/*********************************************************************************
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* Copyright: (C) 2019 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: at91_sysGpio.c
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* Description: This file si GPIO API operatore on /sys/class/gpio/xxx
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*
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* Version: 1.0.0(2019年08月26日)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "2019年08月26日 22时28分19秒"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <string.h>
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#include <errno.h>
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#include "at91_sysGpio.h"
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/* export $port in /sys/class/gpio/export */
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int gpio_export(const char *port)
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{
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char fpath[SYSFILE_LEN];
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FILE *fp;
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int pin;
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if(!port)
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{
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gpio_print("invalid input arguments\n");
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return -1;
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}
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snprintf(fpath, SYSFILE_LEN, "%s/%s", SYSGPIO_PATH, port);
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/* GPIO port already export */
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if( !access(fpath, F_OK) )
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{
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gpio_print("%s already export\n", port);
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return 0;
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}
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if( !(fp=fopen(SYSGPIO_EXPORT_PATH, "w")) )
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{
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gpio_print("open '%s' failure: %s\n", SYSGPIO_EXPORT_PATH, strerror(errno));
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return -2;
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}
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pin = at91_port2pin(port);
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fprintf(fp, "%d", pin);
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fclose(fp);
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return 0;
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}
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/* unexport $port in /sys/class/gpio/unexport */
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int gpio_unexport(const char *port)
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{
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char fpath[SYSFILE_LEN];
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FILE *fp;
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int pin;
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if(!port)
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{
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gpio_print("invalid input arguments\n");
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return -1;
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}
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snprintf(fpath, SYSFILE_LEN, "%s/%s", SYSGPIO_PATH, port);
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/* GPIO port not export */
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if( access(fpath, F_OK) )
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{
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gpio_print("%s not export\n", port);
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return 0;
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}
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if( !(fp=fopen(SYSGPIO_UNEXPORT_PATH, "w")) )
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{
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gpio_print("open '%s' failure: %s\n", SYSGPIO_EXPORT_PATH, strerror(errno));
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return -2;
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}
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pin = at91_port2pin(port);
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fprintf(fp, "%d", pin);
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fclose(fp);
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return 0;
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}
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/* configure $port direction as $mode */
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int gpio_config(const char *port, const char *mode)
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{
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char fpath[SYSFILE_LEN];
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FILE *fp;
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int size;
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if(!port)
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{
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gpio_print("invalid input arguments\n");
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return 0;
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}
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snprintf(fpath, SYSFILE_LEN, "%s/%s", SYSGPIO_PATH, port);
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if( access(fpath, F_OK) ) /* GPIO port not export */
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{
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if( gpio_export(port) < 0 )
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return -1;
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}
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size = SYSFILE_LEN-strlen(fpath);
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strncat(fpath, "/direction", size);
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if( !(fp=fopen(fpath, "w")) )
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{
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gpio_print("open '%s' failure: %s\n", fpath, strerror(errno));
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return -1;
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}
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fputs(mode, fp);
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fclose(fp);
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return 0;
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}
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/* write $value into GPIO $port */
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int gpio_write(const char *port, const char *value)
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{
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char fpath[SYSFILE_LEN];
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FILE *fp;
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int size;
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if(!port)
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{
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gpio_print("invalid input arguments\n");
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return 0;
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}
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snprintf(fpath, SYSFILE_LEN, "%s/%s", SYSGPIO_PATH, port);
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if( access(fpath, F_OK) ) /* GPIO port not export */
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{
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if( gpio_export(port) < 0 )
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return -1;
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}
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size = SYSFILE_LEN-strlen(fpath);
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strncat(fpath, "/value", size);
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if( !(fp=fopen(fpath, "w")) )
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{
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gpio_print("open '%s' failure: %s\n", fpath, strerror(errno));
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return -1;
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}
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fputs(value, fp);
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fclose(fp);
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return 0;
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}
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/* read gpio value from $port */
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int gpio_read(const char *port)
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{
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char fpath[SYSFILE_LEN];
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FILE *fp;
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int size;
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char v_str[32];
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if(!port)
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{
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gpio_print("invalid input arguments\n");
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return 0;
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}
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snprintf(fpath, SYSFILE_LEN, "%s/%s", SYSGPIO_PATH, port);
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if( access(fpath, F_OK) ) /* GPIO port not export */
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{
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return -1;
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}
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size = SYSFILE_LEN-strlen(fpath);
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strncat(fpath, "/value", size);
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if( !(fp=fopen(fpath, "r")) )
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{
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gpio_print("open '%s' failure: %s\n", fpath, strerror(errno));
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return -1;
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}
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memset(v_str, 0, sizeof(v_str));
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fgets(v_str, sizeof(v_str), fp);
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fclose(fp);
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return atoi(v_str);
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}
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