/*
 *  HIDPP protocol for Logitech Unifying receivers
 *
 *  Copyright (c) 2011 Logitech (c)
 *  Copyright (c) 2012-2013 Google (c)
 *  Copyright (c) 2013-2014 Red Hat Inc.
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; version 2 of the License.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/device.h>
#include <linux/input.h>
#include <linux/usb.h>
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/kfifo.h>
#include <linux/input/mt.h>
#include <linux/workqueue.h>
#include <linux/atomic.h>
#include <linux/fixp-arith.h>
#include <asm/unaligned.h>
#include "usbhid/usbhid.h"
#include "hid-ids.h"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_AUTHOR("Nestor Lopez Casado <nlopezcasad@logitech.com>");

static bool disable_raw_mode;
module_param(disable_raw_mode, bool, 0644);
MODULE_PARM_DESC(disable_raw_mode,
	"Disable Raw mode reporting for touchpads and keep firmware gestures.");

static bool disable_tap_to_click;
module_param(disable_tap_to_click, bool, 0644);
MODULE_PARM_DESC(disable_tap_to_click,
	"Disable Tap-To-Click mode reporting for touchpads (only on the K400 currently).");

#define REPORT_ID_HIDPP_SHORT			0x10
#define REPORT_ID_HIDPP_LONG			0x11
#define REPORT_ID_HIDPP_VERY_LONG		0x12

#define HIDPP_REPORT_SHORT_LENGTH		7
#define HIDPP_REPORT_LONG_LENGTH		20
#define HIDPP_REPORT_VERY_LONG_LENGTH		64

#define HIDPP_QUIRK_CLASS_WTP			BIT(0)
#define HIDPP_QUIRK_CLASS_M560			BIT(1)
#define HIDPP_QUIRK_CLASS_K400			BIT(2)
#define HIDPP_QUIRK_CLASS_G920			BIT(3)

/* bits 2..20 are reserved for classes */
#define HIDPP_QUIRK_CONNECT_EVENTS		BIT(21)
#define HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS	BIT(22)
#define HIDPP_QUIRK_NO_HIDINPUT			BIT(23)
#define HIDPP_QUIRK_FORCE_OUTPUT_REPORTS	BIT(24)

#define HIDPP_QUIRK_DELAYED_INIT		(HIDPP_QUIRK_NO_HIDINPUT | \
						 HIDPP_QUIRK_CONNECT_EVENTS)

/*
 * There are two hidpp protocols in use, the first version hidpp10 is known
 * as register access protocol or RAP, the second version hidpp20 is known as
 * feature access protocol or FAP
 *
 * Most older devices (including the Unifying usb receiver) use the RAP protocol
 * where as most newer devices use the FAP protocol. Both protocols are
 * compatible with the underlying transport, which could be usb, Unifiying, or
 * bluetooth. The message lengths are defined by the hid vendor specific report
 * descriptor for the HIDPP_SHORT report type (total message lenth 7 bytes) and
 * the HIDPP_LONG report type (total message length 20 bytes)
 *
 * The RAP protocol uses both report types, whereas the FAP only uses HIDPP_LONG
 * messages. The Unifying receiver itself responds to RAP messages (device index
 * is 0xFF for the receiver), and all messages (short or long) with a device
 * index between 1 and 6 are passed untouched to the corresponding paired
 * Unifying device.
 *
 * The paired device can be RAP or FAP, it will receive the message untouched
 * from the Unifiying receiver.
 */

struct fap {
	u8 feature_index;
	u8 funcindex_clientid;
	u8 params[HIDPP_REPORT_VERY_LONG_LENGTH - 4U];
};

struct rap {
	u8 sub_id;
	u8 reg_address;
	u8 params[HIDPP_REPORT_VERY_LONG_LENGTH - 4U];
};

struct hidpp_report {
	u8 report_id;
	u8 device_index;
	union {
		struct fap fap;
		struct rap rap;
		u8 rawbytes[sizeof(struct fap)];
	};
} __packed;

struct hidpp_device {
	struct hid_device *hid_dev;
	struct mutex send_mutex;
	void *send_receive_buf;
	char *name;		/* will never be NULL and should not be freed */
	wait_queue_head_t wait;
	bool answer_available;
	u8 protocol_major;
	u8 protocol_minor;

	void *private_data;

	struct work_struct work;
	struct kfifo delayed_work_fifo;
	atomic_t connected;
	struct input_dev *delayed_input;

	unsigned long quirks;
};


/* HID++ 1.0 error codes */
#define HIDPP_ERROR				0x8f
#define HIDPP_ERROR_SUCCESS			0x00
#define HIDPP_ERROR_INVALID_SUBID		0x01
#define HIDPP_ERROR_INVALID_ADRESS		0x02
#define HIDPP_ERROR_INVALID_VALUE		0x03
#define HIDPP_ERROR_CONNECT_FAIL		0x04
#define HIDPP_ERROR_TOO_MANY_DEVICES		0x05
#define HIDPP_ERROR_ALREADY_EXISTS		0x06
#define HIDPP_ERROR_BUSY			0x07
#define HIDPP_ERROR_UNKNOWN_DEVICE		0x08
#define HIDPP_ERROR_RESOURCE_ERROR		0x09
#define HIDPP_ERROR_REQUEST_UNAVAILABLE		0x0a
#define HIDPP_ERROR_INVALID_PARAM_VALUE		0x0b
#define HIDPP_ERROR_WRONG_PIN_CODE		0x0c
/* HID++ 2.0 error codes */
#define HIDPP20_ERROR				0xff

static void hidpp_connect_event(struct hidpp_device *hidpp_dev);

static int __hidpp_send_report(struct hid_device *hdev,
				struct hidpp_report *hidpp_report)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	int fields_count, ret;

	hidpp = hid_get_drvdata(hdev);

	switch (hidpp_report->report_id) {
	case REPORT_ID_HIDPP_SHORT:
		fields_count = HIDPP_REPORT_SHORT_LENGTH;
		break;
	case REPORT_ID_HIDPP_LONG:
		fields_count = HIDPP_REPORT_LONG_LENGTH;
		break;
	case REPORT_ID_HIDPP_VERY_LONG:
		fields_count = HIDPP_REPORT_VERY_LONG_LENGTH;
		break;
	default:
		return -ENODEV;
	}

	/*
	 * set the device_index as the receiver, it will be overwritten by
	 * hid_hw_request if needed
	 */
	hidpp_report->device_index = 0xff;

	if (hidpp->quirks & HIDPP_QUIRK_FORCE_OUTPUT_REPORTS) {
		ret = hid_hw_output_report(hdev, (u8 *)hidpp_report, fields_count);
	} else {
		ret = hid_hw_raw_request(hdev, hidpp_report->report_id,
			(u8 *)hidpp_report, fields_count, HID_OUTPUT_REPORT,
			HID_REQ_SET_REPORT);
	}

	return ret == fields_count ? 0 : -1;
}

/**
 * hidpp_send_message_sync() returns 0 in case of success, and something else
 * in case of a failure.
 * - If ' something else' is positive, that means that an error has been raised
 *   by the protocol itself.
 * - If ' something else' is negative, that means that we had a classic error
 *   (-ENOMEM, -EPIPE, etc...)
 */
static int hidpp_send_message_sync(struct hidpp_device *hidpp,
	struct hidpp_report *message,
	struct hidpp_report *response)
{
	int ret;

	mutex_lock(&hidpp->send_mutex);

	hidpp->send_receive_buf = response;
	hidpp->answer_available = false;

	/*
	 * So that we can later validate the answer when it arrives
	 * in hidpp_raw_event
	 */
	*response = *message;

	ret = __hidpp_send_report(hidpp->hid_dev, message);

	if (ret) {
		dbg_hid("__hidpp_send_report returned err: %d\n", ret);
		memset(response, 0, sizeof(struct hidpp_report));
		goto exit;
	}

	if (!wait_event_timeout(hidpp->wait, hidpp->answer_available,
				5*HZ)) {
		dbg_hid("%s:timeout waiting for response\n", __func__);
		memset(response, 0, sizeof(struct hidpp_report));
		ret = -ETIMEDOUT;
	}

	if (response->report_id == REPORT_ID_HIDPP_SHORT &&
	    response->rap.sub_id == HIDPP_ERROR) {
		ret = response->rap.params[1];
		dbg_hid("%s:got hidpp error %02X\n", __func__, ret);
		goto exit;
	}

	if ((response->report_id == REPORT_ID_HIDPP_LONG ||
			response->report_id == REPORT_ID_HIDPP_VERY_LONG) &&
			response->fap.feature_index == HIDPP20_ERROR) {
		ret = response->fap.params[1];
		dbg_hid("%s:got hidpp 2.0 error %02X\n", __func__, ret);
		goto exit;
	}

exit:
	mutex_unlock(&hidpp->send_mutex);
	return ret;

}

static int hidpp_send_fap_command_sync(struct hidpp_device *hidpp,
	u8 feat_index, u8 funcindex_clientid, u8 *params, int param_count,
	struct hidpp_report *response)
{
	struct hidpp_report *message;
	int ret;

	if (param_count > sizeof(message->fap.params))
		return -EINVAL;

	message = kzalloc(sizeof(struct hidpp_report), GFP_KERNEL);
	if (!message)
		return -ENOMEM;

	if (param_count > (HIDPP_REPORT_LONG_LENGTH - 4))
		message->report_id = REPORT_ID_HIDPP_VERY_LONG;
	else
		message->report_id = REPORT_ID_HIDPP_LONG;
	message->fap.feature_index = feat_index;
	message->fap.funcindex_clientid = funcindex_clientid;
	memcpy(&message->fap.params, params, param_count);

	ret = hidpp_send_message_sync(hidpp, message, response);
	kfree(message);
	return ret;
}

static int hidpp_send_rap_command_sync(struct hidpp_device *hidpp_dev,
	u8 report_id, u8 sub_id, u8 reg_address, u8 *params, int param_count,
	struct hidpp_report *response)
{
	struct hidpp_report *message;
	int ret, max_count;

	switch (report_id) {
	case REPORT_ID_HIDPP_SHORT:
		max_count = HIDPP_REPORT_SHORT_LENGTH - 4;
		break;
	case REPORT_ID_HIDPP_LONG:
		max_count = HIDPP_REPORT_LONG_LENGTH - 4;
		break;
	case REPORT_ID_HIDPP_VERY_LONG:
		max_count = HIDPP_REPORT_VERY_LONG_LENGTH - 4;
		break;
	default:
		return -EINVAL;
	}

	if (param_count > max_count)
		return -EINVAL;

	message = kzalloc(sizeof(struct hidpp_report), GFP_KERNEL);
	if (!message)
		return -ENOMEM;
	message->report_id = report_id;
	message->rap.sub_id = sub_id;
	message->rap.reg_address = reg_address;
	memcpy(&message->rap.params, params, param_count);

	ret = hidpp_send_message_sync(hidpp_dev, message, response);
	kfree(message);
	return ret;
}

static void delayed_work_cb(struct work_struct *work)
{
	struct hidpp_device *hidpp = container_of(work, struct hidpp_device,
							work);
	hidpp_connect_event(hidpp);
}

static inline bool hidpp_match_answer(struct hidpp_report *question,
		struct hidpp_report *answer)
{
	return (answer->fap.feature_index == question->fap.feature_index) &&
	   (answer->fap.funcindex_clientid == question->fap.funcindex_clientid);
}

static inline bool hidpp_match_error(struct hidpp_report *question,
		struct hidpp_report *answer)
{
	return ((answer->rap.sub_id == HIDPP_ERROR) ||
	    (answer->fap.feature_index == HIDPP20_ERROR)) &&
	    (answer->fap.funcindex_clientid == question->fap.feature_index) &&
	    (answer->fap.params[0] == question->fap.funcindex_clientid);
}

static inline bool hidpp_report_is_connect_event(struct hidpp_report *report)
{
	return (report->report_id == REPORT_ID_HIDPP_SHORT) &&
		(report->rap.sub_id == 0x41);
}

/**
 * hidpp_prefix_name() prefixes the current given name with "Logitech ".
 */
static void hidpp_prefix_name(char **name, int name_length)
{
#define PREFIX_LENGTH 9 /* "Logitech " */

	int new_length;
	char *new_name;

	if (name_length > PREFIX_LENGTH &&
	    strncmp(*name, "Logitech ", PREFIX_LENGTH) == 0)
		/* The prefix has is already in the name */
		return;

	new_length = PREFIX_LENGTH + name_length;
	new_name = kzalloc(new_length, GFP_KERNEL);
	if (!new_name)
		return;

	snprintf(new_name, new_length, "Logitech %s", *name);

	kfree(*name);

	*name = new_name;
}

/* -------------------------------------------------------------------------- */
/* HIDP++ 1.0 commands                                                        */
/* -------------------------------------------------------------------------- */

#define HIDPP_SET_REGISTER				0x80
#define HIDPP_GET_REGISTER				0x81
#define HIDPP_SET_LONG_REGISTER				0x82
#define HIDPP_GET_LONG_REGISTER				0x83

#define HIDPP_REG_PAIRING_INFORMATION			0xB5
#define DEVICE_NAME					0x40

static char *hidpp_get_unifying_name(struct hidpp_device *hidpp_dev)
{
	struct hidpp_report response;
	int ret;
	/* hid-logitech-dj is in charge of setting the right device index */
	u8 params[1] = { DEVICE_NAME };
	char *name;
	int len;

	ret = hidpp_send_rap_command_sync(hidpp_dev,
					REPORT_ID_HIDPP_SHORT,
					HIDPP_GET_LONG_REGISTER,
					HIDPP_REG_PAIRING_INFORMATION,
					params, 1, &response);
	if (ret)
		return NULL;

	len = response.rap.params[1];

	if (2 + len > sizeof(response.rap.params))
		return NULL;

	name = kzalloc(len + 1, GFP_KERNEL);
	if (!name)
		return NULL;

	memcpy(name, &response.rap.params[2], len);

	/* include the terminating '\0' */
	hidpp_prefix_name(&name, len + 1);

	return name;
}

/* -------------------------------------------------------------------------- */
/* 0x0000: Root                                                               */
/* -------------------------------------------------------------------------- */

#define HIDPP_PAGE_ROOT					0x0000
#define HIDPP_PAGE_ROOT_IDX				0x00

#define CMD_ROOT_GET_FEATURE				0x01
#define CMD_ROOT_GET_PROTOCOL_VERSION			0x11

static int hidpp_root_get_feature(struct hidpp_device *hidpp, u16 feature,
	u8 *feature_index, u8 *feature_type)
{
	struct hidpp_report response;
	int ret;
	u8 params[2] = { feature >> 8, feature & 0x00FF };

	ret = hidpp_send_fap_command_sync(hidpp,
			HIDPP_PAGE_ROOT_IDX,
			CMD_ROOT_GET_FEATURE,
			params, 2, &response);
	if (ret)
		return ret;

	*feature_index = response.fap.params[0];
	*feature_type = response.fap.params[1];

	return ret;
}

static int hidpp_root_get_protocol_version(struct hidpp_device *hidpp)
{
	const u8 ping_byte = 0x5a;
	u8 ping_data[3] = { 0, 0, ping_byte };
	struct hidpp_report response;
	int ret;

	ret = hidpp_send_rap_command_sync(hidpp,
			REPORT_ID_HIDPP_SHORT,
			HIDPP_PAGE_ROOT_IDX,
			CMD_ROOT_GET_PROTOCOL_VERSION,
			ping_data, sizeof(ping_data), &response);

	if (ret == HIDPP_ERROR_INVALID_SUBID) {
		hidpp->protocol_major = 1;
		hidpp->protocol_minor = 0;
		return 0;
	}

	/* the device might not be connected */
	if (ret == HIDPP_ERROR_RESOURCE_ERROR)
		return -EIO;

	if (ret > 0) {
		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
			__func__, ret);
		return -EPROTO;
	}
	if (ret)
		return ret;

	if (response.rap.params[2] != ping_byte) {
		hid_err(hidpp->hid_dev, "%s: ping mismatch 0x%02x != 0x%02x\n",
			__func__, response.rap.params[2], ping_byte);
		return -EPROTO;
	}

	hidpp->protocol_major = response.rap.params[0];
	hidpp->protocol_minor = response.rap.params[1];

	return ret;
}

static bool hidpp_is_connected(struct hidpp_device *hidpp)
{
	int ret;

	ret = hidpp_root_get_protocol_version(hidpp);
	if (!ret)
		hid_dbg(hidpp->hid_dev, "HID++ %u.%u device connected.\n",
			hidpp->protocol_major, hidpp->protocol_minor);
	return ret == 0;
}

/* -------------------------------------------------------------------------- */
/* 0x0005: GetDeviceNameType                                                  */
/* -------------------------------------------------------------------------- */

#define HIDPP_PAGE_GET_DEVICE_NAME_TYPE			0x0005

#define CMD_GET_DEVICE_NAME_TYPE_GET_COUNT		0x01
#define CMD_GET_DEVICE_NAME_TYPE_GET_DEVICE_NAME	0x11
#define CMD_GET_DEVICE_NAME_TYPE_GET_TYPE		0x21

static int hidpp_devicenametype_get_count(struct hidpp_device *hidpp,
	u8 feature_index, u8 *nameLength)
{
	struct hidpp_report response;
	int ret;

	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
		CMD_GET_DEVICE_NAME_TYPE_GET_COUNT, NULL, 0, &response);

	if (ret > 0) {
		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
			__func__, ret);
		return -EPROTO;
	}
	if (ret)
		return ret;

	*nameLength = response.fap.params[0];

	return ret;
}

static int hidpp_devicenametype_get_device_name(struct hidpp_device *hidpp,
	u8 feature_index, u8 char_index, char *device_name, int len_buf)
{
	struct hidpp_report response;
	int ret, i;
	int count;

	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
		CMD_GET_DEVICE_NAME_TYPE_GET_DEVICE_NAME, &char_index, 1,
		&response);

	if (ret > 0) {
		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
			__func__, ret);
		return -EPROTO;
	}
	if (ret)
		return ret;

	switch (response.report_id) {
	case REPORT_ID_HIDPP_VERY_LONG:
		count = HIDPP_REPORT_VERY_LONG_LENGTH - 4;
		break;
	case REPORT_ID_HIDPP_LONG:
		count = HIDPP_REPORT_LONG_LENGTH - 4;
		break;
	case REPORT_ID_HIDPP_SHORT:
		count = HIDPP_REPORT_SHORT_LENGTH - 4;
		break;
	default:
		return -EPROTO;
	}

	if (len_buf < count)
		count = len_buf;

	for (i = 0; i < count; i++)
		device_name[i] = response.fap.params[i];

	return count;
}

static char *hidpp_get_device_name(struct hidpp_device *hidpp)
{
	u8 feature_type;
	u8 feature_index;
	u8 __name_length;
	char *name;
	unsigned index = 0;
	int ret;

	ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_GET_DEVICE_NAME_TYPE,
		&feature_index, &feature_type);
	if (ret)
		return NULL;

	ret = hidpp_devicenametype_get_count(hidpp, feature_index,
		&__name_length);
	if (ret)
		return NULL;

	name = kzalloc(__name_length + 1, GFP_KERNEL);
	if (!name)
		return NULL;

	while (index < __name_length) {
		ret = hidpp_devicenametype_get_device_name(hidpp,
			feature_index, index, name + index,
			__name_length - index);
		if (ret <= 0) {
			kfree(name);
			return NULL;
		}
		index += ret;
	}

	/* include the terminating '\0' */
	hidpp_prefix_name(&name, __name_length + 1);

	return name;
}

/* -------------------------------------------------------------------------- */
/* 0x6010: Touchpad FW items                                                  */
/* -------------------------------------------------------------------------- */

#define HIDPP_PAGE_TOUCHPAD_FW_ITEMS			0x6010

#define CMD_TOUCHPAD_FW_ITEMS_SET			0x10

struct hidpp_touchpad_fw_items {
	uint8_t presence;
	uint8_t desired_state;
	uint8_t state;
	uint8_t persistent;
};

