Updating setup to allow for repeated calls on a pin. Not totally sold on this, but it work and is what RPi.GPIO does. This will close #63

CHANGELOG.rst

@@ -1,3 +1,8 @@
+0.5.6
+---
+* Fix for Issue #63 where re-setting up a pin wasn't lining up with RPi.GPIO standards. Calling setup after the first time will now update direction.
+* README updates to point out the direction() function since that was missing
+
 0.5.5
 ---
 * Fix for Issue #62 where using alternate name of an XIO would cause a segfault due to trying to set pull up/down resistor setting

README.rst

@@ -225,6 +225,16 @@ Read lots of data::
 
 This code was initially added by brettcvz and I cleaned it up and expanded it.
 
+You can quickly change a pins direction::
+
+    GPIO.direction("XIO-P3", GPIO.OUT)
+    GPIO.direction("XIO-P3", GPIO.IN)
+    
+You can also re-setup a pin in order to change direction, not that this is a slower operation::
+
+    GPIO.setup("XIO-P3", GPIO.OUT)
+    GPIO.setup("XIO-P3", GPIO.IN)
+
 The edge detection code below only works for the AP-EINT1, AP-EINT3, and XPO Pins on the CHIP.
 
 Waiting for an edge (GPIO.RISING, GPIO.FALLING, or GPIO.BOTH::
@@ -240,19 +250,21 @@ Detecting events::
     if GPIO.event_detected("XIO-P0"):
         print "event detected!"
 
-CHIP_IO can also handle adding callback functions on any pin that supports edge detection.::
+CHIP_IO can also handle adding callback functions on any pin that supports edge detection.  Note that only one callback function can be specified per Pin, if you try to set more, an exception will be thrown.::
 
     def mycallback(channel):
         print("we hit the edge we want")
 
     GPIO.setup("GPIO3", GPIO.IN)
-    # Add Callback: Falling Edge
-    GPIO.add_event_callback("GPIO3", GPIO.FALLING, mycallback)
-    # Add Callback: Rising Edge
-    GPIO.add_event_callback("GPIO3", GPIO.RISING, mycallback)
-    # Add Callback: Both Edges
-    GPIO.add_event_callback("GPIO3", GPIO.BOTH, mycallback)
-    # Remove callback
+    # Add Event Detect and Callback Separately for Falling Edge
+    GPIO.add_event_detect("GPIO3", GPIO.FALLING)
+    GPIO.add_event_callback("GPIO3", mycallback)
+    # Add Event Detect and Callback Separately for Rising Edge
+    GPIO.add_event_detect("GPIO3", GPIO.RISING)
+    GPIO.add_event_callback("GPIO3", mycallback)
+    # Add Callback for Both Edges using the add_event_detect() method
+    GPIO.add_event_detect("GPIO3", GPIO.BOTH, mycallback)
+    # Remove callback with the following
     GPIO.remove_event_detect("GPIO3")
 
 

debian/changelog

@@ -1,3 +1,10 @@
+chip-io (0.5.6-1) unstable; urgency=low
+
+  * Fix for Issue #63 where re-setting up a pin wasn't lining up with RPi.GPIO standards. Calling setup after the first time will now update direction.
+  * README updates to point out the direction() function since that was missing
+
+ -- Robert Wolterman <robert.wolterman@gmail.com>  Mon, 20 Mar 2017 23:04:00 -0600
+
 chip-io (0.5.5-1) unstable; urgency=low
 
   * Fix for Issue #62 where using alternate name of an XIO would cause a segfault due to trying to set pull up/down resistor setting

debian/files

@@ -1,2 +1,2 @@
-python-chip-io_0.5.4-1_armhf.deb python optional
-python3-chip-io_0.5.4-1_armhf.deb python optional
+python-chip-io_0.5.5-1_armhf.deb python optional
+python3-chip-io_0.5.5-1_armhf.deb python optional

setup.py

@@ -13,7 +13,7 @@ classifiers = ['Development Status :: 3 - Alpha',
                'Topic :: System :: Hardware']
 
 setup(name             = 'CHIP_IO',
-      version          = '0.5.5',
+      version          = '0.5.6',
       author           = 'Robert Wolterman',
       author_email     = 'robert.wolterman@gmail.com',
       description      = 'A module to control CHIP IO channels',

source/constants.c

@@ -85,6 +85,6 @@ void define_constants(PyObject *module)
    bcm = Py_BuildValue("i", BCM);
    PyModule_AddObject(module, "BCM", bcm);
 
-   version = Py_BuildValue("s", "0.5.5");
+   version = Py_BuildValue("s", "0.5.6");
    PyModule_AddObject(module, "VERSION", version);
 }

source/event_gpio.c

@@ -177,7 +177,7 @@ int gpio_export(int gpio)
         char err[256];
         snprintf(err, sizeof(err), "gpio_export: could not write '%s' to %s (%s)", str_gpio, filename, strerror(e_no));
         add_error_msg(err);
-        return -1;
+        return -2;
     }
 
     // add to list

source/py_gpio.c

@@ -215,11 +215,16 @@ static PyObject *py_setup_channel(PyObject *self, PyObject *args, PyObject *kwar
         init_r8_gpio_mem();
     }
  
-    if (gpio_export(gpio) < 0) {
+    int exprtn = gpio_export(gpio);
+    if (exprtn == -1) {
         char err[2000];
         snprintf(err, sizeof(err), "Error setting up channel %s, maybe already exported? (%s)", channel, get_error_msg());
         PyErr_SetString(PyExc_RuntimeError, err);
         return NULL;
+    } else if (exprtn == -2 && gpio_warnings) {
+        char warn[2000];
+        snprintf(warn, sizeof(warn), "Channel %s may already be exported, proceeding with rest of setup", channel);
+        PyErr_WarnEx(PyExc_Warning, warn, 1);
     }
     if (gpio_set_direction(gpio, direction) < 0) {
         char err[2000];