hid: apple: Add DockChannel HID transport driver

This adds the transport layer required to communicate with the
internal keyboard and trackpad on Apple M2 and later MacBooks.
It facilitates HID communication via the DockChannel FIFO
and the "MTP" coprocessor.

Signed-off-by: Michael Reeves <[email protected]>

Author: IntegralPilot

drivers/hid/Kconfig

@@ -1442,6 +1442,8 @@ source "drivers/hid/surface-hid/Kconfig"
 
 source "drivers/hid/intel-thc-hid/Kconfig"
 
+source "drivers/hid/apple-dockchannel-hid/Kconfig"
+
 endif # HID
 
 # USB support may be used with HID disabled

drivers/hid/Makefile

@@ -176,3 +176,5 @@ obj-$(CONFIG_AMD_SFH_HID)       += amd-sfh-hid/
 obj-$(CONFIG_SURFACE_HID_CORE)  += surface-hid/
 
 obj-$(CONFIG_INTEL_THC_HID)     += intel-thc-hid/
+
+obj-$(CONFIG_APPLE_DOCKCHANNEL_HID)   += apple-dockchannel-hid/

drivers/hid/apple-dockchannel-hid/Kconfig

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only OR MIT
+menu "Apple DockChannel HID support"
+	depends on APPLE_DOCKCHANNEL
+
+config APPLE_DOCKCHANNEL_HID
+	tristate "HID over DockChannel transport layer for Apple Silicon SoCs"
+	depends on APPLE_DOCKCHANNEL && INPUT && OF && HID
+	help
+	  This provides a HID transport layer over the Apple DockChannel
+	  interface. This is required to support the internal keyboard
+	  and trackpad on M2 and later MacBook models.
+
+	  Say Y here if you have an M2 or later MacBook.
+
+endmenu

drivers/hid/apple-dockchannel-hid/Makefile

@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only OR MIT
+#
+# Makefile for DockChannel HID transport drivers
+#
+
+obj-$(CONFIG_APPLE_DOCKCHANNEL_HID)	+= apple_dockchannel_hid.o