The class interface allows changing multiple platform profiles on a system
to different values. The semantics of it are similar to the legacy
interface.
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
.../userspace-api/sysfs-platform_profile.rst | 28 +++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/Documentation/userspace-api/sysfs-platform_profile.rst b/Documentation/userspace-api/sysfs-platform_profile.rst
index 4fccde2e45639..418c61b096304 100644
--- a/Documentation/userspace-api/sysfs-platform_profile.rst
+++ b/Documentation/userspace-api/sysfs-platform_profile.rst
@@ -40,3 +40,31 @@ added. Drivers which wish to introduce new profile names must:
1. Explain why the existing profile names cannot be used.
2. Add the new profile name, along with a clear description of the
expected behaviour, to the sysfs-platform_profile ABI documentation.
+
+Multiple driver support
+=======================
+When multiple drivers on a system advertise a platform profile handler, the
+platform profile handler core will only advertise the profiles that are
+commong between all drivers to the ``/sys/firmware/acpi`` interfaces.
+
+This is to ensure there is no ambiguity on what the profile names mean when
+all handlers don't support a profile.
+
+Individual drivers will register a 'platform_profile' class device that has
+similar semantics as the ``/sys/firmware/acpi/platform_profile`` interface.
+
+To discover available profiles from the class interface the user can read the
+``choices`` attribute.
+
+If a user wants to select a profile for a specific driver, they can do so
+by writing to the ``profile`` attribute of the driver's class device.
+
+This will allow users to set different profiles for different drivers on the
+same system. If the selected profile by individual drivers differes the
+platform profile handler core will display the profile 'custom' to indicate
+that the profiles are not the same.
+
+While the ``platform_profile`` attribute has the value ``custom``, writing a
+common profile from ``platform_profile_choices`` to the platform_profile
+attribute of the platform profile handler core will set the profile for all
+drivers.
--
2.43.0
