[PATCH resubmit] rtc: interface: Add RTC offset to alarm after fix-up

[PATCH resubmit] rtc: interface: Add RTC offset to alarm after fix-up

[Csókás, Bence]

`rtc_add_offset()` is called by `__rtc_read_time()`
and `__rtc_read_alarm()` to add the RTC's offset to
the raw read-outs from the device drivers. However,
in the latter case, a fix-up algorithm is run if
the RTC device does not report a full `struct rtc_time`
alarm value. In that case, the offset was forgot to be
added.

Fixes: fd6792bb022e ("rtc: fix alarm read and set offset")

Signed-off-by: Csókás, Bence <csokas.bence@prolan.hu>
---
 drivers/rtc/interface.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 1b63111cdda2..db8dffffed91 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -273,12 +273,11 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 		if (err)
 			return err;
 
 		/* full-function RTCs won't have such missing fields */
 		if (rtc_valid_tm(&alarm->time) == 0) {
-			rtc_add_offset(rtc, &alarm->time);
-			return 0;
+			goto done;
 		}
 
 		/* get the "after" timestamp, to detect wrapped fields */
 		err = rtc_read_time(rtc, &now);
 		if (err < 0)
@@ -378,10 +377,12 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 done:
 	if (err && alarm->enabled)
 		dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
 			 &alarm->time);
 
+	rtc_add_offset(rtc, &alarm->time);
+
 	return err;
 }
 
 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 {
-- 
2.34.1

Re: [PATCH resubmit] rtc: interface: Add RTC offset to alarm after fix-up

[Alexandre Belloni]

On 19/06/2024 15:01:16+0200, Csókás, Bence wrote:
> `rtc_add_offset()` is called by `__rtc_read_time()`
> and `__rtc_read_alarm()` to add the RTC's offset to
> the raw read-outs from the device drivers. However,
> in the latter case, a fix-up algorithm is run if
> the RTC device does not report a full `struct rtc_time`
> alarm value. In that case, the offset was forgot to be
> added.
> 
> Fixes: fd6792bb022e ("rtc: fix alarm read and set offset")
> 
> Signed-off-by: Csókás, Bence <csokas.bence@prolan.hu>
> ---
>  drivers/rtc/interface.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
> index 1b63111cdda2..db8dffffed91 100644
> --- a/drivers/rtc/interface.c
> +++ b/drivers/rtc/interface.c
> @@ -273,12 +273,11 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
>  		if (err)
>  			return err;
>  
>  		/* full-function RTCs won't have such missing fields */
>  		if (rtc_valid_tm(&alarm->time) == 0) {
> -			rtc_add_offset(rtc, &alarm->time);
> -			return 0;
> +			goto done;
>  		}
>  
>  		/* get the "after" timestamp, to detect wrapped fields */
>  		err = rtc_read_time(rtc, &now);
>  		if (err < 0)
> @@ -378,10 +377,12 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
>  done:
>  	if (err && alarm->enabled)
>  		dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
>  			 &alarm->time);
>  
> +	rtc_add_offset(rtc, &alarm->time);
> +

This must not be done when the tm is invalid.

>  	return err;
>  }
>  
>  int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
>  {
> -- 
> 2.34.1
> 
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com