/**
 * send a set state command to the device by reading the current items->state
 * field. items is then filled with the current state.
 */
static int hidpp_touchpad_fw_items_set(struct hidpp_device *hidpp,
				       u8 feature_index,
				       struct hidpp_touchpad_fw_items *items)
{
	struct hidpp_report response;
	int ret;
	u8 *params = (u8 *)response.fap.params;

	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
		CMD_TOUCHPAD_FW_ITEMS_SET, &items->state, 1, &response);

	if (ret > 0) {
		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
			__func__, ret);
		return -EPROTO;
	}
	if (ret)
		return ret;

	items->presence = params[0];
	items->desired_state = params[1];
	items->state = params[2];
	items->persistent = params[3];

	return 0;
}

/* -------------------------------------------------------------------------- */
/* 0x6100: TouchPadRawXY                                                      */
/* -------------------------------------------------------------------------- */

#define HIDPP_PAGE_TOUCHPAD_RAW_XY			0x6100

#define CMD_TOUCHPAD_GET_RAW_INFO			0x01
#define CMD_TOUCHPAD_SET_RAW_REPORT_STATE		0x21

#define EVENT_TOUCHPAD_RAW_XY				0x00

#define TOUCHPAD_RAW_XY_ORIGIN_LOWER_LEFT		0x01
#define TOUCHPAD_RAW_XY_ORIGIN_UPPER_LEFT		0x03

struct hidpp_touchpad_raw_info {
	u16 x_size;
	u16 y_size;
	u8 z_range;
	u8 area_range;
	u8 timestamp_unit;
	u8 maxcontacts;
	u8 origin;
	u16 res;
};

struct hidpp_touchpad_raw_xy_finger {
	u8 contact_type;
	u8 contact_status;
	u16 x;
	u16 y;
	u8 z;
	u8 area;
	u8 finger_id;
};

struct hidpp_touchpad_raw_xy {
	u16 timestamp;
	struct hidpp_touchpad_raw_xy_finger fingers[2];
	u8 spurious_flag;
	u8 end_of_frame;
	u8 finger_count;
	u8 button;
};

static int hidpp_touchpad_get_raw_info(struct hidpp_device *hidpp,
	u8 feature_index, struct hidpp_touchpad_raw_info *raw_info)
{
	struct hidpp_report response;
	int ret;
	u8 *params = (u8 *)response.fap.params;

	ret = hidpp_send_fap_command_sync(hidpp, feature_index,
		CMD_TOUCHPAD_GET_RAW_INFO, NULL, 0, &response);

	if (ret > 0) {
		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
			__func__, ret);
		return -EPROTO;
	}
	if (ret)
		return ret;

	raw_info->x_size = get_unaligned_be16(&params[0]);
	raw_info->y_size = get_unaligned_be16(&params[2]);
	raw_info->z_range = params[4];
	raw_info->area_range = params[5];
	raw_info->maxcontacts = params[7];
	raw_info->origin = params[8];
	/* res is given in unit per inch */
	raw_info->res = get_unaligned_be16(&params[13]) * 2 / 51;

	return ret;
}

static int hidpp_touchpad_set_raw_report_state(struct hidpp_device *hidpp_dev,
		u8 feature_index, bool send_raw_reports,
		bool sensor_enhanced_settings)
{
	struct hidpp_report response;

	/*
	 * Params:
	 *   bit 0 - enable raw
	 *   bit 1 - 16bit Z, no area
	 *   bit 2 - enhanced sensitivity
	 *   bit 3 - width, height (4 bits each) instead of area
	 *   bit 4 - send raw + gestures (degrades smoothness)
	 *   remaining bits - reserved
	 */
	u8 params = send_raw_reports | (sensor_enhanced_settings << 2);

	return hidpp_send_fap_command_sync(hidpp_dev, feature_index,
		CMD_TOUCHPAD_SET_RAW_REPORT_STATE, &params, 1, &response);
}

static void hidpp_touchpad_touch_event(u8 *data,
	struct hidpp_touchpad_raw_xy_finger *finger)
{
	u8 x_m = data[0] << 2;
	u8 y_m = data[2] << 2;

	finger->x = x_m << 6 | data[1];
	finger->y = y_m << 6 | data[3];

	finger->contact_type = data[0] >> 6;
	finger->contact_status = data[2] >> 6;

	finger->z = data[4];
	finger->area = data[5];
	finger->finger_id = data[6] >> 4;
}

static void hidpp_touchpad_raw_xy_event(struct hidpp_device *hidpp_dev,
		u8 *data, struct hidpp_touchpad_raw_xy *raw_xy)
{
	memset(raw_xy, 0, sizeof(struct hidpp_touchpad_raw_xy));
	raw_xy->end_of_frame = data[8] & 0x01;
	raw_xy->spurious_flag = (data[8] >> 1) & 0x01;
	raw_xy->finger_count = data[15] & 0x0f;
	raw_xy->button = (data[8] >> 2) & 0x01;

	if (raw_xy->finger_count) {
		hidpp_touchpad_touch_event(&data[2], &raw_xy->fingers[0]);
		hidpp_touchpad_touch_event(&data[9], &raw_xy->fingers[1]);
	}
}

/* -------------------------------------------------------------------------- */
/* 0x8123: Force feedback support                                             */
/* -------------------------------------------------------------------------- */

#define HIDPP_FF_GET_INFO		0x01
#define HIDPP_FF_RESET_ALL		0x11
#define HIDPP_FF_DOWNLOAD_EFFECT	0x21
#define HIDPP_FF_SET_EFFECT_STATE	0x31
#define HIDPP_FF_DESTROY_EFFECT		0x41
#define HIDPP_FF_GET_APERTURE		0x51
#define HIDPP_FF_SET_APERTURE		0x61
#define HIDPP_FF_GET_GLOBAL_GAINS	0x71
#define HIDPP_FF_SET_GLOBAL_GAINS	0x81

#define HIDPP_FF_EFFECT_STATE_GET	0x00
#define HIDPP_FF_EFFECT_STATE_STOP	0x01
#define HIDPP_FF_EFFECT_STATE_PLAY	0x02
#define HIDPP_FF_EFFECT_STATE_PAUSE	0x03

#define HIDPP_FF_EFFECT_CONSTANT	0x00
#define HIDPP_FF_EFFECT_PERIODIC_SINE		0x01
#define HIDPP_FF_EFFECT_PERIODIC_SQUARE		0x02
#define HIDPP_FF_EFFECT_PERIODIC_TRIANGLE	0x03
#define HIDPP_FF_EFFECT_PERIODIC_SAWTOOTHUP	0x04
#define HIDPP_FF_EFFECT_PERIODIC_SAWTOOTHDOWN	0x05
#define HIDPP_FF_EFFECT_SPRING		0x06
#define HIDPP_FF_EFFECT_DAMPER		0x07
#define HIDPP_FF_EFFECT_FRICTION	0x08
#define HIDPP_FF_EFFECT_INERTIA		0x09
#define HIDPP_FF_EFFECT_RAMP		0x0A

#define HIDPP_FF_EFFECT_AUTOSTART	0x80

#define HIDPP_FF_EFFECTID_NONE		-1
#define HIDPP_FF_EFFECTID_AUTOCENTER	-2

#define HIDPP_FF_MAX_PARAMS	20
#define HIDPP_FF_RESERVED_SLOTS	1

struct hidpp_ff_private_data {
	struct hidpp_device *hidpp;
	u8 feature_index;
	u8 version;
	u16 gain;
	s16 range;
	u8 slot_autocenter;
	u8 num_effects;
	int *effect_ids;
	struct workqueue_struct *wq;
	atomic_t workqueue_size;
};

struct hidpp_ff_work_data {
	struct work_struct work;
	struct hidpp_ff_private_data *data;
	int effect_id;
	u8 command;
	u8 params[HIDPP_FF_MAX_PARAMS];
	u8 size;
};

static const signed short hiddpp_ff_effects[] = {
	FF_CONSTANT,
	FF_PERIODIC,
	FF_SINE,
	FF_SQUARE,
	FF_SAW_UP,
	FF_SAW_DOWN,
	FF_TRIANGLE,
	FF_SPRING,
	FF_DAMPER,
	FF_AUTOCENTER,
	FF_GAIN,
	-1
};

static const signed short hiddpp_ff_effects_v2[] = {
	FF_RAMP,
	FF_FRICTION,
	FF_INERTIA,
	-1
};

static const u8 HIDPP_FF_CONDITION_CMDS[] = {
	HIDPP_FF_EFFECT_SPRING,
	HIDPP_FF_EFFECT_FRICTION,
	HIDPP_FF_EFFECT_DAMPER,
	HIDPP_FF_EFFECT_INERTIA
};

static const char *HIDPP_FF_CONDITION_NAMES[] = {
	"spring",
	"friction",
	"damper",
	"inertia"
};


static u8 hidpp_ff_find_effect(struct hidpp_ff_private_data *data, int effect_id)
{
	int i;

	for (i = 0; i < data->num_effects; i++)
		if (data->effect_ids[i] == effect_id)
			return i+1;

	return 0;
}

static void hidpp_ff_work_handler(struct work_struct *w)
{
	struct hidpp_ff_work_data *wd = container_of(w, struct hidpp_ff_work_data, work);
	struct hidpp_ff_private_data *data = wd->data;
	struct hidpp_report response;
	u8 slot;
	int ret;

	/* add slot number if needed */
	switch (wd->effect_id) {
	case HIDPP_FF_EFFECTID_AUTOCENTER:
		wd->params[0] = data->slot_autocenter;
		break;
	case HIDPP_FF_EFFECTID_NONE:
		/* leave slot as zero */
		break;
	default:
		/* find current slot for effect */
		wd->params[0] = hidpp_ff_find_effect(data, wd->effect_id);
		break;
	}

	/* send command and wait for reply */
	ret = hidpp_send_fap_command_sync(data->hidpp, data->feature_index,
		wd->command, wd->params, wd->size, &response);

	if (ret) {
		hid_err(data->hidpp->hid_dev, "Failed to send command to device!\n");
		goto out;
	}

	/* parse return data */
	switch (wd->command) {
	case HIDPP_FF_DOWNLOAD_EFFECT:
		slot = response.fap.params[0];
		if (slot > 0 && slot <= data->num_effects) {
			if (wd->effect_id >= 0)
				/* regular effect uploaded */
				data->effect_ids[slot-1] = wd->effect_id;
			else if (wd->effect_id >= HIDPP_FF_EFFECTID_AUTOCENTER)
				/* autocenter spring uploaded */
				data->slot_autocenter = slot;
		}
		break;
	case HIDPP_FF_DESTROY_EFFECT:
		if (wd->effect_id >= 0)
			/* regular effect destroyed */
			data->effect_ids[wd->params[0]-1] = -1;
		else if (wd->effect_id >= HIDPP_FF_EFFECTID_AUTOCENTER)
			/* autocenter spring destoyed */
			data->slot_autocenter = 0;
		break;
	case HIDPP_FF_SET_GLOBAL_GAINS:
		data->gain = (wd->params[0] << 8) + wd->params[1];
		break;
	case HIDPP_FF_SET_APERTURE:
		data->range = (wd->params[0] << 8) + wd->params[1];
		break;
	default:
		/* no action needed */
		break;
	}

out:
	atomic_dec(&data->workqueue_size);
	kfree(wd);
}

static int hidpp_ff_queue_work(struct hidpp_ff_private_data *data, int effect_id, u8 command, u8 *params, u8 size)
{
	struct hidpp_ff_work_data *wd = kzalloc(sizeof(*wd), GFP_KERNEL);
	int s;

	if (!wd)
		return -ENOMEM;

	INIT_WORK(&wd->work, hidpp_ff_work_handler);

	wd->data = data;
	wd->effect_id = effect_id;
	wd->command = command;
	wd->size = size;
	memcpy(wd->params, params, size);

	atomic_inc(&data->workqueue_size);
	queue_work(data->wq, &wd->work);

	/* warn about excessive queue size */
	s = atomic_read(&data->workqueue_size);
	if (s >= 20 && s % 20 == 0)
		hid_warn(data->hidpp->hid_dev, "Force feedback command queue contains %d commands, causing substantial delays!", s);

	return 0;
}

static int hidpp_ff_upload_effect(struct input_dev *dev, struct ff_effect *effect, struct ff_effect *old)
{
	struct hidpp_ff_private_data *data = dev->ff->private;
	u8 params[20];
	u8 size;
	int force;

	/* set common parameters */
	params[2] = effect->replay.length >> 8;
	params[3] = effect->replay.length & 255;
	params[4] = effect->replay.delay >> 8;
	params[5] = effect->replay.delay & 255;

	switch (effect->type) {
	case FF_CONSTANT:
		force = (effect->u.constant.level * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
		params[1] = HIDPP_FF_EFFECT_CONSTANT;
		params[6] = force >> 8;
		params[7] = force & 255;
		params[8] = effect->u.constant.envelope.attack_level >> 7;
		params[9] = effect->u.constant.envelope.attack_length >> 8;
		params[10] = effect->u.constant.envelope.attack_length & 255;
		params[11] = effect->u.constant.envelope.fade_level >> 7;
		params[12] = effect->u.constant.envelope.fade_length >> 8;
		params[13] = effect->u.constant.envelope.fade_length & 255;
		size = 14;
		dbg_hid("Uploading constant force level=%d in dir %d = %d\n",
				effect->u.constant.level,
				effect->direction, force);
		dbg_hid("          envelope attack=(%d, %d ms) fade=(%d, %d ms)\n",
				effect->u.constant.envelope.attack_level,
				effect->u.constant.envelope.attack_length,
				effect->u.constant.envelope.fade_level,
				effect->u.constant.envelope.fade_length);
		break;
	case FF_PERIODIC:
	{
		switch (effect->u.periodic.waveform) {
		case FF_SINE:
			params[1] = HIDPP_FF_EFFECT_PERIODIC_SINE;
			break;
		case FF_SQUARE:
			params[1] = HIDPP_FF_EFFECT_PERIODIC_SQUARE;
			break;
		case FF_SAW_UP:
			params[1] = HIDPP_FF_EFFECT_PERIODIC_SAWTOOTHUP;
			break;
		case FF_SAW_DOWN:
			params[1] = HIDPP_FF_EFFECT_PERIODIC_SAWTOOTHDOWN;
			break;
		case FF_TRIANGLE:
			params[1] = HIDPP_FF_EFFECT_PERIODIC_TRIANGLE;
			break;
		default:
			hid_err(data->hidpp->hid_dev, "Unexpected periodic waveform type %i!\n", effect->u.periodic.waveform);
			return -EINVAL;
		}
		force = (effect->u.periodic.magnitude * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
		params[6] = effect->u.periodic.magnitude >> 8;
		params[7] = effect->u.periodic.magnitude & 255;
		params[8] = effect->u.periodic.offset >> 8;
		params[9] = effect->u.periodic.offset & 255;
		params[10] = effect->u.periodic.period >> 8;
		params[11] = effect->u.periodic.period & 255;
		params[12] = effect->u.periodic.phase >> 8;
		params[13] = effect->u.periodic.phase & 255;
		params[14] = effect->u.periodic.envelope.attack_level >> 7;
		params[15] = effect->u.periodic.envelope.attack_length >> 8;
		params[16] = effect->u.periodic.envelope.attack_length & 255;
		params[17] = effect->u.periodic.envelope.fade_level >> 7;
		params[18] = effect->u.periodic.envelope.fade_length >> 8;
		params[19] = effect->u.periodic.envelope.fade_length & 255;
		size = 20;
		dbg_hid("Uploading periodic force mag=%d/dir=%d, offset=%d, period=%d ms, phase=%d\n",
				effect->u.periodic.magnitude, effect->direction,
				effect->u.periodic.offset,
				effect->u.periodic.period,
				effect->u.periodic.phase);
		dbg_hid("          envelope attack=(%d, %d ms) fade=(%d, %d ms)\n",
				effect->u.periodic.envelope.attack_level,
				effect->u.periodic.envelope.attack_length,
				effect->u.periodic.envelope.fade_level,
				effect->u.periodic.envelope.fade_length);
		break;
	}
	case FF_RAMP:
		params[1] = HIDPP_FF_EFFECT_RAMP;
		force = (effect->u.ramp.start_level * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
		params[6] = force >> 8;
		params[7] = force & 255;
		force = (effect->u.ramp.end_level * fixp_sin16((effect->direction * 360) >> 16)) >> 15;
		params[8] = force >> 8;
		params[9] = force & 255;
		params[10] = effect->u.ramp.envelope.attack_level >> 7;
		params[11] = effect->u.ramp.envelope.attack_length >> 8;
		params[12] = effect->u.ramp.envelope.attack_length & 255;
		params[13] = effect->u.ramp.envelope.fade_level >> 7;
		params[14] = effect->u.ramp.envelope.fade_length >> 8;
		params[15] = effect->u.ramp.envelope.fade_length & 255;
		size = 16;
		dbg_hid("Uploading ramp force level=%d -> %d in dir %d = %d\n",
				effect->u.ramp.start_level,
				effect->u.ramp.end_level,
				effect->direction, force);
		dbg_hid("          envelope attack=(%d, %d ms) fade=(%d, %d ms)\n",
				effect->u.ramp.envelope.attack_level,
				effect->u.ramp.envelope.attack_length,
				effect->u.ramp.envelope.fade_level,
				effect->u.ramp.envelope.fade_length);
		break;
	case FF_FRICTION:
	case FF_INERTIA:
	case FF_SPRING:
	case FF_DAMPER:
		params[1] = HIDPP_FF_CONDITION_CMDS[effect->type - FF_SPRING];
		params[6] = effect->u.condition[0].left_saturation >> 9;
		params[7] = (effect->u.condition[0].left_saturation >> 1) & 255;
		params[8] = effect->u.condition[0].left_coeff >> 8;
		params[9] = effect->u.condition[0].left_coeff & 255;
		params[10] = effect->u.condition[0].deadband >> 9;
		params[11] = (effect->u.condition[0].deadband >> 1) & 255;
		params[12] = effect->u.condition[0].center >> 8;
		params[13] = effect->u.condition[0].center & 255;
		params[14] = effect->u.condition[0].right_coeff >> 8;
		params[15] = effect->u.condition[0].right_coeff & 255;
		params[16] = effect->u.condition[0].right_saturation >> 9;
		params[17] = (effect->u.condition[0].right_saturation >> 1) & 255;
		size = 18;
		dbg_hid("Uploading %s force left coeff=%d, left sat=%d, right coeff=%d, right sat=%d\n",
				HIDPP_FF_CONDITION_NAMES[effect->type - FF_SPRING],
				effect->u.condition[0].left_coeff,
				effect->u.condition[0].left_saturation,
				effect->u.condition[0].right_coeff,
				effect->u.condition[0].right_saturation);
		dbg_hid("          deadband=%d, center=%d\n",
				effect->u.condition[0].deadband,
				effect->u.condition[0].center);
		break;
	default:
		hid_err(data->hidpp->hid_dev, "Unexpected force type %i!\n", effect->type);
		return -EINVAL;
	}

	return hidpp_ff_queue_work(data, effect->id, HIDPP_FF_DOWNLOAD_EFFECT, params, size);
}

static int hidpp_ff_playback(struct input_dev *dev, int effect_id, int value)
{
	struct hidpp_ff_private_data *data = dev->ff->private;
	u8 params[2];

	params[1] = value ? HIDPP_FF_EFFECT_STATE_PLAY : HIDPP_FF_EFFECT_STATE_STOP;

	dbg_hid("St%sing playback of effect %d.\n", value?"art":"opp", effect_id);

	return hidpp_ff_queue_work(data, effect_id, HIDPP_FF_SET_EFFECT_STATE, params, ARRAY_SIZE(params));
}

static int hidpp_ff_erase_effect(struct input_dev *dev, int effect_id)
{
	struct hidpp_ff_private_data *data = dev->ff->private;
	u8 slot = 0;

	dbg_hid("Erasing effect %d.\n", effect_id);

	return hidpp_ff_queue_work(data, effect_id, HIDPP_FF_DESTROY_EFFECT, &slot, 1);
}

static void hidpp_ff_set_autocenter(struct input_dev *dev, u16 magnitude)
{
	struct hidpp_ff_private_data *data = dev->ff->private;
	u8 params[18];

	dbg_hid("Setting autocenter to %d.\n", magnitude);

