[PATCH v6 00/17] Add RTC support for Renesas RZ/T2H and RZ/N2H SoCs

[PATCH v6 00/17] Add RTC support for Renesas RZ/T2H and RZ/N2H SoCs

[Prabhakar]

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

Hi all,

This series adds support for the RTC IP found on the Renesas RZ/T2H and
RZ/N2H SoCs.

The RTC block is closely related to the RZ/N1 implementation and can
reuse the existing driver infrastructure when operating in SCMP mode,
which is required on these SoCs due to their 195.3 kHz RTC input clock.

While the RZ/T2H and RZ/N2H variants do not implement the RTCA0SUBU
register present on RZ/N1, this register is not accessed by the driver
in SCMP mode, allowing support to be added with minimal changes.

The RZ/T2H RTC variant also supports a 1 Hz output signal on the
RTCAT1HZ pin, controlled by the RTCA0CTL1[RTCA01HZE] bit. This bit is
marked as reserved in the RZ/N1 hardware manual, making RZ/T2H a
distinct RTC variant despite its overall compatibility with the RZ/N1
implementation.

Patches have been rebased on top of rtc-next commit 78acddfde751.

v5->v6:
- Dropped the output log from commit message.
- Added missing sentinel comment
- Collected Reviewed-by and Tested-by tags from Wolfram

v4->v5:
- Collected Reviewed-by and Tested-by tags from Wolfram
- Added Suggested-by tag from Wolfram.
- Added a new patch to disable interrupts when arming a new alarm
- Added a new patch to handle unset alarm weekday in
  rzn1_rtc_read_alarm()
- Shuffled the pm_runtime_put_sync() patch to be applied before the patch
  that replaces the .remove() callback with devm_add_action_or_reset()
- Renamed rzn1_data to rzn1_rtc_rzn1_data
- Added a print message to indicate that SUBU mode is not supported
  on the variant.
- Added a comment to indicate that the xtal clock is NULL when SUBU
  mode is not supported.
- Renamed rzt2h_data to rzn1_rtc_rzt2h_data

v3->v4:
- Added Reviewed-by tags from Wolfram.
- Made use of tm->tm_wday directly instead of recalculating the weekday
  from the day-of-month.
- Updated commit message in patch #3
- Shortened the comment describing the calculation of RTC_PCLK.
- Updated usleep_range() value to use 2 * rtc->sync_time.
- Added new patch to gate SUBU register access based on OF match data.
- Added new patch to make use of pm_runtime_put_sync() in
  rzn1_rtc_disable_hardware().
- Added new patch to drop trailing comma from OF match table sentinel.
- Added OF rzt2h_data for OF data
- Updated commit message for patch #15

v2->v3:
- Added new patch to fix weekday underflow when alarm crosses month
  boundary.
- Make use of devm_add_action_or_reset() to simplify driver teardown
  and remove the .remove() callback.

v1->v2:
- Dropped wakeup capability support patch.
- Dropped header sort patch as it was already fixed upstream.
- Updated commit message to drop reference about RTCA0TCR register.
- Added Acked-by and Reviewed-by tags.
- Updated Kconfig help text to keep it generic and not specific to
  RZ/N1 SoCs.
- Initialized rate variable to 32768 to avoid timeout_us of 0.
- Made use of RZN1_RTC_SUBU_RTCA0FX mask for SUBU register access
  instead of 0x3F.

v1: https://lore.kernel.org/all/20260615154805.1619693-1-prabhakar.mahadev-lad.rj@bp.renesas.com/

Cheers,
Prabhakar

Lad Prabhakar (17):
  dt-bindings: rtc: renesas,rzn1-rtc: Add RZ/T2H and RZ/N2H support
  rtc: rzn1: Handle EPROBE_DEFER for optional pps interrupt
  rtc: rzn1: Fix weekday underflow when alarm crosses month boundary
  rtc: rzn1: Handle unset alarm weekday in rzn1_rtc_read_alarm
  rtc: rzn1: Fix alarm range check truncation on 32-bit systems
  rtc: rzn1: Disable alarm interrupt before reprogramming alarm
    registers
  rtc: rzn1: Fix malformed MODULE_AUTHOR string
  rtc: Kconfig: Broaden RTC_DRV_RZN1 dependency to ARCH_RENESAS
  rtc: rzn1: Use pm_runtime_put_sync()
  rtc: rzn1: Replace remove callback with devm_add_action_or_reset()
  rtc: rzn1: Dynamically calculate synchronization delay based on clock
    rate
  rtc: rzn1: Use temporary variable for struct device
  rtc: rzn1: Consistently use dev_err_probe()
  rtc: rzn1: use FIELD_PREP/FIELD_GET and GENMASK for register access
  rtc: rzn1: Add OF match data to gate SUBU register access
  rtc: rzn1: Drop trailing comma from OF match table sentinel
  rtc: rzn1: Add support for Renesas RZ/T2H and RZ/N2H SoCs

 .../bindings/rtc/renesas,rzn1-rtc.yaml        |  35 +++-
 drivers/rtc/Kconfig                           |   5 +-
 drivers/rtc/rtc-rzn1.c                        | 197 +++++++++++-------
 3 files changed, 147 insertions(+), 90 deletions(-)


base-commit: 78acddfde75177a27000f076e3e828743e38877e
-- 
2.43.0

[PATCH v6 01/17] dt-bindings: rtc: renesas,rzn1-rtc: Add RZ/T2H and RZ/N2H support

[Prabhakar]

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

Add compatible strings for the RTC block found on the Renesas RZ/T2H
(R9A09G077) and RZ/N2H (R9A09G087) SoCs.

These SoCs integrate a closely related variant of the RZ/N1 RTC IP.
Unlike RZ/N1, they do not implement the RTCA0SUBU register. This is
not a limitation for Linux support, as these registers are not used
when the RTC operates in "scmp" clock mode, which is required on
RZ/T2H and RZ/N2H due to their 195.3 kHz input clock.

The RZ/T2H RTC variant also supports a 1Hz output signal on the
RTCAT1HZ pin, controlled by the RTCA0CTL1[RTCA01HZE] bit. This bit is
marked as reserved in the RZ/N1 hardware manual.

