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/*
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* gpio.cpp
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*
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* Created on: Mar 6, 2012
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* Author: joe
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*/
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#include <fcntl.h>
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#include <termios.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include "gpio.h"
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#define GPIO_DIR_IN 0
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#define GPIO_DIR_OUT 1
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int gpio_export(unsigned gpio)
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{
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int fd, len;
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char buf[11];
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fd = open("/sys/class/gpio/export", O_WRONLY);
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if (fd < 0) {
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perror("gpio/export");
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return fd;
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}
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len = snprintf(buf, sizeof(buf), "%d", gpio);
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write(fd, buf, len);
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close(fd);
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return 0;
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}
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int gpio_unexport(unsigned gpio)
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{
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int fd, len;
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char buf[11];
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fd = open("/sys/class/gpio/unexport", O_WRONLY);
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if (fd < 0) {
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perror("gpio/export");
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return fd;
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}
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len = snprintf(buf, sizeof(buf), "%d", gpio);
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write(fd, buf, len);
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close(fd);
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return 0;
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}
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static int gpio_dir(unsigned gpio, unsigned dir)
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{
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int fd, len;
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char buf[60];
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len = snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", gpio);
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fd = open(buf, O_WRONLY);
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if (fd < 0) {
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perror("gpio/direction");
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return fd;
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}
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if (dir == GPIO_DIR_OUT)
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write(fd, "out", 4);
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else
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write(fd, "in", 3);
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close(fd);
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return 0;
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}
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int gpio_dir_out(unsigned gpio)
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{
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return gpio_dir(gpio, GPIO_DIR_OUT);
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}
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int gpio_dir_in(unsigned gpio)
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{
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return gpio_dir(gpio, GPIO_DIR_IN);
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}
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int gpio_set_value(unsigned gpio, unsigned value)
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{
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int fd, len;
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char buf[60];
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len = snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
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fd = open(buf, O_WRONLY);
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if (fd < 0) {
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perror("gpio/value");
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return fd;
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}
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if (value)
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write(fd, "1", 2);
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else
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write(fd, "0", 2);
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close(fd);
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return 0;
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}
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int gpio_get_value(unsigned gpio, unsigned *value)
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{
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int fd, len;
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char buf[60];
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len = snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
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fd = open(buf, O_RDONLY);
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if (fd < 0) {
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perror("gpio/value");
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return fd;
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}
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read(fd, value, 1);
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if (*value == '1')
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*value = 1;
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else
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*value = 0;
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close(fd);
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return 0;
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}
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