# Re: \[PATCH 3/3\] rtc: rtc\_update\_irq\_enable: rework UIE emulation

- From: Łukasz Stelmach \<l.stelmach@samsung.com\>
- Date: 2021-04-02 10:28:20 
- List: linux-rtc
- Page: https://ratatoskr.run/linux-rtc/2021/04/6325178
- Thread: https://ratatoskr.run/linux-rtc/2021/04/6325178/t.md

```text
It was <2021-03-30 wto 02:03>, when Alexandre Belloni wrote:
> Now that the core is aware of whether alarms are available, it is possible
> to decide whether UIE emulation is required before actually trying to set
> the alarm.
>
> This greatly simplifies rtc_update_irq_enable because there is now only one
> error value to track and is not relying on the return value of
> __rtc_set_alarm anymore.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> ---
>  drivers/rtc/interface.c | 28 +++++++---------------------
>  1 file changed, 7 insertions(+), 21 deletions(-)
>

Tested-by: Łukasz Stelmach <l.stelmach@samsung.com>

> diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
> index dcb34c73319e..b162964d2b39 100644
> --- a/drivers/rtc/interface.c
> +++ b/drivers/rtc/interface.c
> @@ -561,8 +561,12 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
>  	if (rtc->uie_rtctimer.enabled == enabled)
>  		goto out;
>  
> -	if (rtc->uie_unsupported) {
> +	if (rtc->uie_unsupported || !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
> +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
> +		err = rtc_dev_update_irq_enable_emul(rtc, enabled);
> +#else
>  		err = -EINVAL;
> +#endif
>  		goto out;
>  	}
>  
> @@ -570,8 +574,8 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
>  		struct rtc_time tm;
>  		ktime_t now, onesec;
>  
> -		rc = __rtc_read_time(rtc, &tm);
> -		if (rc)
> +		err = __rtc_read_time(rtc, &tm);
> +		if (err)
>  			goto out;
>  		onesec = ktime_set(1, 0);
>  		now = rtc_tm_to_ktime(tm);
> @@ -585,24 +589,6 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
>  out:
>  	mutex_unlock(&rtc->ops_lock);
>  
> -	/*
> -	 * __rtc_read_time() failed, this probably means that the RTC time has
> -	 * never been set or less probably there is a transient error on the
> -	 * bus. In any case, avoid enabling emulation has this will fail when
> -	 * reading the time too.
> -	 */
> -	if (rc)
> -		return rc;
> -
> -#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
> -	/*
> -	 * Enable emulation if the driver returned -EINVAL to signal that it has
> -	 * been configured without interrupts or they are not available at the
> -	 * moment.
> -	 */
> -	if (err == -EINVAL)
> -		err = rtc_dev_update_irq_enable_emul(rtc, enabled);
> -#endif
>  	return err;
>  }
>  EXPORT_SYMBOL_GPL(rtc_update_irq_enable);

-- 
Łukasz Stelmach
Samsung R&D Institute Poland
Samsung Electronics
```

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