[PATCH] dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

[PATCH] dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

[Wolfram Sang]

R-Car Gen5 can make use of it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

Sorry that this has not been noticed when adding Gen5 support, but DMA
support on this platform has only been implemented incrementally, so
this went unnoticed up to now.

 Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
index f9ede03c3287..4148081e3d84 100644
--- a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
+++ b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
@@ -83,14 +83,14 @@ properties:
 
   dmas:
     minItems: 2
-    maxItems: 4
+    maxItems: 6
     description:
       Must contain a list of pairs of references to DMA specifiers, one for
       transmission, and one for reception.
 
   dma-names:
     minItems: 2
-    maxItems: 4
+    maxItems: 6
     items:
       enum:
         - tx
-- 
2.47.3

Re: [PATCH] dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Globally increasing maxItems for 'dmas' and 'dma-names' to 6 allows invalid device trees for older hardware generations (Gen3/Gen4) to silently pass schema validation.
--

commit 25b051c331e08902e326728248cc79cc367f0460
Author: Wolfram Sang <wsa+renesas@sang-engineering.com>

dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

This commit increases the maximum number of DMA channels for the Renesas 
R-Car I2C controller from 4 to 6 to accommodate Gen5 hardware.

> diff --git a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> index c4ace5585e1e2..bfe55e20f1251 100644
> --- a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> +++ b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> @@ -77,14 +77,14 @@ properties:
>  
>    dmas:
>      minItems: 2
> -    maxItems: 4
> +    maxItems: 6

[Severity: Medium]
Doesn't globally increasing maxItems to 6 allow invalid device trees for older
hardware generations (Gen3/Gen4) to silently pass schema validation?

According to the device tree subsystem guidelines, stricter constraints for
older generations must be preserved using if-then conditional blocks when new
hardware variants relax limits. Otherwise, dt_binding_check will incorrectly
accept up to 6 DMA channels for older hardware that only supports 4.

>      description:
>        Must contain a list of pairs of references to DMA specifiers, one for
>        transmission, and one for reception.
>  
>    dma-names:
>      minItems: 2
> -    maxItems: 4
> +    maxItems: 6

[Severity: Medium]
Does this also need a conditional block to protect earlier hardware?

Similar to the dmas property above, globally relaxing the maxItems limit for
dma-names without adding an if-then conditional constraint removes the
4-channel constraint for Gen3/Gen4 hardware.

>      items:
>        enum:
>          - tx

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260825203251.2118-2-wsa+renesas@sang-engineering.com?part=1

Re: [PATCH] dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

[Wolfram Sang]

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> > diff --git a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> > index c4ace5585e1e2..bfe55e20f1251 100644
> > --- a/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> > +++ b/Documentation/devicetree/bindings/i2c/renesas,rcar-i2c.yaml
> > @@ -77,14 +77,14 @@ properties:
> >  
> >    dmas:
> >      minItems: 2
> > -    maxItems: 4
> > +    maxItems: 6
> 
> [Severity: Medium]
> Doesn't globally increasing maxItems to 6 allow invalid device trees for older
> hardware generations (Gen3/Gen4) to silently pass schema validation?

Will fix!


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Re: [PATCH] dt-bindings: i2c: renesas,rcar-i2c: allow 6 DMA channels

[Wolfram Sang]

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On Tue, Aug 25, 2026 at 10:31:28PM +0200, Wolfram Sang wrote:
> R-Car Gen5 can make use of it.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

As the Sashiko review was not send to the I2C list, I will send a v2
based on a valid comment.


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