[PATCH 1/2] dt-bindings: fsi: Add optional chip-id to CFAMs

Rob Herring robh at kernel.org
Wed Jul 4 05:30:17 AEST 2018


On Fri, Jun 22, 2018 at 02:37:55PM +1000, Benjamin Herrenschmidt wrote:
> This represents a physical chip in the system and allows
> a stable numbering scheme to be passed to udev for userspace
> to recognize which chip is which.

I'm sure you're aware, stable numbers is generally not something the 
kernel guarantees...

In the cases where we do have them, we've used aliases.

> Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> ---
>  Documentation/devicetree/bindings/fsi/fsi.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/fsi/fsi.txt b/Documentation/devicetree/bindings/fsi/fsi.txt
> index ab516c673a4b..afb4eccab131 100644
> --- a/Documentation/devicetree/bindings/fsi/fsi.txt
> +++ b/Documentation/devicetree/bindings/fsi/fsi.txt
> @@ -83,6 +83,10 @@ addresses and sizes in the slave address space:
>      #address-cells = <1>;
>      #size-cells = <1>;
>  
> +Optionally, a slave can provide a global unique chip ID which is used to
> +identify the physical location of the chip in a system specific way
> +
> +    chip-id = <0>;
>  
>  FSI engines (devices)
>  ---------------------
> @@ -125,6 +129,7 @@ device tree if no extra platform information is required.
>              reg = <0 0>;
>              #address-cells = <1>;
>              #size-cells = <1>;
> +	    chip-id = <0>;
>  
>              /* FSI engine at 0xc00, using a single page. In this example,
>               * it's an I2C master controller, so subnodes describe the
> -- 
> 2.17.1
> 
> --
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