[PATCH v5 02/17] rtc: rzn1: Handle EPROBE_DEFER for optional pps interrupt

[PATCH v5 02/17] rtc: rzn1: Handle EPROBE_DEFER for optional pps interrupt

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Check for -EPROBE_DEFER from platform_get_irq_byname_optional() and handle
the deferred probe request properly.

Although the "pps" interrupt is optional, an error code of -EPROBE_DEFER
indicates that the interrupt subsystem is not yet ready. Intercept this
specific error condition, assign it to the return value, and jump to the
dis_runtime_pm label to avoid ignoring a valid probe deferral.

Fixes: eea7791e00f33 ("rtc: rzn1: implement one-second accuracy for alarms")
Cc: stable@vger.kernel.org
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v4->v5:
- Added Tested-by tag from Wolfram.

v3->v4:
- Added Reviewed-by tag from Wolfram.

v2->v3:
- No changes

v1->v2:
- No changes
---
 drivers/rtc/rtc-rzn1.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 305f10a8a85b..aa27ad7f5941 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -464,6 +464,10 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	}
 
 	irq = platform_get_irq_byname_optional(pdev, "pps");
+	if (irq == -EPROBE_DEFER) {
+		ret = irq;
+		goto dis_runtime_pm;
+	}
 	if (irq >= 0)
 		ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_1s_irq, 0, "RZN1 RTC 1s", rtc);
 
-- 
2.43.0

[PATCH v5 03/17] rtc: rzn1: Fix weekday underflow when alarm crosses month boundary

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

rzn1_rtc_set_alarm() calculates the alarm weekday from the difference
between the alarm day and the current day of the month. When the alarm
crosses a month boundary, this difference can become negative. Since
days_ahead is unsigned, it underflows and results in an incorrect
weekday being programmed into RZN1_RTC_ALW.

The RTC core already provides a fully populated struct rtc_time for
the alarm, including the correct tm_wday. Use tm->tm_wday directly
instead of recalculating the weekday from the day-of-month.

This avoids the underflow and ensures alarms scheduled across a month
boundary use the correct weekday.

Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
Cc: stable@vger.kernel.org
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Suggested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v4->v5:
- Added Tested-by tag from Wolfram.

v3->v4:
- Made use of tm->tm_wday directly instead of recalculating the weekday
  from the day-of-month.
- Updated commit message.

v2->v3:
- New patch to fix weekday underflow when alarm crosses month boundary.
---
 drivers/rtc/rtc-rzn1.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index aa27ad7f5941..8c70dbf8c7ec 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -260,7 +260,6 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
 	struct rtc_time *tm = &alrm->time, tm_now;
 	unsigned long alarm, farest;
-	unsigned int days_ahead, wday;
 	int ret;
 
 	ret = rzn1_rtc_read_time(dev, &tm_now);
@@ -273,13 +272,9 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	if (time_after(alarm, farest))
 		return -ERANGE;
 
-	/* Convert alarm day into week day */
-	days_ahead = tm->tm_mday - tm_now.tm_mday;
-	wday = (tm_now.tm_wday + days_ahead) % 7;
-
 	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
 	writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH);
-	writel(BIT(wday), rtc->base + RZN1_RTC_ALW);
+	writel(BIT(tm->tm_wday), rtc->base + RZN1_RTC_ALW);
 
 	rtc->tm_alarm = alrm->time;
 
-- 
2.43.0

[PATCH v5 04/17] rtc: rzn1: Handle unset alarm weekday in rzn1_rtc_read_alarm

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

RZN1_RTC_ALW is a weekday bitmask where bit N represents weekday N.
When no alarm has been configured, the register has its power-on-reset
value of zero.

rzn1_rtc_read_alarm() uses fls() to convert the weekday bitmask into a
weekday number. When RZN1_RTC_ALW is zero, fls(0) returns zero and
fls(wday) - 1 evaluates to -1. This invalid weekday is then used to
calculate the alarm date and can either leave tm_wday set to -1 or
produce a fabricated alarm date.

Treat a zero RZN1_RTC_ALW value as an unset alarm weekday and return
without calculating the alarm date. Move reading RZN1_RTC_CTL1 before
this check so that alrm->enabled is updated for both configured and
unconfigured alarms.

