Re: [PATCH 4/4] rtc: pcf2127: support battery low voltage detection function

On 3/11/26 21:02, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <[email protected]>
> 
> Add support for parameter RTC_PARAM_BATTERY_LOW_DETECT in RTC_PARAM_SET
> ioctl to enable/disable/query battery low voltage detection. This is
> especially relevant on the pcf2131 where this function is disabled by
> default, contrary to the pcf2127.
> 
> Signed-off-by: Hugo Villeneuve <[email protected]>
> ---
>   drivers/rtc/rtc-pcf2127.c | 60 ++++++++++++++++++++++++++++++++-------
>   1 file changed, 50 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 0605295026564..05b08867ffcb3 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -364,12 +364,12 @@ static int pcf2127_param_get(struct device *dev, struct rtc_param *param)
>   	u8 value;
>   	int ret;
>   
> +	ret = pcf2127_pwrmng_get(dev, &value);
> +	if (ret < 0)
> +		return ret;
> +
>   	switch (param->param) {
>   	case RTC_PARAM_BACKUP_SWITCH_MODE:
> -		ret = pcf2127_pwrmng_get(dev, &value);
> -		if (ret < 0)
> -			return ret;
> -
>   		if (value < 0x3)
>   			param->uvalue = RTC_BSM_LEVEL;
>   		else if (value < 0x6)
> @@ -379,6 +379,14 @@ static int pcf2127_param_get(struct device *dev, struct rtc_param *param)
>   
>   		break;
>   
> +	case RTC_PARAM_BATTERY_LOW_DETECT:
> +		if (value == 0x0 || value == 0x3)
> +			param->uvalue = RTC_BATTERY_LOW_DETECT_ENABLED;
> +		else
> +			param->uvalue = RTC_BATTERY_LOW_DETECT_DISABLED;
> +
> +		break;
> +
>   	default:
>   		return -EINVAL;
>   	}
> @@ -392,12 +400,12 @@ static int pcf2127_param_set(struct device *dev, struct rtc_param *param)
>   	u8 value;
>   	int ret;
>   
> +	ret = pcf2127_pwrmng_get(dev, &value);
> +	if (ret < 0)
> +		return ret;
> +
>   	switch (param->param) {
>   	case RTC_PARAM_BACKUP_SWITCH_MODE:
> -		ret = pcf2127_pwrmng_get(dev, &value);
> -		if (ret < 0)
> -			return ret;
> -
>   		if (value > 5)
>   			value -= 5;
>   		else if (value > 2)
> @@ -418,13 +426,45 @@ static int pcf2127_param_set(struct device *dev, struct rtc_param *param)
>   			return -EINVAL;
>   		}
>   
> -		return pcf2127_pwrmng_set(dev, mode + value);
> +		break;
> +
> +	case RTC_PARAM_BATTERY_LOW_DETECT:
> +		if (value > 5) {
> +			value -= 5;
> +			mode = 5;
> +		} else if (value > 2) {
> +			value -= 3;
> +			mode = 3;
> +		}
> +
> +		switch (param->uvalue) {
> +		case RTC_BATTERY_LOW_DETECT_DISABLED:
> +			if (mode != 5)
> +				if (value == 0)
> +					value = 1;
> +
> +			break;
> +		case RTC_BATTERY_LOW_DETECT_ENABLED:
> +			if (mode != 5)
> +				value = 0; /* Enable battery low detection. */
> +			else
> +				return -EINVAL; /*
> +						 * battery low detection can't be enabled if
> +						 * battery switch over is disabled.
> +						 */
> +			break;
> +
> +		default:
> +			return -EINVAL;
> +		}
> +
> +		break;
>   
>   	default:
>   		return -EINVAL;
>   	}
>   
> -	return 0;
> +	return pcf2127_pwrmng_set(dev, mode + value);
>   }
>   
>   static int pcf2127_rtc_ioctl(struct device *dev,

Works as expected, thank you!

Reviewed-by: Stefan Kerkmann <[email protected]>
Tested-by: Stefan Kerkmann <[email protected]>

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