Re: [PATCH v5 2/9] soc: microchip: add mfd drivers for two syscon regions on PolarFire SoC

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

Hi, Conor,

On 10/13/25 20:45, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> The control-scb and mss-top-sysreg regions on PolarFire SoC both fulfill
> multiple purposes. The former is used for mailbox functions in addition
> to the temperature & voltage sensor while the latter is used for clocks,
> resets, interrupt muxing and pinctrl.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  drivers/soc/microchip/Kconfig               | 13 ++++++
>  drivers/soc/microchip/Makefile              |  1 +
>  drivers/soc/microchip/mpfs-control-scb.c    | 45 +++++++++++++++++++
>  drivers/soc/microchip/mpfs-mss-top-sysreg.c | 48 +++++++++++++++++++++
>  4 files changed, 107 insertions(+)
>  create mode 100644 drivers/soc/microchip/mpfs-control-scb.c
>  create mode 100644 drivers/soc/microchip/mpfs-mss-top-sysreg.c
> 
> diff --git a/drivers/soc/microchip/Kconfig b/drivers/soc/microchip/Kconfig
> index 19f4b576f822..31d188311e05 100644
> --- a/drivers/soc/microchip/Kconfig
> +++ b/drivers/soc/microchip/Kconfig
> @@ -9,3 +9,16 @@ config POLARFIRE_SOC_SYS_CTRL
>  	  module will be called mpfs_system_controller.
>  
>  	  If unsure, say N.
> +
> +config POLARFIRE_SOC_SYSCONS
> +	bool "PolarFire SoC (MPFS) syscon drivers"
> +	default y
> +	depends on ARCH_MICROCHIP
> +	select MFD_CORE
> +	help
> +	  These drivers add support for the syscons on PolarFire SoC (MPFS).
> +	  Without these drivers core parts of the kernel such as clocks
> +	  and resets will not function correctly.
> +
> +	  If unsure, and on a PolarFire SoC, say y.
> +

This empty line could be dropped.

> diff --git a/drivers/soc/microchip/Makefile b/drivers/soc/microchip/Makefile
> index 14489919fe4b..1a3a1594b089 100644
> --- a/drivers/soc/microchip/Makefile
> +++ b/drivers/soc/microchip/Makefile
> @@ -1 +1,2 @@
>  obj-$(CONFIG_POLARFIRE_SOC_SYS_CTRL)	+= mpfs-sys-controller.o
> +obj-$(CONFIG_POLARFIRE_SOC_SYSCONS)	+= mpfs-control-scb.o mpfs-mss-top-sysreg.o
> diff --git a/drivers/soc/microchip/mpfs-control-scb.c b/drivers/soc/microchip/mpfs-control-scb.c
> new file mode 100644
> index 000000000000..d1a8e79c232e
> --- /dev/null
> +++ b/drivers/soc/microchip/mpfs-control-scb.c
> @@ -0,0 +1,45 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/array_size.h>

Looks like this one can be dropped or maybe you want to use
ARRAY_SIZE(mpfs_control_scb_devs) as 4th argument of mfd_add_devices().

> +#include <linux/of.h>
> +#include <linux/of_address.h>

Looks like this one can be dropped.

> +#include <linux/mfd/core.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_platform.h>

Same with this one?

> +#include <linux/platform_device.h>
> +
> +static const struct mfd_cell mpfs_control_scb_devs[] = {
> +	{ .name = "mpfs-tvs", },

I think you can use:

MFD_CELL_NAME("mpfs-tvs")

> +};
> +
> +static int mpfs_control_scb_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	ret = mfd_add_devices(dev, PLATFORM_DEVID_NONE, mpfs_control_scb_devs,
> +			      1, NULL, 0, NULL);
> +	if (ret)
> +		return ret;
> +
> +	return 0;

You can use directly:

	return mfd_add_device(...);

> +}
> +
> +static const struct of_device_id mpfs_control_scb_of_match[] = {
> +	{.compatible = "microchip,mpfs-control-scb", },

This looks un-documented.

> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mpfs_control_scb_of_match);
> +
> +static struct platform_driver mpfs_control_scb_driver = {
> +	.driver = {
> +		.name = "mpfs-control-scb",
> +		.of_match_table = mpfs_control_scb_of_match,
> +	},
> +	.probe = mpfs_control_scb_probe,
> +};
> +module_platform_driver(mpfs_control_scb_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
> +MODULE_DESCRIPTION("PolarFire SoC control scb driver");
> diff --git a/drivers/soc/microchip/mpfs-mss-top-sysreg.c b/drivers/soc/microchip/mpfs-mss-top-sysreg.c
> new file mode 100644
> index 000000000000..9b2e7b84cdba
> --- /dev/null
> +++ b/drivers/soc/microchip/mpfs-mss-top-sysreg.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/array_size.h>

Looks like this one can be dropped or maybe you want to use
ARRAY_SIZE(mpfs_mss_top_sysreg_devs) as 4th argument of mfd_add_devices()

> +#include <linux/of.h>
> +#include <linux/of_address.h>

Unused?

> +#include <linux/mfd/core.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_platform.h>

Unused?

> +#include <linux/platform_device.h>
> +
> +static const struct mfd_cell mpfs_mss_top_sysreg_devs[] = {
> +	{ .name = "mpfs-reset", },

MFD_CELL_NAME() ?

> +};
> +
> +static int mpfs_mss_top_sysreg_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	ret = mfd_add_devices(dev, PLATFORM_DEVID_NONE, mpfs_mss_top_sysreg_devs,
> +			      1, NULL, 0, NULL);
> +	if (ret)
> +		return ret;
> +
> +	if (devm_of_platform_populate(dev))
> +		dev_err(dev, "Error populating children\n");

Is it OK return 0 above if there are failures here?

> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mpfs_mss_top_sysreg_of_match[] = {
> +	{.compatible = "microchip,mpfs-mss-top-sysreg", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mpfs_mss_top_sysreg_of_match);
> +
> +static struct platform_driver mpfs_mss_top_sysreg_driver = {
> +	.driver = {
> +		.name = "mpfs-mss-top-sysreg",
> +		.of_match_table = mpfs_mss_top_sysreg_of_match,
> +	},
> +	.probe = mpfs_mss_top_sysreg_probe,
> +};
> +module_platform_driver(mpfs_mss_top_sysreg_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
> +MODULE_DESCRIPTION("PolarFire SoC mss top sysreg driver");