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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/>.
*/
#include <poll.h>
#include <stdio.h>
#include <string.h>
#include <time.h> /* needs -lrt, for clock_gettime as timeout helper */
#include <unistd.h>
#include "hidpp.h"
#include "debug.h"
#define VID_LOGITECH 0x046d
#define PID_NANO_RECEIVER 0xc52f
#define RECEIVER_NAME "logitech-djreceiver"
static inline bool is_valid_device_index(uint8_t ix)
{
return ix >= 1 && ix <= MAX_DEVICES;
}
static long long unsigned get_timestamp_ms(void)
{
struct timespec tp;
clock_gettime(CLOCK_MONOTONIC, &tp);
return tp.tv_sec * 1000 + tp.tv_nsec / 1000000;
}
static ssize_t poll_read(int fd, int timeout, void *buf, size_t count)
{
int r;
struct pollfd pollfd = {
.fd = fd,
.events = POLLIN
};
r = poll(&pollfd, 1, timeout);
if (r < 0) {
perror("poll");
return 0;
} else if (r == 0) {
trace_log("poll timeout reached!\n");
return 0;
}
r = read(fd, buf, count);
if (r < 0) {
perror("read");
return 0;
}
return r;
}
static void hidpp_discard_messages(int fd)
{
char c;
/* kernel discards remainder of message */
while (poll_read(fd, 1, &c, 1)) ;
}
bool hidpp_write_report(int fd, struct HidppMessage *msg)
{
ssize_t r, payload_size = HIDPP_SHORT_LEN;
if (msg->report_id == HIDPP_LONG) {
payload_size = HIDPP_LONG_LEN;
}
/* start with an empty queue to avoid interference */
hidpp_discard_messages(fd);
trace_dump_data("wr", (uint8_t *) msg, payload_size);
r = write(fd, msg, payload_size);
if (r < 0) {
perror("write");
}
return payload_size == r;
}
bool hidpp_read_msg(int fd, int timeout, HidppMessage *msg,
hidpp_msg_cb_t *cb, void *userdata)
{
int r;
long long unsigned begin_ms = 0, end_ms;
HidppMessage response;
do {
end_ms = get_timestamp_ms();
if (begin_ms > 0)
timeout -= end_ms - begin_ms;
begin_ms = end_ms;
if (timeout <= 0)
break;
memset(&response, 0, sizeof(response));
r = poll_read(fd, timeout, &response, sizeof(response));
if (r > 0) {
trace_dump_data("rd", (uint8_t *) msg, r);
if (r < HIDPP_SHORT_LEN) {
trace_log("Impossible short read: %i\n", r);
} else if (response.report_id == HIDPP_SHORT ||
response.report_id == HIDPP_LONG) {
uint8_t ix = response.device_index;
if (!is_valid_device_index(ix) && ix != 0xFF) {
trace_log("Invalid device index: %i\n", ix);
} else if (cb(&response, userdata)) {
/* response is accepted, return message */
memcpy(msg, &response, sizeof(response));
return true;
}
}
}
} while (1);
/* timeout expired, no report found unfortunately */
return false;
}
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