Update the binding schema to require the additional clock inputs used by
these SoCs.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v5->v6:
- No changes.

v4->v5:
- No changes.

v3->v4:
- No changes.

v2->v3:
- No changes

v1->v2:
- Updated commit message to drop reference about RTCA0TCR register.
- Added Acked-by and Reviewed-by tags.
---
 .../bindings/rtc/renesas,rzn1-rtc.yaml        | 35 +++++++++++++++----
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
index 1860f0e4c31a..ea7b039a91e7 100644
--- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
@@ -9,15 +9,19 @@ title: Renesas RZ/N1 SoCs Real-Time Clock
 maintainers:
   - Miquel Raynal <miquel.raynal@bootlin.com>
 
-allOf:
-  - $ref: rtc.yaml#
-
 properties:
   compatible:
-    items:
-      - enum:
-          - renesas,r9a06g032-rtc
-      - const: renesas,rzn1-rtc
+    oneOf:
+      - items:
+          - enum:
+              - renesas,r9a06g032-rtc
+          - const: renesas,rzn1-rtc
+
+      - const: renesas,r9a09g077-rtc
+
+      - items:
+          - const: renesas,r9a09g087-rtc
+          - const: renesas,r9a09g077-rtc
 
   reg:
     maxItems: 1
@@ -54,6 +58,23 @@ required:
   - clock-names
   - power-domains
 
+allOf:
+  - $ref: rtc.yaml#
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - renesas,r9a09g077-rtc
+              - renesas,r9a09g087-rtc
+    then:
+      properties:
+        clocks:
+          minItems: 2
+        clock-names:
+          minItems: 2
+
 unevaluatedProperties: false
 
 examples:
-- 
2.43.0

[PATCH v6 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>
---
v5->v6:
- No changes.

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 c4ed43735457..f81d691c8b9a 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -465,6 +465,10 @@ 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 v6 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>
---
v5->v6:
- No changes.

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 f81d691c8b9a..56284a4320ae 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -261,7 +261,6 @@ 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);
@@ -274,13 +273,9 @@ 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 v6 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.

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>
---
v5->v6:
- Dropped the output log from commit message.
- Added Reviewed-by and Tested-by tags from Wolfram.

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 56284a4320ae..d4cba0d415b6 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -235,13 +235,24 @@ 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;
 
@@ -250,9 +261,6 @@ 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

[PATCH v6 05/17] rtc: rzn1: Fix alarm range check truncation on 32-bit systems

[Prabhakar]

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

alarm and farest were declared as unsigned long, but
rtc_tm_to_time64() returns time64_t (s64). On 32-bit systems where
unsigned long is 32 bits, the assignment silently truncates the upper
32 bits of the timestamp.

Fix by declaring alarm and farest as time64_t and replacing
time_after() with a direct signed comparison, which is correct for
time64_t values that will never realistically overflow.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v5->v6:
- No changes.

v4->v5:
- Added Tested-by tag from Wolfram.

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

v2->v3:
- No changes.

v1->v2:
- Added Reviewed-by tag.
---
 drivers/rtc/rtc-rzn1.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index d4cba0d415b6..f3268655fd37 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -268,7 +268,7 @@ 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;
+	time64_t alarm, farest;
 	int ret;
 
 	ret = rzn1_rtc_read_time(dev, &tm_now);
@@ -278,7 +278,7 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	/* We cannot set alarms more than one week ahead */
 	farest = rtc_tm_to_time64(&tm_now) + rtc->rtcdev->alarm_offset_max;
 	alarm = rtc_tm_to_time64(tm);
-	if (time_after(alarm, farest))
+	if (alarm > farest)
 		return -ERANGE;
 
 	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
-- 
2.43.0

[PATCH v6 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>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v5->v6:
- Added Reviewed-by and Tested-by tags from Wolfram.

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 f3268655fd37..42e57bf0b4aa 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -281,6 +281,11 @@ 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

[PATCH v6 07/17] rtc: rzn1: Fix malformed MODULE_AUTHOR string

[Prabhakar]

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

Fix a malformed MODULE_AUTHOR macro in the rtc-rzn1 driver where a missing
closing angle bracket on the second author entry creates an invalid format.
Correct it to the standard "Name <email>" format.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v5->v6:
- No changes.

v4->v5:
- Added Tested-by tag from Wolfram.

v3->v4:
- No changes.

v2->v3:
- No changes.

v1->v2:
- Added Reviewed-by tags.
---
 drivers/rtc/rtc-rzn1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 42e57bf0b4aa..12c52003a7dc 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -525,6 +525,6 @@ static struct platform_driver rzn1_rtc_driver = {
 module_platform_driver(rzn1_rtc_driver);
 
 MODULE_AUTHOR("Michel Pollet <buserror@gmail.com>");
-MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
 MODULE_DESCRIPTION("RZ/N1 RTC driver");
 MODULE_LICENSE("GPL");
-- 
2.43.0

[PATCH v6 08/17] rtc: Kconfig: Broaden RTC_DRV_RZN1 dependency to ARCH_RENESAS

[Prabhakar]

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

Replace the ARCH_RZN1 dependency with ARCH_RENESAS for the RTC_DRV_RZN1
config option to make the driver available across both ARM32 and ARM64
Renesas architectures.

The newer RZ/T2H and RZ/N2H ARM64 SoCs integrate a closely related variant
of the RTC IP block found on the RZ/N1 SoCs. Update the build dependency
and expand the Kconfig help text to allow this driver to be selected for
these additional platforms.

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>
---
v5->v6:
- No changes.

v4->v5:
- Added Tested-by tag from Wolfram.

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

v2->v3:
- No changes.

v1->v2:
- Updated help text to keep it generic and not specific to RZ/N1 SoCs.
---
 drivers/rtc/Kconfig | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 01def8231873..d23a0fbe8d89 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1635,10 +1635,11 @@ config RTC_DRV_RS5C313
 
 config RTC_DRV_RZN1
 	tristate "Renesas RZ/N1 RTC"
-	depends on ARCH_RZN1 || COMPILE_TEST
+	depends on ARCH_RENESAS || COMPILE_TEST
 	depends on OF && HAS_IOMEM
 	help
-	  If you say yes here you get support for the Renesas RZ/N1 RTC.
+	  If you say yes here you get support for the RTC initially found on
+	  Renesas RZ/N1 SoCs.
 
 config RTC_DRV_GENERIC
 	tristate "Generic RTC support"
-- 
2.43.0

[PATCH v6 09/17] rtc: rzn1: Use pm_runtime_put_sync()

[Prabhakar]

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

pm_runtime_put() may trigger the idle check after pm_runtime_disable()
is run as part of devm_pm_runtime_enable()'s cleanup action, leaving
runtime PM active.

Use pm_runtime_put_sync() to ensure the idle check runs synchronously.

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>
---
v5->v6:
- Added Reviewed-by and Tested-by tags from Wolfram

v4->v5:
- Updated commit message
- Moved the patch prior to the patch that replaces the .remove() callback
  with devm_add_action_or_reset() 

v3->v4:
- New patch
---
 drivers/rtc/rtc-rzn1.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 12c52003a7dc..84ec8dc397e5 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -493,7 +493,7 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	return 0;
 
 dis_runtime_pm:
-	pm_runtime_put(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
 
 	return ret;
 }
@@ -505,7 +505,7 @@ static void rzn1_rtc_remove(struct platform_device *pdev)
 	/* Disable all interrupts */
 	writel(0, rtc->base + RZN1_RTC_CTL1);
 
-	pm_runtime_put(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
 }
 
 static const struct of_device_id rzn1_rtc_of_match[] = {
-- 
2.43.0

[PATCH v6 10/17] rtc: rzn1: Replace remove callback with devm_add_action_or_reset()

[Prabhakar]

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

Simplify the driver teardown by registering a managed cleanup action with
devm_add_action_or_reset(). This eliminates the explicit probe error path
and allows the .remove() callback to be dropped.

