Hi Richard
On Mon, 3 Mar 2025 at 22:59, Richard Leitner <richard.leitner@xxxxxxxxx> wrote:
>
> Add V4L2_CID_FLASH_TIMEOUT support using the "strobe_frame_span"
> feature of the sensor. This is implemented by transforming the given µs
> value by an interpolated formula to a "span step width" value and
> writing it to register PWM_CTRL_25, PWM_CTRL_26, PWM_CTRL_27,
> PWM_CTRL_28 (0x3925, 0x3926, 0x3927, 0x3928).
>
> The maximum control value is set to the period of the current framerate.
> This must be changed to a dynamic range as soon as this driver
> implements the set_frame_interval() pad operation.
>
> All register values are based on the OV9281 datasheet v1.53 (jan 2019)
> and tested using an ov9281 VisionComponents module.
>
> Signed-off-by: Richard Leitner <richard.leitner@xxxxxxxxx>
> ---
> drivers/media/i2c/ov9282.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> index c98ba466e9aea29baff0b13578d760bf69c958c5..f7dfe8987e524b73af7e16e12567e96627b4f89a 100644
> --- a/drivers/media/i2c/ov9282.c
> +++ b/drivers/media/i2c/ov9282.c
> @@ -97,6 +97,10 @@
> #define OV9282_REG_MIPI_CTRL00 0x4800
> #define OV9282_GATED_CLOCK BIT(5)
>
> +/* Flash/Strobe control registers */
> +#define OV9282_REG_FLASH_DURATION 0x3925
> +#define OV9282_FLASH_DURATION_DEFAULT 0x0000001A
> +
> /* Input clock rate */
> #define OV9282_INCLK_RATE 24000000
>
> @@ -193,6 +197,7 @@ struct ov9282_mode {
> * @again_ctrl: Pointer to analog gain control
> * @pixel_rate: Pointer to pixel rate control
> * @flash_led_mode: Pointer to flash led mode control
> + * @flash_timeout: Pointer to flash timeout control
> * @vblank: Vertical blanking in lines
> * @noncontinuous_clock: Selection of CSI2 noncontinuous clock mode
> * @cur_mode: Pointer to current selected sensor mode
> @@ -216,6 +221,7 @@ struct ov9282 {
> };
> struct v4l2_ctrl *pixel_rate;
> struct v4l2_ctrl *flash_led_mode;
> + struct v4l2_ctrl *flash_timeout;
You only access this in ov9282_set_ctrl where you already have the
struct v4l2_ctrl, so there is no need to store this in the main device
state.
Dave
> u32 vblank;
> bool noncontinuous_clock;
> const struct ov9282_mode *cur_mode;
> @@ -689,6 +695,24 @@ static int ov9282_set_ctrl_flash_led_mode(struct ov9282 *ov9282, int mode)
> current_val);
> }
>
> +static int ov9282_set_ctrl_flash_timeout(struct ov9282 *ov9282, int value)
> +{
> + /* Calculate "strobe_frame_span" increments from a given value (µs).
> + * This is quite tricky as "The step width of shift and span is
> + * programmable under system clock domain.", but it's not documented
> + * how to program this step width (at least in the datasheet available
> + * to the author at time of writing).
> + * The formula below is interpolated from different modes/framerates
> + * and should work quite well for most settings.
> + */
> + u32 val = value * 192 / (ov9282->cur_mode->width + ov9282->hblank_ctrl->val);
> +
> + ov9282_write_reg(ov9282, OV9282_REG_FLASH_DURATION, 1, (val >> 24) & 0xff);
> + ov9282_write_reg(ov9282, OV9282_REG_FLASH_DURATION + 1, 1, (val >> 16) & 0xff);
> + ov9282_write_reg(ov9282, OV9282_REG_FLASH_DURATION + 2, 1, (val >> 8) & 0xff);
> + return ov9282_write_reg(ov9282, OV9282_REG_FLASH_DURATION + 3, 1, val & 0xff);
> +}
> +
> /**
> * ov9282_set_ctrl() - Set subdevice control
> * @ctrl: pointer to v4l2_ctrl structure
> @@ -758,6 +782,9 @@ static int ov9282_set_ctrl(struct v4l2_ctrl *ctrl)
> case V4L2_CID_FLASH_LED_MODE:
> ret = ov9282_set_ctrl_flash_led_mode(ov9282, ctrl->val);
> break;
> + case V4L2_CID_FLASH_TIMEOUT:
> + ret = ov9282_set_ctrl_flash_timeout(ov9282, ctrl->val);
> + break;
> default:
> dev_err(ov9282->dev, "Invalid control %d", ctrl->id);
> ret = -EINVAL;
> @@ -1420,6 +1447,10 @@ static int ov9282_init_controls(struct ov9282 *ov9282)
> (1 << V4L2_FLASH_LED_MODE_TORCH),
> V4L2_FLASH_LED_MODE_NONE);
>
> + ov9282->flash_timeout = v4l2_ctrl_new_std(ctrl_hdlr, &ov9282_ctrl_ops,
> + V4L2_CID_FLASH_TIMEOUT,
> + 0, 13900, 1, 8);
> +
> ret = v4l2_fwnode_device_parse(ov9282->dev, &props);
> if (!ret) {
> /* Failure sets ctrl_hdlr->error, which we check afterwards anyway */
>
> --
> 2.47.2
>
>
