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@linux.dev>
---
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;
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
Hi Richard
On Mon, 3 Mar 2025 at 22:59, Richard Leitner <richard.leitner@linux.dev> 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@linux.dev>
> ---
> 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
>
>
On Tue, Mar 04, 2025 at 10:28:45AM +0000, Dave Stevenson wrote:
> Hi Richard
>
> On Mon, 3 Mar 2025 at 22:59, Richard Leitner <richard.leitner@linux.dev> 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@linux.dev>
> > ---
> > 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.
Sure. Thanks for reviewing and pointing this out. Will fix that in v2.
(At least I was consistent and made the same mistakes for both controls ;-))
regards;rl
>
> 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
> >
> >
On Tue, 4 Mar 2025 at 10:28, Dave Stevenson
<dave.stevenson@raspberrypi.com> wrote:
>
> Hi Richard
>
> On Mon, 3 Mar 2025 at 22:59, Richard Leitner <richard.leitner@linux.dev> 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.
Rereading the patch as I'm looking at the whole series.
set_frame_interval() will never be implemented as it is the wrong API
for raw sensors.
See https://www.kernel.org/doc/html/latest/userspace-api/media/drivers/camera-sensor.html#raw-camera-sensors
This driver already implements PIXEL_RATE, HBLANK, and VBLANK for
frame interval configuration.
> >
> > 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@linux.dev>
> > ---
> > 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
> >
> >
Hi Dave,
On Tue, Mar 04, 2025 at 05:30:13PM +0000, Dave Stevenson wrote:
> On Tue, 4 Mar 2025 at 10:28, Dave Stevenson
> <dave.stevenson@raspberrypi.com> wrote:
> >
> > Hi Richard
> >
> > On Mon, 3 Mar 2025 at 22:59, Richard Leitner <richard.leitner@linux.dev> 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.
>
> Rereading the patch as I'm looking at the whole series.
>
> set_frame_interval() will never be implemented as it is the wrong API
> for raw sensors.
> See https://www.kernel.org/doc/html/latest/userspace-api/media/drivers/camera-sensor.html#raw-camera-sensors
> This driver already implements PIXEL_RATE, HBLANK, and VBLANK for
> frame interval configuration.
Thanks Dave for bringing this up and sorry for not having known that
before posting this series. It's my first work on camera sensors/v4l2
and altough I have read a ton of docs I somehow missed this one.
So regarding this patch: Should the maximum flash duration be calculated
from the frame interval (as described in the docs)?
Or is a "pretty high" constant maximum value preferred?
regards;rl
>
> > >
> > > 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@linux.dev>
> > > ---
> > > 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
> > >
> > >
© 2016 - 2026 Red Hat, Inc.