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>
---
v5->v6:
- No changes.

v4->v5:
- Fixed conflict due to moving the pm_runtime_put_sync() patch prior to this one.
- Added Tested-by tag from Wolfram.

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

v2->v3:
- New patch to replace the remove callback with devm_add_action_or_reset().
---
 drivers/rtc/rtc-rzn1.c | 56 +++++++++++++++++-------------------------
 1 file changed, 23 insertions(+), 33 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 84ec8dc397e5..f90785827945 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -385,6 +385,17 @@ static const struct rtc_class_ops rzn1_rtc_ops_scmp = {
 	.alarm_irq_enable = rzn1_rtc_alarm_irq_enable,
 };
 
+static void rzn1_rtc_disable_hardware(void *data)
+{
+	struct device *dev = data;
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+
+	/* Disable all interrupts */
+	writel(0, rtc->base + RZN1_RTC_CTL1);
+
+	pm_runtime_put_sync(dev);
+}
+
 static int rzn1_rtc_probe(struct platform_device *pdev)
 {
 	struct rzn1_rtc *rtc;
@@ -422,18 +433,19 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
+	ret = devm_add_action_or_reset(&pdev->dev, rzn1_rtc_disable_hardware, &pdev->dev);
+	if (ret)
+		return ret;
+
 	/* Only switch to scmp if we have an xtal clock with a valid rate and != 32768 */
 	xtal = devm_clk_get_optional(&pdev->dev, "xtal");
 	if (IS_ERR(xtal)) {
-		ret = PTR_ERR(xtal);
-		goto dis_runtime_pm;
+		return PTR_ERR(xtal);
 	} else if (xtal) {
 		rate = clk_get_rate(xtal);
 
-		if (rate < 32000 || rate > BIT(22)) {
-			ret = -EOPNOTSUPP;
-			goto dis_runtime_pm;
-		}
+		if (rate < 32000 || rate > BIT(22))
+			return -EOPNOTSUPP;
 
 		if (rate != 32768)
 			scmp_val = RZN1_RTC_CTL0_SLSB_SCMP;
@@ -446,7 +458,7 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL0, val,
 				 !(val & RZN1_RTC_CTL0_CEST), 62, 123);
 	if (ret)
-		goto dis_runtime_pm;
+		return ret;
 
 	/* Set desired modes leaving the controller disabled */
 	writel(RZN1_RTC_CTL0_AMPM | scmp_val, rtc->base + RZN1_RTC_CTL0);
@@ -469,14 +481,12 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_alarm_irq, 0, "RZN1 RTC Alarm", rtc);
 	if (ret) {
 		dev_err(&pdev->dev, "RTC alarm interrupt not available\n");
-		goto dis_runtime_pm;
+		return ret;
 	}
 
 	irq = platform_get_irq_byname_optional(pdev, "pps");
-	if (irq == -EPROBE_DEFER) {
-		ret = irq;
-		goto dis_runtime_pm;
-	}
+	if (irq == -EPROBE_DEFER)
+		return irq;
 	if (irq >= 0)
 		ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_1s_irq, 0, "RZN1 RTC 1s", rtc);
 
@@ -486,26 +496,7 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 		dev_warn(&pdev->dev, "RTC pps interrupt not available. Alarm has only minute accuracy\n");
 	}
 
-	ret = devm_rtc_register_device(rtc->rtcdev);
-	if (ret)
-		goto dis_runtime_pm;
-
-	return 0;
-
-dis_runtime_pm:
-	pm_runtime_put_sync(&pdev->dev);
-
-	return ret;
-}
-
-static void rzn1_rtc_remove(struct platform_device *pdev)
-{
-	struct rzn1_rtc *rtc = platform_get_drvdata(pdev);
-
-	/* Disable all interrupts */
-	writel(0, rtc->base + RZN1_RTC_CTL1);
-
-	pm_runtime_put_sync(&pdev->dev);
+	return devm_rtc_register_device(rtc->rtcdev);
 }
 
 static const struct of_device_id rzn1_rtc_of_match[] = {
@@ -516,7 +507,6 @@ MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
 
 static struct platform_driver rzn1_rtc_driver = {
 	.probe = rzn1_rtc_probe,
-	.remove = rzn1_rtc_remove,
 	.driver = {
 		.name	= "rzn1-rtc",
 		.of_match_table = rzn1_rtc_of_match,
-- 
2.43.0

[PATCH v6 11/17] rtc: rzn1: Dynamically calculate synchronization delay based on clock rate

[Prabhakar]

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

Replace the hardcoded hardware synchronization delays with a calculated
time window derived from the operating sub-clock frequency.

The driver currently hardcodes microsecond ranges assuming a fixed
sub-clock frequency of 32.768 kHz. Newer SoC variants, such as the
RZ/T2H, drive this hardware block using a much faster clock rate
(~195.3 kHz). Hardcoding these wait windows forces faster blocks to
over-sleep, introducing unnecessary delays during clock initialization
and register configuration.

Calculate the duration of the required clock cycles in microseconds based
on the runtime clock rate, and store this value in the driver private
structure to adjust the usleep_range() and readl_poll_timeout() boundaries
dynamically.

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>
---
v5->v6:
- No change.

v4->v5:
- Added Reviewed-by and Tested-by tags from Wolfram.

v3->v4:
- Shortened the comment describing the calculation of RTC_PCLK.
- Updated usleep_range() value to use 2 * rtc->sync_time.

v2->v3:
- No changes.

v1->v2:
- Initialized rate variable to 32768 to avoid timeout_us of 0.
---
 drivers/rtc/rtc-rzn1.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index f90785827945..4e62f7bc2e34 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -70,6 +70,7 @@ struct rzn1_rtc {
 	 */
 	spinlock_t ctl1_access_lock;
 	struct rtc_time tm_alarm;
+	unsigned long sync_time;
 };
 
 static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm)
@@ -120,8 +121,8 @@ static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
 		/* Hold the counter if it was counting up */
 		writel(RZN1_RTC_CTL2_WAIT, rtc->base + RZN1_RTC_CTL2);
 
-		/* Wait for the counter to stop: two 32k clock cycles */
-		usleep_range(61, 100);
+		/* Wait 2-4 RTC_PCLK clock cycles for the counter to stop */
+		usleep_range(rtc->sync_time, rtc->sync_time * 2);
 		ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
 					 val & RZN1_RTC_CTL2_WST, 0, 100);
 		if (ret)
@@ -398,10 +399,10 @@ static void rzn1_rtc_disable_hardware(void *data)
 
 static int rzn1_rtc_probe(struct platform_device *pdev)
 {
+	unsigned long rate = 32768;
 	struct rzn1_rtc *rtc;
 	u32 val, scmp_val = 0;
 	struct clk *xtal;
-	unsigned long rate;
 	int irq, ret;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
@@ -451,12 +452,16 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 			scmp_val = RZN1_RTC_CTL0_SLSB_SCMP;
 	}
 
