Add idle function

This patch adds the mtdev_idle() function, which checks the kernel
device for activity. Useful when implementing timing logic.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/iobuf.c b/src/iobuf.c
index 6d238ec..83e531a 100644
--- a/src/iobuf.c
+++ b/src/iobuf.c
@@ -28,6 +28,18 @@
 
 #include "iobuf.h"
 #include "state.h"
+#include <poll.h>
+
+int mtdev_idle(struct mtdev *dev, int fd, int ms)
+{
+        struct mtdev_state *state = dev->state;
+        struct mtdev_iobuf *buf = &state->iobuf;
+        struct pollfd fds = { fd, POLLIN, 0 };
+        return evbuf_empty(&state->outbuf) &&
+                evbuf_empty(&state->inbuf) &&
+                buf->head == buf->tail &&
+                poll(&fds, 1, ms) <= 0;
+}
 
 int mtdev_fetch(struct mtdev *dev, struct input_event *ev, int fd)
 {