[PATCH v3 00/12] Add RTC support for Renesas RZ/T2H and RZ/N2H SoCs

[PATCH v3 00/12] 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 next-20260706.

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 (12):
  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: Fix malformed MODULE_AUTHOR string
  rtc: Kconfig: Broaden RTC_DRV_RZN1 dependency to ARCH_RENESAS
  rtc: rzn1: Fix alarm range check truncation on 32-bit systems
  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 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                        | 159 ++++++++++--------
 3 files changed, 116 insertions(+), 83 deletions(-)

-- 
2.54.0

[PATCH v3 01/12] 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>
---
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:
-- 
2.54.0

Re: [PATCH v3 01/12] dt-bindings: rtc: renesas,rzn1-rtc: Add RZ/T2H and RZ/N2H support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The RZ/T2H RTC variant adds a 1Hz clock output capability but the binding schema fails to document and require the `#clock-cells` property.
--

commit 521c08a40b8b1ac0b30dec5219ca0271639457ef
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

dt-bindings: rtc: renesas,rzn1-rtc: Add RZ/T2H and RZ/N2H support

This commit adds compatible strings for the RTC block found on the Renesas
RZ/T2H and RZ/N2H SoCs. It also updates the binding schema to require the
additional clock inputs used by these variants.

> diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> --- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> +++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
[ ... ]
> @@ -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

[Severity: Medium]
The commit message mentions that the RZ/T2H RTC variant supports a 1Hz clock
output signal on the RTCAT1HZ pin. Since this introduces a clock provider
capability, shouldn't the #clock-cells property be documented and required
here with an appropriate const constraint?

Without documenting this property, adding #clock-cells to an RTC node using
the renesas,r9a09g077-rtc compatible string will cause device trees to fail
dt_binding_check validation due to the unevaluatedProperties: false constraint.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=1

[PATCH v3 02/12] 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>
---
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);
 
-- 
2.54.0

Re: [PATCH v3 02/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=2

[PATCH v3 03/12] rtc: rzn1: fix weekday underflow when alarm crosses month boundary

[Prabhakar]

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

In rzn1_rtc_set_alarm(), the driver attempts to calculate the weekday
for an alarm by computing the day delta between the alarm time and the
current time:

    days_ahead = tm->tm_mday - tm_now.tm_mday;
    wday = (tm_now.tm_wday + days_ahead) % 7;

However, if an alarm is scheduled for the beginning of the next month
while the current time is at the end of the month (e.g., current day is
31, alarm day is 1), `tm->tm_mday - tm_now.tm_mday` results in a negative
value (-30). Since `days_ahead` is an unsigned int, this underflows to a
large positive number, leading to an incorrect `wday` being written to
the RZN1_RTC_ALW register. As a result, the alarm fails to fire.

Fix this by utilizing the already computed `alarm` time64_t timestamp.
Convert it back into an rtc_time struct via rtc_time64_to_tm(), which
automatically handles month boundaries and correctly populates the
`tm_wday` field.

Fixes: b5ad1bf00d2c4 ("rtc: rzn1: Add alarm support")
Cc: stable@vger.kernel.org
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v2->v3:
- New patch to fix weekday underflow when alarm crosses month boundary.
---
 drivers/rtc/rtc-rzn1.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index aa27ad7f5941..3c83f95c18c4 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -260,7 +260,8 @@ 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;
+	struct rtc_time alarm_tm;
+	unsigned int wday;
 	int ret;
 
 	ret = rzn1_rtc_read_time(dev, &tm_now);
@@ -274,8 +275,8 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 		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;
+	rtc_time64_to_tm(alarm, &alarm_tm);
+	wday = alarm_tm.tm_wday;
 
 	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
 	writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH);
-- 
2.54.0

Re: [PATCH v3 03/12] rtc: rzn1: fix weekday underflow when alarm crosses month boundary

[sashiko-bot]

> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> In rzn1_rtc_set_alarm(), the driver attempts to calculate the weekday
> for an alarm by computing the day delta between the alarm time and the
> current time:
> 
>     days_ahead = tm->tm_mday - tm_now.tm_mday;
>     wday = (tm_now.tm_wday + days_ahead) % 7;
> 
> However, if an alarm is scheduled for the beginning of the next month
> while the current time is at the end of the month (e.g., current day is
> 31, alarm day is 1), `tm->tm_mday - tm_now.tm_mday` results in a negative
> value (-30). Since `days_ahead` is an unsigned int, this underflows to a
> large positive number, leading to an incorrect `wday` being written to
> the RZN1_RTC_ALW register. As a result, the alarm fails to fire.
> 
> Fix this by utilizing the already computed `alarm` time64_t timestamp.
> Convert it back into an rtc_time struct via rtc_time64_to_tm(), which
> automatically handles month boundaries and correctly populates the
> `tm_wday` field.
> 
> 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/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=3

