[PATCH] dt-bindings: serial: renesas,hscif: Increase number of DMA channels to 6

[PATCH] dt-bindings: serial: renesas,hscif: Increase number of DMA channels to 6

[Geert Uytterhoeven]

On R-Car X5H, HSCIF serial interfaces are wired to three DMACs, hence
referring to up to six DMA channels.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 Documentation/devicetree/bindings/serial/renesas,hscif.yaml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/renesas,hscif.yaml b/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
index 4b3f98a46cd9ded0..409cab32de3d8932 100644
--- a/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
+++ b/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
@@ -97,14 +97,14 @@ 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
-- 
2.43.0

Re: [PATCH] dt-bindings: serial: renesas,hscif: Increase number of DMA channels to 6

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] dt-bindings: serial: renesas,hscif: global DMA maxItems relaxation permits invalid configurations
--

commit 5201605fb4ecc80faa0e010c992a164bfb0972af
Author: Geert Uytterhoeven <geert@linux-m68k.org>

dt-bindings: serial: renesas,hscif: Increase number of DMA channels to 6

This commit increases the maximum number of DMA channels for HSCIF serial
interfaces from 4 to 6. This change is intended to support the R-Car X5H
hardware, which has interfaces wired to three DMACs.

> diff --git a/Documentation/devicetree/bindings/serial/renesas,hscif.yaml b/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
> index 4b3f98a46cd9d..409cab32de3d8 100644
> --- a/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
> +++ b/Documentation/devicetree/bindings/serial/renesas,hscif.yaml
> @@ -97,14 +97,14 @@ properties:
>  
>    dmas:
>      minItems: 2
> -    maxItems: 4
> +    maxItems: 6

[Severity: Medium]
Does this global change to maxItems permit invalid configurations for older
hardware generations?

By globally increasing the maximum allowed items from 4 to 6 to support Gen5
hardware, the schema will now incorrectly pass validation for Gen1-Gen4 nodes
that specify 5 or 6 DMA channels, despite those SoCs only supporting up to 4.

Should an if:then conditional block be used instead to enforce maxItems: 4
for earlier generations, or to allow 6 only for Gen5 hardware?

>      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 weaken the schema validation for dma-names on older hardware
generations in the same way?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/a08834717c1df2c8974cb0b8300a20cc33c426fa.1789653869.git.geert@linux-m68k.org?part=1

Re: [PATCH] dt-bindings: serial: renesas,hscif: Increase number of DMA channels to 6

[Wolfram Sang]

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On Thu, Sep 17, 2026 at 04:06:15PM +0200, Geert Uytterhoeven wrote:
> On R-Car X5H, HSCIF serial interfaces are wired to three DMACs, hence
> referring to up to six DMA channels.
> 
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

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


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