core: implement the event API

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/core.c b/core.c
index a90c2ecc4fe1af3e93961fcc39eee99d8d2b66a5..2ccec52a52c89c70a7fce0822f5067a6da9f51dd 100644 (file)
--- a/core.c
+++ b/core.c
@@ -19,6 +19,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
+#include <sys/poll.h>
 #include <linux/gpio.h>
 
 static const char dev_dir[] = "/dev/";
@@ -64,6 +65,12 @@ static bool is_unsigned_int(const char *str)
        return *str == '\0';
 }
 
+static void nsec_to_timespec(uint64_t nsec, struct timespec *ts)
+{
+       ts->tv_sec = nsec / 1000000000ULL;
+       ts->tv_nsec = (nsec % 1000000000ULL);
+}
+
 static int gpio_ioctl(int fd, unsigned long request, void *data)
 {
        int status;
@@ -129,10 +136,12 @@ int gpiod_simple_get_value(const char *device, unsigned int offset)
 
 struct gpiod_line {
        bool requested;
+       bool event_requested;
        bool up_to_date;
        struct gpiod_chip *chip;
        struct gpioline_info info;
        struct gpiohandle_request *req;
+       struct gpioevent_request event;
 };
 
 static void line_set_offset(struct gpiod_line *line, unsigned int offset)
@@ -421,6 +430,130 @@ int gpiod_line_set_value_bulk(struct gpiod_line_bulk *line_bulk, int *values)
        return 0;
 }
 
+int gpiod_line_event_request(struct gpiod_line *line,
+                            struct gpiod_line_evreq_config *config)
+{
+       struct gpioevent_request *req;
+       struct gpiod_chip *chip;
+       int status, fd;
+
+       if (line->event_requested)
+               return -EBUSY;
+
+       req = &line->event;
+
+       memset(req, 0, sizeof(*req));
+       strncpy(req->consumer_label, config->consumer,
+               sizeof(req->consumer_label) - 1);
+       req->lineoffset = gpiod_line_offset(line);
+       req->handleflags |= GPIOHANDLE_REQUEST_INPUT;
+
+       if (config->line_flags & GPIOD_REQUEST_OPEN_DRAIN)
+               req->handleflags |= GPIOHANDLE_REQUEST_OPEN_DRAIN;
+       if (config->line_flags & GPIOD_REQUEST_OPEN_SOURCE)
+               req->handleflags |= GPIOHANDLE_REQUEST_OPEN_SOURCE;
+
+       if (config->polarity == GPIOD_POLARITY_ACTIVE_LOW)
+               req->handleflags |= GPIOHANDLE_REQUEST_ACTIVE_LOW;
+
+       if (config->event_type == GPIOD_EVENT_RISING_EDGE)
+               req->eventflags |= GPIOEVENT_EVENT_RISING_EDGE;
+       else if (config->event_type == GPIOD_EVENT_FALLING_EDGE)
+               req->eventflags |= GPIOEVENT_EVENT_FALLING_EDGE;
+       else if (req->eventflags |= GPIOD_EVENT_BOTH_EDGES)
+               req->eventflags |= GPIOEVENT_REQUEST_BOTH_EDGES;
+
+       chip = gpiod_line_get_chip(line);
+       fd = gpiod_chip_get_fd(chip);
+
+       status = gpio_ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, req);
+       if (status < 0)
+               return -1;
+
+       line->event_requested = true;
+
+       return 0;
+}
+
+void gpiod_line_event_release(struct gpiod_line *line)
+{
+       close(line->event.fd);
+       line->event_requested = false;
+}
+
+bool gpiod_line_event_is_requested(struct gpiod_line *line)
+{
+       return line->event_requested;
+}
+
+int gpiod_line_event_wait(struct gpiod_line *line,
+                         const struct timespec *timeout,
+                         struct gpiod_line_event *event)
+{
+       struct gpiod_line_bulk bulk;
+
+       gpiod_line_bulk_init(&bulk);
+       gpiod_line_bulk_add(&bulk, line);
+
+       return gpiod_line_event_wait_bulk(&bulk, timeout, event);
+}
+
+int gpiod_line_event_wait_bulk(struct gpiod_line_bulk *bulk,
+                              const struct timespec *timeout,
+                              struct gpiod_line_event *event)
+{
+       struct pollfd fds[GPIOD_REQUEST_MAX_LINES];
+       struct gpioevent_data evdata;
+       struct gpiod_line *line;
+       unsigned int i;
+       int status;
+       ssize_t rd;
+
+       memset(fds, 0, sizeof(fds));
+       memset(&evdata, 0, sizeof(evdata));
+
+       /* TODO Check if all lines are requested. */
+
+       for (i = 0; i < bulk->num_lines; i++) {
+               line = bulk->lines[i];
+
+               fds[i].fd = line->event.fd;
+               fds[i].events = POLLIN | POLLPRI;
+       }
+
+       status = ppoll(fds, bulk->num_lines, timeout, NULL);
+       if (status < 0) {
+               last_error_from_errno();
+               return -1;
+       } else if (status == 0) {
+               return 0;
+       }
+
+       for (i = 0; !fds[i].revents; i++);
+
+       rd = read(fds[i].fd, &evdata, sizeof(evdata));
+       if (rd < 0) {
+               last_error_from_errno();
+               return -1;
+       } else if (rd != sizeof(evdata)) {
+               set_last_error(EIO);
+               return -1;
+       }
+
+       event->line = bulk->lines[i];
+       event->event_type = evdata.id == GPIOEVENT_EVENT_RISING_EDGE
+                                               ? GPIOD_EVENT_RISING_EDGE
+                                               : GPIOD_EVENT_FALLING_EDGE;
+       nsec_to_timespec(evdata.timestamp, &event->ts);
+
+       return 1;
+}
+
+int gpiod_line_event_get_fd(struct gpiod_line *line)
+{
+       return line->event_requested ? line->event.fd : -1;
+}
+
 struct gpiod_chip
 {
        int fd;

