Re: [PATCH 1/2] leds: flash: lm3643: Return to standby when the last output is switched off

[Lee Jones <lee@kernel.org>]

--- checkpatch.pl: clean (0 issues) ---

On Thu, 24 Sep 2026, Ruslan Koreev wrote:

> Setting the torch brightness of an output to 0 only cleared its enable
> bit and left the mode bits at torch (or flash), so the chip kept its
> boost converter running with no output enabled. Likewise switching the
> strobe off returned early when the output's enable bit had already been
> cleared, leaving the mode bits at flash. Both were flagged by the
> Sashiko review of the RFC, which Lee Jones asked to have addressed.
>
> Clear the mode bits together with the enable bit whenever the sibling
> output is not active, so that the chip goes back to standby when its
> last output is switched off.
>
> Signed-off-by: Ruslan Koreev <koreev.r@gmail.com>

Given that the base series hasn't been merged yet, please coordinate with
Rillian to fold these fixes directly into the next version of the original
series rather than sending fix-up patches on top of an unapplied RFC.

> ---
>  drivers/leds/flash/leds-lm3643.c | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/leds/flash/leds-lm3643.c b/drivers/leds/flash/leds-lm3643.c
> index 48e164261..bbe9358c9 100644
> --- a/drivers/leds/flash/leds-lm3643.c
> +++ b/drivers/leds/flash/leds-lm3643.c
> @@ -271,9 +271,15 @@ static int lm3643_torch_set_brightness(struct led_classdev *led_cdev,
>  	    mode != LM3643_MODE_TORCH)
>  		return -EBUSY;
>
> -	if (brightness == 0)
> -		return regmap_update_bits(led->regmap, LM3643_REG_ENABLE,
> -				chan->enable_bit, 0);
> +	if (brightness == 0) {
> +		unsigned int mask = chan->enable_bit;
> +
> +		/* Last active output: leave torch mode, back to standby */
> +		if (!(enable & sibling_bit))
> +			mask |= LM3643_MODE_MASK;
> +
> +		return regmap_update_bits(led->regmap, LM3643_REG_ENABLE, mask, 0);
> +	}
>
>  	ret = regmap_update_bits(led->regmap, chan->torch_br_reg, LM3643_TORCH_BR_MASK,
>  				 LM3643_TORCH_BR_CDEV_TO_CODE(brightness));
> @@ -365,11 +371,16 @@ static int lm3643_flash_strobe_set(struct led_classdev_flash *fled_cdev, bool st
>  	mode = enable_reg & LM3643_MODE_MASK;
>
>  	if (!state) {
> -		if (mode != LM3643_MODE_FLASH || !(enable_reg & chan->enable_bit))
> +		unsigned int mask = chan->enable_bit;
> +
> +		if (mode != LM3643_MODE_FLASH)
>  			return 0;
>
> -		return regmap_update_bits(led->regmap, LM3643_REG_ENABLE,
> -			LM3643_MODE_MASK, LM3643_MODE_STANDBY);
> +		/* Leave flash mode once no other output is strobing */
> +		if (!(enable_reg & sibling_bit))
> +			mask |= LM3643_MODE_MASK;
> +
> +		return regmap_update_bits(led->regmap, LM3643_REG_ENABLE, mask, 0);
>  	}
>  	if ((enable_reg & sibling_bit) && mode != LM3643_MODE_STANDBY)
>  		return -EBUSY;
> -- 
> 2.55.0
>

-- 
Lee Jones