+	/* Calculate the duration of two RTC_PCLK clock cycles */
+	rtc->sync_time = DIV_ROUND_UP(2 * USEC_PER_SEC, rate);
+
 	/* Disable controller during SUBU/SCMP setup */
 	val = readl(rtc->base + RZN1_RTC_CTL0) & ~RZN1_RTC_CTL0_CE;
 	writel(val, rtc->base + RZN1_RTC_CTL0);
-	/* Wait 2-4 32k clock cycles for the disabled controller */
+	/* Wait 2-4 RTC_PCLK clock cycles for the disabled controller to stop */
 	ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL0, val,
-				 !(val & RZN1_RTC_CTL0_CEST), 62, 123);
+				 !(val & RZN1_RTC_CTL0_CEST), rtc->sync_time,
+				 rtc->sync_time * 2);
 	if (ret)
 		return ret;
 
-- 
2.43.0

[PATCH v6 12/17] rtc: rzn1: Use temporary variable for struct device

[Prabhakar]

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

Use a temporary variable for the struct device pointers to avoid
dereferencing.

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>
---
v5->v6:
- No change

v4->v5:
- Added Tested-by tag from Wolfram.

v3->v4:
- No changes.

v2->v3:
- No changes.

v1->v2:
- Added Reviewed-by tag.
---
 drivers/rtc/rtc-rzn1.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 4e62f7bc2e34..7598efc31e09 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -399,13 +399,14 @@ static void rzn1_rtc_disable_hardware(void *data)
 
 static int rzn1_rtc_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	unsigned long rate = 32768;
 	struct rzn1_rtc *rtc;
 	u32 val, scmp_val = 0;
 	struct clk *xtal;
 	int irq, ret;
 
-	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;
 
@@ -413,13 +414,13 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 
 	rtc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rtc->base))
-		return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
+		return dev_err_probe(dev, PTR_ERR(rtc->base), "Missing reg\n");
 
 	irq = platform_get_irq_byname(pdev, "alarm");
 	if (irq < 0)
 		return irq;
 
-	rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
+	rtc->rtcdev = devm_rtc_allocate_device(dev);
 	if (IS_ERR(rtc->rtcdev))
 		return PTR_ERR(rtc->rtcdev);
 
@@ -427,19 +428,19 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
 	rtc->rtcdev->alarm_offset_max = 7 * 86400;
 
-	ret = devm_pm_runtime_enable(&pdev->dev);
+	ret = devm_pm_runtime_enable(dev);
 	if (ret < 0)
 		return ret;
-	ret = pm_runtime_resume_and_get(&pdev->dev);
+	ret = pm_runtime_resume_and_get(dev);
 	if (ret < 0)
 		return ret;
 
-	ret = devm_add_action_or_reset(&pdev->dev, rzn1_rtc_disable_hardware, &pdev->dev);
+	ret = devm_add_action_or_reset(dev, rzn1_rtc_disable_hardware, dev);
 	if (ret)
 		return ret;
 
 	/* Only switch to scmp if we have an xtal clock with a valid rate and != 32768 */
-	xtal = devm_clk_get_optional(&pdev->dev, "xtal");
+	xtal = devm_clk_get_optional(dev, "xtal");
 	if (IS_ERR(xtal)) {
 		return PTR_ERR(xtal);
 	} else if (xtal) {
@@ -483,9 +484,9 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 
 	spin_lock_init(&rtc->ctl1_access_lock);
 
-	ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_alarm_irq, 0, "RZN1 RTC Alarm", rtc);
+	ret = devm_request_irq(dev, irq, rzn1_rtc_alarm_irq, 0, "RZN1 RTC Alarm", rtc);
 	if (ret) {
-		dev_err(&pdev->dev, "RTC alarm interrupt not available\n");
+		dev_err(dev, "RTC alarm interrupt not available\n");
 		return ret;
 	}
 
@@ -493,12 +494,12 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	if (irq == -EPROBE_DEFER)
 		return irq;
 	if (irq >= 0)
-		ret = devm_request_irq(&pdev->dev, irq, rzn1_rtc_1s_irq, 0, "RZN1 RTC 1s", rtc);
+		ret = devm_request_irq(dev, irq, rzn1_rtc_1s_irq, 0, "RZN1 RTC 1s", rtc);
 
 	if (irq < 0 || ret) {
 		set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtcdev->features);
 		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
-		dev_warn(&pdev->dev, "RTC pps interrupt not available. Alarm has only minute accuracy\n");
+		dev_warn(dev, "RTC pps interrupt not available. Alarm has only minute accuracy\n");
 	}
 
 	return devm_rtc_register_device(rtc->rtcdev);
-- 
2.43.0

[PATCH v6 13/17] rtc: rzn1: Consistently use dev_err_probe()

[Prabhakar]

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

Use dev_err_probe() in the IRQ request error path to make error handling
consistent with the rest of rzn1_rtc_probe().

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v5->v6:
- No change

v4->v5:
- Added Tested-by tag from Wolfram.

v3->v4:
- No changes.

v2->v3:
- No changes.

v1->v2:
- Added Reviewed-by tags.
---
 drivers/rtc/rtc-rzn1.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 7598efc31e09..9fc93afee1e5 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -485,10 +485,8 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	spin_lock_init(&rtc->ctl1_access_lock);
 
 	ret = devm_request_irq(dev, irq, rzn1_rtc_alarm_irq, 0, "RZN1 RTC Alarm", rtc);
-	if (ret) {
-		dev_err(dev, "RTC alarm interrupt not available\n");
-		return ret;
-	}
+	if (ret)
+		return dev_err_probe(dev, ret, "RTC alarm interrupt not available\n");
 
 	irq = platform_get_irq_byname_optional(pdev, "pps");
 	if (irq == -EPROBE_DEFER)
-- 
2.43.0

[PATCH v6 14/17] rtc: rzn1: use FIELD_PREP/FIELD_GET and GENMASK for register access

[Prabhakar]

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

Replace open-coded shift and mask operations with the bitfield API.

Note that the weekday field is changed from an explicit 0x0f mask to
an 8-bit field definition, matching the hardware manual. This does not
change behaviour, as valid weekday values cannot exceed 7.

