[PATCH v13 04/10] Documentation: ABI: Add sysfs-class-reboot-mode-reboot_modes

[André Draszik]

On Sun, 2025-07-27 at 21:54 +0530, Shivendra Pratap wrote:
> Add ABI documentation for /sys/class/reboot-mode/*/reboot_modes,
> a read-only sysfs attribute exposing the list of supported
> reboot-mode arguments. This file is created by reboot-mode
> framework and provides a user-readable interface to query
> available reboot-mode arguments.
> 
> Signed-off-by: Shivendra Pratap <shivendra.pratap at oss.qualcomm.com>
> ---
>  .../testing/sysfs-class-reboot-mode-reboot_modes   | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-reboot-mode-reboot_modes b/Documentation/ABI/testing/sysfs-class-reboot-mode-
> reboot_modes
> new file mode 100644
> index 0000000000000000000000000000000000000000..7147a781e5d4d11977c3a156bf4308aa13310e39
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-reboot-mode-reboot_modes
> @@ -0,0 +1,39 @@
> +What:		/sys/class/reboot-mode/<driver>/reboot_modes
> +Date:		July 2025
> +KernelVersion:	6.16

The version should probably be updated.

> +Contact:	linux-pm at vger.kernel.org
> +		Description:
> +		This interface exposes the reboot-mode arguments
> +		registered with the reboot-mode framework. It is
> +		a read-only interface and provides a comma
> +		separated list of reboot-mode arguments supported
> +		on the current platform.
> +		Example:
> +		 recovery,fastboot,bootloader

I'd personally find space separated like e.g. in files below /sys/power
and many other similar files below /sys easier to read.

Cheers,
Andre'


> +
> +		The exact sysfs path may vary depending on the
> +		name of the driver that registers the arguments.
> +		Example:
> +		 /sys/class/reboot-mode/nvmem-reboot-mode/reboot_modes
> +		 /sys/class/reboot-mode/syscon-reboot-mode/reboot_modes
> +		 /sys/class/reboot-mode/qcom-pon/reboot_modes
> +
> +		The supported arguments can be used by userspace
> +		to invoke device reset using the reboot() system
> +		call, with the "argument" as string to "*arg"
> +		parameter along with LINUX_REBOOT_CMD_RESTART2.
> +		Example:
> +		 reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
> +		        LINUX_REBOOT_CMD_RESTART2, "bootloader");
> +
> +		A driver can expose the supported arguments by
> +		registering them with the reboot-mode framework
> +		using the property names that follow the
> +		mode-<argument> format.
> +		Example:
> +		 mode-bootloader, mode-recovery.
> +
> +		This attribute is useful for scripts or initramfs
> +		logic that need to programmatically determine
> +		which reboot-mode arguments are valid before
> +		triggering a reboot.