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/*
* Generic HID++ definitions and helpers.
*
* Copyright (C) 2014 Peter Wu <peter@lekensteyn.nl>
*
* 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, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef HIDPP_H
#define HIDPP_H
#include <stdbool.h>
#include <stdint.h>
#define MAX_DEVICES 6
/* report ID for short and long HID++ messages */
#define HIDPP_SHORT 0x10
#define HIDPP_SHORT_LEN 7
#define HIDPP_LONG 0x11
#define HIDPP_LONG_LEN 20
typedef struct HidppMessage {
uint8_t report_id;
uint8_t device_index;
union {
struct {
uint8_t sub_id;
uint8_t address;
}; /**< HID++ 1.0 naming */
struct {
uint8_t feature_id;
uint8_t func; /* (func << 4) | swId */
}; /**< HID++ 2.0 naming */
};
union {
uint8_t params[3];
uint8_t params_l[16];
};
} HidppMessage;
/**
* Locates a /dev/hidrawX device for a Logitech Unifying receiver.
*
* @return A file descriptor to the hidraw device which must be closed with
* close().
*/
int hidpp_open(void);
/**
* Callback function for new messages.
*
* @param msg[in] An incoming HID++ message.
* @param userdata Data passed through the invoker.
* @return true iff the no more messages should be read.
*/
typedef bool hidpp_msg_cb_t(HidppMessage *msg, void *userdata);
/**
* Sends the message to the receiver device.
*
* @param fd File descriptor of the hidraw device.
* @param msg[in] The report to be delivered.
* @return true iff the message is properly formatted and the dispatch is
* successful.
*/
bool hidpp_write_report(int fd, HidppMessage *msg);
/**
* Reads messages and try to accept on one of them.
*
* @param fd File descriptor of the hidraw device.
* @param timeout Timeout for this function in milliseconds.
* @param msg[out] On success, the message is written to this pointer.
* Otherwise, the contents are unmodified.
* @param cb Function that should be called for new HID++ messages.
* If true is returned, then no more messages are read. msg is
* not allowed to be modified if the callback returns false.
* @param userdata Data that is passed unchanged to the callback function.
* @return true iff there exists a message that was accepted by the callback
* function within the timeout.
*/
bool hidpp_read_msg(int fd, int timeout, HidppMessage *msg,
hidpp_msg_cb_t *cb, void *userdata);
#endif
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