Re: [PATCH v2 1/7] platform/x86: uniwill-laptop: Properly initialize charging threshold

[Ilpo Järvinen]

On Fri, 17 Apr 2026, Armin Wolf wrote:

> The EC might initialize the charge threshold with 0 to signal that
> said threshold is uninitialized. Detect this and replace said value
> with 100 to signal the EC that we want to take control of battery
> charging. Also set the threshold to 100 if the EC-provided value
> is invalid.
> 
> Fixes: d050479693bb ("platform/x86: Add Uniwill laptop driver")
> Reviewed-by: Werner Sembach <wse@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> ---
>  drivers/platform/x86/uniwill/uniwill-acpi.c | 28 ++++++++++++++++++++-
>  1 file changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/uniwill/uniwill-acpi.c b/drivers/platform/x86/uniwill/uniwill-acpi.c
> index faade4cf08be..8f16c94221aa 100644
> --- a/drivers/platform/x86/uniwill/uniwill-acpi.c
> +++ b/drivers/platform/x86/uniwill/uniwill-acpi.c
> @@ -1404,7 +1404,12 @@ static int uniwill_get_property(struct power_supply *psy, const struct power_sup
>  		if (ret < 0)
>  			return ret;
>  
> -		val->intval = clamp_val(FIELD_GET(CHARGE_CTRL_MASK, regval), 0, 100);
> +		regval = FIELD_GET(CHARGE_CTRL_MASK, regval);
> +		if (!regval)
> +			val->intval = 100;
> +		else
> +			val->intval = min(regval, 100);

...

> +	/*
> +	 * The charge control threshold might be initialized with 0 by
> +	 * the EC to signal that said threshold is uninitialized. We thus
> +	 * need to replace this value with 100 to signal that we want to
> +	 * take control of battery charging. For the sake of completeness
> +	 * we also set the charging threshold to 100 if the EC-provided
> +	 * value is invalid.
> +	 */
> +	threshold = FIELD_GET(CHARGE_CTRL_MASK, value);
> +	if (threshold == 0 || threshold > 100) {
> +		FIELD_MODIFY(CHARGE_CTRL_MASK, &value, 100);

AFAICT, this does exactly the same thing as the other code above (but 
looks very different on surface). Wouldn't it make sense to have them 
share code?

-- 
 i.