Re: [PATCH v2 1/5] dt-binding: mtd: nand: Document gpio-cs property

Rob Herring
2021-05-10T16:52:08Z

On Mon, May 10, 2021 at 12:40:47PM +0200, Miquel Raynal wrote:
> To reach higher capacities, arrays of chips are now pretty common.
> Unfortunately, most of the controllers have been designed a decade ago
> and did not all anticipate the need for several chip-selects. The new
> cs-gpios property allows to workaround this limitation by adding as many
> GPIO chip-select as needed.

Subject and example have wrong property name.

>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
> .../devicetree/bindings/mtd/nand-controller.yaml | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/mtd/nand-controller.yaml b/Documentation/devicetree/bindings/mtd/nand-controller.yaml
> index 678b39952502..70a400e385b2 100644
> --- a/Documentation/devicetree/bindings/mtd/nand-controller.yaml
> +++ b/Documentation/devicetree/bindings/mtd/nand-controller.yaml
> @@ -38,6 +38,15 @@ properties:
>
> ranges: true
>
> + cs-gpios:
> + description:
> + Array of chip-select available to the controller. The first
> + entries are a 1:1 mapping of the available chip-select on the
> + NAND controller (even if they are not used). As many additional
> + chip-select as needed may follow and should be phandles of GPIO
> + lines. 'reg' entries of the NAND chip subnodes become indexes of
> + this array when this property is present.

Can we put some 'maxItems' value here. I want to make the meta-schema
enforce that. I realize there's not really one here, but a 'should be
enough' value is fine. We can bump it up if needed.

> +
> patternProperties:
> "^nand@[a-f0-9]$":
> type: object
> @@ -164,14 +173,19 @@ examples:
> nand-controller {
> #address-cells = <1>;
> #size-cells = <0>;
> + gpio-cs = <0>, <&gpioA 1>; /* A single native CS is available */
>
> /* controller specific properties */
>
> nand@0 {
> - reg = <0>;
> + reg = <0>; /* Native CS */
> nand-use-soft-ecc-engine;
> nand-ecc-algo = "bch";
>
> /* controller specific properties */
> };
> +
> + nand@1 {
> + reg = <1>; /* GPIO CS */
> + };
> };
> --
> 2.27.0