platform: Add gen5 MS Surface platform support

Add platform/ACPI support for 5th generation Microsoft Surface devices.
This provides support for the embedded controller on those devices,
required for battery-status and thermal events, as well as keyboard
support for Surface Laptop devices and proper detachment handling for
the Surface Book 2 clipboard.

Author: qzed

drivers/platform/x86/Kconfig

@@ -573,6 +573,103 @@ config THINKPAD_ACPI_HOTKEY_POLL
 	  If you are not sure, say Y here.  The driver enables polling only if
 	  it is strictly necessary to do so.
 
+config SURFACE_ACPI
+	depends on ACPI
+	tristate "Microsoft Surface ACPI/Platform Drivers"
+	---help---
+	  ACPI and platform drivers for Microsoft Surface devices.
+
+config SURFACE_ACPI_SSH
+	bool "Surface Serial Hub Driver"
+	depends on SURFACE_ACPI
+	depends on X86_INTEL_LPSS
+	depends on SERIAL_8250_DW
+	depends on SERIAL_8250_DMA
+	depends on SERIAL_DEV_CTRL_TTYPORT
+	select CRC_CCITT
+	default y
+	---help---
+	  Surface Serial Hub driver for 5th generation (or later) Microsoft
+	  Surface devices.
+
+	  This is the base driver for the embedded serial controller found on
+	  5th generation (and later) Microsoft Surface devices (e.g. Book 2,
+	  Laptop, Laptop 2, Pro 2017, Pro 6, ...). This driver itself only
+	  provides access to the embedded controller and subsequent drivers are
+	  required for the respective functionalities.
+
+	  If you have a 5th generation (or later) Microsoft Surface device, say
+	  Y or M here.
+
+config SURFACE_ACPI_SSH_DEBUG_DEVICE
+	bool "Surface Serial Hub Debug Device"
+	depends on SURFACE_ACPI_SSH
+	default n
+	---help---
+	  Debug device for direct communication with the embedded controller
+	  found on 5th generation (and later) Microsoft Surface devices (e.g.
+	  Book 2, Laptop, Laptop 2, Pro 2017, Pro 6, ...) via sysfs.
+
+	  If you are not sure, say N here.
+
+config SURFACE_ACPI_SAN
+	bool "Surface ACPI Notify Driver"
+	depends on SURFACE_ACPI_SSH
+	default y
+	---help---
+	  Surface ACPI Notify driver for 5th generation (or later) Microsoft
+	  Surface devices.
+
+	  This driver enables basic ACPI events and requests, such as battery
+	  status requests/events, thermal events, lid status, and possibly more,
+	  which would otherwise not work on these devices.
+
+	  If you are not sure, say Y here.
+
+config SURFACE_ACPI_VHF
+	bool "Surface Virtual HID Framework Driver"
+	depends on SURFACE_ACPI_SSH
+	depends on HID
+	default y
+	---help---
+	  Surface Virtual HID Framework driver for 5th generation (or later)
+	  Microsoft Surface devices.
+
+	  This driver provides support for the Microsoft Virtual HID framework,
+	  which is required for the Surface Laptop (1 and newer) keyboard.
+
+	  If you are not sure, say Y here.
+
+config SURFACE_ACPI_DTX
+	bool "Surface Detachment System (DTX) Driver"
+	depends on SURFACE_ACPI_SSH
+	depends on INPUT
+	default y
+	---help---
+	  Surface Detachment System (DTX) driver for the Microsoft Surface Book
+	  2. This driver provides support for proper detachment handling in
+	  user-space, status-events relating to the base and support for
+	  the safe-guard keeping the base attached when the discrete GPU
+	  contained in it is running via the special /dev/surface-dtx device.
+
+	  Also provides a standard input device to provide SW_TABLET_MODE events
+	  upon device mode change.
+
+	  If you are not sure, say Y here.
+
+config SURFACE_ACPI_SID
+	bool "Surface Platform Integration Driver"
+	depends on SURFACE_ACPI_SSH
+	default y
+	---help---
+	  Surface Platform Integration Driver for the Microsoft Surface Devices.
+	  Currently only supports the Surface Book 2. This driver provides suport
+	  for setting performance-modes via the perf_mode sysfs attribute.
+	  Performance-modes directly influence the fan-profile of the device,
+	  allowing to choose between higher performance or quieter operation.
+
+	  If you are not sure, say Y here.
+
 config SENSORS_HDAPS
 	tristate "Thinkpad Hard Drive Active Protection System (hdaps)"
 	depends on INPUT

drivers/platform/x86/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_TC1100_WMI)	+= tc1100-wmi.o
 obj-$(CONFIG_SONY_LAPTOP)	+= sony-laptop.o
 obj-$(CONFIG_IDEAPAD_LAPTOP)	+= ideapad-laptop.o
 obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
+obj-$(CONFIG_SURFACE_ACPI)	+= surface_acpi.o
 obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_FUJITSU_LAPTOP)	+= fujitsu-laptop.o
 obj-$(CONFIG_FUJITSU_TABLET)	+= fujitsu-tablet.o