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

[Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>]

Hi Frank,

Le vendredi 7 novembre 2025, 17:07:10 heure normale d’Europe centrale Frank Li 
a écrit :
> 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.

Thanks for this suggestion, I will split this into two for v3. I am just 
waiting a bit to see if other remarks are emerging, in order to not spam with 
multiple versions :-).

Thanks,
JM

> 
> Frank
> 
> > diff --git a/arch/m68k/coldfire/device.c b/arch/m68k/coldfire/device.c
> > index
> > 20adba27a687029ef53249bad71b342d563d612b..4183929b0b501459da25d1b4cde7d77
> > f19c3dc16 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..ab5b006372379294db3b522820de881
> > 37bfb7e78 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..dd64cdfcad3e810254c6854b9de5b6b
> > beb67b950 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..e046eabaac2d9053a5a4a98c6e3733b
> > b19258e54 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..44f20a05de0a425cb6ff7b2a347b111
> > 750ac3702 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