[PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Wolfram Sang]

Renesas RZ/N1D has this UART with and without DMA support. Currently,
only the binding with DMA support is described. Add the missing one
without DMA support which can fallback even more.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 .../bindings/serial/snps-dw-apb-uart.yaml     | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index 1c163cb5dff1..645b14ffde90 100644
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -13,6 +13,20 @@ allOf:
   - $ref: serial.yaml#
   - $ref: rs485.yaml#
 
+  - if:
+      properties:
+        compatible:
+          items:
+            - enum:
+                - renesas,r9a06g032-uart
+                - renesas,r9a06g033-uart
+            - const: renesas,rzn1-uart
+            - const: snps,dw-apb-uart
+    then:
+      properties:
+        dmas: false
+        dma-names: false
+
   - if:
       properties:
         compatible:
@@ -30,6 +44,12 @@ allOf:
 properties:
   compatible:
     oneOf:
+      - items:
+          - enum:
+              - renesas,r9a06g032-uart
+              - renesas,r9a06g033-uart
+          - const: renesas,rzn1-uart
+          - const: snps,dw-apb-uart
       - items:
           - enum:
               - renesas,r9a06g032-uart
-- 
2.47.2

Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Geert Uytterhoeven]

Hi Wolfram,

On Tue, 18 Mar 2025 at 09:54, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> Renesas RZ/N1D has this UART with and without DMA support. Currently,
> only the binding with DMA support is described. Add the missing one
> without DMA support which can fallback even more.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Thanks for your patch!

> --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> @@ -13,6 +13,20 @@ allOf:
>    - $ref: serial.yaml#
>    - $ref: rs485.yaml#
>
> +  - if:
> +      properties:
> +        compatible:
> +          items:
> +            - enum:
> +                - renesas,r9a06g032-uart
> +                - renesas,r9a06g033-uart

I think you can simplify by replacing the enum by

    - pattern: "^renesas,.*$"

> +            - const: renesas,rzn1-uart
> +            - const: snps,dw-apb-uart
> +    then:
> +      properties:
> +        dmas: false
> +        dma-names: false
> +
>    - if:
>        properties:
>          compatible:

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Wolfram Sang]

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> > +            - enum:
> > +                - renesas,r9a06g032-uart
> > +                - renesas,r9a06g033-uart
> 
> I think you can simplify by replacing the enum by
> 
>     - pattern: "^renesas,.*$"

I still plan to remove r9a06g033 bindings from the kernel because that
SoC cannot run Linux with only 4MB of internal SRAM. So, all this will
become "const: renesas,r9a06g032-uart" in the future anyhow. But one
step after the other...


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Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Geert Uytterhoeven]

Hi Wolfram,

On Tue, 18 Mar 2025 at 10:11, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> > > +            - enum:
> > > +                - renesas,r9a06g032-uart
> > > +                - renesas,r9a06g033-uart
> >
> > I think you can simplify by replacing the enum by
> >
> >     - pattern: "^renesas,.*$"
>
> I still plan to remove r9a06g033 bindings from the kernel because that
> SoC cannot run Linux with only 4MB of internal SRAM. So, all this will
> become "const: renesas,r9a06g032-uart" in the future anyhow. But one
> step after the other...

DT is not just for Linux. I guess it can run Zephyr?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Wolfram Sang]

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> DT is not just for Linux. I guess it can run Zephyr?

Since nobody has been bothered to include the essential bindings over
the last 7 years, I don't know why we would want to handle those 4
random bindings for it which make life only complicated for us.


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Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Miquel Raynal]

Hello Wolfram,

On 18/03/2025 at 09:53:53 +01, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:

> Renesas RZ/N1D has this UART with and without DMA support. Currently,
> only the binding with DMA support is described. Add the missing one
> without DMA support which can fallback even more.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

That's true indeed.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miquèl

Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Rob Herring (Arm)]

On Tue, 18 Mar 2025 09:53:53 +0100, Wolfram Sang wrote:
> Renesas RZ/N1D has this UART with and without DMA support. Currently,
> only the binding with DMA support is described. Add the missing one
> without DMA support which can fallback even more.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  .../bindings/serial/snps-dw-apb-uart.yaml     | 20 +++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 

Acked-by: Rob Herring (Arm) <robh@kernel.org>

[PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Wolfram Sang]

Renesas RZ/N1D has this UART with and without DMA support. Currently,
only the binding with DMA support is described. Add the missing one
without DMA support which can fallback even more.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 .../devicetree/bindings/serial/snps-dw-apb-uart.yaml        | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index 1c163cb5dff1..5b5799c21243 100644
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -30,6 +30,12 @@ allOf:
 properties:
   compatible:
     oneOf:
+      - items:
+          - enum:
+              - renesas,r9a06g032-uart
+              - renesas,r9a06g033-uart
+          - const: renesas,rzn1-uart
+          - const: snps,dw-apb-uart
       - items:
           - enum:
               - renesas,r9a06g032-uart
-- 
2.47.2

Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Geert Uytterhoeven]

Hi Wolfram,

On Mon, 17 Mar 2025 at 13:04, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> Renesas RZ/N1D has this UART with and without DMA support. Currently,
> only the binding with DMA support is described. Add the missing one
> without DMA support which can fallback even more.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Thanks for your patch!

> --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
> @@ -30,6 +30,12 @@ allOf:
>  properties:
>    compatible:
>      oneOf:
> +      - items:
> +          - enum:
> +              - renesas,r9a06g032-uart
> +              - renesas,r9a06g033-uart
> +          - const: renesas,rzn1-uart
> +          - const: snps,dw-apb-uart
>        - items:
>            - enum:
>                - renesas,r9a06g032-uart

This is the alternative I suggested, which Miquel likes more than [1],
and which I was just about to formalize into a real patch ;-)
I think it would be wiese to add extra logic to prohibit the dmas
property when both renesas,rzn1-uart and snps,dw-apb-uart are present.

[1] "[PATCH 2/2] ARM: dts: renesas: r9a06g032: Drop snps,dw-apb-uart
compatibility"
https://lore.kernel.org/all/e290dd28ecb68b4e164172a905da18a5a2d438a1.1739525488.git.geert+renesas@glider.be

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] dt-bindings: serial: snps-dw-apb-uart: document RZ/N1 binding without DMA

[Wolfram Sang]

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> This is the alternative I suggested, which Miquel likes more than [1],
> and which I was just about to formalize into a real patch ;-)
> I think it would be wiese to add extra logic to prohibit the dmas
> property when both renesas,rzn1-uart and snps,dw-apb-uart are present.

I'll think about it.

Sorry for overlooking your patch series :(


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