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>
---
v5->v6:
- No change

v4->v5:
- Added Tested-by tag from Wolfram.

v3->v4:
- Added RB tag from Wolfram

v2->v3:
- No changes.

v1->v2:
- Made use of RZN1_RTC_SUBU_RTCA0FX mask for SUBU register access
  instead of 0x3F.
---
 drivers/rtc/rtc-rzn1.c | 50 +++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 9fc93afee1e5..33c7ef5c1eba 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -12,6 +12,8 @@
  */
 
 #include <linux/bcd.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/init.h>
 #include <linux/iopoll.h>
@@ -39,14 +41,18 @@
 #define   RZN1_RTC_CTL2_STOPPED (RZN1_RTC_CTL2_WAIT | RZN1_RTC_CTL2_WST)
 
 #define RZN1_RTC_TIME 0x30
-#define RZN1_RTC_TIME_MIN_SHIFT 8
-#define RZN1_RTC_TIME_HOUR_SHIFT 16
+#define RZN1_RTC_TIME_SEC GENMASK(7, 0)
+#define RZN1_RTC_TIME_MIN GENMASK(15, 8)
+#define RZN1_RTC_TIME_HOUR GENMASK(23, 16)
+
 #define RZN1_RTC_CAL 0x34
-#define RZN1_RTC_CAL_DAY_SHIFT 8
-#define RZN1_RTC_CAL_MON_SHIFT 16
-#define RZN1_RTC_CAL_YEAR_SHIFT 24
+#define RZN1_RTC_CAL_WDAY GENMASK(7, 0)
+#define RZN1_RTC_CAL_DAY GENMASK(15, 8)
+#define RZN1_RTC_CAL_MON GENMASK(23, 16)
+#define RZN1_RTC_CAL_YEAR GENMASK(31, 24)
 
 #define RZN1_RTC_SUBU 0x38
+#define   RZN1_RTC_SUBU_RTCA0FX GENMASK(5, 0)
 #define   RZN1_RTC_SUBU_DEV BIT(7)
 #define   RZN1_RTC_SUBU_DECR BIT(6)
 
@@ -78,15 +84,15 @@ static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm
 	u32 val;
 
 	val = readl(rtc->base + RZN1_RTC_TIMEC);
-	tm->tm_sec = bcd2bin(val);
-	tm->tm_min = bcd2bin(val >> RZN1_RTC_TIME_MIN_SHIFT);
-	tm->tm_hour = bcd2bin(val >> RZN1_RTC_TIME_HOUR_SHIFT);
+	tm->tm_sec = bcd2bin(FIELD_GET(RZN1_RTC_TIME_SEC, val));
+	tm->tm_min = bcd2bin(FIELD_GET(RZN1_RTC_TIME_MIN, val));
+	tm->tm_hour = bcd2bin(FIELD_GET(RZN1_RTC_TIME_HOUR, val));
 
 	val = readl(rtc->base + RZN1_RTC_CALC);
-	tm->tm_wday = val & 0x0f;
-	tm->tm_mday = bcd2bin(val >> RZN1_RTC_CAL_DAY_SHIFT);
-	tm->tm_mon = bcd2bin(val >> RZN1_RTC_CAL_MON_SHIFT) - 1;
-	tm->tm_year = bcd2bin(val >> RZN1_RTC_CAL_YEAR_SHIFT) + 100;
+	tm->tm_wday = FIELD_GET(RZN1_RTC_CAL_WDAY, val);
+	tm->tm_mday = bcd2bin(FIELD_GET(RZN1_RTC_CAL_DAY, val));
+	tm->tm_mon = bcd2bin(FIELD_GET(RZN1_RTC_CAL_MON, val)) - 1;
+	tm->tm_year = bcd2bin(FIELD_GET(RZN1_RTC_CAL_YEAR, val)) + 100;
 }
 
 static int rzn1_rtc_read_time(struct device *dev, struct rtc_time *tm)
@@ -129,15 +135,15 @@ static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
 			return ret;
 	}
 
-	val = bin2bcd(tm->tm_sec);
-	val |= bin2bcd(tm->tm_min) << RZN1_RTC_TIME_MIN_SHIFT;
-	val |= bin2bcd(tm->tm_hour) << RZN1_RTC_TIME_HOUR_SHIFT;
+	val = FIELD_PREP(RZN1_RTC_TIME_SEC, bin2bcd(tm->tm_sec)) |
+	      FIELD_PREP(RZN1_RTC_TIME_MIN, bin2bcd(tm->tm_min)) |
+	      FIELD_PREP(RZN1_RTC_TIME_HOUR, bin2bcd(tm->tm_hour));
 	writel(val, rtc->base + RZN1_RTC_TIME);
 
-	val = tm->tm_wday;
-	val |= bin2bcd(tm->tm_mday) << RZN1_RTC_CAL_DAY_SHIFT;
-	val |= bin2bcd(tm->tm_mon + 1) << RZN1_RTC_CAL_MON_SHIFT;
-	val |= bin2bcd(tm->tm_year - 100) << RZN1_RTC_CAL_YEAR_SHIFT;
+	val = FIELD_PREP(RZN1_RTC_CAL_WDAY, tm->tm_wday) |
+	      FIELD_PREP(RZN1_RTC_CAL_DAY, bin2bcd(tm->tm_mday)) |
+	      FIELD_PREP(RZN1_RTC_CAL_MON, bin2bcd(tm->tm_mon + 1)) |
+	      FIELD_PREP(RZN1_RTC_CAL_YEAR, bin2bcd(tm->tm_year - 100));
 	writel(val, rtc->base + RZN1_RTC_CAL);
 
 	writel(0, rtc->base + RZN1_RTC_CTL2);
@@ -308,12 +314,12 @@ static int rzn1_rtc_read_offset(struct device *dev, long *offset)
 	val = readl(rtc->base + RZN1_RTC_SUBU);
 	ppb_per_step = val & RZN1_RTC_SUBU_DEV ? 1017 : 3051;
 	subtract = val & RZN1_RTC_SUBU_DECR;
-	val &= 0x3F;
+	val = FIELD_GET(RZN1_RTC_SUBU_RTCA0FX, val);
 
 	if (!val)
 		*offset = 0;
 	else if (subtract)
-		*offset = -(((~val) & 0x3F) + 1) * ppb_per_step;
+		*offset = -(((~val) & RZN1_RTC_SUBU_RTCA0FX) + 1) * ppb_per_step;
 	else
 		*offset = (val - 1) * ppb_per_step;
 
@@ -355,7 +361,7 @@ static int rzn1_rtc_set_offset(struct device *dev, long offset)
 		subu |= steps + 1;
 	} else {
 		subu |= RZN1_RTC_SUBU_DECR;
-		subu |= (~(-steps - 1)) & 0x3F;
+		subu |= (~(-steps - 1)) & RZN1_RTC_SUBU_RTCA0FX;
 	}
 
 	ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, ctl2,
-- 
2.43.0

[PATCH v6 15/17] rtc: rzn1: Add OF match data to gate SUBU register access

[Prabhakar]

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

The RZ/N1 RTC driver selects SCMP mode only when an optional xtal clock
is provided at a valid rate other than 32768 Hz. Without an xtal clock,
or when it runs at 32768 Hz, the driver uses SUBU mode.

