@@ -128,6 +128,8 @@
#define OV9282_REG_MIN 0x00
#define OV9282_REG_MAX 0xfffff
+#define OV9282_STROBE_SPAN_FACTOR 192
+
static const char * const ov9282_supply_names[] = {
"avdd", /* Analog power */
"dovdd", /* Digital I/O power */
@@ -691,7 +693,7 @@ static int ov9282_set_ctrl_flash_led_mode(struct ov9282 *ov9282, int mode)
current_val);
}
-static int ov9282_set_ctrl_flash_duration(struct ov9282 *ov9282, int value)
+static u32 ov9282_us_to_flash_duration(struct ov9282 *ov9282, u32 value)
{
/*
* Calculate "strobe_frame_span" increments from a given value (µs).
@@ -702,7 +704,31 @@ static int ov9282_set_ctrl_flash_duration(struct ov9282 *ov9282, int value)
* 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);
+ u32 frame_width = ov9282->cur_mode->width + ov9282->hblank_ctrl->val;
+
+ return value * OV9282_STROBE_SPAN_FACTOR / frame_width;
+}
+
+static u32 ov9282_flash_duration_to_us(struct ov9282 *ov9282, u32 value)
+{
+ /*
+ * As the calculation in ov9282_us_to_flash_duration uses an integer
+ * divison calculate in ns here to get more precision. Then check if
+ * we need to compensate that divison by incrementing the µs result.
+ */
+ u32 frame_width = ov9282->cur_mode->width + ov9282->hblank_ctrl->val;
+ u64 ns = value * 1000 * frame_width / OV9282_STROBE_SPAN_FACTOR;
+ u32 us = ns / 1000;
+ u32 remainder = ns % 1000;
+
+ if (remainder > 0)
+ us++;
+ return us;
+}
+
+static int ov9282_set_ctrl_flash_duration(struct ov9282 *ov9282, int value)
+{
+ u32 val = ov9282_us_to_flash_duration(ov9282, value);
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);
@@ -792,9 +818,35 @@ static int ov9282_set_ctrl(struct v4l2_ctrl *ctrl)
return ret;
}
+static int ov9282_try_ctrl(struct v4l2_ctrl *ctrl)
+{
+ struct ov9282 *ov9282 =
+ container_of(ctrl->handler, struct ov9282, ctrl_handler);
+
+ if (ctrl->id == V4L2_CID_FLASH_DURATION) {
+ u32 fd = ov9282_us_to_flash_duration(ov9282, ctrl->val);
+ u32 us = ctrl->val;
+ u32 us0 = ov9282_flash_duration_to_us(ov9282, fd);
+ u32 us1 = ov9282_flash_duration_to_us(ov9282, (fd + 1));
+
+ if ((us1 - us) < (us - us0))
+ ctrl->val = us1;
+ else
+ ctrl->val = us0;
+
+ if (us != ctrl->val) {
+ dev_dbg(ov9282->dev, "using next valid strobe_duration %u instead of %u\n",
+ ctrl->val, us);
+ }
+ }
+
+ return 0;
+}
+
/* V4l2 subdevice control ops*/
static const struct v4l2_ctrl_ops ov9282_ctrl_ops = {
.s_ctrl = ov9282_set_ctrl,
+ .try_ctrl = ov9282_try_ctrl,
};
/**
As the granularity of the hardware supported values is lower than the control value, implement a try_ctrl() function for V4L2_CID_FLASH_DURATION. This function calculates the nearest possible µs strobe duration for the given value and returns it back to the caller. Signed-off-by: Richard Leitner <richard.leitner@linux.dev> --- drivers/media/i2c/ov9282.c | 56 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 2 deletions(-)