From 6b562738a22cfdbfedaaac7db5f83c11700ebb15 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Mon, 10 May 2021 19:18:00 +0200 Subject: [PATCH] dt-binding: mtd: nand: Document the cs-gpios property 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. Signed-off-by: Miquel Raynal Reviewed-by: Rob Herring Link: https://lore.kernel.org/linux-mtd/20210510171800.27225-1-miquel.raynal@bootlin.com --- .../bindings/mtd/nand-controller.yaml | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/mtd/nand-controller.yaml b/Documentation/devicetree/bindings/mtd/nand-controller.yaml index 678b39952502..bd217e6f5018 100644 --- a/Documentation/devicetree/bindings/mtd/nand-controller.yaml +++ b/Documentation/devicetree/bindings/mtd/nand-controller.yaml @@ -38,6 +38,17 @@ properties: ranges: true + cs-gpios: + minItems: 1 + maxItems: 8 + 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. + patternProperties: "^nand@[a-f0-9]$": type: object @@ -164,14 +175,19 @@ examples: nand-controller { #address-cells = <1>; #size-cells = <0>; + cs-gpios = <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 */ + }; }; -- 2.34.1