Added support for timeouts in wait_for_edge

Author: jpbarraca

README.rst

@@ -89,6 +89,10 @@ Waiting for an edge (GPIO.RISING, GPIO.FALLING, or GPIO.BOTH::
 
     GPIO.wait_for_edge(channel, GPIO.RISING)
 
+    or
+    
+    GPIO.wait_for_edge(channel, GPIO.RISING, timeout)
+
 Detecting events::
 
     GPIO.add_event_detect("P9_12", GPIO.FALLING) 

source/event_gpio.c

@@ -587,7 +587,7 @@ void event_cleanup(void)
     exports_cleanup();
 }
 
-int blocking_wait_for_edge(unsigned int gpio, unsigned int edge)
+int blocking_wait_for_edge(unsigned int gpio, unsigned int edge, int timeout)
 // standalone from all the event functions above
 {
     int fd = fd_lookup(gpio);
@@ -624,7 +624,7 @@ int blocking_wait_for_edge(unsigned int gpio, unsigned int edge)
 
     // epoll for event
     for (i = 0; i<2; i++) // first time triggers with current state, so ignore
-       if ((n = epoll_wait(epfd, &events, 1, -1)) == -1)
+       if ((n = epoll_wait(epfd, &events, 1, timeout)) == -1)
        {
            gpio_event_remove(gpio);
            return 5;
@@ -647,5 +647,5 @@ int blocking_wait_for_edge(unsigned int gpio, unsigned int edge)
 
     gpio_event_remove(gpio);
     close(epfd);
-    return 0;
+    return (n == 1) ? 0 : -1;
 }

source/event_gpio.h

@@ -61,4 +61,4 @@ int gpio_event_remove(unsigned int gpio);
 int gpio_is_evented(unsigned int gpio);
 int event_initialise(void);
 void event_cleanup(void);
-int blocking_wait_for_edge(unsigned int gpio, unsigned int edge);
+int blocking_wait_for_edge(unsigned int gpio, unsigned int edge, int timeout);

source/py_gpio.c

@@ -388,12 +388,14 @@ static PyObject *py_event_detected(PyObject *self, PyObject *args)
 static PyObject *py_wait_for_edge(PyObject *self, PyObject *args)
 {
    unsigned int gpio;
-   int edge, result;
+   int edge, result, timeout;
    char *channel;
    char error[30];
 
-   if (!PyArg_ParseTuple(args, "si", &channel, &edge))
-      return NULL;
+   if (!PyArg_ParseTuple(args, "sii", &channel, &edge, &timeout))
+      timeout = -1
+      if (!PyArg_ParseTuple(args, "si", &channel, &edge))
+         return NULL;
 
    if (get_gpio_number(channel, &gpio))
       return NULL;
@@ -413,12 +415,14 @@ static PyObject *py_wait_for_edge(PyObject *self, PyObject *args)
    }
 
    Py_BEGIN_ALLOW_THREADS // disable GIL
-   result = blocking_wait_for_edge(gpio, edge);
+   result = blocking_wait_for_edge(gpio, edge, timeout);
    Py_END_ALLOW_THREADS   // enable GIL
 
    if (result == 0) {
       Py_INCREF(Py_None);
       return Py_None;
+   }else if (result == -1){
+      Py_RETURN_FALSE
    } else if (result == 2) {
       PyErr_SetString(PyExc_RuntimeError, "Edge detection events already enabled for this GPIO channel");
       return NULL;
@@ -483,7 +487,7 @@ PyMethodDef gpio_methods[] = {
    {"remove_event_detect", py_remove_event_detect, METH_VARARGS, "Remove edge detection for a particular GPIO channel\ngpio - gpio channel"},
    {"event_detected", py_event_detected, METH_VARARGS, "Returns True if an edge has occured on a given GPIO.  You need to enable edge detection using add_event_detect() first.\ngpio - gpio channel"},
    {"add_event_callback", (PyCFunction)py_add_event_callback, METH_VARARGS | METH_KEYWORDS, "Add a callback for an event already defined using add_event_detect()\ngpio         - gpio channel\ncallback     - a callback function\n[bouncetime] - Switch bounce timeout in ms"},
-   {"wait_for_edge", py_wait_for_edge, METH_VARARGS, "Wait for an edge.\ngpio - gpio channel\nedge - RISING, FALLING or BOTH"},
+   {"wait_for_edge", py_wait_for_edge, METH_VARARGS, "Wait for an edge.\ngpio - gpio channel\nedge - RISING, FALLING or BOTH\ntimeout (optional) - time to wait in miliseconds. -1 will wait forever (default)"},
    {"gpio_function", py_gpio_function, METH_VARARGS, "Return the current GPIO function (IN, OUT, ALT0)\ngpio - gpio channel"},
    {"setwarnings", py_setwarnings, METH_VARARGS, "Enable or disable warning messages"},
    {NULL, NULL, 0, NULL}