2615,
-		.fll_min = 2615,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_3268x2448_regs),
@@ -392,7 +391,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 3264,
 		.height = 2448,
 		.fll_def = 2615,
-		.fll_min = 2615,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_3264x2448_regs),
@@ -408,7 +406,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1940,
 		.height = 1096,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1940x1096_regs),
@@ -424,7 +421,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1936,
 		.height = 1096,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1936x1096_regs),
@@ -440,7 +436,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1924,
 		.height = 1080,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1924x1080_regs),
@@ -456,7 +451,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1920,
 		.height = 1080,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1920x1080_regs),
@@ -472,7 +466,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1640,
 		.height = 1232,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1640x1232_regs),
@@ -488,7 +481,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1640,
 		.height = 922,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1640x922_regs),
@@ -504,7 +496,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1300,
 		.height = 736,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1300x736_regs),
@@ -520,7 +511,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1296,
 		.height = 736,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1296x736_regs),
@@ -536,7 +526,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1284,
 		.height = 720,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1284x720_regs),
@@ -552,7 +541,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 1280,
 		.height = 720,
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1280x720_regs),
@@ -568,7 +556,6 @@ static const struct imx355_mode supported_modes[] = {
 		.width = 820,
 		.height = 616,
 		.fll_def = 652,
-		.fll_min = 652,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_820x616_regs),
@@ -857,7 +844,6 @@ imx355_set_pad_format(struct v4l2_subdev *sd,
 	const struct imx355_mode *mode;
 	struct v4l2_mbus_framefmt *framefmt;
 	s32 vblank_def;
-	s32 vblank_min;
 	s64 h_blank;
 	u32 height;
 
@@ -882,10 +868,9 @@ imx355_set_pad_format(struct v4l2_subdev *sd,
 		/* Update limits and set FPS to default */
 		height = imx355->cur_mode->height;
 		vblank_def = imx355->cur_mode->fll_def - height;
-		vblank_min = imx355->cur_mode->fll_min - height;
 		height = IMX355_FLL_MAX - height;
-		__v4l2_ctrl_modify_range(imx355->vblank, vblank_min, height, 1,
-					 vblank_def);
+		__v4l2_ctrl_modify_range(imx355->vblank, IMX355_FLL_OFFSET,
+					 height, 1, vblank_def);
 		__v4l2_ctrl_s_ctrl(imx355->vblank, vblank_def);
 		h_blank = mode->llp - imx355->cur_mode->width;
 		/*
@@ -1146,7 +1131,6 @@ static int imx355_init_controls(struct imx355 *imx355)
 	struct v4l2_ctrl_handler *ctrl_hdlr;
 	s64 exposure_max;
 	s64 vblank_def;
-	s64 vblank_min;
 	s64 hblank;
 	u64 pixel_rate;
 	const struct imx355_mode *mode;
@@ -1176,9 +1160,8 @@ static int imx355_init_controls(struct imx355 *imx355)
 	/* Initialize vblank/hblank/exposure parameters based on current mode */
 	mode = imx355->cur_mode;
 	vblank_def = mode->fll_def - mode->height;
-	vblank_min = mode->fll_min - mode->height;
 	imx355->vblank = v4l2_ctrl_new_std(ctrl_hdlr, &imx355_ctrl_ops,
-					   V4L2_CID_VBLANK, vblank_min,
+					   V4L2_CID_VBLANK, IMX355_FLL_OFFSET,
 					   IMX355_FLL_MAX - mode->height,
 					   1, vblank_def);
 

-- 
2.34.1