[PATCH v3 04/12] 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>
---
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 3c83f95c18c4..2a0f0362dd52 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -517,6 +517,6 @@ 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");
-- 
2.54.0

Re: [PATCH v3 04/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=4

[PATCH v3 05/12] 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>
---
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"
-- 
2.54.0

Re: [PATCH v3 05/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=5

[PATCH v3 06/12] 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>
---
v2->v3:
- No changes.

v1->v2:
- Added Reviewed-by tag.
---
 drivers/rtc/rtc-rzn1.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 2a0f0362dd52..a5283e680e36 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -20,6 +20,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/rtc.h>
 #include <linux/spinlock.h>
+#include <linux/time64.h>
 
 #define RZN1_RTC_CTL0 0x00
 #define   RZN1_RTC_CTL0_SLSB_SCMP BIT(4)
@@ -259,8 +260,8 @@ 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;
 	struct rtc_time alarm_tm;
+	time64_t alarm, farest;
 	unsigned int wday;
 	int ret;
 
@@ -271,7 +272,7 @@ 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;
 
 	/* Convert alarm day into week day */
-- 
2.54.0

Re: [PATCH v3 06/12] 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/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=6

[PATCH v3 07/12] 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>
---
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 a5283e680e36..1e6d26a122b8 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -378,6 +378,17 @@ 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(dev);
+}
+
 static int rzn1_rtc_probe(struct platform_device *pdev)
 {
 	struct rzn1_rtc *rtc;
@@ -415,18 +426,19 @@ 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;
@@ -439,7 +451,7 @@ 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);
@@ -462,14 +474,12 @@ 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);
 
@@ -479,26 +489,7 @@ 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(&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(&pdev->dev);
+	return devm_rtc_register_device(rtc->rtcdev);
 }
 
 static const struct of_device_id rzn1_rtc_of_match[] = {
@@ -509,7 +500,6 @@ 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,
-- 
2.54.0

Re: [PATCH v3 07/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=7

[PATCH v3 08/12] 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>
---
v2->v3:
- No changes.

v1->v2:
- Initialized rate variable to 32768 to avoid timeout_us of 0.
---
 drivers/rtc/rtc-rzn1.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 1e6d26a122b8..763d9a98fd62 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 for the counter to stop: two RTC_PCLK clock cycles */
+		usleep_range(rtc->sync_time, rtc->sync_time + 100);
 		ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
 					 val & RZN1_RTC_CTL2_WST, 0, 100);
 		if (ret)
@@ -391,10 +392,10 @@ 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);
@@ -444,12 +445,20 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 			scmp_val = RZN1_RTC_CTL0_SLSB_SCMP;
 	}
 
+	/*
+	 * The internal clock counter operates in synchronization with the
+	 * RTC_PCLK clock. Calculate the duration of two RTC_PCLK clock
+	 * cycles in microseconds required for operations to complete.
+	 */
+	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;
 
-- 
2.54.0

Re: [PATCH v3 08/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=8

[PATCH v3 09/12] 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>
---
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 763d9a98fd62..27a92c77f071 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -392,13 +392,14 @@ 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;
 
@@ -406,13 +407,13 @@ 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);
 
@@ -420,19 +421,19 @@ 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) {
@@ -480,9 +481,9 @@ 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;
 	}
 
@@ -490,12 +491,12 @@ 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);
-- 
2.54.0

Re: [PATCH v3 09/12] rtc: rzn1: Use temporary variable for struct device

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Asynchronous pm_runtime_put() is used immediately before pm_runtime_disable() during devres cleanup, creating a race condition that leaves the device active.
--

commit 5ee7d58e34962ad10d6a886e40f4b4757bc5611e
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

rtc: rzn1: Use temporary variable for struct device

This commit introduces a temporary variable to store the device pointer in
the probe function. This replaces multiple occurrences to avoid repeated
dereferencing.

> diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
> index 12bbbc18f7eab..4917bd223efd7 100644
> --- a/drivers/rtc/rtc-rzn1.c
> +++ b/drivers/rtc/rtc-rzn1.c

[ ... ]

> @@ -421,19 +422,19 @@ 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);

[Severity: High]
This is a pre-existing issue, but does the async suspend queued by
rzn1_rtc_disable_hardware() race with the subsequent runtime PM disable?

During devres cleanup (such as probe failure or driver removal), the cleanup
actions execute in reverse order (LIFO). First, the custom hardware disable
action runs:

static void rzn1_rtc_disable_hardware(void *data)
{
        ...
        pm_runtime_put(dev);
}

Because this is an asynchronous put, the suspend work is only queued.