diff --git a/gpiod.h b/gpiod.h
index 3121ef571f523ae2d487659e63e3fd40182820b7..7b158ac809af651715c9b497ee81fcf640f919af 100644 (file)
--- a/gpiod.h
+++ b/gpiod.h
@@ -137,6 +137,42 @@ int gpiod_line_set_value_bulk(struct gpiod_line_bulk *line_bulk,
 
 struct gpiod_line * gpiod_line_find_by_name(const char *name) GPIOD_API;
 
+enum {
+       GPIOD_EVENT_RISING_EDGE,
+       GPIOD_EVENT_FALLING_EDGE,
+       GPIOD_EVENT_BOTH_EDGES,
+};
+
+struct gpiod_line_evreq_config {
+       const char *consumer;
+       int event_type;
+       int polarity;
+       int line_flags;
+};
+
+struct gpiod_line_event {
+       struct gpiod_line *line;
+       struct timespec ts;
+       int event_type;
+};
+
+int gpiod_line_event_request(struct gpiod_line *line,
+                            struct gpiod_line_evreq_config *config) GPIOD_API;
+
+void gpiod_line_event_release(struct gpiod_line *line) GPIOD_API;
+
+bool gpiod_line_event_is_requested(struct gpiod_line *line) GPIOD_API;
+
+int gpiod_line_event_wait(struct gpiod_line *line,
+                         const struct timespec *timeout,
+                         struct gpiod_line_event *event) GPIOD_API;
+
+int gpiod_line_event_wait_bulk(struct gpiod_line_bulk *bulk,
+                              const struct timespec *timeout,
+                              struct gpiod_line_event *event) GPIOD_API;
+
+int gpiod_line_event_get_fd(struct gpiod_line *line) GPIOD_API;
+
 struct gpiod_chip;
 
 struct gpiod_chip * gpiod_chip_open(const char *path) GPIOD_API;