However, the RTCA0SUBU register used by SUBU mode is not present on all
SoCs that integrate a similar variant of the RTC block. Allowing SUBU
mode on those variants would expose RTC offset operations that access a
non-existent register.

Add OF match data to describe whether the RTC supports the SUBU register.
Reject probe with -EOPNOTSUPP when SUBU mode would be selected on a
variant without SUBU support.

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>
---
v5->v6:
- Fixed merge-conflict on rtc-next
- Added Reviewed-by and Tested-by tags from Wolfram

v4->v5:
- Renamed rzn1_data to rzn1_rtc_rzn1_data
- Added a print message to indicate that SUBU mode is not supported
  on the variant.
- Added a comment to indicate that the xtal clock is NULL when SUBU
  mode is not supported.
- Added Suggested-by tag from Wolfram.

v3->v4:
- New patch
---
 drivers/rtc/rtc-rzn1.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 33c7ef5c1eba..8c3dbbc34717 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -19,6 +19,7 @@
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/rtc.h>
@@ -66,6 +67,10 @@
 #define RZN1_RTC_TIMEC 0x68
 #define RZN1_RTC_CALC 0x6c
 
+struct rzn1_rtc_data {
+	bool has_subu;
+};
+
 struct rzn1_rtc {
 	struct rtc_device *rtcdev;
 	void __iomem *base;
@@ -405,6 +410,7 @@ static void rzn1_rtc_disable_hardware(void *data)
 
 static int rzn1_rtc_probe(struct platform_device *pdev)
 {
+	const struct rzn1_rtc_data *data;
 	struct device *dev = &pdev->dev;
 	unsigned long rate = 32768;
 	struct rzn1_rtc *rtc;
@@ -412,6 +418,10 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	struct clk *xtal;
 	int irq, ret;
 
+	data = of_device_get_match_data(dev);
+	if (!data)
+		return -ENODEV;
+
 	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;
@@ -455,8 +465,12 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 		if (rate < 32000 || rate > BIT(22))
 			return -EOPNOTSUPP;
 
-		if (rate != 32768)
+		if (rate != 32768 || !data->has_subu)
 			scmp_val = RZN1_RTC_CTL0_SLSB_SCMP;
+	} else if (!data->has_subu) {
+		/* xtal is NULL here */
+		return dev_err_probe(dev, -EOPNOTSUPP,
+				     "No valid XTAL provided and SUBU mode not supported\n");
 	}
 
 	/* Calculate the duration of two RTC_PCLK clock cycles */
@@ -509,8 +523,12 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	return devm_rtc_register_device(rtc->rtcdev);
 }
 
+static const struct rzn1_rtc_data rzn1_rtc_rzn1_data = {
+	.has_subu = true,
+};
+
 static const struct of_device_id rzn1_rtc_of_match[] = {
-	{ .compatible	= "renesas,rzn1-rtc" },
+	{ .compatible	= "renesas,rzn1-rtc", .data = &rzn1_rtc_rzn1_data },
 	{},
 };
 MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
-- 
2.43.0

[PATCH v6 16/17] rtc: rzn1: Drop trailing comma from OF match table sentinel

[Prabhakar]

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

Drop the trailing comma from the final empty entry in the RZN1 RTC OF
match table and mark it explicitly as the sentinel.

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>
---
v5->v6:
- Added missing sentinel comment

v4->v5:
- Added Reviewed-by and Tested-by tag from Wolfram.

v3->v4:
- New patch
---
 drivers/rtc/rtc-rzn1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 8c3dbbc34717..906d03c65df3 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -529,7 +529,7 @@ static const struct rzn1_rtc_data rzn1_rtc_rzn1_data = {
 
 static const struct of_device_id rzn1_rtc_of_match[] = {
 	{ .compatible	= "renesas,rzn1-rtc", .data = &rzn1_rtc_rzn1_data },
-	{},
+	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
 
-- 
2.43.0

[PATCH v6 17/17] rtc: rzn1: Add support for Renesas RZ/T2H and RZ/N2H SoCs

[Prabhakar]

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

Add support for the RTC block found on the Renesas RZ/T2H (R9A09G077)
and RZ/N2H (R9A09G087) SoCs.

These SoCs integrate a closely related variant of the RZ/N1 RTC IP, but
do not implement the RTCA0SUBU register. Use variant-specific match data
to disable SUBU support for these SoCs.

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>
---
v5->v6:
- No change

v4->v5:
- Renamed rzt2h_data to rzn1_rtc_rzt2h_data
- Added Reviewed-by and Tested-by tag from Wolfram.

v3->v4:
- Dropped RB tag from Wolfram.
- Added OF rzt2h_data
- Updated commit message.

v2->v3:
- No changes.

v1->v2:
- Updated commit message to drop reference about RTCA0TCR register.
- Added Reviewed-by tag.
---
 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 906d03c65df3..1e1676a7f3cc 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -523,11 +523,16 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	return devm_rtc_register_device(rtc->rtcdev);
 }
 
+static const struct rzn1_rtc_data rzn1_rtc_rzt2h_data = {
+	.has_subu = false,
+};
+
 static const struct rzn1_rtc_data rzn1_rtc_rzn1_data = {
 	.has_subu = true,
 };
 
 static const struct of_device_id rzn1_rtc_of_match[] = {
+	{ .compatible	= "renesas,r9a09g077-rtc", .data = &rzn1_rtc_rzt2h_data },
 	{ .compatible	= "renesas,rzn1-rtc", .data = &rzn1_rtc_rzn1_data },
 	{ /* sentinel */ }
 };
-- 
2.43.0

Re: [PATCH v6 07/17] rtc: rzn1: Fix malformed MODULE_AUTHOR string

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Fix a malformed MODULE_AUTHOR macro in the rtc-rzn1 driver where a missing
> closing angle bracket on the second author entry creates an invalid format.
> Correct it to the standard "Name <email>" format.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 08/17] rtc: Kconfig: Broaden RTC_DRV_RZN1 dependency to ARCH_RENESAS

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Replace the ARCH_RZN1 dependency with ARCH_RENESAS for the RTC_DRV_RZN1
> config option to make the driver available across both ARM32 and ARM64
> Renesas architectures.
> 
> The newer RZ/T2H and RZ/N2H ARM64 SoCs integrate a closely related variant
> of the RTC IP block found on the RZ/N1 SoCs. Update the build dependency
> and expand the Kconfig help text to allow this driver to be selected for
> these additional platforms.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 11/17] rtc: rzn1: Dynamically calculate synchronization delay based on clock rate

