c_gpio cleanup: pep7, added documentation, removed experimental event…

… methods

.gitignore

@@ -1,8 +1,5 @@
 *.py[cod]
 
-# C extensions
-*.so
-
 # Packages
 *.egg
 *.egg-info
@@ -33,5 +30,6 @@ nosetests.xml
 .mr.developer.cfg
 .project
 .pydevproject
+.cproject
 
 documentation/build/

source/c_gpio/c_gpio.c

@@ -1,30 +1,15 @@
 /*
-Copyright (c) 2012-2013 Ben Croston
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
-*/
+Based on c_gpio.c by Ben Croston.
 
+Changes:
+- PEP7 cleanup
+- Added some documentation
+- Removed experimental event detection methods
+*/
 #include <stdint.h>
 #include <stdlib.h>
 #include <fcntl.h>
 #include <sys/mman.h>
-#include "c_gpio.h"
 
 #define BCM2708_PERI_BASE   0x20000000
 #define GPIO_BASE           (BCM2708_PERI_BASE + 0x200000)
@@ -43,27 +28,42 @@ SOFTWARE.
 #define PAGE_SIZE  (4*1024)
 #define BLOCK_SIZE (4*1024)
 
+#define SETUP_OK          0
+#define SETUP_DEVMEM_FAIL 1
+#define SETUP_MALLOC_FAIL 2
+#define SETUP_MMAP_FAIL   3
+
+#define INPUT  1 // is really 0 for control register!
+#define OUTPUT 0 // is really 1 for control register!
+#define ALT0   4
+
+#define HIGH 1
+#define LOW  0
+
+#define PUD_OFF  0
+#define PUD_DOWN 1
+#define PUD_UP   2
+
 static volatile uint32_t *gpio_map;
 
-void short_wait(void)
+// `short_wait` waits 150 cycles
+void
+short_wait(void)
 {
-    int i;
-
-    for (i=0; i<150; i++)     // wait 150 cycles
-    {
-		asm volatile("nop");
+    for (int i=0; i<150; i++) {
+        asm volatile("nop");
     }
 }
 
-int setup(void)
+// `setup` is run when GPIO is imported in Python
+int
+setup(void)
 {
     int mem_fd;
     uint8_t *gpio_mem;
 
     if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0)
-    {
         return SETUP_DEVMEM_FAIL;
-    }
 
     if ((gpio_mem = malloc(BLOCK_SIZE + (PAGE_SIZE-1))) == NULL)
         return SETUP_MALLOC_FAIL;
@@ -79,103 +79,31 @@ int setup(void)
     return SETUP_OK;
 }
 
