[PATCH 0/6] rtc: rzn1: cleanups, no irq support, R-Car Gen5 enablement

[PATCH 0/6] rtc: rzn1: cleanups, no irq support, R-Car Gen5 enablement

[Wolfram Sang]

The main intention of this series is to enable RTC support for the
Renesas R-Car Gen5 X5H SoC (patches 5+6). Because interrupts are not
wired there, patches to make interrupts optional are included (patches
3+4). Some cleanups I came up with are prepended (patches 1+2).

These patches have been tested on the original RZ/N1D board and the new
X5H Ironhide board. 'rtctest' passed on both SoCs. On X5H, some tests
are skipped, of course, because no alarms are supported.

'dt_binding_check' and 'dtbs_check' also did not find any issues.

A branch can be found here:

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/x5h/rtc-experimental

Looking forward to comments.


Wolfram Sang (6):
  dt-bindings: rtc: rzn1: drop unneeded 'start-year' from example
  dt-bindings: rtc: rzn1: add SoC names next to their IDs
  dt-bindings: rtc: rzn1: interrupts are not required
  rtc: rzn1: make interrupts optional
  dt-bindings: rtc: rzn1: add R-Car X5H support
  rtc: rzn1: add R-Car X5H support

 .../bindings/rtc/renesas,rzn1-rtc.yaml        | 19 +++---
 drivers/rtc/rtc-rzn1.c                        | 59 +++++++++----------
 2 files changed, 38 insertions(+), 40 deletions(-)

-- 
2.53.0

[PATCH 1/6] dt-bindings: rtc: rzn1: drop unneeded 'start-year' from example

[Wolfram Sang]

We don't use 'start-year' in upstream DTs because the driver does the
right thing by default, ranging from 2000 to 2099. So, drop it from the
example, too.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
index ea7b039a91e7..e96007981c34 100644
--- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
@@ -91,5 +91,4 @@ examples:
         clocks = <&sysctrl R9A06G032_HCLK_RTC>;
         clock-names = "hclk";
         power-domains = <&sysctrl>;
-        start-year = <2000>;
     };
-- 
2.53.0

[PATCH 2/6] dt-bindings: rtc: rzn1: add SoC names next to their IDs

[Wolfram Sang]

This helps maintaining because the numbers are easy to confuse.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 .../devicetree/bindings/rtc/renesas,rzn1-rtc.yaml      | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
index e96007981c34..7ea77cd0bee1 100644
--- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
@@ -14,14 +14,14 @@ properties:
     oneOf:
       - items:
           - enum:
-              - renesas,r9a06g032-rtc
-          - const: renesas,rzn1-rtc
+              - renesas,r9a06g032-rtc # RZ/N1D
+          - const: renesas,rzn1-rtc   # RZ/N1
 
-      - const: renesas,r9a09g077-rtc
+      - const: renesas,r9a09g077-rtc  # RZ/T2H
 
       - items:
-          - const: renesas,r9a09g087-rtc
-          - const: renesas,r9a09g077-rtc
+          - const: renesas,r9a09g087-rtc  # RZ/N2H
+          - const: renesas,r9a09g077-rtc  # RZ/T2H
 
   reg:
     maxItems: 1
-- 
2.53.0

[PATCH 3/6] dt-bindings: rtc: rzn1: interrupts are not required

[Wolfram Sang]

Interrupts are only needed for alarms to work. Reading/Setting the RTC
works fine without interrupts. Drop the requirement for interrupts
because an upcoming SoC does not have interrupts wired.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
index 7ea77cd0bee1..b426a34958d6 100644
--- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
@@ -52,8 +52,6 @@ properties:
 required:
   - compatible
   - reg
-  - interrupts
-  - interrupt-names
   - clocks
   - clock-names
   - power-domains
-- 
2.53.0

[PATCH 5/6] dt-bindings: rtc: rzn1: add R-Car X5H support

[Wolfram Sang]

Identical to RZ/T2H except that interrupts are not wired.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
index b426a34958d6..55e1a33c566b 100644
--- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
@@ -23,6 +23,11 @@ properties:
           - const: renesas,r9a09g087-rtc  # RZ/N2H
           - const: renesas,r9a09g077-rtc  # RZ/T2H
 
+      - items:
+          - enum:
+              - renesas,r8a78000-rtc      # R-Car X5H
+          - const: renesas,rcar-gen5-rtc  # R-Car Gen5
+
   reg:
     maxItems: 1
 
@@ -66,6 +71,7 @@ allOf:
             enum:
               - renesas,r9a09g077-rtc
               - renesas,r9a09g087-rtc
+              - renesas,rcar-gen5-rtc
     then:
       properties:
         clocks:
-- 
2.53.0

Re: [PATCH 2/6] dt-bindings: rtc: rzn1: add SoC names next to their IDs

[sashiko-bot]

> This helps maintaining because the numbers are easy to confuse.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260914211826.73727-8-wsa+renesas@sang-engineering.com?part=2

