Re: [PATCH v2] mtd: nand: document the NAND controller/NAND chip DT representation

Boris Brezillon
2016-04-04T21:48:47Z

On Fri, 1 Apr 2016 14:26:35 +0200
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> Standardize the NAND controller/NAND chip DT representation. Now, all new
> NAND controller drivers should comply with this representation, even if
> they are only supporting a single NAND chip.
>
> Existing drivers can keep support for the old representation (where only
> the NAND chip was described), but are encouraged to also support the new
> one.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Applied.

> ---
> Changes since v1:
> - fix typo
> ---
> Documentation/devicetree/bindings/mtd/nand.txt | 37 +++++++++++++++++++++++++-
> 1 file changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
> index b53f92e..a17662b 100644
> --- a/Documentation/devicetree/bindings/mtd/nand.txt
> +++ b/Documentation/devicetree/bindings/mtd/nand.txt
> @@ -1,4 +1,23 @@
> -* MTD generic binding
> +* NAND chip and NAND controller generic binding
> +
> +NAND controller/NAND chip representation:
> +
> +The NAND controller should be represented with its own DT node, and all
> +NAND chips attached to this controller should be defined as children nodes
> +of the NAND controller. This representation should be enforced even for
> +simple controllers supporting only one chip.
> +
> +Mandatory NAND controller properties:
> +- #address-cells: depends on your controller. Should at least be 1 to
> + encode the CS line id.
> +- #size-cells: depends on your controller. Put zero unless you need a
> + mapping between CS lines and dedicated memory regions
> +
> +Optional NAND controller properties
> +- ranges: only needed if you need to define a mapping between CS lines and
> + memory regions
> +
> +Optional NAND chip properties:
>
> - nand-ecc-mode : String, operation mode of the NAND ecc mode.
> Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first",
> @@ -19,3 +38,19 @@ errors per {size} bytes".
> The interpretation of these parameters is implementation-defined, so not all
> implementations must support all possible combinations. However, implementations
> are encouraged to further specify the value(s) they support.
> +
> +Example:
> +
> + nand-controller {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + /* controller specific properties */
> +
> + nand@0 {
> + reg = <0>;
> + nand-ecc-mode = "soft_bch";
> +
> + /* controller specific properties */
> + };
> + };

--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering