Re: [PATCH v2 2/2] m68k: coldfire: Add RNG support for MCF54418

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Jean-Michel,

On Fri, 7 Nov 2025 at 11:29, Jean-Michel Hautbois
<jeanmichel.hautbois@yoseli.org> wrote:
> Add platform device support for the MCF54418 RNGB hardware with clock
> enabled at platform initialization.
>
> The imx-rngc driver now uses devm_clk_get_optional() to support both
> Coldfire (always-on clock) and i.MX platforms (managed clock).
>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>

Thanks for your patch!

> --- a/drivers/char/hw_random/Kconfig
> +++ b/drivers/char/hw_random/Kconfig
> @@ -270,12 +270,13 @@ config HW_RANDOM_MXC_RNGA
>  config HW_RANDOM_IMX_RNGC
>         tristate "Freescale i.MX RNGC Random Number Generator"
>         depends on HAS_IOMEM
> -       depends on SOC_IMX25 || SOC_IMX6SL || SOC_IMX6SLL || SOC_IMX6UL || COMPILE_TEST
> +       depends on SOC_IMX25 || SOC_IMX6SL || SOC_IMX6SLL || SOC_IMX6UL || M5441x || COMPILE_TEST

Is the same RNG present in other Coldfire SoCs?

>         default HW_RANDOM
>         help
>           This driver provides kernel-side support for the Random Number
>           Generator Version C hardware found on some Freescale i.MX
>           processors. Version B is also supported by this driver.
> +         Also supports RNGB on Freescale MCF54418 (Coldfire V4e).
>
>           To compile this driver as a module, choose M here: the
>           module will be called imx-rngc.
> diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
> index 241664a9b5d9ac7244f15cbe5d5302ca3787ebea..44f20a05de0a425cb6ff7b2a347b111750ac3702 100644
> --- a/drivers/char/hw_random/imx-rngc.c
> +++ b/drivers/char/hw_random/imx-rngc.c
> @@ -353,12 +353,19 @@ static const struct of_device_id imx_rngc_dt_ids[] = {
>  };
>  MODULE_DEVICE_TABLE(of, imx_rngc_dt_ids);
>
> +static const struct platform_device_id imx_rngc_devtype[] = {
> +       { .name = "imx-rngc" },

I believe this is identical to KBUILD_MODNAME, so the .name below
should be sufficient for binding?

> +       { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(platform, imx_rngc_devtype);

Or do you need this mainly for the addition of MODULE_DEVICE_TABLE(),
i.e. the module is not auto-loaded based on just KBUILD_MODNAME?

> +
>  static struct platform_driver imx_rngc_driver = {
>         .driver = {
>                 .name = KBUILD_MODNAME,
                  ^^^^^^^^^^^^^^^^^^^^^^^

>                 .pm = pm_ptr(&imx_rngc_pm_ops),
>                 .of_match_table = imx_rngc_dt_ids,
>         },
> +       .id_table = imx_rngc_devtype,
>  };
>
>  module_platform_driver_probe(imx_rngc_driver, imx_rngc_probe);

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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