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Replace the hardcoded hardware synchronization delays with a calculated
> time window derived from the operating sub-clock frequency.
> 
> The driver currently hardcodes microsecond ranges assuming a fixed
> sub-clock frequency of 32.768 kHz. Newer SoC variants, such as the
> RZ/T2H, drive this hardware block using a much faster clock rate
> (~195.3 kHz). Hardcoding these wait windows forces faster blocks to
> over-sleep, introducing unnecessary delays during clock initialization
> and register configuration.
> 
> Calculate the duration of the required clock cycles in microseconds based
> on the runtime clock rate, and store this value in the driver private
> structure to adjust the usleep_range() and readl_poll_timeout() boundaries
> dynamically.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 10/17] rtc: rzn1: Replace remove callback with devm_add_action_or_reset()

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Simplify the driver teardown by registering a managed cleanup action with
> devm_add_action_or_reset(). This eliminates the explicit probe error path
> and allows the .remove() callback to be dropped.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 13/17] rtc: rzn1: Consistently use dev_err_probe()

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Use dev_err_probe() in the IRQ request error path to make error handling
> consistent with the rest of rzn1_rtc_probe().
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 16/17] rtc: rzn1: Drop trailing comma from OF match table sentinel

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Drop the trailing comma from the final empty entry in the RZN1 RTC OF
> match table and mark it explicitly as the sentinel.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 12/17] rtc: rzn1: Use temporary variable for struct device

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Use a temporary variable for the struct device pointers to avoid
> dereferencing.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 04/17] rtc: rzn1: Handle unset alarm weekday in rzn1_rtc_read_alarm

[sashiko-bot]

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

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Re: [PATCH v6 09/17] rtc: rzn1: Use pm_runtime_put_sync()

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> pm_runtime_put() may trigger the idle check after pm_runtime_disable()
> is run as part of devm_pm_runtime_enable()'s cleanup action, leaving
> runtime PM active.
> 
> Use pm_runtime_put_sync() to ensure the idle check runs synchronously.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 01/17] dt-bindings: rtc: renesas,rzn1-rtc: Add RZ/T2H and RZ/N2H support

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Add compatible strings for the RTC block found on the Renesas RZ/T2H
> (R9A09G077) and RZ/N2H (R9A09G087) SoCs.
> 
> These SoCs integrate a closely related variant of the RZ/N1 RTC IP.
> Unlike RZ/N1, they do not implement the RTCA0SUBU register. This is
> not a limitation for Linux support, as these registers are not used
> when the RTC operates in "scmp" clock mode, which is required on
> RZ/T2H and RZ/N2H due to their 195.3 kHz input clock.
> 
> The RZ/T2H RTC variant also supports a 1Hz output signal on the
> RTCAT1HZ pin, controlled by the RTCA0CTL1[RTCA01HZE] bit. This bit is
> marked as reserved in the RZ/N1 hardware manual.
> 
> Update the binding schema to require the additional clock inputs used by
> these SoCs.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 14/17] rtc: rzn1: use FIELD_PREP/FIELD_GET and GENMASK for register access

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Replace open-coded shift and mask operations with the bitfield API.
> 
> Note that the weekday field is changed from an explicit 0x0f mask to
> an 8-bit field definition, matching the hardware manual. This does not
> change behaviour, as valid weekday values cannot exceed 7.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 02/17] rtc: rzn1: Handle EPROBE_DEFER for optional pps interrupt

[sashiko-bot]

> 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>

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Re: [PATCH v6 15/17] rtc: rzn1: Add OF match data to gate SUBU register access

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> The RZ/N1 RTC driver selects SCMP mode only when an optional xtal clock
> is provided at a valid rate other than 32768 Hz. Without an xtal clock,
> or when it runs at 32768 Hz, the driver uses SUBU mode.
> 
> However, the RTCA0SUBU register used by SUBU mode is not present on all
> SoCs that integrate a similar variant of the RTC block. Allowing SUBU
> mode on those variants would expose RTC offset operations that access a
> non-existent register.
> 
> Add OF match data to describe whether the RTC supports the SUBU register.
> Reject probe with -EOPNOTSUPP when SUBU mode would be selected on a
> variant without SUBU support.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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Re: [PATCH v6 05/17] rtc: rzn1: Fix alarm range check truncation on 32-bit systems

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> alarm and farest were declared as unsigned long, but
> rtc_tm_to_time64() returns time64_t (s64). On 32-bit systems where
> unsigned long is 32 bits, the assignment silently truncates the upper
> 32 bits of the timestamp.
> 
> Fix by declaring alarm and farest as time64_t and replacing
> time_after() with a direct signed comparison, which is correct for
> time64_t values that will never realistically overflow.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260821211032.13554-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=5

Re: [PATCH v6 17/17] rtc: rzn1: Add support for Renesas RZ/T2H and RZ/N2H SoCs

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Add support for the RTC block found on the Renesas RZ/T2H (R9A09G077)
> and RZ/N2H (R9A09G087) SoCs.
> 
> These SoCs integrate a closely related variant of the RZ/N1 RTC IP, but
> do not implement the RTCA0SUBU register. Use variant-specific match data
> to disable SUBU support for these SoCs.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260821211032.13554-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=17

Re: [PATCH v6 03/17] rtc: rzn1: Fix weekday underflow when alarm crosses month boundary

[sashiko-bot]

> 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>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260821211032.13554-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=3

Re: [PATCH v6 06/17] rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:

Pre-existing issues:
- [High] Data race and TOCTOU in IRQ handler leading to spurious interrupts and incomplete synchronization
- [High] Hardware state lockup on timeout in rzn1_rtc_set_time()
- [High] Alarm logic erroneously uses 1-second interrupt for past alarms with the same minute
- [Medium] Race window in rzn1_rtc_read_time() fallback logic can produce inconsistent timestamps
--

--- Patch [6]: [PATCH v6 06/17] rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers ---
commit 0be1a07839b0e52a936e0315319b64b90371633b
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers

This commit updates rzn1_rtc_set_alarm() to disable alarm interrupts before
reprogramming the alarm registers (ALM, ALH, ALW). This prevents a scenario
where an existing alarm interrupt fires while the registers contain a mixture
of old and new values.

> diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
> index f3268655fd373..42e57bf0b4aaa 100644
> --- a/drivers/rtc/rtc-rzn1.c
> +++ b/drivers/rtc/rtc-rzn1.c
> @@ -281,6 +281,11 @@ 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);

[Severity: High]
This is a pre-existing issue, but does disabling the IRQ here fully prevent
the race without a call to synchronize_irq()?

If a previous alarm interrupt fires right as rzn1_rtc_set_alarm() is called,
CPU0 could enter rzn1_rtc_alarm_irq(), read tm_sec locklessly, and wait for
the spinlock.

CPU1 could then call rzn1_rtc_alarm_irq_enable(dev, 0), holding and releasing
the lock.

