Re: [PATCH/RFC v10 08/19] leds: Add support for max77693 mfd flash cell

[Jacek Anaszewski]

Hi Pavel,

Thanks for the review.

On 01/09/2015 07:46 PM, Pavel Machek wrote:
> On Fri 2015-01-09 16:22:58, Jacek Anaszewski wrote:
> > This patch adds led-flash support to Maxim max77693 chipset.
> > A device can be exposed to user space through LED subsystem
> > sysfs interface. Device supports up to two leds which can
> > work in flash and torch mode. The leds can be triggered
> > externally or by software.
>
> > +struct max77693_sub_led {
> > +	/* related FLED output identifier */
>
> ->flash LED, about 4x.
>
> > +/* split composite current @i into two @iout according to @imax weights */
> > +static void __max77693_calc_iout(u32 iout[2], u32 i, u32 imax[2])
> > +{
> > +	u64 t = i;
> > +
> > +	t *= imax[1];
> > +	do_div(t, imax[0] + imax[1]);
> > +
> > +	iout[1] = (u32)t / FLASH_IOUT_STEP * FLASH_IOUT_STEP;
> > +	iout[0] = i - iout[1];
> > +}
>
> Is 64-bit arithmetics neccessary here? Could we do the FLASH_IOUT_STEP
> divisons before t *=, so that 64-bit division is not neccessary?

It is required. All these operations allow for splitting the composite
current into both outputs according to weights given in the imax array.

> > +static int max77693_led_flash_strobe_get(
> > +				struct led_classdev_flash *fled_cdev,
> > +				bool *state)
> > +{
> > +	struct max77693_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
> > +	struct max77693_led_device *led = sub_led_to_led(sub_led);
> > +	int ret;
> > +
> > +	if (!state)
> > +		return -EINVAL;
> > +
> > +	mutex_lock(&led->lock);
> > +
> > +	ret = max77693_strobe_status_get(led, state);
> > +
> > +	*state = !!(*state && (led->strobing_sub_led_id == sub_led->fled_id));
> > +
> > +
> > +	mutex_unlock(&led->lock);
> > +
> > +	return ret;
> > +}
>
> Maybe remove some empty lines?

Of course.

--
Best Regards,
Jacek Anaszewski
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/