Re: [PATCH v7,1/3] dt-bindings: binding for jz4780-{nand,bch}

Boris Brezillon
2015-11-04T07:58:22Z

Hi Harvey,

On Tue, 6 Oct 2015 17:27:15 +0100
Harvey Hunt <harvey.hunt@imgtec.com> wrote:

> From: Alex Smith <alex.smith@imgtec.com>
>
> Add DT bindings for NAND devices connected to the NEMC on JZ4780 SoCs,
> as well as the hardware BCH controller, used by the jz4780_{nand,bch}
> drivers.

Patch 3 does not seem to follow this binding: it still uses the
ingenic,ecc-xxx properties and defines NAND timings.

Also, as answered to patch 3, I think it would be clearer to separate
the nand controller and nand chip representation.

Best Regards,

Boris

>
> Signed-off-by: Alex Smith <alex.smith@imgtec.com>
> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Brian Norris <computersforpeace@gmail.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: devicetree@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: Alex Smith <alex@alex-smith.me.uk>
> Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
> ---
> v6 -> v7:
> - Add nand-ecc-mode to DT bindings.
> - Add nand-on-flash-bbt to DT bindings.
>
> v5 -> v6:
> - No change.
>
> v4 -> v5:
> - Rename ingenic,bch-device to ingenic,bch-controller to fit with
> existing convention.
>
> v3 -> v4:
> - No change
>
> v2 -> v3:
> - Rebase to 4.0-rc6
> - Changed ingenic,ecc-size to common nand-ecc-step-size
> - Changed ingenic,ecc-strength to common nand-ecc-strength
> - Changed ingenic,busy-gpio to common rb-gpios
> - Changed ingenic,wp-gpio to common wp-gpios
>
> v1 -> v2:
> - Rebase to 4.0-rc3
>
> .../bindings/mtd/ingenic,jz4780-nand.txt | 61 ++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt
>
> diff --git a/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt b/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt
> new file mode 100644
> index 0000000..44a0468
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/ingenic,jz4780-nand.txt
> @@ -0,0 +1,61 @@
> +* Ingenic JZ4780 NAND/BCH
> +
> +This file documents the device tree bindings for NAND flash devices on the
> +JZ4780. NAND devices are connected to the NEMC controller (described in
> +memory-controllers/ingenic,jz4780-nemc.txt), and thus NAND device nodes must
> +be children of the NEMC node.
> +
> +Required NAND device properties:
> +- compatible: Should be set to "ingenic,jz4780-nand".
> +- reg: For each bank with a NAND chip attached, should specify a bank number,
> + an offset of 0 and a size of 0x1000000 (i.e. the whole NEMC bank).
> +
> +Optional NAND device properties:
> +- ingenic,bch-controller: To make use of the hardware BCH controller, this
> + property must contain a phandle for the BCH controller node. The required
> + properties for this node are described below. If this is not specified,
> + software BCH will be used instead.
> +- nand-ecc-step-size: ECC block size in bytes.
> +- nand-ecc-strength: ECC strength (max number of correctable bits).
> +- nand-ecc-mode: String, operation mode of the NAND ecc mode. "hw" by default
> +- nand-on-flash-bbt: boolean to enable on flash bbt option if not present false
> +- rb-gpios: GPIO specifier for the busy pin.
> +- wp-gpios: GPIO specifier for the write protect pin.
> +
> +Example:
> +
> +nemc: nemc@13410000 {
> + ...
> +
> + nand: nand@1 {
> + compatible = "ingenic,jz4780-nand";
> + reg = <1 0 0x1000000>; /* Bank 1 */
> +
> + ingenic,bch-controller = <&bch>;
> + nand-ecc-step-size = <1024>;
> + nand-ecc-strength = <24>;
> + nand-ecc-mode = "hw";
> + nand-on-flash-bbt;
> +
> + rb-gpios = <&gpa 20 GPIO_ACTIVE_LOW>;
> + wp-gpios = <&gpf 22 GPIO_ACTIVE_LOW>;
> + };
> +};
> +
> +The BCH controller is a separate SoC component used for error correction on
> +NAND devices. The following is a description of the device properties for a
> +BCH controller.
> +
> +Required BCH properties:
> +- compatible: Should be set to "ingenic,jz4780-bch".
> +- reg: Should specify the BCH controller registers location and length.
> +- clocks: Clock for the BCH controller.
> +
> +Example:
> +
> +bch: bch@134d0000 {
> + compatible = "ingenic,jz4780-bch";
> + reg = <0x134d0000 0x10000>;
> +
> + clocks = <&cgu JZ4780_CLK_BCH>;
> +};

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