int add_edge_detect(unsigned int gpio, unsigned int edge, int bouncetime)
// return values:
// 0 - Success
// 1 - Edge detection already added
// 2 - Other error
{
pthread_t threads;
struct epoll_event ev;
long t = 0;
struct gpios *g;
int i = -1;
i = gpio_event_added(gpio);
if (i == 0) { // event not already added
if ((g = new_gpio(gpio)) == NULL)
return 2;
gpio_set_edge(gpio, edge);
g->edge = edge;
g->bouncetime = bouncetime;
} else if (i == edge) { // get existing event
g = get_gpio(gpio);
if ((bouncetime != -666 && g->bouncetime != bouncetime) || // different event bouncetime used
(g->thread_added)) // event already added
return 1;
} else {
return 1;
}
// create epfd_thread if not already open
if ((epfd_thread == -1) && ((epfd_thread = epoll_create(1)) == -1))
return 2;
// add to epoll fd
ev.events = EPOLLIN | EPOLLET | EPOLLPRI;
ev.data.fd = g->value_fd;
if (epoll_ctl(epfd_thread, EPOLL_CTL_ADD, g->value_fd, &ev) == -1) {
remove_edge_detect(gpio);
return 2;
}
g->thread_added = 1;
// start poll thread if it is not already running
if (!thread_running) {
if (pthread_create(&threads, NULL, poll_thread, (void *)t) != 0) {
remove_edge_detect(gpio);
return 2;
}
}
return 0;
}
int add_edge_detect(unsigned int gpio, unsigned int edge, unsigned int bouncetime)
// return values:
// 0 - Success
// 1 - Edge detection already added
// 2 - Other error
{
pthread_t threads;
struct epoll_event ev;
long t = 0;
struct gpios *g;
// check to see if this gpio has been added already
if (gpio_event_added(gpio) != 0)
return 1;
// create epfd if not already open
if ((epfd == -1) && ((epfd = epoll_create(1)) == -1))
return 2;
if ((g = new_gpio(gpio)) == NULL)
return 2;
gpio_set_edge(gpio, edge);
g->bouncetime = bouncetime;
// add to epoll fd
ev.events = EPOLLIN | EPOLLET | EPOLLPRI;
ev.data.fd = g->value_fd;
if (epoll_ctl(epfd, EPOLL_CTL_ADD, g->value_fd, &ev) == -1) {
remove_edge_detect(gpio);
return 2;
}
// start poll thread if it is not already running
if (!thread_running) {
if (pthread_create(&threads, NULL, poll_thread, (void *)t) != 0) {
remove_edge_detect(gpio);
return 2;
}
}
return 0;
}
int blocking_wait_for_edge(unsigned int gpio, unsigned int edge, int bouncetime, int timeout)
// return values:
// 1 - Success (edge detected)
// 0 - Timeout
// -1 - Edge detection already added
// -2 - Other error
{
int n, ed;
struct epoll_event events, ev;
char buf;
struct gpios *g = NULL;
struct timeval tv_timenow;
unsigned long long timenow;
int finished = 0;
int initial_edge = 1;
if (callback_exists(gpio))
return -1;
// add gpio if it has not been added already
ed = gpio_event_added(gpio);
if (ed == edge) { // get existing record
g = get_gpio(gpio);
if (g->bouncetime != -666 && g->bouncetime != bouncetime) {
return -1;
}
} else if (ed == NO_EDGE) { // not found so add event
if ((g = new_gpio(gpio)) == NULL) {
return -2;
}
gpio_set_edge(gpio, edge);
g->edge = edge;
g->bouncetime = bouncetime;
} else { // ed != edge - event for a different edge
g = get_gpio(gpio);
gpio_set_edge(gpio, edge);
g->edge = edge;
g->bouncetime = bouncetime;
g->initial_wait = 1;
}
// create epfd_blocking if not already open
if ((epfd_blocking == -1) && ((epfd_blocking = epoll_create(1)) == -1)) {
return -2;
}
// add to epoll fd
ev.events = EPOLLIN | EPOLLET | EPOLLPRI;
ev.data.fd = g->value_fd;
if (epoll_ctl(epfd_blocking, EPOLL_CTL_ADD, g->value_fd, &ev) == -1) {
return -2;
}
// wait for edge
while (!finished) {
if ((n = epoll_wait(epfd_blocking, &events, 1, timeout)) == -1) {
epoll_ctl(epfd_blocking, EPOLL_CTL_DEL, g->value_fd, &ev);
return -2;
}
if (initial_edge) { // first time triggers with current state, so ignore
initial_edge = 0;
} else {
gettimeofday(&tv_timenow, NULL);
timenow = tv_timenow.tv_sec*1E6 + tv_timenow.tv_usec;
if (g->bouncetime == -666 || timenow - g->lastcall > g->bouncetime*1000 || g->lastcall == 0 || g->lastcall > timenow) {
g->lastcall = timenow;
finished = 1;
}
}
}
// check event was valid
if (n > 0) {
lseek(events.data.fd, 0, SEEK_SET);
if ((read(events.data.fd, &buf, 1) != 1) || (events.data.fd != g->value_fd)) {
epoll_ctl(epfd_blocking, EPOLL_CTL_DEL, g->value_fd, &ev);
return -2;
}
}
epoll_ctl(epfd_blocking, EPOLL_CTL_DEL, g->value_fd, &ev);
if (n == 0) {
return 0; // timeout
} else {
return 1; // edge found
}
}