	/* start a standard spring effect */
	params[1] = HIDPP_FF_EFFECT_SPRING | HIDPP_FF_EFFECT_AUTOSTART;
	/* zero delay and duration */
	params[2] = params[3] = params[4] = params[5] = 0;
	/* set coeff to 25% of saturation */
	params[8] = params[14] = magnitude >> 11;
	params[9] = params[15] = (magnitude >> 3) & 255;
	params[6] = params[16] = magnitude >> 9;
	params[7] = params[17] = (magnitude >> 1) & 255;
	/* zero deadband and center */
	params[10] = params[11] = params[12] = params[13] = 0;

	hidpp_ff_queue_work(data, HIDPP_FF_EFFECTID_AUTOCENTER, HIDPP_FF_DOWNLOAD_EFFECT, params, ARRAY_SIZE(params));
}

static void hidpp_ff_set_gain(struct input_dev *dev, u16 gain)
{
	struct hidpp_ff_private_data *data = dev->ff->private;
	u8 params[4];

	dbg_hid("Setting gain to %d.\n", gain);

	params[0] = gain >> 8;
	params[1] = gain & 255;
	params[2] = 0; /* no boost */
	params[3] = 0;

	hidpp_ff_queue_work(data, HIDPP_FF_EFFECTID_NONE, HIDPP_FF_SET_GLOBAL_GAINS, params, ARRAY_SIZE(params));
}

static ssize_t hidpp_ff_range_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct hid_device *hid = to_hid_device(dev);
	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
	struct input_dev *idev = hidinput->input;
	struct hidpp_ff_private_data *data = idev->ff->private;

	return scnprintf(buf, PAGE_SIZE, "%u\n", data->range);
}

static ssize_t hidpp_ff_range_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct hid_device *hid = to_hid_device(dev);
	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
	struct input_dev *idev = hidinput->input;
	struct hidpp_ff_private_data *data = idev->ff->private;
	u8 params[2];
	int range = simple_strtoul(buf, NULL, 10);

	range = clamp(range, 180, 900);

	params[0] = range >> 8;
	params[1] = range & 0x00FF;

	hidpp_ff_queue_work(data, -1, HIDPP_FF_SET_APERTURE, params, ARRAY_SIZE(params));

	return count;
}

static DEVICE_ATTR(range, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH, hidpp_ff_range_show, hidpp_ff_range_store);

static void hidpp_ff_destroy(struct ff_device *ff)
{
	struct hidpp_ff_private_data *data = ff->private;

	kfree(data->effect_ids);
}

static int hidpp_ff_init(struct hidpp_device *hidpp, u8 feature_index)
{
	struct hid_device *hid = hidpp->hid_dev;
	struct hid_input *hidinput;
	struct input_dev *dev;
	const struct usb_device_descriptor *udesc = &(hid_to_usb_dev(hid)->descriptor);
	const u16 bcdDevice = le16_to_cpu(udesc->bcdDevice);
	struct ff_device *ff;
	struct hidpp_report response;
	struct hidpp_ff_private_data *data;
	int error, j, num_slots;
	u8 version;

	if (list_empty(&hid->inputs)) {
		hid_err(hid, "no inputs found\n");
		return -ENODEV;
	}
	hidinput = list_entry(hid->inputs.next, struct hid_input, list);
	dev = hidinput->input;

	if (!dev) {
		hid_err(hid, "Struct input_dev not set!\n");
		return -EINVAL;
	}

	/* Get firmware release */
	version = bcdDevice & 255;

	/* Set supported force feedback capabilities */
	for (j = 0; hiddpp_ff_effects[j] >= 0; j++)
		set_bit(hiddpp_ff_effects[j], dev->ffbit);
	if (version > 1)
		for (j = 0; hiddpp_ff_effects_v2[j] >= 0; j++)
			set_bit(hiddpp_ff_effects_v2[j], dev->ffbit);

	/* Read number of slots available in device */
	error = hidpp_send_fap_command_sync(hidpp, feature_index,
		HIDPP_FF_GET_INFO, NULL, 0, &response);
	if (error) {
		if (error < 0)
			return error;
		hid_err(hidpp->hid_dev, "%s: received protocol error 0x%02x\n",
			__func__, error);
		return -EPROTO;
	}

	num_slots = response.fap.params[0] - HIDPP_FF_RESERVED_SLOTS;

	error = input_ff_create(dev, num_slots);

	if (error) {
		hid_err(dev, "Failed to create FF device!\n");
		return error;
	}

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;
	data->effect_ids = kcalloc(num_slots, sizeof(int), GFP_KERNEL);
	if (!data->effect_ids) {
		kfree(data);
		return -ENOMEM;
	}
	data->wq = create_singlethread_workqueue("hidpp-ff-sendqueue");
	if (!data->wq) {
		kfree(data->effect_ids);
		kfree(data);
		return -ENOMEM;
	}

	data->hidpp = hidpp;
	data->feature_index = feature_index;
	data->version = version;
	data->slot_autocenter = 0;
	data->num_effects = num_slots;
	for (j = 0; j < num_slots; j++)
		data->effect_ids[j] = -1;

	ff = dev->ff;
	ff->private = data;

	ff->upload = hidpp_ff_upload_effect;
	ff->erase = hidpp_ff_erase_effect;
	ff->playback = hidpp_ff_playback;
	ff->set_gain = hidpp_ff_set_gain;
	ff->set_autocenter = hidpp_ff_set_autocenter;
	ff->destroy = hidpp_ff_destroy;


	/* reset all forces */
	error = hidpp_send_fap_command_sync(hidpp, feature_index,
		HIDPP_FF_RESET_ALL, NULL, 0, &response);

	/* Read current Range */
	error = hidpp_send_fap_command_sync(hidpp, feature_index,
		HIDPP_FF_GET_APERTURE, NULL, 0, &response);
	if (error)
		hid_warn(hidpp->hid_dev, "Failed to read range from device!\n");
	data->range = error ? 900 : get_unaligned_be16(&response.fap.params[0]);

	/* Create sysfs interface */
	error = device_create_file(&(hidpp->hid_dev->dev), &dev_attr_range);
	if (error)
		hid_warn(hidpp->hid_dev, "Unable to create sysfs interface for \"range\", errno %d!\n", error);

	/* Read the current gain values */
	error = hidpp_send_fap_command_sync(hidpp, feature_index,
		HIDPP_FF_GET_GLOBAL_GAINS, NULL, 0, &response);
	if (error)
		hid_warn(hidpp->hid_dev, "Failed to read gain values from device!\n");
	data->gain = error ? 0xffff : get_unaligned_be16(&response.fap.params[0]);
	/* ignore boost value at response.fap.params[2] */

	/* init the hardware command queue */
	atomic_set(&data->workqueue_size, 0);

	/* initialize with zero autocenter to get wheel in usable state */
	hidpp_ff_set_autocenter(dev, 0);

	hid_info(hid, "Force feeback support loaded (firmware release %d).\n", version);

	return 0;
}

static int hidpp_ff_deinit(struct hid_device *hid)
{
	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
	struct input_dev *dev = hidinput->input;
	struct hidpp_ff_private_data *data;

	if (!dev) {
		hid_err(hid, "Struct input_dev not found!\n");
		return -EINVAL;
	}

	hid_info(hid, "Unloading HID++ force feedback.\n");
	data = dev->ff->private;
	if (!data) {
		hid_err(hid, "Private data not found!\n");
		return -EINVAL;
	}

	destroy_workqueue(data->wq);
	device_remove_file(&hid->dev, &dev_attr_range);

	return 0;
}


/* ************************************************************************** */
/*                                                                            */
/* Device Support                                                             */
/*                                                                            */
/* ************************************************************************** */

/* -------------------------------------------------------------------------- */
/* Touchpad HID++ devices                                                     */
/* -------------------------------------------------------------------------- */

#define WTP_MANUAL_RESOLUTION				39

struct wtp_data {
	struct input_dev *input;
	u16 x_size, y_size;
	u8 finger_count;
	u8 mt_feature_index;
	u8 button_feature_index;
	u8 maxcontacts;
	bool flip_y;
	unsigned int resolution;
};

static int wtp_input_mapping(struct hid_device *hdev, struct hid_input *hi,
		struct hid_field *field, struct hid_usage *usage,
		unsigned long **bit, int *max)
{
	return -1;
}

static void wtp_populate_input(struct hidpp_device *hidpp,
		struct input_dev *input_dev, bool origin_is_hid_core)
{
	struct wtp_data *wd = hidpp->private_data;

	__set_bit(EV_ABS, input_dev->evbit);
	__set_bit(EV_KEY, input_dev->evbit);
	__clear_bit(EV_REL, input_dev->evbit);
	__clear_bit(EV_LED, input_dev->evbit);

	input_set_abs_params(input_dev, ABS_MT_POSITION_X, 0, wd->x_size, 0, 0);
	input_abs_set_res(input_dev, ABS_MT_POSITION_X, wd->resolution);
	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, 0, wd->y_size, 0, 0);
	input_abs_set_res(input_dev, ABS_MT_POSITION_Y, wd->resolution);

