Hi Jacek,
Jacek Anaszewski wrote:
...
>>> +#define call_flash_op(v4l2_flash, op, arg) \
>>> + (has_flash_op(v4l2_flash,
>>> op) ? \
>>> + v4l2_flash->ops->op(v4l2_flash,
>>> arg) : \
>>> + -EINVAL)
>>> +
>>> +static enum led_brightness __intensity_to_led_brightness(
>>> + struct v4l2_ctrl *ctrl,
>>> + s32 intensity)
>>
>> Fits on previous line.
>>
>>> +{
>>> + s64 intensity64 = intensity - ctrl->minimum;
>>
>> intensity, ctrl->step and ctrl->minimum are 32-bit signed integers.
>> Do you need a 64-bit integer here?
>
> step is u64.
Nevertheless integer controls will not have values outside the s32
range, using a step value that's outside the range makes no sense
either. I think you should use s32 instead.
>
>>
>>> +
>>> + do_div(intensity64, ctrl->step);
>>> +
>>> + /*
>>> + * Indicator LEDs, unlike torch LEDs, are turned on/off
>>> basing on
>>> + * the state of V4L2_CID_FLASH_INDICATOR_INTENSITY control
>>> only.
>>> + * Therefore it must be possible to set it to 0 level
>>> which in
>>> + * the LED subsystem reflects LED_OFF state.
>>> + */
>>> + if (ctrl->id != V4L2_CID_FLASH_INDICATOR_INTENSITY)
>>> + ++intensity64;
>>
>> I think the condition could simply be ctrl->minimum instead, that way
>> I find it easier to understand what's happening here. I'd expect the
>> minimum for non-intensity controls always to be non-zero, though, so
>> the end result is the same. Up to you.
>
> Minimum for indicator control must be 0 to make possible
> turning the indicator LED off only with this control.
Would torch be still on if the minimum torch current was 0 mA? I'd say no.
Although in that case I'd expect the driver to use a different range,
and selecting the off mode would then turn it off, I still think that's
a better condition than relying on the control id.
...
>>> +static int v4l2_flash_g_volatile_ctrl(struct v4l2_ctrl *c)
>>> +{
>>> + struct v4l2_flash *v4l2_flash = v4l2_ctrl_to_v4l2_flash(c);
>>> + struct led_classdev_flash *fled_cdev =
>>> v4l2_flash->fled_cdev;
>>> + bool is_strobing;
>>> + int ret;
>>> +
>>> + switch (c->id) {
>>> + case V4L2_CID_FLASH_TORCH_INTENSITY:
>>> + case V4L2_CID_FLASH_INDICATOR_INTENSITY:
>>> + return
>>> v4l2_flash_update_led_brightness(v4l2_flash, c);
>>> + case V4L2_CID_FLASH_INTENSITY:
>>> + ret = led_update_flash_brightness(fled_cdev);
>>> + if (ret < 0)
>>> + return ret;
>>> + /* no conversion is needed */
>>
>> Maybe a stupid question, but why is it not needed?
>
> Because LED Flash class also uses microamperes.
Right, I had missed that. It'd be nice if that was said in the comment,
it might not be obvious to others either.
--
Kind regards,
Sakari Ailus
sakari.ai...@iki.fi
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