[PATCH v2 3/3] media: i2c: imx219: Scale the pixel rate for analog binning

Jai Luthra
2024-11-21T12:09:22Z

When the analog binning mode is used for high framerate operation,
the pixel rate is effectively doubled. Account for this when setting up
the pixel clock rate, and applying the vblank and exposure controls.

The previous logic only used analog binning for 8-bit modes, but normal
binning limits the framerate on 10-bit 480p [1]. So with this patch we
switch to using special binning (with 2x pixel rate) for all formats of
480p mode and 8-bit 1232p.

To do this cleanly, re-introduce the book-keeping for which binning mode
is used with which resolution/format.

[1]: https://github.com/raspberrypi/linux/issues/5493

Co-developed-by: Naushir Patuck <naush@raspberrypi.com>
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Co-developed-by: Vinay Varma <varmavinaym@gmail.com>
Signed-off-by: Vinay Varma <varmavinaym@gmail.com>
Signed-off-by: Jai Luthra <jai.luthra@ideasonboard.com>
---
drivers/media/i2c/imx219.c | 138 ++++++++++++++++++++++++++++++---------------
1 file changed, 94 insertions(+), 44 deletions(-)

diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
index 970e6362d0ae3a9078daf337155e83d637bc1ca1..ec795569361987ae30bff234e97fa34600bf5975 100644
--- a/drivers/media/i2c/imx219.c
+++ b/drivers/media/i2c/imx219.c
@@ -149,6 +149,18 @@
#define IMX219_PIXEL_ARRAY_WIDTH 3280U
#define IMX219_PIXEL_ARRAY_HEIGHT 2464U

+enum binning_mode {
+ BINNING_NONE = IMX219_BINNING_NONE,
+ BINNING_X2 = IMX219_BINNING_X2,
+ BINNING_ANALOG_X2 = IMX219_BINNING_X2_ANALOG,
+};
+
+enum binning_bit_depths {
+ BINNING_IDX_8_BIT,
+ BINNING_IDX_10_BIT,
+ BINNING_IDX_MAX
+};
+
/* Mode : resolution and related config&values */
struct imx219_mode {
/* Frame width */
@@ -158,6 +170,9 @@ struct imx219_mode {

/* V-timing */
unsigned int vts_def;
+
+ /* binning mode based on format code */
+ enum binning_mode binning[BINNING_IDX_MAX];
};

static const struct cci_reg_sequence imx219_common_regs[] = {
@@ -293,24 +308,40 @@ static const struct imx219_mode supported_modes[] = {
.width = 3280,
.height = 2464,
.vts_def = 3526,
+ .binning = {
+ [BINNING_IDX_8_BIT] = BINNING_NONE,
+ [BINNING_IDX_10_BIT] = BINNING_NONE,
+ },
},
{
/* 1080P 30fps cropped */
.width = 1920,
.height = 1080,
.vts_def = 1763,
+ .binning = {
+ [BINNING_IDX_8_BIT] = BINNING_NONE,
+ [BINNING_IDX_10_BIT] = BINNING_NONE,
+ },
},
{
/* 2x2 binned 30fps mode */
.width = 1640,
.height = 1232,
.vts_def = 1763,
+ .binning = {
+ [BINNING_IDX_8_BIT] = BINNING_ANALOG_X2,
+ [BINNING_IDX_10_BIT] = BINNING_X2,
+ },
},
{
/* 640x480 30fps mode */
.width = 640,
.height = 480,
.vts_def = 1763,
+ .binning = {
+ [BINNING_IDX_8_BIT] = BINNING_ANALOG_X2,
+ [BINNING_IDX_10_BIT] = BINNING_ANALOG_X2,
+ },
},
};

@@ -337,6 +368,9 @@ struct imx219 {

/* Two or Four lanes */
u8 lanes;
+
+ /* Binning mode */
+ enum binning_mode binning;
};

static inline struct imx219 *to_imx219(struct v4l2_subdev *_sd)
@@ -362,6 +396,36 @@ static u32 imx219_get_format_code(struct imx219 *imx219, u32 code)
return imx219_mbus_formats[i];
}

+static u32 imx219_get_format_bpp(const struct v4l2_mbus_framefmt *format)
+{
+ switch (format->code) {
+ case MEDIA_BUS_FMT_SRGGB8_1X8:
+ case MEDIA_BUS_FMT_SGRBG8_1X8:
+ case MEDIA_BUS_FMT_SGBRG8_1X8:
+ case MEDIA_BUS_FMT_SBGGR8_1X8:
+ return 8;
+
+ case MEDIA_BUS_FMT_SRGGB10_1X10:
+ case MEDIA_BUS_FMT_SGRBG10_1X10:
+ case MEDIA_BUS_FMT_SGBRG10_1X10:
+ case MEDIA_BUS_FMT_SBGGR10_1X10:
+ default:
+ return 10;
+ }
+}
+
+static int imx219_get_rate_factor(struct imx219 *imx219)
+{
+ switch (imx219->binning) {
+ case BINNING_NONE:
+ case BINNING_X2:
+ return 1;
+ case BINNING_ANALOG_X2:
+ return 2;
+ }
+ return -EINVAL;
+}
+
/* -----------------------------------------------------------------------------
* Controls
*/
@@ -373,10 +437,12 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
struct i2c_client *client = v4l2_get_subdevdata(&imx219->sd);
const struct v4l2_mbus_framefmt *format;
struct v4l2_subdev_state *state;
+ int rate_factor;
int ret = 0;

