HID: ite: Add hid-ite driver

The ITE8595 keyboard uses the HID_GD_RFKILL_BTN usage code
from the Wireless Radio Controls Application Collection Microsoft
has defined for Windows 8 and later.

However it has a quirk, when the rfkill hotkey is pressed it does
generate a report for the collection, but the reported value is
always 0. Luckily it is the only button in this collection / report,
and it sends a report on release only, so receiving a report means the
button was pressed.

This commit adds a hid-ite driver which watches for the Wireless Radio
Controls Application Collection report and then reports a KEY_RFKILL event,
ignoring the value, making the rfkill on this keyboard work.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/Kconfig

@@ -386,6 +386,13 @@ config HID_ICADE
 	To compile this driver as a module, choose M here: the
 	module will be called hid-icade.
 
+config HID_ITE
+	tristate "ITE devices"
+	depends on HID
+	default !EXPERT
+	---help---
+	Support for ITE devices not fully compliant with HID standard.
+
 config HID_TWINHAN
 	tristate "Twinhan IR remote control"
 	depends on HID

drivers/hid/Makefile

@@ -50,6 +50,7 @@ obj-$(CONFIG_HID_HOLTEK)	+= hid-holtek-mouse.o
 obj-$(CONFIG_HID_HOLTEK)	+= hid-holtekff.o
 obj-$(CONFIG_HID_HYPERV_MOUSE)	+= hid-hyperv.o
 obj-$(CONFIG_HID_ICADE)		+= hid-icade.o
+obj-$(CONFIG_HID_ITE)		+= hid-ite.o
 obj-$(CONFIG_HID_KENSINGTON)	+= hid-kensington.o
 obj-$(CONFIG_HID_KEYTOUCH)	+= hid-keytouch.o
 obj-$(CONFIG_HID_KYE)		+= hid-kye.o

drivers/hid/hid-core.c

@@ -1913,6 +1913,7 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_HOLTEK_ALT, USB_DEVICE_ID_HOLTEK_ALT_MOUSE_A081) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_HOLTEK_ALT, USB_DEVICE_ID_HOLTEK_ALT_MOUSE_A0C2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_HUION, USB_DEVICE_ID_HUION_TABLET) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ITE, USB_DEVICE_ID_ITE8595) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_JESS, USB_DEVICE_ID_JESS_ZEN_AIO_KBD) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_JESS2, USB_DEVICE_ID_JESS2_COLOR_RUMBLE_PAD) },
 	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ION, USB_DEVICE_ID_ICADE) },

drivers/hid/hid-ids.h

@@ -559,6 +559,7 @@
 #define USB_DEVICE_ID_ITE_LENOVO_YOGA   0x8386
 #define USB_DEVICE_ID_ITE_LENOVO_YOGA2  0x8350
 #define USB_DEVICE_ID_ITE_LENOVO_YOGA900	0x8396
+#define USB_DEVICE_ID_ITE8595		0x8595
 
 #define USB_VENDOR_ID_JABRA		0x0b0e
 #define USB_DEVICE_ID_JABRA_SPEAK_410	0x0412

drivers/hid/hid-ite.c

@@ -0,0 +1,56 @@
+/*
+ * HID driver for some ITE "special" devices
+ * Copyright (c) 2017 Hans de Goede <hdegoede@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+static int ite_event(struct hid_device *hdev, struct hid_field *field,
+		     struct hid_usage *usage, __s32 value)
+{
+	struct input_dev *input;
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput)
+		return 0;
+
+	input = field->hidinput->input;
+
+	/*
+	 * The ITE8595 always reports 0 as value for the rfkill button. Luckily
+	 * it is the only button in its report, and it sends a report on
+	 * release only, so receiving a report means the button was pressed.
+	 */
+	if (usage->hid == HID_GD_RFKILL_BTN) {
+		input_event(input, EV_KEY, KEY_RFKILL, 1);
+		input_sync(input);
+		input_event(input, EV_KEY, KEY_RFKILL, 0);
+		input_sync(input);
+		return 1;
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id ite_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ITE, USB_DEVICE_ID_ITE8595) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ite_devices);
+
+static struct hid_driver ite_driver = {
+	.name = "itetech",
+	.id_table = ite_devices,
+	.event = ite_event,
+};
+module_hid_driver(ite_driver);
+
+MODULE_LICENSE("GPL");