platform/surface: aggregator: Add comment for KIP subsystem category

The KIP subsystem (full name unknown, abbreviation has been obtained
through reverse engineering) handles detachable peripherals such as the
keyboard cover on the Surface Pro X and Surface Pro 8.

It is currently not entirely clear what this subsystem entails, but at
the very least it provides event notifications for when the keyboard
cover on the Surface Pro X and Surface Pro 8 have been detached or
re-attached, as well as the state that the keyboard cover is currently
in (e.g. folded-back, folded laptop-like, closed, etc.).

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-9-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/include/linux/surface_aggregator/serial_hub.h b/include/linux/surface_aggregator/serial_hub.h
index c3de43edcffa8002410a483d0d18907f5f799b7a..26b95ec127331d5781ec340c9ac34b688f2af366 100644 (file)
--- a/include/linux/surface_aggregator/serial_hub.h
+++ b/include/linux/surface_aggregator/serial_hub.h
@@ -306,7 +306,7 @@ enum ssam_ssh_tc {
        SSAM_SSH_TC_LPC = 0x0b,
        SSAM_SSH_TC_TCL = 0x0c,
        SSAM_SSH_TC_SFL = 0x0d,
-       SSAM_SSH_TC_KIP = 0x0e,
+       SSAM_SSH_TC_KIP = 0x0e, /* Manages detachable peripherals (Pro X/8 keyboard cover) */
        SSAM_SSH_TC_EXT = 0x0f,
        SSAM_SSH_TC_BLD = 0x10,
        SSAM_SSH_TC_BAS = 0x11, /* Detachment system (Surface Book 2/3). */