Re: [PATCH v23 09/13] mfd: psci-mfd: Add psci-reboot-mode child cell

[Bartosz Golaszewski]

On Tue, 14 Jul 2026 19:16:37 +0200, Shivendra Pratap
<shivendra.pratap@xxxxxxxxxxxxxxxx> said:
> The PSCI "reboot-mode" node does not define a compatible because it is a
> configuration of boot-states provided by the underlying firmware. With
> the new firmware-node based cells in mfd-core, this node can now be
> exposed as a proper child cell.
>
> Add the psci-reboot-mode child cell to the psci-mfd driver with a
> named_fwnode. Add psci-cpuidle-domain cell first to isolate it from
> reboot-mode failures.
>
> Suggested-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> Signed-off-by: Shivendra Pratap <shivendra.pratap@xxxxxxxxxxxxxxxx>
> ---
>  drivers/mfd/psci-mfd.c      | 30 +++++++++++++++++++++++++++++-
>  drivers/power/reset/Kconfig |  2 +-
>  2 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mfd/psci-mfd.c b/drivers/mfd/psci-mfd.c
> index 7affd6bb09dd..8c6b78ac471b 100644
> --- a/drivers/mfd/psci-mfd.c
> +++ b/drivers/mfd/psci-mfd.c
> @@ -7,6 +7,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> +#include <linux/property.h>
>
>  static const struct mfd_cell psci_cells[] = {
>  	{
> @@ -14,10 +15,37 @@ static const struct mfd_cell psci_cells[] = {
>  	},
>  };
>
> +static const struct mfd_cell psci_reboot_mode_cell[] = {
> +	{
> +		.name = "psci-reboot-mode",
> +		.named_fwnode = "reboot-mode",
> +	},
> +};
> +
>  static int psci_mfd_probe(struct platform_device *pdev)
>  {
> -	return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, psci_cells,
> +	struct fwnode_handle *fwnode;
> +	int ret;
> +
> +	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, psci_cells,
>  				   ARRAY_SIZE(psci_cells), NULL, 0, NULL);
> +	if (ret)
> +		return ret;
> +
> +	fwnode = device_get_named_child_node(&pdev->dev, "reboot-mode");
> +	if (!fwnode)
> +		return 0;
> +
> +	fwnode_handle_put(fwnode);
> +
> +	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
> +				   psci_reboot_mode_cell,
> +				   ARRAY_SIZE(psci_reboot_mode_cell),
> +				   NULL, 0, NULL);
> +	if (ret)
> +		dev_warn(&pdev->dev, "reboot-mode child cell failed to add: %d\n", ret);

Why do we have to look up the named node here anyway? Shouldn't MFD core handle
that already in a generic way?

Bart