	/* Max pressure is not given by the devices, pick one */
	input_set_abs_params(input_dev, ABS_MT_PRESSURE, 0, 50, 0, 0);

	input_set_capability(input_dev, EV_KEY, BTN_LEFT);

	if (hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS)
		input_set_capability(input_dev, EV_KEY, BTN_RIGHT);
	else
		__set_bit(INPUT_PROP_BUTTONPAD, input_dev->propbit);

	input_mt_init_slots(input_dev, wd->maxcontacts, INPUT_MT_POINTER |
		INPUT_MT_DROP_UNUSED);

	wd->input = input_dev;
}

static void wtp_touch_event(struct wtp_data *wd,
	struct hidpp_touchpad_raw_xy_finger *touch_report)
{
	int slot;

	if (!touch_report->finger_id || touch_report->contact_type)
		/* no actual data */
		return;

	slot = input_mt_get_slot_by_key(wd->input, touch_report->finger_id);

	input_mt_slot(wd->input, slot);
	input_mt_report_slot_state(wd->input, MT_TOOL_FINGER,
					touch_report->contact_status);
	if (touch_report->contact_status) {
		input_event(wd->input, EV_ABS, ABS_MT_POSITION_X,
				touch_report->x);
		input_event(wd->input, EV_ABS, ABS_MT_POSITION_Y,
				wd->flip_y ? wd->y_size - touch_report->y :
					     touch_report->y);
		input_event(wd->input, EV_ABS, ABS_MT_PRESSURE,
				touch_report->area);
	}
}

static void wtp_send_raw_xy_event(struct hidpp_device *hidpp,
		struct hidpp_touchpad_raw_xy *raw)
{
	struct wtp_data *wd = hidpp->private_data;
	int i;

	for (i = 0; i < 2; i++)
		wtp_touch_event(wd, &(raw->fingers[i]));

	if (raw->end_of_frame &&
	    !(hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS))
		input_event(wd->input, EV_KEY, BTN_LEFT, raw->button);

	if (raw->end_of_frame || raw->finger_count <= 2) {
		input_mt_sync_frame(wd->input);
		input_sync(wd->input);
	}
}

static int wtp_mouse_raw_xy_event(struct hidpp_device *hidpp, u8 *data)
{
	struct wtp_data *wd = hidpp->private_data;
	u8 c1_area = ((data[7] & 0xf) * (data[7] & 0xf) +
		      (data[7] >> 4) * (data[7] >> 4)) / 2;
	u8 c2_area = ((data[13] & 0xf) * (data[13] & 0xf) +
		      (data[13] >> 4) * (data[13] >> 4)) / 2;
	struct hidpp_touchpad_raw_xy raw = {
		.timestamp = data[1],
		.fingers = {
			{
				.contact_type = 0,
				.contact_status = !!data[7],
				.x = get_unaligned_le16(&data[3]),
				.y = get_unaligned_le16(&data[5]),
				.z = c1_area,
				.area = c1_area,
				.finger_id = data[2],
			}, {
				.contact_type = 0,
				.contact_status = !!data[13],
				.x = get_unaligned_le16(&data[9]),
				.y = get_unaligned_le16(&data[11]),
				.z = c2_area,
				.area = c2_area,
				.finger_id = data[8],
			}
		},
		.finger_count = wd->maxcontacts,
		.spurious_flag = 0,
		.end_of_frame = (data[0] >> 7) == 0,
		.button = data[0] & 0x01,
	};

	wtp_send_raw_xy_event(hidpp, &raw);

	return 1;
}

static int wtp_raw_event(struct hid_device *hdev, u8 *data, int size)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct wtp_data *wd = hidpp->private_data;
	struct hidpp_report *report = (struct hidpp_report *)data;
	struct hidpp_touchpad_raw_xy raw;

	if (!wd || !wd->input)
		return 1;

	switch (data[0]) {
	case 0x02:
		if (size < 2) {
			hid_err(hdev, "Received HID report of bad size (%d)",
				size);
			return 1;
		}
		if (hidpp->quirks & HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS) {
			input_event(wd->input, EV_KEY, BTN_LEFT,
					!!(data[1] & 0x01));
			input_event(wd->input, EV_KEY, BTN_RIGHT,
					!!(data[1] & 0x02));
			input_sync(wd->input);
			return 0;
		} else {
			if (size < 21)
				return 1;
			return wtp_mouse_raw_xy_event(hidpp, &data[7]);
		}
	case REPORT_ID_HIDPP_LONG:
		/* size is already checked in hidpp_raw_event. */
		if ((report->fap.feature_index != wd->mt_feature_index) ||
		    (report->fap.funcindex_clientid != EVENT_TOUCHPAD_RAW_XY))
			return 1;
		hidpp_touchpad_raw_xy_event(hidpp, data + 4, &raw);

		wtp_send_raw_xy_event(hidpp, &raw);
		return 0;
	}

	return 0;
}

static int wtp_get_config(struct hidpp_device *hidpp)
{
	struct wtp_data *wd = hidpp->private_data;
	struct hidpp_touchpad_raw_info raw_info = {0};
	u8 feature_type;
	int ret;

	ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_TOUCHPAD_RAW_XY,
		&wd->mt_feature_index, &feature_type);
	if (ret)
		/* means that the device is not powered up */
		return ret;

	ret = hidpp_touchpad_get_raw_info(hidpp, wd->mt_feature_index,
		&raw_info);
	if (ret)
		return ret;

	wd->x_size = raw_info.x_size;
	wd->y_size = raw_info.y_size;
	wd->maxcontacts = raw_info.maxcontacts;
	wd->flip_y = raw_info.origin == TOUCHPAD_RAW_XY_ORIGIN_LOWER_LEFT;
	wd->resolution = raw_info.res;
	if (!wd->resolution)
		wd->resolution = WTP_MANUAL_RESOLUTION;

	return 0;
}

static int wtp_allocate(struct hid_device *hdev, const struct hid_device_id *id)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct wtp_data *wd;

	wd = devm_kzalloc(&hdev->dev, sizeof(struct wtp_data),
			GFP_KERNEL);
	if (!wd)
		return -ENOMEM;

	hidpp->private_data = wd;

	return 0;
};

static int wtp_connect(struct hid_device *hdev, bool connected)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct wtp_data *wd = hidpp->private_data;
	int ret;

	if (!connected)
		return 0;

	if (!wd->x_size) {
		ret = wtp_get_config(hidpp);
		if (ret) {
			hid_err(hdev, "Can not get wtp config: %d\n", ret);
			return ret;
		}
	}

	return hidpp_touchpad_set_raw_report_state(hidpp, wd->mt_feature_index,
			true, true);
}

/* ------------------------------------------------------------------------- */
/* Logitech M560 devices                                                     */
/* ------------------------------------------------------------------------- */

/*
 * Logitech M560 protocol overview
 *
 * The Logitech M560 mouse, is designed for windows 8. When the middle and/or
 * the sides buttons are pressed, it sends some keyboard keys events
 * instead of buttons ones.
 * To complicate things further, the middle button keys sequence
 * is different from the odd press and the even press.
 *
 * forward button -> Super_R
 * backward button -> Super_L+'d' (press only)
 * middle button -> 1st time: Alt_L+SuperL+XF86TouchpadOff (press only)
 *                  2nd time: left-click (press only)
 * NB: press-only means that when the button is pressed, the
 * KeyPress/ButtonPress and KeyRelease/ButtonRelease events are generated
 * together sequentially; instead when the button is released, no event is
 * generated !
 *
 * With the command
 *	10<xx>0a 3500af03 (where <xx> is the mouse id),
 * the mouse reacts differently:
 * - it never sends a keyboard key event
 * - for the three mouse button it sends:
 *	middle button               press   11<xx>0a 3500af00...
 *	side 1 button (forward)     press   11<xx>0a 3500b000...
 *	side 2 button (backward)    press   11<xx>0a 3500ae00...
 *	middle/side1/side2 button   release 11<xx>0a 35000000...
 */

static const u8 m560_config_parameter[] = {0x00, 0xaf, 0x03};

struct m560_private_data {
	struct input_dev *input;
};

/* how buttons are mapped in the report */
#define M560_MOUSE_BTN_LEFT		0x01
#define M560_MOUSE_BTN_RIGHT		0x02
#define M560_MOUSE_BTN_WHEEL_LEFT	0x08
#define M560_MOUSE_BTN_WHEEL_RIGHT	0x10

#define M560_SUB_ID			0x0a
#define M560_BUTTON_MODE_REGISTER	0x35

static int m560_send_config_command(struct hid_device *hdev, bool connected)
{
	struct hidpp_report response;
	struct hidpp_device *hidpp_dev;

	hidpp_dev = hid_get_drvdata(hdev);

	if (!connected)
		return -ENODEV;

	return hidpp_send_rap_command_sync(
		hidpp_dev,
		REPORT_ID_HIDPP_SHORT,
		M560_SUB_ID,
		M560_BUTTON_MODE_REGISTER,
		(u8 *)m560_config_parameter,
		sizeof(m560_config_parameter),
		&response
	);
}

static int m560_allocate(struct hid_device *hdev)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct m560_private_data *d;

	d = devm_kzalloc(&hdev->dev, sizeof(struct m560_private_data),
			GFP_KERNEL);
	if (!d)
		return -ENOMEM;

	hidpp->private_data = d;

	return 0;
};

static int m560_raw_event(struct hid_device *hdev, u8 *data, int size)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct m560_private_data *mydata = hidpp->private_data;

	/* sanity check */
	if (!mydata || !mydata->input) {
		hid_err(hdev, "error in parameter\n");
		return -EINVAL;
	}

	if (size < 7) {
		hid_err(hdev, "error in report\n");
		return 0;
	}

	if (data[0] == REPORT_ID_HIDPP_LONG &&
	    data[2] == M560_SUB_ID && data[6] == 0x00) {
		/*
		 * m560 mouse report for middle, forward and backward button
		 *
		 * data[0] = 0x11
		 * data[1] = device-id
		 * data[2] = 0x0a
		 * data[5] = 0xaf -> middle
		 *	     0xb0 -> forward
		 *	     0xae -> backward
		 *	     0x00 -> release all
		 * data[6] = 0x00
		 */

		switch (data[5]) {
		case 0xaf:
			input_report_key(mydata->input, BTN_MIDDLE, 1);
			break;
		case 0xb0:
			input_report_key(mydata->input, BTN_FORWARD, 1);
			break;
		case 0xae:
			input_report_key(mydata->input, BTN_BACK, 1);
			break;
		case 0x00:
			input_report_key(mydata->input, BTN_BACK, 0);
			input_report_key(mydata->input, BTN_FORWARD, 0);
			input_report_key(mydata->input, BTN_MIDDLE, 0);
			break;
		default:
			hid_err(hdev, "error in report\n");
			return 0;
		}
		input_sync(mydata->input);

	} else if (data[0] == 0x02) {
		/*
		 * Logitech M560 mouse report
		 *
		 * data[0] = type (0x02)
		 * data[1..2] = buttons
		 * data[3..5] = xy
		 * data[6] = wheel
		 */

		int v;

		input_report_key(mydata->input, BTN_LEFT,
			!!(data[1] & M560_MOUSE_BTN_LEFT));
		input_report_key(mydata->input, BTN_RIGHT,
			!!(data[1] & M560_MOUSE_BTN_RIGHT));

		if (data[1] & M560_MOUSE_BTN_WHEEL_LEFT)
			input_report_rel(mydata->input, REL_HWHEEL, -1);
		else if (data[1] & M560_MOUSE_BTN_WHEEL_RIGHT)
			input_report_rel(mydata->input, REL_HWHEEL, 1);

		v = hid_snto32(hid_field_extract(hdev, data+3, 0, 12), 12);
		input_report_rel(mydata->input, REL_X, v);

		v = hid_snto32(hid_field_extract(hdev, data+3, 12, 12), 12);
		input_report_rel(mydata->input, REL_Y, v);

		v = hid_snto32(data[6], 8);
		input_report_rel(mydata->input, REL_WHEEL, v);

		input_sync(mydata->input);
	}

	return 1;
}

static void m560_populate_input(struct hidpp_device *hidpp,
		struct input_dev *input_dev, bool origin_is_hid_core)
{
	struct m560_private_data *mydata = hidpp->private_data;

	mydata->input = input_dev;

	__set_bit(EV_KEY, mydata->input->evbit);
	__set_bit(BTN_MIDDLE, mydata->input->keybit);
	__set_bit(BTN_RIGHT, mydata->input->keybit);
	__set_bit(BTN_LEFT, mydata->input->keybit);
	__set_bit(BTN_BACK, mydata->input->keybit);
	__set_bit(BTN_FORWARD, mydata->input->keybit);

	__set_bit(EV_REL, mydata->input->evbit);
	__set_bit(REL_X, mydata->input->relbit);
	__set_bit(REL_Y, mydata->input->relbit);
	__set_bit(REL_WHEEL, mydata->input->relbit);
	__set_bit(REL_HWHEEL, mydata->input->relbit);
}

static int m560_input_mapping(struct hid_device *hdev, struct hid_input *hi,
		struct hid_field *field, struct hid_usage *usage,
		unsigned long **bit, int *max)
{
	return -1;
}

/* ------------------------------------------------------------------------- */
/* Logitech K400 devices                                                     */
/* ------------------------------------------------------------------------- */

/*
 * The Logitech K400 keyboard has an embedded touchpad which is seen
 * as a mouse from the OS point of view. There is a hardware shortcut to disable
 * tap-to-click but the setting is not remembered accross reset, annoying some
 * users.
 *
 * We can toggle this feature from the host by using the feature 0x6010:
 * Touchpad FW items
 */

struct k400_private_data {
	u8 feature_index;
};

static int k400_disable_tap_to_click(struct hidpp_device *hidpp)
{
	struct k400_private_data *k400 = hidpp->private_data;
	struct hidpp_touchpad_fw_items items = {};
	int ret;
	u8 feature_type;

	if (!k400->feature_index) {
		ret = hidpp_root_get_feature(hidpp,
			HIDPP_PAGE_TOUCHPAD_FW_ITEMS,
			&k400->feature_index, &feature_type);
		if (ret)
			/* means that the device is not powered up */
			return ret;
	}

	ret = hidpp_touchpad_fw_items_set(hidpp, k400->feature_index, &items);
	if (ret)
		return ret;

	return 0;
}

static int k400_allocate(struct hid_device *hdev)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct k400_private_data *k400;

	k400 = devm_kzalloc(&hdev->dev, sizeof(struct k400_private_data),
			    GFP_KERNEL);
	if (!k400)
		return -ENOMEM;

	hidpp->private_data = k400;

	return 0;
};

static int k400_connect(struct hid_device *hdev, bool connected)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);

	if (!connected)
		return 0;

	if (!disable_tap_to_click)
		return 0;

	return k400_disable_tap_to_click(hidpp);
}

/* ------------------------------------------------------------------------- */
/* Logitech G920 Driving Force Racing Wheel for Xbox One                     */
/* ------------------------------------------------------------------------- */

#define HIDPP_PAGE_G920_FORCE_FEEDBACK			0x8123

static int g920_get_config(struct hidpp_device *hidpp)
{
	u8 feature_type;
	u8 feature_index;
	int ret;

	/* Find feature and store for later use */
	ret = hidpp_root_get_feature(hidpp, HIDPP_PAGE_G920_FORCE_FEEDBACK,
		&feature_index, &feature_type);
	if (ret)
		return ret;

	ret = hidpp_ff_init(hidpp, feature_index);
	if (ret)
		hid_warn(hidpp->hid_dev, "Unable to initialize force feedback support, errno %d\n",
				ret);

	return 0;
}

/* -------------------------------------------------------------------------- */
/* Generic HID++ devices                                                      */
/* -------------------------------------------------------------------------- */

static int hidpp_input_mapping(struct hid_device *hdev, struct hid_input *hi,
		struct hid_field *field, struct hid_usage *usage,
		unsigned long **bit, int *max)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);

	if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)
		return wtp_input_mapping(hdev, hi, field, usage, bit, max);
	else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560 &&
			field->application != HID_GD_MOUSE)
		return m560_input_mapping(hdev, hi, field, usage, bit, max);

	return 0;
}

static int hidpp_input_mapped(struct hid_device *hdev, struct hid_input *hi,
		struct hid_field *field, struct hid_usage *usage,
		unsigned long **bit, int *max)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);

	/* Ensure that Logitech G920 is not given a default fuzz/flat value */
	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
		if (usage->type == EV_ABS && (usage->code == ABS_X ||
				usage->code == ABS_Y || usage->code == ABS_Z ||
				usage->code == ABS_RZ)) {
			field->application = HID_GD_MULTIAXIS;
		}
	}

	return 0;
}


static void hidpp_populate_input(struct hidpp_device *hidpp,
		struct input_dev *input, bool origin_is_hid_core)
{
	if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)
		wtp_populate_input(hidpp, input, origin_is_hid_core);
	else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560)
		m560_populate_input(hidpp, input, origin_is_hid_core);
}

static int hidpp_input_configured(struct hid_device *hdev,
				struct hid_input *hidinput)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	struct input_dev *input = hidinput->input;

	hidpp_populate_input(hidpp, input, true);

	return 0;
}

static int hidpp_raw_hidpp_event(struct hidpp_device *hidpp, u8 *data,
		int size)
{
	struct hidpp_report *question = hidpp->send_receive_buf;
	struct hidpp_report *answer = hidpp->send_receive_buf;
	struct hidpp_report *report = (struct hidpp_report *)data;

	/*
	 * If the mutex is locked then we have a pending answer from a
	 * previously sent command.
	 */
	if (unlikely(mutex_is_locked(&hidpp->send_mutex))) {
		/*
		 * Check for a correct hidpp20 answer or the corresponding
		 * error
		 */
		if (hidpp_match_answer(question, report) ||
				hidpp_match_error(question, report)) {
			*answer = *report;
			hidpp->answer_available = true;
			wake_up(&hidpp->wait);
			/*
			 * This was an answer to a command that this driver sent
			 * We return 1 to hid-core to avoid forwarding the
			 * command upstream as it has been treated by the driver
			 */

			return 1;
		}
	}

	if (unlikely(hidpp_report_is_connect_event(report))) {
		atomic_set(&hidpp->connected,
				!(report->rap.params[0] & (1 << 6)));
		if ((hidpp->quirks & HIDPP_QUIRK_CONNECT_EVENTS) &&
		    (schedule_work(&hidpp->work) == 0))
			dbg_hid("%s: connect event already queued\n", __func__);
		return 1;
	}

	return 0;
}

static int hidpp_raw_event(struct hid_device *hdev, struct hid_report *report,
		u8 *data, int size)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	int ret = 0;

	/* Generic HID++ processing. */
	switch (data[0]) {
	case REPORT_ID_HIDPP_VERY_LONG:
		if (size != HIDPP_REPORT_VERY_LONG_LENGTH) {
			hid_err(hdev, "received hid++ report of bad size (%d)",
				size);
			return 1;
		}
		ret = hidpp_raw_hidpp_event(hidpp, data, size);
		break;
	case REPORT_ID_HIDPP_LONG:
		if (size != HIDPP_REPORT_LONG_LENGTH) {
			hid_err(hdev, "received hid++ report of bad size (%d)",
				size);
			return 1;
		}
		ret = hidpp_raw_hidpp_event(hidpp, data, size);
		break;
	case REPORT_ID_HIDPP_SHORT:
		if (size != HIDPP_REPORT_SHORT_LENGTH) {
			hid_err(hdev, "received hid++ report of bad size (%d)",
				size);
			return 1;
		}
		ret = hidpp_raw_hidpp_event(hidpp, data, size);
		break;
	}

	/* If no report is available for further processing, skip calling
	 * raw_event of subclasses. */
	if (ret != 0)
		return ret;

	if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)
		return wtp_raw_event(hdev, data, size);
	else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560)
		return m560_raw_event(hdev, data, size);

	return 0;
}

static void hidpp_overwrite_name(struct hid_device *hdev, bool use_unifying)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);
	char *name;

	if (use_unifying)
		/*
		 * the device is connected through an Unifying receiver, and
		 * might not be already connected.
		 * Ask the receiver for its name.
		 */
		name = hidpp_get_unifying_name(hidpp);
	else
		name = hidpp_get_device_name(hidpp);

	if (!name) {
		hid_err(hdev, "unable to retrieve the name of the device");
	} else {
		dbg_hid("HID++: Got name: %s\n", name);
		snprintf(hdev->name, sizeof(hdev->name), "%s", name);
	}

	kfree(name);
}

static int hidpp_input_open(struct input_dev *dev)
{
	struct hid_device *hid = input_get_drvdata(dev);

	return hid_hw_open(hid);
}

static void hidpp_input_close(struct input_dev *dev)
{
	struct hid_device *hid = input_get_drvdata(dev);

	hid_hw_close(hid);
}

static struct input_dev *hidpp_allocate_input(struct hid_device *hdev)
{
	struct input_dev *input_dev = devm_input_allocate_device(&hdev->dev);
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);

	if (!input_dev)
		return NULL;

	input_set_drvdata(input_dev, hdev);
	input_dev->open = hidpp_input_open;
	input_dev->close = hidpp_input_close;

	input_dev->name = hidpp->name;
	input_dev->phys = hdev->phys;
	input_dev->uniq = hdev->uniq;
	input_dev->id.bustype = hdev->bus;
	input_dev->id.vendor  = hdev->vendor;
	input_dev->id.product = hdev->product;
	input_dev->id.version = hdev->version;
	input_dev->dev.parent = &hdev->dev;

	return input_dev;
}

static void hidpp_connect_event(struct hidpp_device *hidpp)
{
	struct hid_device *hdev = hidpp->hid_dev;
	int ret = 0;
	bool connected = atomic_read(&hidpp->connected);
	struct input_dev *input;
	char *name, *devm_name;

	if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) {
		ret = wtp_connect(hdev, connected);
		if (ret)
			return;
	} else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560) {
		ret = m560_send_config_command(hdev, connected);
		if (ret)
			return;
	} else if (hidpp->quirks & HIDPP_QUIRK_CLASS_K400) {
		ret = k400_connect(hdev, connected);
		if (ret)
			return;
	}

	if (!connected || hidpp->delayed_input)
		return;

	/* the device is already connected, we can ask for its name and
	 * protocol */
	if (!hidpp->protocol_major) {
		ret = !hidpp_is_connected(hidpp);
		if (ret) {
			hid_err(hdev, "Can not get the protocol version.\n");
			return;
		}
		hid_info(hdev, "HID++ %u.%u device connected.\n",
			 hidpp->protocol_major, hidpp->protocol_minor);
	}

	if (!(hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT))
		/* if HID created the input nodes for us, we can stop now */
		return;

	if (!hidpp->name || hidpp->name == hdev->name) {
		name = hidpp_get_device_name(hidpp);
		if (!name) {
			hid_err(hdev,
				"unable to retrieve the name of the device");
			return;
		}

		devm_name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "%s", name);
		kfree(name);
		if (!devm_name)
			return;

		hidpp->name = devm_name;
	}

	input = hidpp_allocate_input(hdev);
	if (!input) {
		hid_err(hdev, "cannot allocate new input device: %d\n", ret);
		return;
	}

	hidpp_populate_input(hidpp, input, false);

	ret = input_register_device(input);
	if (ret)
		input_free_device(input);

	hidpp->delayed_input = input;
}

static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
	struct hidpp_device *hidpp;
	int ret;
	bool connected;
	unsigned int connect_mask = HID_CONNECT_DEFAULT;

	hidpp = devm_kzalloc(&hdev->dev, sizeof(struct hidpp_device),
			GFP_KERNEL);
	if (!hidpp)
		return -ENOMEM;

	hidpp->hid_dev = hdev;
	hidpp->name = hdev->name;
	hid_set_drvdata(hdev, hidpp);

	hidpp->quirks = id->driver_data;

	if (disable_raw_mode) {
		hidpp->quirks &= ~HIDPP_QUIRK_CLASS_WTP;
		hidpp->quirks &= ~HIDPP_QUIRK_CONNECT_EVENTS;
		hidpp->quirks &= ~HIDPP_QUIRK_NO_HIDINPUT;
	}

	if (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP) {
		ret = wtp_allocate(hdev, id);
		if (ret)
			goto allocate_fail;
	} else if (hidpp->quirks & HIDPP_QUIRK_CLASS_M560) {
		ret = m560_allocate(hdev);
		if (ret)
			goto allocate_fail;
	} else if (hidpp->quirks & HIDPP_QUIRK_CLASS_K400) {
		ret = k400_allocate(hdev);
		if (ret)
			goto allocate_fail;
	}

	INIT_WORK(&hidpp->work, delayed_work_cb);
	mutex_init(&hidpp->send_mutex);
	init_waitqueue_head(&hidpp->wait);

	ret = hid_parse(hdev);
	if (ret) {
		hid_err(hdev, "%s:parse failed\n", __func__);
		goto hid_parse_fail;
	}

	if (hidpp->quirks & HIDPP_QUIRK_NO_HIDINPUT)
		connect_mask &= ~HID_CONNECT_HIDINPUT;

	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
		ret = hid_hw_start(hdev, connect_mask);
		if (ret) {
			hid_err(hdev, "hw start failed\n");
			goto hid_hw_start_fail;
		}
		ret = hid_hw_open(hdev);
		if (ret < 0) {
			dev_err(&hdev->dev, "%s:hid_hw_open returned error:%d\n",
				__func__, ret);
			hid_hw_stop(hdev);
			goto hid_hw_start_fail;
		}
	}


	/* Allow incoming packets */
	hid_device_io_start(hdev);

	connected = hidpp_is_connected(hidpp);
	if (id->group != HID_GROUP_LOGITECH_DJ_DEVICE) {
		if (!connected) {
			ret = -ENODEV;
			hid_err(hdev, "Device not connected");
			goto hid_hw_open_failed;
		}

		hid_info(hdev, "HID++ %u.%u device connected.\n",
			 hidpp->protocol_major, hidpp->protocol_minor);
	}

	hidpp_overwrite_name(hdev, id->group == HID_GROUP_LOGITECH_DJ_DEVICE);
	atomic_set(&hidpp->connected, connected);

	if (connected && (hidpp->quirks & HIDPP_QUIRK_CLASS_WTP)) {
		ret = wtp_get_config(hidpp);
		if (ret)
			goto hid_hw_open_failed;
	} else if (connected && (hidpp->quirks & HIDPP_QUIRK_CLASS_G920)) {
		ret = g920_get_config(hidpp);
		if (ret)
			goto hid_hw_open_failed;
	}

	/* Block incoming packets */
	hid_device_io_stop(hdev);

	if (!(hidpp->quirks & HIDPP_QUIRK_CLASS_G920)) {
		ret = hid_hw_start(hdev, connect_mask);
		if (ret) {
			hid_err(hdev, "%s:hid_hw_start returned error\n", __func__);
			goto hid_hw_start_fail;
		}
	}

	if (hidpp->quirks & HIDPP_QUIRK_CONNECT_EVENTS) {
		/* Allow incoming packets */
		hid_device_io_start(hdev);

		hidpp_connect_event(hidpp);
	}

	return ret;

hid_hw_open_failed:
	hid_device_io_stop(hdev);
	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
		hid_hw_close(hdev);
		hid_hw_stop(hdev);
	}
hid_hw_start_fail:
hid_parse_fail:
	cancel_work_sync(&hidpp->work);
	mutex_destroy(&hidpp->send_mutex);
allocate_fail:
	hid_set_drvdata(hdev, NULL);
	return ret;
}

static void hidpp_remove(struct hid_device *hdev)
{
	struct hidpp_device *hidpp = hid_get_drvdata(hdev);

	if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
		hidpp_ff_deinit(hdev);
		hid_hw_close(hdev);
	}
	hid_hw_stop(hdev);
	cancel_work_sync(&hidpp->work);
	mutex_destroy(&hidpp->send_mutex);
}

static const struct hid_device_id hidpp_devices[] = {
	{ /* wireless touchpad */
	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
		USB_VENDOR_ID_LOGITECH, 0x4011),
	  .driver_data = HIDPP_QUIRK_CLASS_WTP | HIDPP_QUIRK_DELAYED_INIT |
			 HIDPP_QUIRK_WTP_PHYSICAL_BUTTONS },
	{ /* wireless touchpad T650 */
	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
		USB_VENDOR_ID_LOGITECH, 0x4101),
	  .driver_data = HIDPP_QUIRK_CLASS_WTP | HIDPP_QUIRK_DELAYED_INIT },
	{ /* wireless touchpad T651 */
	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH,
		USB_DEVICE_ID_LOGITECH_T651),
	  .driver_data = HIDPP_QUIRK_CLASS_WTP },
	{ /* Mouse logitech M560 */
	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
		USB_VENDOR_ID_LOGITECH, 0x402d),
	  .driver_data = HIDPP_QUIRK_DELAYED_INIT | HIDPP_QUIRK_CLASS_M560 },
	{ /* Keyboard logitech K400 */
	  HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
		USB_VENDOR_ID_LOGITECH, 0x4024),
	  .driver_data = HIDPP_QUIRK_CONNECT_EVENTS | HIDPP_QUIRK_CLASS_K400 },

	{ HID_DEVICE(BUS_USB, HID_GROUP_LOGITECH_DJ_DEVICE,
		USB_VENDOR_ID_LOGITECH, HID_ANY_ID)},

	{ HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_LOGITECH_G920_WHEEL),
		.driver_data = HIDPP_QUIRK_CLASS_G920 | HIDPP_QUIRK_FORCE_OUTPUT_REPORTS},
	{}
};

MODULE_DEVICE_TABLE(hid, hidpp_devices);

static struct hid_driver hidpp_driver = {
	.name = "logitech-hidpp-device",
	.id_table = hidpp_devices,
	.probe = hidpp_probe,
	.remove = hidpp_remove,
	.raw_event = hidpp_raw_event,
	.input_configured = hidpp_input_configured,
	.input_mapping = hidpp_input_mapping,
	.input_mapped = hidpp_input_mapped,
};

module_hid_driver(hidpp_driver);