Create pwrbutton_max2play.c

Improving performance for Powerbutton: Running a interrupt driven program to catch the powerbutton event is better in performance than a shell script with sleeps.

pwrbutton_max2play.c

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+/*
+ Shutdownbutton for Audiophonics Max2Play Setup
+ 
+ build with gcc -I. -o pwrbutton pwrbutton_max2play.c -lwiringPi
+ 
+ add this programm to autostart /etc/rc.local before "exit 0" like this:
+    /opt/pwrbutton &
+ 
+ @Copyright 2017 Stefan Rick
+ @author Stefan Rick
+ Mail: stefan@netzberater.de
+ Web: https://www.max2play.com
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <wiringPi.h>
+
+typedef enum { false, true } bool;
+
+// Set WiringPi GPIO
+int gpiopin = 17;
+int debug = 0;
+int block = 0;
+
+void myInterrupt(void) {
+  // Do not run this multiple times!
+  if(block == 1)
+    return;
+  else
+    block = 2;
+  int sysreturn = 0;
+  char command[100];
+  sprintf(command ,"poweroff");
+  sysreturn = system(command);
+  printf("System: %d", sysreturn);
+  return;
+}
+
+int main (int argc, char *argv[])
+{
+   printf("Usage: %s [-d]\n", argv[0]);
+   printf(" -d Enable DEBUG output\n\n");
+
+   int opt;
+   while ((opt = getopt(argc, argv, "dc")) != -1) {
+       switch (opt) {
+                case 'd': debug = 1; break;
+                case 'c': break; // change config Path
+                default:
+                    break;
+                }
+    }
+  wiringPiSetupGpio () ;
+
+  // Initialize Button Light (static ON)
+  pinMode(22, OUTPUT);
+  digitalWrite(22, 1);
+
+  // Create Interrupt Code for Button Pressed Event
+  wiringPiISR (gpiopin, INT_EDGE_RISING, &myInterrupt) ;
+
+  printf("Initialize GPIO Pin %d\n", gpiopin);
+
+  for (;;) {
+    sleep(1000);
+  }
+  return 0 ;
+}
+