Immediately after, devres unwinds devm_pm_runtime_enable() which calls
pm_runtime_disable(). This cleanup triggers __pm_runtime_barrier(), canceling
any pending async idle or suspend work and leaving the hardware powered on.

Should rzn1_rtc_disable_hardware() use pm_runtime_put_sync() instead to
ensure the suspend completes before runtime PM is disabled?

>  	if (ret)
>  		return ret;
>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=9

[PATCH v3 10/12] 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>
---
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 27a92c77f071..f6272eb5a896 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -482,10 +482,8 @@ 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)
-- 
2.54.0

Re: [PATCH v3 10/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=10

[PATCH v3 11/12] 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>
---
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 f6272eb5a896..2c3c82f8c693 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);
@@ -301,12 +307,12 @@ 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;
 
@@ -348,7 +354,7 @@ 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,
-- 
2.54.0

Re: [PATCH v3 11/12] 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>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=11

[PATCH v3 12/12] 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 by matching the new
"renesas,r9a09g077-rtc" compatible string.

These SoCs integrate a closely related variant of the RZ/N1 RTC IP.
Unlike the RZ/N1 implementation, the RZ/T2H and RZ/N2H variants lack
the RTCA0SUBU register. However, this register is not accessed when
operating in SCMP mode using the existing rzn1_rtc_ops_scmp
configuration, allowing the current driver infrastructure to be reused
without modification.

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.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v2->v3:
- No changes.

v1->v2:
- Updated commit message to drop reference about RTCA0TCR register.
- Added Reviewed-by tag.
---
 drivers/rtc/rtc-rzn1.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 2c3c82f8c693..2a6ac98a206c 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -507,6 +507,7 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 }
 
 static const struct of_device_id rzn1_rtc_of_match[] = {
+	{ .compatible	= "renesas,r9a09g077-rtc" },
 	{ .compatible	= "renesas,rzn1-rtc" },
 	{},
 };
-- 
2.54.0

Re: [PATCH v3 12/12] rtc: rzn1: Add support for Renesas RZ/T2H and RZ/N2H SoCs

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The driver may incorrectly fall back to SUBU mode on RZ/T2H and RZ/N2H SoCs, leading to accesses of the non-existent RTCA0SUBU register and a potential kernel panic.
--

commit ee14aa230b364e5ad7677d78cb0c0a8599351c1c
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

rtc: rzn1: Add support for Renesas RZ/T2H and RZ/N2H SoCs
    
This commit adds support for the RTC block on Renesas RZ/T2H and RZ/N2H SoCs
using a new compatible string. It notes that the variants lack the RTCA0SUBU
register, but rely on the existing SCMP mode to function without it.

> diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
> index d1a974c6b8bbe..1d4d8d01749d3 100644
> --- a/drivers/rtc/rtc-rzn1.c
> +++ b/drivers/rtc/rtc-rzn1.c
> @@ -508,6 +508,7 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
>  }
>  
>  static const struct of_device_id rzn1_rtc_of_match[] = {
> +	{ .compatible	= "renesas,r9a09g077-rtc" },

[Severity: High]
If the devicetree for this SoC omits the "xtal" clock or specifies a standard
32768 Hz frequency, will the driver inadvertently fall back to SUBU mode?

Looking at rzn1_rtc_probe(), the driver sets scmp_val = 0 for 32768 Hz
crystals or when the clock is absent:

drivers/rtc/rtc-rzn1.c:rzn1_rtc_probe() {
    ...
	xtal = devm_clk_get_optional(dev, "xtal");
	if (IS_ERR(xtal)) {
		return PTR_ERR(xtal);
	} else if (xtal) {
		rate = clk_get_rate(xtal);
        ...
		if (rate != 32768)
			scmp_val = RZN1_RTC_CTL0_SLSB_SCMP;
	}
    ...
	if (scmp_val) {
        ...
	} else {
		rtc->rtcdev->ops = &rzn1_rtc_ops_subu;
	}
    ...
}

If this happens on the RZ/T2H, rzn1_rtc_ops_subu exposes the .read_offset
and .set_offset callbacks. Any userspace read of the offset sysfs node
would then trigger a hardware access to the missing register:

drivers/rtc/rtc-rzn1.c:rzn1_rtc_read_offset() {
    ...
	val = readl(rtc->base + RZN1_RTC_SUBU);
    ...
}

Can this lead to a synchronous external abort (kernel panic) when an
unprivileged user reads /sys/class/rtc/rtc0/offset?

Should we add match data to this compatible string to identify the variant
and explicitly reject probe with -EOPNOTSUPP if the clock configuration
would require the unsupported SUBU mode?

>  	{ .compatible	= "renesas,rzn1-rtc" },
>  	{},
>  };

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260706175138.12587-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=12