Documentation: ABI: Add sysfs-class-reboot-mode-reboot_modes

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.

Reviewed-by: Bartosz Golaszewski <brgl@kernel.org>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
Link: https://patch.msgid.link/20260224-next-15nov_expose_sysfs-v24-1-4ee5b49d5a06@oss.qualcomm.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

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 (file)
index 0000000..a16c54a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-reboot-mode-reboot_modes
@@ -0,0 +1,36 @@
+What:          /sys/class/reboot-mode/<driver>/reboot_modes
+Date:          March 2026(TBD)
+KernelVersion: TBD
+Contact:       linux-pm@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 space
+               separated list of reboot-mode arguments supported
+               on the current platform.
+               Example:
+                recovery fastboot bootloader
+
+               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 standard reboot() system
+               call interface, with the "argument" as string to "*arg"
+               parameter along with LINUX_REBOOT_CMD_RESTART2.
+
+               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.