[PATCH v2] riscv: dts: canaan: Fix SPI3 bus width

[Geert Uytterhoeven]

Hi Niklas,

On Tue, Mar 8, 2022 at 2:30 PM Niklas Cassel <Niklas.Cassel at wdc.com> wrote:
> From: Niklas Cassel <niklas.cassel at wdc.com>
> According to the K210 Standalone SDK Programming guide:
> https://canaan-creative.com/wp-content/uploads/2020/03/kendryte_standalone_programming_guide_20190311144158_en.pdf
>
> Section 15.4.3.3:
> SPI0 and SPI1 supports: standard, dual, quad and octal transfers.
> SPI3 supports: standard, dual and quad transfers (octal is not supported).
>
> In order to support quad transfers (Quad SPI), SPI3 must have four IO wires
> connected to the SPI flash.
>
> Update the device tree to specify the correct bus width.
>
> Tested on maix bit, maix dock and maixduino, which all have the same
> SPI flash (gd25lq128d) connected to SPI3. maix go is untested, but it
> would not make sense for this k210 board to be designed differently.
>
> Signed-off-by: Niklas Cassel <niklas.cassel at wdc.com>
> ---
> Changes since v1:
> -Add the new properties directly after spi-max-frequency for all DT board
>  files.

Thanks for your patch, which is now commit 6846d656106add3a ("riscv:
dts: canaan: Fix SPI3 bus width") in v5.18-rc1.

> --- a/arch/riscv/boot/dts/canaan/sipeed_maix_bit.dts
> +++ b/arch/riscv/boot/dts/canaan/sipeed_maix_bit.dts
> @@ -203,6 +203,8 @@ flash at 0 {
>                 compatible = "jedec,spi-nor";
>                 reg = <0>;
>                 spi-max-frequency = <50000000>;
> +               spi-tx-bus-width = <4>;
> +               spi-rx-bus-width = <4>;
>                 m25p,fast-read;
>                 broken-flash-reset;
>         };

On MAiX BiT, I get:

    +spi spi1.0: setup: ignoring unsupported mode bits a00
     spi-nor spi1.0: gd25lq128d (16384 Kbytes)

Perhaps this depends on a not-yet-applied patch to add quad support
to the SPI driver?

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds