HID: corsair: Add Corsair Vengeance K90 driver

This patch implements a HID driver for the Corsair Vengeance K90 keyboard.

It fixes the behaviour of the keys using incorrect HID usage codes and exposes
the macro playback mode and current profile to the user space through sysfs
attributes. It also adds two LED class devices controlling the "record" LED and
the backlight.

Signed-off-by: Clément Vuchener <clement.vuchener@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/ABI/testing/sysfs-driver-hid-corsair

@@ -0,0 +1,15 @@
+What:		/sys/bus/drivers/corsair/<dev>/macro_mode
+Date:		August 2015
+KernelVersion:	4.2
+Contact:	Clement Vuchener <clement.vuchener@gmail.com>
+Description:	Get/set the current playback mode. "SW" for software mode
+		where G-keys triggers their regular key codes. "HW" for
+		hardware playback mode where the G-keys play their macro
+		from the on-board memory.
+
+
+What:		/sys/bus/drivers/corsair/<dev>/current_profile
+Date:		August 2015
+KernelVersion:	4.2
+Contact:	Clement Vuchener <clement.vuchener@gmail.com>
+Description:	Get/set the current selected profile. Values are from 1 to 3.

drivers/hid/Kconfig

@@ -171,6 +171,16 @@ config HID_CHICONY
 	---help---
 	Support for Chicony Tactical pad.
 
+config HID_CORSAIR
+	tristate "Corsair devices"
+	depends on HID && USB && LEDS_CLASS
+	---help---
+	Support for Corsair devices that are not fully compliant with the
+	HID standard.
+
+	Supported devices:
+	- Vengeance K90
+
 config HID_PRODIKEYS
 	tristate "Prodikeys PC-MIDI Keyboard support"
 	depends on HID && SND

drivers/hid/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_HID_BELKIN)	+= hid-belkin.o
 obj-$(CONFIG_HID_BETOP_FF)	+= hid-betopff.o
 obj-$(CONFIG_HID_CHERRY)	+= hid-cherry.o
 obj-$(CONFIG_HID_CHICONY)	+= hid-chicony.o
+obj-$(CONFIG_HID_CORSAIR)	+= hid-corsair.o
 obj-$(CONFIG_HID_CP2112)	+= hid-cp2112.o
 obj-$(CONFIG_HID_CYPRESS)	+= hid-cypress.o
 obj-$(CONFIG_HID_DRAGONRISE)	+= hid-dr.o

drivers/hid/hid-core.c

@@ -1828,6 +1828,7 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_CHICONY_WIRELESS2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_CHICONY_AK1D) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_CHICONY_ACER_SWITCH12) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_DEVICE_ID_CORSAIR_K90) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CREATIVELABS, USB_DEVICE_ID_PRODIKEYS_PCMIDI) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_CP2112) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_1) },