[PATCH v2 10/20] media: imx355: Remove redundant fll_min, and implement fixed offset
From: Dave Stevenson
Date: Tue Jul 07 2026 - 13:10:47 EST
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@xxxxxxxxxxxxxxxx>
Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
---
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