-void clear_event_detect(int gpio)
-{
-	int offset = EVENT_DETECT_OFFSET + (gpio/32);
-    int shift = (gpio%32);
-
-    *(gpio_map+offset) |= (1 << shift);
-    short_wait();
-    *(gpio_map+offset) = 0;
-}
-
-int event_detected(int gpio)
-{
-	int offset, value, bit;
-
-    offset = EVENT_DETECT_OFFSET + (gpio/32);
-    bit = (1 << (gpio%32));
-    value = *(gpio_map+offset) & bit;
-    if (value)
-    {
-        clear_event_detect(gpio);
-	}
-    return value;
-}
-
-void set_rising_event(int gpio, int enable)
-{
-	int offset = RISING_ED_OFFSET + (gpio/32);
-    int shift = (gpio%32);
-
-	if (enable)
-	    *(gpio_map+offset) |= 1 << shift;
-	else
-	    *(gpio_map+offset) &= ~(1 << shift);
-    clear_event_detect(gpio);
-}
-
-void set_falling_event(int gpio, int enable)
-{
-	int offset = FALLING_ED_OFFSET + (gpio/32);
-    int shift = (gpio%32);
-
-	if (enable)
-	{
-	    *(gpio_map+offset) |= (1 << shift);
-	    *(gpio_map+offset) = (1 << shift);
-	} else {
-	    *(gpio_map+offset) &= ~(1 << shift);
-	}
-    clear_event_detect(gpio);
-}
-
-void set_high_event(int gpio, int enable)
-{
-	int offset = HIGH_DETECT_OFFSET + (gpio/32);
-    int shift = (gpio%32);
-
-	if (enable)
-	{
-	    *(gpio_map+offset) |= (1 << shift);
-	} else {
-	    *(gpio_map+offset) &= ~(1 << shift);
-	}
-    clear_event_detect(gpio);
-}
-
-void set_low_event(int gpio, int enable)
-{
-	int offset = LOW_DETECT_OFFSET + (gpio/32);
-    int shift = (gpio%32);
-
-	if (enable)
-	    *(gpio_map+offset) |= 1 << shift;
-	else
-	    *(gpio_map+offset) &= ~(1 << shift);
-    clear_event_detect(gpio);
-}
-
-void set_pullupdn(int gpio, int pud)
+// Sets a pullup or -down resistor on a GPIO
+void
+set_pullupdn(int gpio, int pud)
 {
     int clk_offset = PULLUPDNCLK_OFFSET + (gpio/32);
     int shift = (gpio%32);
-    
+
     if (pud == PUD_DOWN)
        *(gpio_map+PULLUPDN_OFFSET) = (*(gpio_map+PULLUPDN_OFFSET) & ~3) | PUD_DOWN;
     else if (pud == PUD_UP)
        *(gpio_map+PULLUPDN_OFFSET) = (*(gpio_map+PULLUPDN_OFFSET) & ~3) | PUD_UP;
     else  // pud == PUD_OFF
        *(gpio_map+PULLUPDN_OFFSET) &= ~3;
-    
+
     short_wait();
     *(gpio_map+clk_offset) = 1 << shift;
     short_wait();
     *(gpio_map+PULLUPDN_OFFSET) &= ~3;
     *(gpio_map+clk_offset) = 0;
 }
 
-void setup_gpio(int gpio, int direction, int pud)
+// Sets a GPIO to either output or input (input can have an optional pullup
+// or -down resistor).
+void
+setup_gpio(int gpio, int direction, int pud)
 {
     int offset = FSEL_OFFSET + (gpio/10);
     int shift = (gpio%10)*3;
@@ -187,42 +115,44 @@ void setup_gpio(int gpio, int direction, int pud)
         *(gpio_map+offset) = (*(gpio_map+offset) & ~(7<<shift));
 }
 
+// Returns the function of a GPIO: 0=input, 1=output, 4=alt0
 // Contribution by Eric Ptak <[email protected]>
-int gpio_function(int gpio)
+int
+gpio_function(int gpio)
 {
-   int offset = FSEL_OFFSET + (gpio/10);
-   int shift = (gpio%10)*3;
-   int value = *(gpio_map+offset);
-   value >>= shift;
-   value &= 7;
-   return value; // 0=input, 1=output, 4=alt0
+    int offset = FSEL_OFFSET + (gpio/10);
+    int shift = (gpio%10)*3;
+    int value = *(gpio_map+offset);
+    value >>= shift;
+    value &= 7;
+    return value;
 }
 
-void output_gpio(int gpio, int value)
+// Sets a GPIO output to 1 or 0
+void
+output_gpio(int gpio, int value)
 {
     int offset, shift;
-
     if (value) // value == HIGH
         offset = SET_OFFSET + (gpio/32);
     else       // value == LOW
         offset = CLR_OFFSET + (gpio/32);
-
-    shift = (gpio%32);
-
-    *(gpio_map+offset) = 1 << shift;
+    *(gpio_map+offset) = 1 << gpio % 32;
 }
 
-int input_gpio(int gpio)
+// Returns the value of a GPIO input (1 or 0)
+int
+input_gpio(int gpio)
 {
    int offset, value, mask;
-
    offset = PINLEVEL_OFFSET + (gpio/32);
    mask = (1 << gpio%32);
    value = *(gpio_map+offset) & mask;
    return value;
 }
 
-void cleanup(void)
+void
+cleanup(void)
 {
     // fixme - set all gpios back to input
     munmap((caddr_t)gpio_map, BLOCK_SIZE);