Re: [PATCH v3 3/5] mtd: ofpart: update devicetree binding specification

[Brian Norris <computersforpeace@gmail.com>]

Hi DT maintainers,

It's a bit hypocritical of me, since I've been a slow reviewer as well,
but... can we get some review on this one? Usually, I'm comfortable
taking driver DT bindings without your review, but this one is a bit
more generic and is more far-reaching than the average driver.

I'm not a big fan of this change, and I don't quite understand why the
bus driver (the SPI bus, which is a level up from the SPI device / MTD
node) can specify its grandchildren (see spi-samsung.txt). But given the
constraints, I think Michal's solution is OK. And I do agree that MTD's
ofpart should be bit more specific.

Anyway, a quick look and an Ack/Nak would be appreciated.

Thanks,
Brian

On Tue, Aug 18, 2015 at 03:34:08PM -0000, Michal Suchanek wrote:
> To avoid conflict with other drivers using subnodes of the mtd device
> create only one ofpart-specific node rather than any number of
> arbitrary partition subnodes.
> 
> Signed-off-by: Michal Suchanek <hramrach@gmail.com>
> ---
> v3:
> 
>  - rename DT node ofpart -> partitions
> ---
>  .../devicetree/bindings/mtd/partition.txt          | 68 +++++++++++++---------
>  1 file changed, 40 insertions(+), 28 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/partition.txt b/Documentation/devicetree/bindings/mtd/partition.txt
> index 8e5557d..8c2aff7 100644
> --- a/Documentation/devicetree/bindings/mtd/partition.txt
> +++ b/Documentation/devicetree/bindings/mtd/partition.txt
> @@ -4,10 +4,16 @@ Partitions can be represented by sub-nodes of an mtd device. This can be used
>  on platforms which have strong conventions about which portions of a flash are
>  used for what purposes, but which don't use an on-flash partition table such
>  as RedBoot.
> +
> +The partition table should be partitions subnode of the mtd node. Partitions are
> +defined in subnodes of the partitions node.
> +
> +For backwards compatibility partitions as direct subnodes of the mtd device are
> +supported. This use is discouraged.
>  NOTE: if the sub-node has a compatible string, then it is not a partition.
>  
> -#address-cells & #size-cells must both be present in the mtd device. There are
> -two valid values for both:
> +#address-cells & #size-cells must both be present in the partitions subnode of the
> +mtd device. There are two valid values for both:
>  <1>: for partitions that require a single 32-bit cell to represent their
>       size/address (aka the value is below 4 GiB)
>  <2>: for partitions that require two 32-bit cells to represent their
> @@ -28,44 +34,50 @@ Examples:
>  
>  
>  flash@0 {
> -	#address-cells = <1>;
> -	#size-cells = <1>;
> +	partitions {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
>  
> -	partition@0 {
> -		label = "u-boot";
> -		reg = <0x0000000 0x100000>;
> -		read-only;
> -	};
> +		partition@0 {
> +			label = "u-boot";
> +			reg = <0x0000000 0x100000>;
> +			read-only;
> +		};
>  
> -	uimage@100000 {
> -		reg = <0x0100000 0x200000>;
> +		uimage@100000 {
> +			reg = <0x0100000 0x200000>;
> +		};
>  	};
>  };
>  
>  flash@1 {
> -	#address-cells = <1>;
> -	#size-cells = <2>;
> +	partitions {
> +		#address-cells = <1>;
> +		#size-cells = <2>;
>  
> -	/* a 4 GiB partition */
> -	partition@0 {
> -		label = "filesystem";
> -		reg = <0x00000000 0x1 0x00000000>;
> +		/* a 4 GiB partition */
> +		partition@0 {
> +			label = "filesystem";
> +			reg = <0x00000000 0x1 0x00000000>;
> +		};
>  	};
>  };
>  
>  flash@2 {
> -	#address-cells = <2>;
> -	#size-cells = <2>;
> +	partitions {
> +		#address-cells = <2>;
> +		#size-cells = <2>;
>  
> -	/* an 8 GiB partition */
> -	partition@0 {
> -		label = "filesystem #1";
> -		reg = <0x0 0x00000000 0x2 0x00000000>;
> -	};
> +		/* an 8 GiB partition */
> +		partition@0 {
> +			label = "filesystem #1";
> +			reg = <0x0 0x00000000 0x2 0x00000000>;
> +		};
>  
> -	/* a 4 GiB partition */
> -	partition@200000000 {
> -		label = "filesystem #2";
> -		reg = <0x2 0x00000000 0x1 0x00000000>;
> +		/* a 4 GiB partition */
> +		partition@200000000 {
> +			label = "filesystem #2";
> +			reg = <0x2 0x00000000 0x1 0x00000000>;
> +		};
>  	};
>  };
> -- 
> 2.1.4
>