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Date:   Tue, 5 Nov 2019 22:46:05 -0600
From:   Rob Herring <robh@kernel.org>
To:     Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>
Cc:     linux-realtek-soc@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org
Subject: Re: [RFC 05/11] dt-bindings: soc: realtek: rtd1195-chip: Extend reg
 property
Message-ID: <20191106044605.GA28959@bogus>
References: <20191103013645.9856-1-afaerber@suse.de>
 <20191103013645.9856-6-afaerber@suse.de>
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On Sun, Nov 03, 2019 at 02:36:39AM +0100, Andreas F?rber wrote:
> Allow to optionally specify a second register to identify the chip.
> Whether needed and which register to specify depends on the family;
> RTD1295 family will want the CHIP_INFO1 register.
> 
> Signed-off-by: Andreas F?rber <afaerber@suse.de>
> ---
>  A SoC specific binding would defeat the purpose of the generic Linux driver;

Why? You can map any number of compatibles to a generic driver.

>  is it possible to check the root node's compatible in an if: expression
>  to prohibit using more than one reg on "realtek,rtd1195"?

The "rule" is different programming model, different compatible string 
for the block. But this looks simple enough, I don't really care.

>  
>  .../devicetree/bindings/soc/realtek/realtek,rtd1195-chip.yaml  | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1195-chip.yaml b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1195-chip.yaml
> index 565ad2419553..e431cf559b66 100644
> --- a/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1195-chip.yaml
> +++ b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1195-chip.yaml
> @@ -11,13 +11,15 @@ maintainers:
>  
>  description: |
>    The Realtek SoCs have some registers to identify the chip and revision.
> +  To identify the exact model within a family, further registers are needed.
>  
>  properties:
>    compatible:
>      const: "realtek,rtd1195-chip"
>  
>    reg:
> -    maxItems: 1
> +    minItems: 1
> +    maxItems: 2
>  
>  required:
>    - compatible
> @@ -29,4 +31,10 @@ examples:
>          compatible = "realtek,rtd1195-chip";
>          reg = <0x1801a200 0x8>;
>      };
> +  - |
> +    chip-info@9801a200 {
> +        compatible = "realtek,rtd1195-chip";
> +        reg = <0x9801a200 0x8>,
> +              <0x98007028 0x4>;
> +    };
>  ...
> -- 
> 2.16.4
>