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::

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

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];