Re: [PATCH v3 4/4] dt-bindings: mfd: Document Macronix MX25F0A controller bindings

Miquel Raynal
2019-05-12T13:24:04Z

Hi Mason,

Mason Yang <masonccyang@mxic.com.tw> wrote on Mon, 15 Apr 2019 17:23:54
+0800:

> Document the bindings used by the Macronix MX25F0A MFD controller.
>
> Signed-off-by: Mason Yang <masonccyang@mxic.com.tw>
> ---
> .../devicetree/bindings/mfd/mxic-mx25f0a.txt | 51 ++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mfd/mxic-mx25f0a.txt
>
> diff --git a/Documentation/devicetree/bindings/mfd/mxic-mx25f0a.txt b/Documentation/devicetree/bindings/mfd/mxic-mx25f0a.txt
> new file mode 100644
> index 0000000..7f3e0f8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/mxic-mx25f0a.txt
> @@ -0,0 +1,51 @@
> +Macronix MX25F0A MultiFunction Device Tree Bindings
> +----------------------------------------------------
> +
> +MX25F0A is a MultiFunction Device with SPI and raw NAND, which
> +supports either spi host controller or raw nand controller.

Acronyms in plain English should be in upper case.

> +
> +Required properties:
> +- compatible: should be "mxic,mx25f0a"
> +- #address-cells: should be 1
> +- #size-cells: should be 0
> +- reg: should contain 2 entries, one for the registers and one for the direct
> + mapping area in SPI mode.
> +- reg-names: should contain "regs" and "dirmap"
> +- interrupts: interrupt line connected to this MFD controller
> +- SPI controller driver:
> + - clock-names: should contain "ps_clk", "send_clk" and
> + "send_dly_clk"
> + - clocks: should contain 3 entries for the "ps_clk", "send_clk"
> + and "send_dly_clk" clocks
> +
> +- Raw nand controller driver.
> + - nand-ecc-mode = "soft";
> + - nand-ecc-algo = "bch";
> +
> +Example:
> +
> + mxic: mx25f0a@43c30000 {
> + compatible = "mxic,mx25f0a";
> + reg = <0x43c30000 0x10000>, <0xa0000000 0x4000000>;
> + reg-names = "regs", "dirmap";
> +
> + /* spi */
> + clocks = <&clkwizard 0>, <&clkwizard 1>, <&clkc 15>;
> + clock-names = "send_clk", "send_dly_clk", "ps_clk";
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + flash@0 {
> + compatible = "jedec,spi-nor";
> + reg = <0>;
> + spi-max-frequency = <25000000>;
> + spi-tx-bus-width = <4>;
> + spi-rx-bus-width = <4>;
> + };
> +
> + /* nand */
> + nand-ecc-mode = "soft";
> + nand-ecc-algo = "bch";
> + nand-ecc-step-size = <512>;
> + nand-ecc-strength = <8>;

Any reason to enforce 512B/8b correction? Why not letting the core
choose for you depending on the NAND chip's requirements?

Anyway, I think you can have only one or the other (NAND or SPI), not
both, and you probably should have a compatible or a property to tell
the kernel which one you are using, right?

Thanks,
Miquèl