Re: [PATCH v4 1/2] mtd: mediatek: device tree docs for MTK Smart Device Gen1 NAND

Boris Brezillon
2016-05-06T13:38:16Z

Hi Jorge,

On Fri, 29 Apr 2016 12:17:21 -0400
Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org> wrote:

> This patch adds documentation support for Smart Device Gen1 type of
> NAND controllers.
>
> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
> ---
> Documentation/devicetree/bindings/mtd/mtk-nand.txt | 161 +++++++++++++++++++++
> 1 file changed, 161 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mtd/mtk-nand.txt
>
> diff --git a/Documentation/devicetree/bindings/mtd/mtk-nand.txt b/Documentation/devicetree/bindings/mtd/mtk-nand.txt
> new file mode 100644
> index 0000000..175767d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/mtk-nand.txt

[...]

> +
> +Children nodes properties:
> +- reg: Chip Select Signal, default 0.
> + Set as reg = <0>, <1> when need 2 CS.
> +Optional:
> +- nand-on-flash-bbt: Store BBT on NAND Flash.
> +- nand-ecc-mode: the NAND ecc mode (check driver for supported modes)
> +- nand-ecc-step-size: Number of data bytes covered by a single ECC step.
> + The controller only supports 512 and 1024.
> + For large page NANDs ther recommended value is 1024.
> +- nand-ecc-strength: Number of bits to correct per ECC step.
> + The valid values that the controller supports are: 4, 6,
> + 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, 40, 44,
> + 48, 52, 56, 60.
> + The strength should be calculated as follows:
> + E = (S - F) * 8 / 14
> + S = O / (P / Q)
> + E :nand-ecc-strength;
> + S :spare size per sector;
> + F : FDM size, should be in the range [1,8].
> + It is used to store free oob data.
> + O : oob size;
> + P : page size;
> + Q :nand-ecc-step-size
> + If the result does not match any one of the listed
> + choices above, please select the smaller valid value from
> + the list.
> + (otherwise the driver will do the clamping at runtime).
> +- vmch-supply: NAND power supply.

Where is this supply name coming from? I most datasheets I see Vdd or
Vcc, but nothing close to Vmch.

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