[PATCH v2 10/20] media: imx355: Remove redundant fll_min, and implement fixed offset

[Dave Stevenson <dave.stevenson@raspberrypi.com>]

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 the 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.

Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/media/i2c/imx355.c | 26 ++++----------------------
 1 file changed, 4 insertions(+), 22 deletions(-)

diff --git a/drivers/media/i2c/imx355.c b/drivers/media/i2c/imx355.c
index 9d977bac23b6..354092295b7c 100644
--- a/drivers/media/i2c/imx355.c
+++ b/drivers/media/i2c/imx355.c
@@ -32,6 +32,7 @@
 /* V_TIMING internal */
 #define IMX355_REG_FLL			0x0340
 #define IMX355_FLL_MAX			0xffff
+#define IMX355_VBLANK_MIN		20
 
 #define IMX355_REG_LLP			0x0342
 #define IMX355_LLP_MAX			0xffff
@@ -105,7 +106,6 @@ struct imx355_mode {
 
 	/* V-timing */
 	u32 fll_def;
-	u32 fll_min;
 
 	/* H-timing */
 	u32 llp;
@@ -358,7 +358,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 0,
 		},
 		.fll_def = 2615,
-		.fll_min = 2615,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_3280x2464_regs),
@@ -375,7 +374,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 8,
 		},
 		.fll_def = 2615,
-		.fll_min = 2615,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_3268x2448_regs),
@@ -392,7 +390,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 8,
 		},
 		.fll_def = 2615,
-		.fll_min = 2615,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_3264x2448_regs),
@@ -409,7 +406,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 684,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1940x1096_regs),
@@ -426,7 +422,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 684,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1936x1096_regs),
@@ -443,7 +438,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 692,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1924x1080_regs),
@@ -460,7 +454,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 692,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1920x1080_regs),
@@ -477,7 +470,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 0,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1640x1232_regs),
@@ -494,7 +486,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 304,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1640x922_regs),
@@ -511,7 +502,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 496,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1300x736_regs),
@@ -528,7 +518,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 496,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1296x736_regs),
@@ -545,7 +534,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 512,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1284x720_regs),
@@ -562,7 +550,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 512,
 		},
 		.fll_def = 1306,
-		.fll_min = 1306,
 		.llp = 1836,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_1280x720_regs),
@@ -579,7 +566,6 @@ static const struct imx355_mode supported_modes[] = {
 			.top = 0,
 		},
 		.fll_def = 652,
-		.fll_min = 652,
 		.llp = 3672,
 		.reg_list = {
 			.num_of_regs = ARRAY_SIZE(mode_820x616_regs),
@@ -863,7 +849,6 @@ 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;
 
@@ -888,10 +873,9 @@ 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_VBLANK_MIN,
+					 height, 1, vblank_def);
 		__v4l2_ctrl_s_ctrl(imx355->vblank, vblank_def);
 		h_blank = mode->llp - imx355->cur_mode->width;
 		/*
@@ -1151,7 +1135,6 @@ 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;
@@ -1181,9 +1164,8 @@ 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_VBLANK_MIN,
 					   IMX355_FLL_MAX - mode->height,
 					   1, vblank_def);
 

-- 
2.34.1