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

[Frank Li <Frank.li@nxp.com>]

On Fri, Nov 07, 2025 at 11:29:44AM +0100, Jean-Michel Hautbois 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>
> ---
>  arch/m68k/coldfire/device.c       | 28 ++++++++++++++++++++++++++++
>  arch/m68k/coldfire/m5441x.c       |  2 +-
>  arch/m68k/include/asm/m5441xsim.h |  9 +++++++++
>  drivers/char/hw_random/Kconfig    |  3 ++-
>  drivers/char/hw_random/imx-rngc.c |  9 ++++++++-
>  5 files changed, 48 insertions(+), 3 deletions(-)

Most likely need two patches, one patch change rngc use devm_clk_get_optional().
one patch update arch/m68k/coldfire.

so difference mantainer can pick up easily.

Frank

>
> diff --git a/arch/m68k/coldfire/device.c b/arch/m68k/coldfire/device.c
> index 20adba27a687029ef53249bad71b342d563d612b..4183929b0b501459da25d1b4cde7d77f19c3dc16 100644
> --- a/arch/m68k/coldfire/device.c
> +++ b/arch/m68k/coldfire/device.c
> @@ -622,6 +622,31 @@ static struct platform_device mcf_flexcan0 = {
>  };
>  #endif /* MCFFLEXCAN_SIZE */
>
> +#ifdef MCF_RNG_BASE
> +/*
> + * Random Number Generator (RNG) - only on MCF54418
> + */
> +static const struct resource mcf_rng_resource[] = {
> +	{
> +		.start = MCF_RNG_BASE,
> +		.end   = MCF_RNG_BASE + MCF_RNG_SIZE - 1,
> +		.flags = IORESOURCE_MEM,
> +	},
> +	{
> +		.start = MCF_IRQ_RNG,
> +		.end   = MCF_IRQ_RNG,
> +		.flags = IORESOURCE_IRQ,
> +	},
> +};
> +
> +static struct platform_device mcf_rng = {
> +	.name           = "imx-rngc",
> +	.id             = -1,
> +	.num_resources  = ARRAY_SIZE(mcf_rng_resource),
> +	.resource       = mcf_rng_resource,
> +};
> +#endif /* MCF_RNG_BASE */
> +
>  static struct platform_device *mcf_devices[] __initdata = {
>  	&mcf_uart,
>  #ifdef MCFFEC_BASE0
> @@ -660,6 +685,9 @@ static struct platform_device *mcf_devices[] __initdata = {
>  #ifdef MCFFLEXCAN_SIZE
>  	&mcf_flexcan0,
>  #endif
> +#ifdef MCF_RNG_BASE
> +	&mcf_rng,
> +#endif
>  };
>
>  /*
> diff --git a/arch/m68k/coldfire/m5441x.c b/arch/m68k/coldfire/m5441x.c
> index 7a25cfc7ac07570ff15da3c55d080a717cf93a06..ab5b006372379294db3b522820de88137bfb7e78 100644
> --- a/arch/m68k/coldfire/m5441x.c
> +++ b/arch/m68k/coldfire/m5441x.c
> @@ -158,6 +158,7 @@ static struct clk * const enable_clks[] __initconst = {
>  	&__clk_0_33, /* pit.1 */
>  	&__clk_0_37, /* eport */
>  	&__clk_0_48, /* pll */
> +	&__clk_0_49, /* rng */
>  	&__clk_0_51, /* esdhc */
>
>  	&__clk_1_36, /* CCM/reset module/Power management */
> @@ -179,7 +180,6 @@ static struct clk * const disable_clks[] __initconst = {
>  	&__clk_0_44, /* usb otg */
>  	&__clk_0_45, /* usb host */
>  	&__clk_0_47, /* ssi.0 */
> -	&__clk_0_49, /* rng */
>  	&__clk_0_50, /* ssi.1 */
>  	&__clk_0_53, /* enet-fec */
>  	&__clk_0_54, /* enet-fec */
> diff --git a/arch/m68k/include/asm/m5441xsim.h b/arch/m68k/include/asm/m5441xsim.h
> index f48cf63bd7822fd53c33788128f984585c0c421a..dd64cdfcad3e810254c6854b9de5b6bbeb67b950 100644
> --- a/arch/m68k/include/asm/m5441xsim.h
> +++ b/arch/m68k/include/asm/m5441xsim.h
> @@ -198,6 +198,15 @@
>  #define MCFRTC_SIZE		(0xfc0a8840 - 0xfc0a8000)
>  #define MCF_IRQ_RTC		(MCFINT2_VECBASE + MCFINT2_RTC)
>
> +/*
> + *  Random Number Generator (RNG) Module.
> + *  Note: Only present in MCF54418, not in MCF54410/54415/54417
> + */
> +#define MCF_RNG_BASE		0xfc0c4000
> +#define MCF_RNG_SIZE		0x1c
> +#define MCFINT2_RNG		28
> +#define MCF_IRQ_RNG		(MCFINT2_VECBASE + MCFINT2_RNG)
> +
>  /*
>   *  GPIO Module.
>   */
> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
> index 492a2a61a65be8bd9e46b0a70f3e43703973512e..e046eabaac2d9053a5a4a98c6e3733bb19258e54 100644
> --- 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
>  	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
> @@ -259,7 +259,7 @@ static int __init imx_rngc_probe(struct platform_device *pdev)
>  	if (IS_ERR(rngc->base))
>  		return PTR_ERR(rngc->base);
>
> -	rngc->clk = devm_clk_get(&pdev->dev, NULL);
> +	rngc->clk = devm_clk_get_optional(&pdev->dev, NULL);
>  	if (IS_ERR(rngc->clk))
>  		return dev_err_probe(&pdev->dev, PTR_ERR(rngc->clk), "Cannot get rng_clk\n");
>
> @@ -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" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(platform, imx_rngc_devtype);
> +
>  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);
>
> --
> 2.39.5
>