Re: [PATCH 1/6] dt-bindings: rtc: rzn1: drop unneeded 'start-year' from example

[sashiko-bot]

> We don't use 'start-year' in upstream DTs because the driver does the
> right thing by default, ranging from 2000 to 2099. So, drop it from the
> example, too.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

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

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260914211826.73727-8-wsa+renesas@sang-engineering.com?part=1

Re: [PATCH 3/6] dt-bindings: rtc: rzn1: interrupts are not required

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] Globally removing `interrupts` and `interrupt-names` from `required` weakens schema validation for existing SoCs.
- [Medium] Making `interrupts` and `interrupt-names` optional without adding a schema dependency allows incomplete interrupt specifications.
--

commit 963405de649fb7157801d57b7a47cf959108ca2c
Author: Wolfram Sang <wsa+renesas@sang-engineering.com>

dt-bindings: rtc: rzn1: interrupts are not required

This commit drops the interrupts and interrupt-names properties from the
required list in the rzn1-rtc binding. This change is made to support an
upcoming SoC where interrupts are not wired to the RTC.

> diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> index 7ea77cd0bee15..b426a34958d6d 100644
> --- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> +++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> @@ -52,8 +52,6 @@ properties:
>  required:
>    - compatible
>    - reg
> -  - interrupts
> -  - interrupt-names

[Severity: Medium]
Does globally removing these properties weaken schema validation for existing
SoCs? Device trees for existing SoCs where interrupts are physically wired
could now incorrectly omit the interrupts and silently pass the schema
checker, resulting in incomplete hardware descriptions.

To accommodate the new SoC without affecting existing ones, should we
conditionally require these properties for the older compatible strings
using an allOf -> if -> then block?

[Severity: Medium]
By making these properties optional independently, could this allow
incomplete interrupt specifications? If a device tree specifies interrupts
but omits interrupt-names, schema validation will pass. However, the driver
uses platform_get_irq_byname_optional(), which will fail with -EINVAL at
runtime if names are missing, silently disabling alarm functionality.

Would it be better to include a dependencies block (e.g.,
interrupts: [ interrupt-names ]) to ensure complete descriptions when
interrupts are provided?

>    - clocks
>    - clock-names
>    - power-domains

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260914211826.73727-8-wsa+renesas@sang-engineering.com?part=3

Re: [PATCH 5/6] dt-bindings: rtc: rzn1: add R-Car X5H support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [Medium] The R-Car X5H compatible string is missing an `if-then` conditional block to explicitly disallow interrupts.

Pre-existing issues:
- [High] The driver dynamically modifies a global static `rtc_class_ops` structure during probe, causing operations to be incorrectly shared and corrupted across all device instances.
--

commit a9257218efe4782b04de9171568942363749f822
Author: Wolfram Sang <wsa+renesas@sang-engineering.com>

    dt-bindings: rtc: rzn1: add R-Car X5H support

This patch adds support for the R-Car X5H hardware variant to the RZ/N1 RTC
device tree binding schema. The commit message explicitly notes that this
hardware is identical to RZ/T2H except that interrupts are not wired.

> 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
[ ... ]
> @@ -66,6 +71,7 @@ allOf:
>              enum:
>                - renesas,r9a09g077-rtc
>                - renesas,r9a09g087-rtc
> +              - renesas,rcar-gen5-rtc
>      then:
>        properties:
>          clocks:

[Severity: Medium]
Since the commit message states that interrupts are not wired for R-Car X5H,
should there be another if-then block added to the allOf section to
explicitly restrict the interrupts property for renesas,rcar-gen5-rtc?

Without this conditional check, a device tree incorrectly defining an
interrupts property for this compatible string would silently pass schema
validation despite the hardware limitation.

While reviewing the associated driver code, I noticed a separate issue:

drivers/rtc/rtc-rzn1.c:rzn1_rtc_probe() {
[ ... ]
	if (scmp_val) {
		writel(rate - 1, rtc->base + RZN1_RTC_SCMP);
	} else {
		rzn1_rtc_ops.read_offset = rzn1_rtc_read_offset;
		rzn1_rtc_ops.set_offset = rzn1_rtc_set_offset;
	}
[ ... ]
		rzn1_rtc_ops.read_alarm = rzn1_rtc_read_alarm;
		rzn1_rtc_ops.set_alarm = rzn1_rtc_set_alarm;
		rzn1_rtc_ops.alarm_irq_enable = rzn1_rtc_alarm_irq_enable;
	}

	return devm_rtc_register_device(rtc->rtcdev);
}

[Severity: High]
This is a pre-existing issue, but does mutating the global static rzn1_rtc_ops
structure during probe cause state corruption across device instances?

If multiple RTC instances exist, devices probed subsequently that lack
certain capabilities (like no SUBU register or no alarm interrupt) will
incorrectly inherit the callbacks set by previously probed devices. Could
this lead to unhandled behavior if unsupported operations are invoked?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260914211826.73727-8-wsa+renesas@sang-engineering.com?part=5

Re: [PATCH 1/6] dt-bindings: rtc: rzn1: drop unneeded 'start-year' from example

[Lad, Prabhakar]

On Mon, Sep 14, 2026 at 10:19 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> We don't use 'start-year' in upstream DTs because the driver does the
> right thing by default, ranging from 2000 to 2099. So, drop it from the
> example, too.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml | 1 -
>  1 file changed, 1 deletion(-)
>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Cheers,
Prabhakar

> diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> index ea7b039a91e7..e96007981c34 100644
> --- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> +++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> @@ -91,5 +91,4 @@ examples:
>          clocks = <&sysctrl R9A06G032_HCLK_RTC>;
>          clock-names = "hclk";
>          power-domains = <&sysctrl>;
> -        start-year = <2000>;
>      };
> --
> 2.53.0
>
>

Re: [PATCH 2/6] dt-bindings: rtc: rzn1: add SoC names next to their IDs

[Lad, Prabhakar]

On Mon, Sep 14, 2026 at 10:19 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> This helps maintaining because the numbers are easy to confuse.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  .../devicetree/bindings/rtc/renesas,rzn1-rtc.yaml      | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Cheers,
Prabhakar

> diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> index e96007981c34..7ea77cd0bee1 100644
> --- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> +++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> @@ -14,14 +14,14 @@ properties:
>      oneOf:
>        - items:
>            - enum:
> -              - renesas,r9a06g032-rtc
> -          - const: renesas,rzn1-rtc
> +              - renesas,r9a06g032-rtc # RZ/N1D
> +          - const: renesas,rzn1-rtc   # RZ/N1
>
> -      - const: renesas,r9a09g077-rtc
> +      - const: renesas,r9a09g077-rtc  # RZ/T2H
>
>        - items:
> -          - const: renesas,r9a09g087-rtc
> -          - const: renesas,r9a09g077-rtc
> +          - const: renesas,r9a09g087-rtc  # RZ/N2H
> +          - const: renesas,r9a09g077-rtc  # RZ/T2H
>
>    reg:
>      maxItems: 1
> --
> 2.53.0
>
>

Re: [PATCH 3/6] dt-bindings: rtc: rzn1: interrupts are not required

[Lad, Prabhakar]

Hi Wolfram,

Thank you for the patch.

On Mon, Sep 14, 2026 at 10:24 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> Interrupts are only needed for alarms to work. Reading/Setting the RTC
> works fine without interrupts. Drop the requirement for interrupts
> because an upcoming SoC does not have interrupts wired.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> index 7ea77cd0bee1..b426a34958d6 100644
> --- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> +++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> @@ -52,8 +52,6 @@ properties:
>  required:
>    - compatible
>    - reg
> -  - interrupts
> -  - interrupt-names
Maybe we can add a conditional schema check for SoCs where
interrupts{-names} are required.

Cheers,
Prabhakar

>    - clocks
>    - clock-names
>    - power-domains
> --
> 2.53.0
>
>

Re: [PATCH 3/6] dt-bindings: rtc: rzn1: interrupts are not required

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 1486 bytes --]

On Tue, Sep 15, 2026 at 10:55:20AM +0100, Lad, Prabhakar wrote:
> Hi Wolfram,
> 
> Thank you for the patch.
> 
> On Mon, Sep 14, 2026 at 10:24 PM Wolfram Sang
> <wsa+renesas@sang-engineering.com> wrote:
> >
> > Interrupts are only needed for alarms to work. Reading/Setting the RTC
> > works fine without interrupts. Drop the requirement for interrupts
> > because an upcoming SoC does not have interrupts wired.
> >
> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > ---
> >  Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml | 2 --
> >  1 file changed, 2 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> > index 7ea77cd0bee1..b426a34958d6 100644
> > --- a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> > +++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
> > @@ -52,8 +52,6 @@ properties:
> >  required:
> >    - compatible
> >    - reg
> > -  - interrupts
> > -  - interrupt-names
> Maybe we can add a conditional schema check for SoCs where
> interrupts{-names} are required.

Yeah, I'd prefer this. If all current devices have the interrupt wired,
there's little value in permitting them to not be populated and thereby
lose the support for alarms.

> 
> Cheers,
> Prabhakar
> 
> >    - clocks
> >    - clock-names
> >    - power-domains
> > --
> > 2.53.0
> >
> >

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Re: [PATCH 2/6] dt-bindings: rtc: rzn1: add SoC names next to their IDs

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

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Re: [PATCH 1/6] dt-bindings: rtc: rzn1: drop unneeded 'start-year' from example

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 75 bytes --]

Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

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Re: [PATCH 3/6] dt-bindings: rtc: rzn1: interrupts are not required

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 370 bytes --]


> > Maybe we can add a conditional schema check for SoCs where
> > interrupts{-names} are required.
> 
> Yeah, I'd prefer this. If all current devices have the interrupt wired,
> there's little value in permitting them to not be populated and thereby
> lose the support for alarms.

Okay, I will refactor like this.

Thank you for your comments, everyone!


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