Re: [PATCH v5 1/2] dt-bindings: memory: document Renesas RPC-IF bindings

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Sergei,

On Tue, Jun 16, 2020 at 10:01 PM Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> Renesas Reduced Pin Count Interface (RPC-IF) allows a SPI flash or
> HyperFlash connected to the SoC to be accessed via the external address
> space read mode or the manual mode.
>
> Document the device tree bindings for the Renesas RPC-IF found in the R-Car
> gen3 SoCs.
>
> Based on the original patch by Mason Yang <masonccyang@mxic.com.tw>.
>
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

Thanks for your patch!

> --- /dev/null
> +++ linux/Documentation/devicetree/bindings/memory-controllers/renesas,rpc-if.yaml
> @@ -0,0 +1,88 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/memory-controllers/renesas,rpc-if.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Renesas Reduced Pin Count Interface (RPC-IF)
> +
> +maintainers:
> +  - Sergei Shtylyov <sergei.shtylyov@gmail.com>
> +
> +description: |
> +  Renesas RPC-IF allows a SPI flash or HyperFlash connected to the SoC to
> +  be accessed via the external address space read mode or the manual mode.
> +
> +  The flash chip itself should be represented by a subnode of the RPC-IF node.
> +  The flash interface is selected based on the "compatible" property of this
> +  subnode:
> +  - if it contains "jedec,spi-nor", then SPI is used;
> +  - if it contains "cfi-flash", then HyperFlash is used.

> +patternProperties:
> +  "flash@[0-9a-f]+$":
> +    type: object
> +    properties:
> +      compatible:
> +        enum:
> +          - cfi-flash
> +          - jedec,spi-nor

The above does not allow specifying e.g.

    compatible = "spansion,s25fs512s", "jedec,spi-nor";

arch/arm64/boot/dts/renesas/r8a77970-eagle.dt.yaml: spi@ee200000:
flash@0:compatible: Additional items are not allowed ('jedec,spi-nor'
was unexpected)
arch/arm64/boot/dts/renesas/r8a77970-eagle.dt.yaml: spi@ee200000:
flash@0:compatible:0: 'spansion,s25fs512s' is not one of ['cfi-flash',
'jedec,spi-nor']

> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/renesas-cpg-mssr.h>
> +    #include <dt-bindings/power/r8a77995-sysc.h>
> +
> +    spi@ee200000 {
> +      compatible = "renesas,r8a77995-rpc-if", "renesas,rcar-gen3-rpc-if";
> +      reg = <0xee200000 0x200>,
> +            <0x08000000 0x4000000>,
> +            <0xee208000 0x100>;
> +      reg-names = "regs", "dirmap", "wbuf";
> +      clocks = <&cpg CPG_MOD 917>;
> +      power-domains = <&sysc R8A77995_PD_ALWAYS_ON>;
> +      resets = <&cpg 917>;
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      flash@0 {
> +        compatible = "jedec,spi-nor";

... which you nicely circumvented in the example ;-)

> +        reg = <0>;
> +        spi-max-frequency = <40000000>;
> +        spi-tx-bus-width = <1>;
> +        spi-rx-bus-width = <1>;
> +      };
> +    };

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

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