On a cold-booted board with no alarm configured, the following was
observed before the fix:

    root@rzn2h-evk:~# cat /proc/driver/rtc
    rtc_time        : 00:00:19
    rtc_date        : 2000-01-01
    alrm_time       : 00:00:00
    alrm_date       : 2000-01-07
    alarm_IRQ       : no
    alrm_pending    : no
    update IRQ enabled      : no
    periodic IRQ enabled    : no
    periodic IRQ frequency  : 1
    max user IRQ frequency  : 64
    24hr            : yes

After the fix:

    root@rzn2h-evk:~# cat /proc/driver/rtc
    rtc_time        : 00:00:25
    rtc_date        : 2000-01-01
    alrm_time       : 00:00:00
    alrm_date       : 2000-01-01
    alarm_IRQ       : no
    alrm_pending    : no
    update IRQ enabled      : no
    periodic IRQ enabled    : no
    periodic IRQ frequency  : 1
    max user IRQ frequency  : 64
    24hr            : yes

Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
Cc: stable@vger.kernel.org
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v4->v5:
- New patch
---
 drivers/rtc/rtc-rzn1.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 8c70dbf8c7ec..e0fdb591ba91 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -234,13 +234,24 @@ static int rzn1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	if (ret)
 		return ret;
 
+	ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
+	alrm->enabled = !!(ctl1 & (RZN1_RTC_CTL1_ALME | RZN1_RTC_CTL1_1SE));
+
 	min = readl(rtc->base + RZN1_RTC_ALM);
 	hour = readl(rtc->base + RZN1_RTC_ALH);
-	wday = readl(rtc->base + RZN1_RTC_ALW);
 
 	tm->tm_sec = 0;
 	tm->tm_min = bcd2bin(min);
 	tm->tm_hour = bcd2bin(hour);
+
+	/*
+	 * If wday is zero, no bit is set in RZN1_RTC_ALW. This is the
+	 * register's power-on reset value.
+	 */
+	wday = readl(rtc->base + RZN1_RTC_ALW);
+	if (!wday)
+		return 0;
+
 	delta_days = ((fls(wday) - 1) - tm->tm_wday + 7) % 7;
 	tm->tm_wday = fls(wday) - 1;
 
@@ -249,9 +260,6 @@ static int rzn1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 		rtc_time64_to_tm(alarm, tm);
 	}
 
-	ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
-	alrm->enabled = !!(ctl1 & (RZN1_RTC_CTL1_ALME | RZN1_RTC_CTL1_1SE));
-
 	return 0;
 }
 
-- 
2.43.0

Re: [PATCH v5 04/17] rtc: rzn1: Handle unset alarm weekday in rzn1_rtc_read_alarm

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 2225 bytes --]

On Fri, Aug 21, 2026 at 02:55:55PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> RZN1_RTC_ALW is a weekday bitmask where bit N represents weekday N.
> When no alarm has been configured, the register has its power-on-reset
> value of zero.
> 
> rzn1_rtc_read_alarm() uses fls() to convert the weekday bitmask into a
> weekday number. When RZN1_RTC_ALW is zero, fls(0) returns zero and
> fls(wday) - 1 evaluates to -1. This invalid weekday is then used to
> calculate the alarm date and can either leave tm_wday set to -1 or
> produce a fabricated alarm date.
> 
> Treat a zero RZN1_RTC_ALW value as an unset alarm weekday and return
> without calculating the alarm date. Move reading RZN1_RTC_CTL1 before
> this check so that alrm->enabled is updated for both configured and
> unconfigured alarms.
> 
> On a cold-booted board with no alarm configured, the following was
> observed before the fix:
> 
>     root@rzn2h-evk:~# cat /proc/driver/rtc
>     rtc_time        : 00:00:19
>     rtc_date        : 2000-01-01
>     alrm_time       : 00:00:00
>     alrm_date       : 2000-01-07
>     alarm_IRQ       : no
>     alrm_pending    : no
>     update IRQ enabled      : no
>     periodic IRQ enabled    : no
>     periodic IRQ frequency  : 1
>     max user IRQ frequency  : 64
>     24hr            : yes
> 
> After the fix:
> 
>     root@rzn2h-evk:~# cat /proc/driver/rtc
>     rtc_time        : 00:00:25
>     rtc_date        : 2000-01-01
>     alrm_time       : 00:00:00
>     alrm_date       : 2000-01-01
>     alarm_IRQ       : no
>     alrm_pending    : no
>     update IRQ enabled      : no
>     periodic IRQ enabled    : no
>     periodic IRQ frequency  : 1
>     max user IRQ frequency  : 64
>     24hr            : yes

The output of the tests could be dropped IMO, but I'll leave this for
the RTC maintainers.

> Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Other than that:

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>


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Re: [PATCH v5 04/17] rtc: rzn1: Handle unset alarm weekday in rzn1_rtc_read_alarm

[Lad, Prabhakar]

Hi Wolfram,

THank you for the review.

On Fri, Aug 21, 2026 at 4:08 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> On Fri, Aug 21, 2026 at 02:55:55PM +0100, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > RZN1_RTC_ALW is a weekday bitmask where bit N represents weekday N.
> > When no alarm has been configured, the register has its power-on-reset
> > value of zero.
> >
> > rzn1_rtc_read_alarm() uses fls() to convert the weekday bitmask into a
> > weekday number. When RZN1_RTC_ALW is zero, fls(0) returns zero and
> > fls(wday) - 1 evaluates to -1. This invalid weekday is then used to
> > calculate the alarm date and can either leave tm_wday set to -1 or
> > produce a fabricated alarm date.
> >
> > Treat a zero RZN1_RTC_ALW value as an unset alarm weekday and return
> > without calculating the alarm date. Move reading RZN1_RTC_CTL1 before
> > this check so that alrm->enabled is updated for both configured and
> > unconfigured alarms.
> >
> > On a cold-booted board with no alarm configured, the following was
> > observed before the fix:
> >
> >     root@rzn2h-evk:~# cat /proc/driver/rtc
> >     rtc_time        : 00:00:19
> >     rtc_date        : 2000-01-01
> >     alrm_time       : 00:00:00
> >     alrm_date       : 2000-01-07
> >     alarm_IRQ       : no
> >     alrm_pending    : no
> >     update IRQ enabled      : no
> >     periodic IRQ enabled    : no
> >     periodic IRQ frequency  : 1
> >     max user IRQ frequency  : 64
> >     24hr            : yes
> >
> > After the fix:
> >
> >     root@rzn2h-evk:~# cat /proc/driver/rtc
> >     rtc_time        : 00:00:25
> >     rtc_date        : 2000-01-01
> >     alrm_time       : 00:00:00
> >     alrm_date       : 2000-01-01
> >     alarm_IRQ       : no
> >     alrm_pending    : no
> >     update IRQ enabled      : no
> >     periodic IRQ enabled    : no
> >     periodic IRQ frequency  : 1
> >     max user IRQ frequency  : 64
> >     24hr            : yes
>
> The output of the tests could be dropped IMO, but I'll leave this for
> the RTC maintainers.
>
I'll drop it.

Cheers,
Prabhakar

> > Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Other than that:
>
> Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
>

[PATCH v5 06/17] rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

rzn1_rtc_set_alarm() updates RZN1_RTC_ALM, RZN1_RTC_ALH and
RZN1_RTC_ALW using separate MMIO writes without first disabling the
alarm interrupt. If a previous alarm is still enabled, the interrupt
can fire while the alarm registers contain a mixture of old and newly
written values.

Fix this by disabling the alarm interrupt before reprogramming ALM, ALH
and ALW with a call to rzn1_rtc_alarm_irq_enable().

Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
Cc: stable@vger.kernel.org
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v4->v5:
- New patch
---
 drivers/rtc/rtc-rzn1.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 44e8db466cb7..09631a3a5134 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -280,6 +280,11 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	if (alarm > farest)
 		return -ERANGE;
 
+	/* Disable alarm interrupts before reprogramming the alarm. */
+	ret = rzn1_rtc_alarm_irq_enable(dev, 0);
+	if (ret)
+		return ret;
+
 	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
 	writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH);
 	writel(BIT(tm->tm_wday), rtc->base + RZN1_RTC_ALW);
-- 
2.43.0

Re: [PATCH v5 06/17] rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 852 bytes --]

On Fri, Aug 21, 2026 at 02:55:57PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> rzn1_rtc_set_alarm() updates RZN1_RTC_ALM, RZN1_RTC_ALH and
> RZN1_RTC_ALW using separate MMIO writes without first disabling the
> alarm interrupt. If a previous alarm is still enabled, the interrupt
> can fire while the alarm registers contain a mixture of old and newly
> written values.
> 
> Fix this by disabling the alarm interrupt before reprogramming ALM, ALH
> and ALW with a call to rzn1_rtc_alarm_irq_enable().
> 
> Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>


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