state = v4l2_subdev_get_locked_active_state(&imx219->sd);
format = v4l2_subdev_state_get_format(state, 0);
+ rate_factor = imx219_get_rate_factor(imx219);

if (ctrl->id == V4L2_CID_VBLANK) {
int exposure_max, exposure_def;
@@ -405,7 +471,7 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
break;
case V4L2_CID_EXPOSURE:
cci_write(imx219->regmap, IMX219_REG_EXPOSURE,
- ctrl->val, &ret);
+ ctrl->val / rate_factor, &ret);
break;
case V4L2_CID_DIGITAL_GAIN:
cci_write(imx219->regmap, IMX219_REG_DIGITAL_GAIN,
@@ -422,7 +488,7 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
break;
case V4L2_CID_VBLANK:
cci_write(imx219->regmap, IMX219_REG_VTS,
- format->height + ctrl->val, &ret);
+ (format->height + ctrl->val) / rate_factor, &ret);
break;
case V4L2_CID_HBLANK:
cci_write(imx219->regmap, IMX219_REG_HTS,
@@ -463,7 +529,8 @@ static const struct v4l2_ctrl_ops imx219_ctrl_ops = {

static unsigned long imx219_get_pixel_rate(struct imx219 *imx219)
{
- return (imx219->lanes == 2) ? IMX219_PIXEL_RATE : IMX219_PIXEL_RATE_4LANE;
+ return ((imx219->lanes == 2) ? IMX219_PIXEL_RATE :
+ IMX219_PIXEL_RATE_4LANE) * imx219_get_rate_factor(imx219);
}

/* Initialize control handlers */
@@ -592,29 +659,12 @@ static int imx219_set_framefmt(struct imx219 *imx219,
{
const struct v4l2_mbus_framefmt *format;
const struct v4l2_rect *crop;
- unsigned int bpp;
- u64 bin_h, bin_v;
+ u32 bpp;
int ret = 0;

format = v4l2_subdev_state_get_format(state, 0);
crop = v4l2_subdev_state_get_crop(state, 0);
-
- switch (format->code) {
- case MEDIA_BUS_FMT_SRGGB8_1X8:
- case MEDIA_BUS_FMT_SGRBG8_1X8:
- case MEDIA_BUS_FMT_SGBRG8_1X8:
- case MEDIA_BUS_FMT_SBGGR8_1X8:
- bpp = 8;
- break;
-
- case MEDIA_BUS_FMT_SRGGB10_1X10:
- case MEDIA_BUS_FMT_SGRBG10_1X10:
- case MEDIA_BUS_FMT_SGBRG10_1X10:
- case MEDIA_BUS_FMT_SBGGR10_1X10:
- default:
- bpp = 10;
- break;
- }
+ bpp = imx219_get_format_bpp(format);

cci_write(imx219->regmap, IMX219_REG_X_ADD_STA_A,
crop->left - IMX219_PIXEL_ARRAY_LEFT, &ret);
@@ -625,28 +675,8 @@ static int imx219_set_framefmt(struct imx219 *imx219,
cci_write(imx219->regmap, IMX219_REG_Y_ADD_END_A,
crop->top - IMX219_PIXEL_ARRAY_TOP + crop->height - 1, &ret);

- switch (crop->width / format->width) {
- case 1:
- default:
- bin_h = IMX219_BINNING_NONE;
- break;
- case 2:
- bin_h = bpp == 8 ? IMX219_BINNING_X2_ANALOG : IMX219_BINNING_X2;
- break;
- }
-
- switch (crop->height / format->height) {
- case 1:
- default:
- bin_v = IMX219_BINNING_NONE;
- break;
- case 2:
- bin_v = bpp == 8 ? IMX219_BINNING_X2_ANALOG : IMX219_BINNING_X2;
- break;
- }
-
- cci_write(imx219->regmap, IMX219_REG_BINNING_MODE_H, bin_h, &ret);
- cci_write(imx219->regmap, IMX219_REG_BINNING_MODE_V, bin_v, &ret);
+ cci_write(imx219->regmap, IMX219_REG_BINNING_MODE_H, imx219->binning, &ret);
+ cci_write(imx219->regmap, IMX219_REG_BINNING_MODE_V, imx219->binning, &ret);

cci_write(imx219->regmap, IMX219_REG_X_OUTPUT_SIZE,
format->width, &ret);
@@ -851,6 +881,21 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
int exposure_max;
int exposure_def;
int hblank;
+ int pixel_rate;
+
+ /* Update binning mode based on format */
+ switch (imx219_get_format_bpp(format)) {
+ case 8:
+ imx219->binning = mode->binning[BINNING_IDX_8_BIT];
+ break;
+
+ case 10:
+ imx219->binning = mode->binning[BINNING_IDX_10_BIT];
+ break;
+
+ default:
+ imx219->binning = BINNING_NONE;
+ }

/* Update limits and set FPS to default */
__v4l2_ctrl_modify_range(imx219->vblank, IMX219_VBLANK_MIN,
@@ -879,6 +924,11 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
IMX219_PPL_MAX - mode->width,
1, IMX219_PPL_MIN - mode->width);
__v4l2_ctrl_s_ctrl(imx219->hblank, hblank);
+
+ /* Scale the pixel rate based on the mode specific factor */
+ pixel_rate = imx219_get_pixel_rate(imx219);
+ __v4l2_ctrl_modify_range(imx219->pixel_rate, pixel_rate,
+ pixel_rate, 1, pixel_rate);
}

return 0;

--
2.47.0