Hi Dave
On Tue, May 30, 2023 at 06:29:49PM +0100, Dave Stevenson wrote:
> V4L2 sensor drivers are expected are expected to clip the supported
> exposure range based on the VBLANK configured.
> IMX258 wasn't doing that as register 0x350 (FRM_LENGTH_CTL)
> switches it to a mode where frame length tracks coarse exposure time.
>
> Disable this mode and clip the range for V4L2_CID_EXPOSURE appropriately
> based on V4L2_CID_VBLANK.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
Ah, here you go!
Reviewed-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
thanks
j
> ---
> drivers/media/i2c/imx258.c | 25 +++++++++++++++++++++++--
> 1 file changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
> index 433dff7f1fa0..82ffe09e3bdc 100644
> --- a/drivers/media/i2c/imx258.c
> +++ b/drivers/media/i2c/imx258.c
> @@ -37,10 +37,11 @@
>
> /* Exposure control */
> #define IMX258_REG_EXPOSURE 0x0202
> +#define IMX258_EXPOSURE_OFFSET 10
> #define IMX258_EXPOSURE_MIN 4
> #define IMX258_EXPOSURE_STEP 1
> #define IMX258_EXPOSURE_DEFAULT 0x640
> -#define IMX258_EXPOSURE_MAX 65535
> +#define IMX258_EXPOSURE_MAX (IMX258_VTS_MAX - IMX258_EXPOSURE_OFFSET)
>
> /* Analog gain control */
> #define IMX258_REG_ANALOG_GAIN 0x0204
> @@ -366,7 +367,7 @@ static const struct imx258_reg mode_common_regs[] = {
> { 0x303A, 0x00 },
> { 0x303B, 0x10 },
> { 0x300D, 0x00 },
> - { 0x0350, 0x01 },
> + { 0x0350, 0x00 },
> { 0x0204, 0x00 },
> { 0x0205, 0x00 },
> { 0x020E, 0x01 },
> @@ -739,6 +740,19 @@ static int imx258_update_digital_gain(struct imx258 *imx258, u32 len, u32 val)
> return 0;
> }
>
> +static void imx258_adjust_exposure_range(struct imx258 *imx258)
> +{
> + int exposure_max, exposure_def;
> +
> + /* Honour the VBLANK limits when setting exposure. */
> + exposure_max = imx258->cur_mode->height + imx258->vblank->val -
> + IMX258_EXPOSURE_OFFSET;
> + exposure_def = min(exposure_max, imx258->exposure->val);
> + __v4l2_ctrl_modify_range(imx258->exposure, imx258->exposure->minimum,
> + exposure_max, imx258->exposure->step,
> + exposure_def);
> +}
> +
> static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
> {
> struct imx258 *imx258 =
> @@ -746,6 +760,13 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
> struct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);
> int ret = 0;
>
> + /*
> + * The VBLANK control may change the limits of usable exposure, so check
> + * and adjust if necessary.
> + */
> + if (ctrl->id == V4L2_CID_VBLANK)
> + imx258_adjust_exposure_range(imx258);
> +
> /*
> * Applying V4L2 control value only happens
> * when power is up for streaming
> --
> 2.25.1
>
