Documentation/spi/spidev_test.c

   1 /*
   2  * SPI testing utility (using spidev driver)
   3  *
   4  * Copyright (c) 2007  MontaVista Software, Inc.
   5  * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License.
  10  *
  11  * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
  12  */
  13
  14 #include <stdint.h>
  15 #include <unistd.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <getopt.h>
  19 #include <fcntl.h>
  20 #include <sys/ioctl.h>
  21 #include <linux/types.h>
  22 #include <linux/spi/spidev.h>
  23
  24 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
  25
  26 static void pabort(const char *s)
  27 {
  28         perror(s);
  29         abort();
  30 }
  31
  32 static const char *device = "/dev/spidev1.1";
  33 static uint8_t mode;
  34 static uint8_t bits = 8;
  35 static uint32_t speed = 500000;
  36 static uint16_t delay;
  37
  38 static void transfer(int fd)
  39 {
  40         int ret;
  41         uint8_t tx[] = {
  42                 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
  43                 0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
  44                 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
  45                 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
  46                 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
  47                 0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xAD,
  48                 0xF0, 0x0D,
  49         };
  50         uint8_t rx[ARRAY_SIZE(tx)] = {0, };
  51         struct spi_ioc_transfer tr = {
  52                 .tx_buf = (unsigned long)tx,
  53                 .rx_buf = (unsigned long)rx,
  54                 .len = ARRAY_SIZE(tx),
  55                 .delay_usecs = delay,
  56                 .speed_hz = speed,
  57                 .bits_per_word = bits,
  58         };
  59
  60         ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
  61         if (ret == 1)
  62                 pabort("can't send spi message");
  63
  64         for (ret = 0; ret < ARRAY_SIZE(tx); ret++) {
  65                 if (!(ret % 6))
  66                         puts("");
  67                 printf("%.2X ", rx[ret]);
  68         }
  69         puts("");
  70 }
  71
  72 void print_usage(const char *prog)
  73 {
  74         printf("Usage: %s [-DsbdlHOLC3]\n", prog);
  75         puts("  -D --device   device to use (default /dev/spidev1.1)\n"
  76              "  -s --speed    max speed (Hz)\n"
  77              "  -d --delay    delay (usec)\n"
  78              "  -b --bpw      bits per word \n"
  79              "  -l --loop     loopback\n"
  80              "  -H --cpha     clock phase\n"
  81              "  -O --cpol     clock polarity\n"
  82              "  -L --lsb      least significant bit first\n"
  83              "  -C --cs-high  chip select active high\n"
  84              "  -3 --3wire    SI/SO signals shared\n");
  85         exit(1);
  86 }
  87
  88 void parse_opts(int argc, char *argv[])
  89 {
  90         while (1) {
  91                 static const struct option lopts[] = {
  92                         { "device",  1, 0, 'D' },
  93                         { "speed",   1, 0, 's' },
  94                         { "delay",   1, 0, 'd' },
  95                         { "bpw",     1, 0, 'b' },
  96                         { "loop",    0, 0, 'l' },
  97                         { "cpha",    0, 0, 'H' },
  98                         { "cpol",    0, 0, 'O' },
  99                         { "lsb",     0, 0, 'L' },
 100                         { "cs-high", 0, 0, 'C' },
 101                         { "3wire",   0, 0, '3' },
 102                         { NULL, 0, 0, 0 },
 103                 };
 104                 int c;
 105
 106                 c = getopt_long(argc, argv, "D:s:d:b:lHOLC3", lopts, NULL);
 107
 108                 if (c == -1)
 109                         break;
 110
 111                 switch (c) {
 112                 case 'D':
 113                         device = optarg;
 114                         break;
 115                 case 's':
 116                         speed = atoi(optarg);
 117                         break;
 118                 case 'd':
 119                         delay = atoi(optarg);
 120                         break;
 121                 case 'b':
 122                         bits = atoi(optarg);
 123                         break;
 124                 case 'l':
 125                         mode |= SPI_LOOP;
 126                         break;
 127                 case 'H':
 128                         mode |= SPI_CPHA;
 129                         break;
 130                 case 'O':
 131                         mode |= SPI_CPOL;
 132                         break;
 133                 case 'L':
 134                         mode |= SPI_LSB_FIRST;
 135                         break;
 136                 case 'C':
 137                         mode |= SPI_CS_HIGH;
 138                         break;
 139                 case '3':
 140                         mode |= SPI_3WIRE;
 141                         break;
 142                 default:
 143                         print_usage(argv[0]);
 144                         break;
 145                 }
 146         }
 147 }
 148
 149 int main(int argc, char *argv[])
 150 {
 151         int ret = 0;
 152         int fd;
 153
 154         parse_opts(argc, argv);
 155
 156         fd = open(device, O_RDWR);
 157         if (fd < 0)
 158                 pabort("can't open device");
 159
 160         /*
 161          * spi mode
 162          */
 163         ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
 164         if (ret == -1)
 165                 pabort("can't set spi mode");
 166
 167         ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
 168         if (ret == -1)
 169                 pabort("can't get spi mode");
 170
 171         /*
 172          * bits per word
 173          */
 174         ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
 175         if (ret == -1)
 176                 pabort("can't set bits per word");
 177
 178         ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
 179         if (ret == -1)
 180                 pabort("can't get bits per word");
 181
 182         /*
 183          * max speed hz
 184          */
 185         ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
 186         if (ret == -1)
 187                 pabort("can't set max speed hz");
 188
 189         ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
 190         if (ret == -1)
 191                 pabort("can't get max speed hz");
 192
 193         printf("spi mode: %d\n", mode);
 194         printf("bits per word: %d\n", bits);
 195         printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);
 196
 197         transfer(fd);
 198
 199         close(fd);
 200
 201         return ret;
 202 }