drivers/hid/hid-razer.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  HID driver for gaming keys on Razer Blackwidow gaming keyboards
 *  Macro Key Keycodes: M1 = 191, M2 = 192, M3 = 193, M4 = 194, M5 = 195
 *
 *  Copyright (c) 2021 Jelle van der Waa <jvanderwaa@redhat.com>
 */

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/usb.h>
#include <linux/wait.h>

#include "hid-ids.h"

#define map_key_clear(c) hid_map_usage_clear(hi, usage, bit, max, EV_KEY, (c))

#define RAZER_BLACKWIDOW_TRANSFER_BUF_SIZE	91

static bool macro_key_remapping = 1;
module_param(macro_key_remapping, bool, 0644);
MODULE_PARM_DESC(macro_key_remapping, " on (Y) off (N)");


static unsigned char blackwidow_init[RAZER_BLACKWIDOW_TRANSFER_BUF_SIZE] = {
	0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x04,
	0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x04, 0x00
};

static int razer_input_mapping(struct hid_device *hdev,
		struct hid_input *hi, struct hid_field *field,
		struct hid_usage *usage, unsigned long **bit, int *max)
{

	if (!macro_key_remapping)
		return 0;

	if ((usage->hid & HID_UP_KEYBOARD) != HID_UP_KEYBOARD)
		return 0;

	switch (usage->hid & ~HID_UP_KEYBOARD) {
	case 0x68:
		map_key_clear(KEY_MACRO1);
		return 1;
	case 0x69:
		map_key_clear(KEY_MACRO2);
		return 1;
	case 0x6a:
		map_key_clear(KEY_MACRO3);
		return 1;
	case 0x6b:
		map_key_clear(KEY_MACRO4);
		return 1;
	case 0x6c:
		map_key_clear(KEY_MACRO5);
		return 1;
	}

	return 0;
}

static int razer_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
	char *buf;
	int ret = 0;

	ret = hid_parse(hdev);
	if (ret)
		return ret;

	/*
	 * Only send the enable macro keys command for the third device
	 * identified as mouse input.
	 */
	if (hdev->type == HID_TYPE_USBMOUSE) {
		buf = kmemdup(blackwidow_init, RAZER_BLACKWIDOW_TRANSFER_BUF_SIZE, GFP_KERNEL);
		if (buf == NULL)
			return -ENOMEM;

		ret = hid_hw_raw_request(hdev, 0, buf, RAZER_BLACKWIDOW_TRANSFER_BUF_SIZE,
				HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
		if (ret != RAZER_BLACKWIDOW_TRANSFER_BUF_SIZE)
			hid_err(hdev, "failed to enable macro keys: %d\n", ret);

		kfree(buf);
	}

	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
}

static const struct hid_device_id razer_devices[] = {
	{ HID_USB_DEVICE(USB_VENDOR_ID_RAZER,
		USB_DEVICE_ID_RAZER_BLACKWIDOW) },
	{ HID_USB_DEVICE(USB_VENDOR_ID_RAZER,
		USB_DEVICE_ID_RAZER_BLACKWIDOW_CLASSIC) },
	{ HID_USB_DEVICE(USB_VENDOR_ID_RAZER,
		USB_DEVICE_ID_RAZER_BLACKWIDOW_ULTIMATE) },
	{ }
};
MODULE_DEVICE_TABLE(hid, razer_devices);

static struct hid_driver razer_driver = {
	.name = "razer",
	.id_table = razer_devices,
	.input_mapping = razer_input_mapping,
	.probe = razer_probe,
};
module_hid_driver(razer_driver);

MODULE_AUTHOR("Jelle van der Waa <jvanderwaa@redhat.com>");
MODULE_DESCRIPTION("HID driver for gaming keys on Razer Blackwidow gaming keyboards");
MODULE_LICENSE("GPL");