CPU0 could then acquire the lock and unconditionally write its locklessly
computed set_irq_bits to CTL1, re-enabling the interrupt:

drivers/rtc/rtc-rzn1.c:rzn1_rtc_alarm_irq() {
	if (rtc->tm_alarm.tm_sec == 0)
		rtc_update_irq(rtc->rtcdev, 1, RTC_AF | RTC_IRQF);
	else
		/* Switch to 1s interrupts */
		set_irq_bits = RZN1_RTC_CTL1_1SE;

	guard(spinlock)(&rtc->ctl1_access_lock);
	...
	ctl1 &= ~RZN1_RTC_CTL1_ALME;
	ctl1 |= set_irq_bits;
	writel(ctl1, rtc->base + RZN1_RTC_CTL1);
}

Could this allow the handler to override the synchronization intended by
this patch?

> +	if (ret)
> +		return ret;
> +
>  	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);

[ ... ]


[Severity: High]
This isn't a bug introduced by this patch, but does the error path in
rzn1_rtc_set_time() leave the hardware in a locked-up state?

drivers/rtc/rtc-rzn1.c:rzn1_rtc_set_time() {
	...
		ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
					 val & RZN1_RTC_CTL2_WST, 0, 100);
		if (ret)
			return ret;
	...
}

If the system is under heavy load causing a preemption delay longer than
the 100us timeout, the function returns -ETIMEDOUT immediately without
clearing RZN1_RTC_CTL2_WAIT.

Could this stop the RTC hardware from ticking entirely across the system?


[Severity: Medium]
This is a pre-existing issue, but does the fallback logic in
rzn1_rtc_read_time() leave a race window for preemption to corrupt the
timestamp?

drivers/rtc/rtc-rzn1.c:rzn1_rtc_read_time() {
	...
	rzn1_rtc_get_time_snapshot(rtc, tm);
	secs = readl(rtc->base + RZN1_RTC_SECC);
	if (tm->tm_sec != bcd2bin(secs))
		rzn1_rtc_get_time_snapshot(rtc, tm);

	return 0;
}

If the thread is preempted precisely between the TIMEC and CALC reads in the
second snapshot, could this return an inconsistent timestamp to userspace
since there is no loop to verify the second snapshot?


[Severity: High]
This is a pre-existing issue, but does the alarm logic erroneously fall back
to the 1-second interrupt for past alarms?

drivers/rtc/rtc-rzn1.c:rzn1_rtc_alarm_irq_enable() {
	...
			if (rtc_tm_sub(tm, &tm_now) > 59 || tm->tm_min != tm_now.tm_min)
				ctl1 |= RZN1_RTC_CTL1_ALME;
			else
				ctl1 |= RZN1_RTC_CTL1_1SE;
	...
}

If an alarm is set for a time in the past where tm_min matches but
rtc_tm_sub() is negative, does this logic incorrectly apply the 1-second
interrupt and cause late or spurious wakeups?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260821211032.13554-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=6

Re: [PATCH v6 06/17] rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers

[Wolfram Sang]

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On Fri, Aug 21, 2026 at 09:26:11PM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 4 potential issue(s) to consider:
> 
> Pre-existing issues:
> - [High] Data race and TOCTOU in IRQ handler leading to spurious interrupts and incomplete synchronization
> - [High] Hardware state lockup on timeout in rzn1_rtc_set_time()
> - [High] Alarm logic erroneously uses 1-second interrupt for past alarms with the same minute
> - [Medium] Race window in rzn1_rtc_read_time() fallback logic can produce inconsistent timestamps

All pre-existing issues, should be handled incrementally.


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Re: [PATCH v6 00/17] Add RTC support for Renesas RZ/T2H and RZ/N2H SoCs

[Wolfram Sang]

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> v5->v6:
> - Dropped the output log from commit message.
> - Added missing sentinel comment
> - Collected Reviewed-by and Tested-by tags from Wolfram

I have no more review comments and re-testing the series was also
successful. It is really good to go from my side.

Thank you for keeping at it and especially for carefully adding the
"change since last version" information. That made the review a lot
easier. Good work!


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Re: [PATCH v6 00/17] Add RTC support for Renesas RZ/T2H and RZ/N2H SoCs

[Alexandre Belloni]

On Fri, 21 Aug 2026 22:10:15 +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Hi all,
> 
> This series adds support for the RTC IP found on the Renesas RZ/T2H and
> RZ/N2H SoCs.
> 
> [...]

Applied, thanks!

[01/17] dt-bindings: rtc: renesas,rzn1-rtc: Add RZ/T2H and RZ/N2H support
        https://git.kernel.org/abelloni/c/1ffb5be3e4be
[02/17] rtc: rzn1: Handle EPROBE_DEFER for optional pps interrupt
        https://git.kernel.org/abelloni/c/708546aa3956
[03/17] rtc: rzn1: Fix weekday underflow when alarm crosses month boundary
        https://git.kernel.org/abelloni/c/022a2839a520
[04/17] rtc: rzn1: Handle unset alarm weekday in rzn1_rtc_read_alarm
        https://git.kernel.org/abelloni/c/457b5dbce312
[05/17] rtc: rzn1: Fix alarm range check truncation on 32-bit systems
        https://git.kernel.org/abelloni/c/c3e735e9f620
[06/17] rtc: rzn1: Disable alarm interrupt before reprogramming alarm registers
        https://git.kernel.org/abelloni/c/51458d5b0a1c
[07/17] rtc: rzn1: Fix malformed MODULE_AUTHOR string
        https://git.kernel.org/abelloni/c/cd54d8f09d9b
[08/17] rtc: Kconfig: Broaden RTC_DRV_RZN1 dependency to ARCH_RENESAS
        https://git.kernel.org/abelloni/c/960987abe58d
[09/17] rtc: rzn1: Use pm_runtime_put_sync()
        https://git.kernel.org/abelloni/c/ea0ef2e7f83b
[10/17] rtc: rzn1: Replace remove callback with devm_add_action_or_reset()
        https://git.kernel.org/abelloni/c/6e0d7d480f2d
[11/17] rtc: rzn1: Dynamically calculate synchronization delay based on clock rate
        https://git.kernel.org/abelloni/c/afb8972b9e36
[12/17] rtc: rzn1: Use temporary variable for struct device
        https://git.kernel.org/abelloni/c/b587001387c1
[13/17] rtc: rzn1: Consistently use dev_err_probe()
        https://git.kernel.org/abelloni/c/0e1ae8c654f0
[14/17] rtc: rzn1: use FIELD_PREP/FIELD_GET and GENMASK for register access
        https://git.kernel.org/abelloni/c/5ae93269d3e5
[15/17] rtc: rzn1: Add OF match data to gate SUBU register access
        https://git.kernel.org/abelloni/c/38a3a3b09958
[16/17] rtc: rzn1: Drop trailing comma from OF match table sentinel
        https://git.kernel.org/abelloni/c/8af6331c6e7a
[17/17] rtc: rzn1: Add support for Renesas RZ/T2H and RZ/N2H SoCs
        https://git.kernel.org/abelloni/c/b418fa370ea6

Best regards,

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