waveshare_epaper

Waveshare e-paper display shenanigans
git clone git://bsandro.tech/waveshare_epaper
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sysfs_gpio.c (4138B)

      1 /*****************************************************************************
      2 * | File        :   SYSFS_GPIO.c
      3 * | Author      :   Waveshare team
      4 * | Function    :   Drive SYSFS_ GPIO
      5 * | Info        :   Read and write /sys/class/gpio
      6 *----------------
      7 * |	This version:   V1.0
      8 * | Date        :   2019-06-04
      9 * | Info        :   Basic version
     10 *
     11 #
     12 # Permission is hereby granted, free of charge, to any person obtaining a copy
     13 # of this software and associated documnetation files (the "Software"), to deal
     14 # in the Software without restriction, including without limitation the rights
     15 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     16 # copies of the Software, and to permit persons to  whom the Software is
     17 # furished to do so, subject to the following conditions:
     18 #
     19 # The above copyright notice and this permission notice shall be included in
     20 # all copies or substantial portions of the Software.
     21 #
     22 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     23 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     24 # FITNESS OR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     25 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     26 # LIABILITY WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     27 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     28 # THE SOFTWARE.
     29 #
     30 ******************************************************************************/
     31 #include "sysfs_gpio.h"
     32 #include <sys/stat.h>
     33 #include <sys/types.h>
     34 #include <fcntl.h>
     35 #include <stdio.h>
     36 #include <stdlib.h>
     37 #include <string.h>
     38 #include <unistd.h>
     39 
     40 int SYSFS_GPIO_Export(int Pin)
     41 {
     42     char buffer[NUM_MAXBUF];
     43     int len;
     44     int fd;
     45 
     46     fd = open("/sys/class/gpio/export", O_WRONLY);
     47     if (fd < 0) {
     48         SYSFS_GPIO_Debug( "Export Failed: Pin%d\n", Pin);
     49         return -1;
     50     }
     51 
     52     len = snprintf(buffer, NUM_MAXBUF, "%d", Pin);
     53     write(fd, buffer, len);
     54     
     55     SYSFS_GPIO_Debug( "Export: Pin%d\r\n", Pin);
     56 
     57     close(fd);
     58     return 0;
     59 }
     60 
     61 int SYSFS_GPIO_Unexport(int Pin)
     62 {
     63     char buffer[NUM_MAXBUF];
     64     int len;
     65     int fd;
     66 
     67     fd = open("/sys/class/gpio/unexport", O_WRONLY);
     68     if (fd < 0) {
     69         SYSFS_GPIO_Debug( "unexport Failed: Pin%d\n", Pin);
     70         return -1;
     71     }
     72 
     73     len = snprintf(buffer, NUM_MAXBUF, "%d", Pin);
     74     write(fd, buffer, len);
     75     
     76     SYSFS_GPIO_Debug( "Unexport: Pin%d\r\n", Pin);
     77     
     78     close(fd);
     79     return 0;
     80 }
     81 
     82 int SYSFS_GPIO_Direction(int Pin, int Dir)
     83 {
     84     const char dir_str[]  = "in\0out";
     85     char path[DIR_MAXSIZ];
     86     int fd;
     87     
     88     snprintf(path, DIR_MAXSIZ, "/sys/class/gpio/gpio%d/direction", Pin);
     89     fd = open(path, O_WRONLY);
     90     if (fd < 0) {
     91         SYSFS_GPIO_Debug( "Set Direction failed: Pin%d\n", Pin);
     92         return -1;
     93     }
     94 
     95     if (write(fd, &dir_str[Dir == IN ? 0 : 3], Dir == IN ? 2 : 3) < 0) {
     96         SYSFS_GPIO_Debug("failed to set direction!\r\n");
     97         return -1;
     98     }
     99 
    100     if(Dir == IN){
    101         SYSFS_GPIO_Debug("Pin%d:intput\r\n", Pin);
    102     }else{
    103         SYSFS_GPIO_Debug("Pin%d:Output\r\n", Pin);
    104     }
    105     
    106     close(fd);
    107     return 0;
    108 }
    109 
    110 int SYSFS_GPIO_Read(int Pin)
    111 {
    112     char path[DIR_MAXSIZ];
    113     char value_str[3];
    114     int fd;
    115     
    116     snprintf(path, DIR_MAXSIZ, "/sys/class/gpio/gpio%d/value", Pin);
    117     fd = open(path, O_RDONLY);
    118     if (fd < 0) {
    119         SYSFS_GPIO_Debug( "Read failed Pin%d\n", Pin);
    120         return -1;
    121     }
    122 
    123     if (read(fd, value_str, 3) < 0) {
    124         SYSFS_GPIO_Debug( "failed to read value!\n");
    125         return -1;
    126     }
    127 
    128     close(fd);
    129     return(atoi(value_str));
    130 }
    131 
    132 int SYSFS_GPIO_Write(int Pin, int value)
    133 {
    134     const char s_values_str[] = "01";
    135     char path[DIR_MAXSIZ];
    136     int fd;
    137     
    138     snprintf(path, DIR_MAXSIZ, "/sys/class/gpio/gpio%d/value", Pin);
    139     fd = open(path, O_WRONLY);
    140     if (fd < 0) {
    141         SYSFS_GPIO_Debug( "Write failed : Pin%d,value = %d\n", Pin, value);
    142         return -1;
    143     }
    144 
    145     if (write(fd, &s_values_str[value == LOW ? 0 : 1], 1) < 0) {
    146         SYSFS_GPIO_Debug( "failed to write value!\n");
    147         return -1;
    148     }
    149     
    150     close(fd);
    151     return 0;
    152 }