root/tools/spi/spidev_fdx.c

DEFINITIONS

1. do_read
2. do_msg
3. dumpstat
4. main

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <stdio.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <fcntl.h>
   6 #include <string.h>
   7 
   8 #include <sys/ioctl.h>
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11 
  12 #include <linux/types.h>
  13 #include <linux/spi/spidev.h>
  14 
  15 
  16 static int verbose;
  17 
  18 static void do_read(int fd, int len)
  19 {
  20         unsigned char   buf[32], *bp;
  21         int             status;
  22 
  23         /* read at least 2 bytes, no more than 32 */
  24         if (len < 2)
  25                 len = 2;
  26         else if (len > sizeof(buf))
  27                 len = sizeof(buf);
  28         memset(buf, 0, sizeof buf);
  29 
  30         status = read(fd, buf, len);
  31         if (status < 0) {
  32                 perror("read");
  33                 return;
  34         }
  35         if (status != len) {
  36                 fprintf(stderr, "short read\n");
  37                 return;
  38         }
  39 
  40         printf("read(%2d, %2d): %02x %02x,", len, status,
  41                 buf[0], buf[1]);
  42         status -= 2;
  43         bp = buf + 2;
  44         while (status-- > 0)
  45                 printf(" %02x", *bp++);
  46         printf("\n");
  47 }
  48 
  49 static void do_msg(int fd, int len)
  50 {
  51         struct spi_ioc_transfer xfer[2];
  52         unsigned char           buf[32], *bp;
  53         int                     status;
  54 
  55         memset(xfer, 0, sizeof xfer);
  56         memset(buf, 0, sizeof buf);
  57 
  58         if (len > sizeof buf)
  59                 len = sizeof buf;
  60 
  61         buf[0] = 0xaa;
  62         xfer[0].tx_buf = (unsigned long)buf;
  63         xfer[0].len = 1;
  64 
  65         xfer[1].rx_buf = (unsigned long) buf;
  66         xfer[1].len = len;
  67 
  68         status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);
  69         if (status < 0) {
  70                 perror("SPI_IOC_MESSAGE");
  71                 return;
  72         }
  73 
  74         printf("response(%2d, %2d): ", len, status);
  75         for (bp = buf; len; len--)
  76                 printf(" %02x", *bp++);
  77         printf("\n");
  78 }
  79 
  80 static void dumpstat(const char *name, int fd)
  81 {
  82         __u8    lsb, bits;
  83         __u32   mode, speed;
  84 
  85         if (ioctl(fd, SPI_IOC_RD_MODE32, &mode) < 0) {
  86                 perror("SPI rd_mode");
  87                 return;
  88         }
  89         if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {
  90                 perror("SPI rd_lsb_fist");
  91                 return;
  92         }
  93         if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) {
  94                 perror("SPI bits_per_word");
  95                 return;
  96         }
  97         if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) {
  98                 perror("SPI max_speed_hz");
  99                 return;
 100         }
 101 
 102         printf("%s: spi mode 0x%x, %d bits %sper word, %d Hz max\n",
 103                 name, mode, bits, lsb ? "(lsb first) " : "", speed);
 104 }
 105 
 106 int main(int argc, char **argv)
 107 {
 108         int             c;
 109         int             readcount = 0;
 110         int             msglen = 0;
 111         int             fd;
 112         const char      *name;
 113 
 114         while ((c = getopt(argc, argv, "hm:r:v")) != EOF) {
 115                 switch (c) {
 116                 case 'm':
 117                         msglen = atoi(optarg);
 118                         if (msglen < 0)
 119                                 goto usage;
 120                         continue;
 121                 case 'r':
 122                         readcount = atoi(optarg);
 123                         if (readcount < 0)
 124                                 goto usage;
 125                         continue;
 126                 case 'v':
 127                         verbose++;
 128                         continue;
 129                 case 'h':
 130                 case '?':
 131 usage:
 132                         fprintf(stderr,
 133                                 "usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n",
 134                                 argv[0]);
 135                         return 1;
 136                 }
 137         }
 138 
 139         if ((optind + 1) != argc)
 140                 goto usage;
 141         name = argv[optind];
 142 
 143         fd = open(name, O_RDWR);
 144         if (fd < 0) {
 145                 perror("open");
 146                 return 1;
 147         }
 148 
 149         dumpstat(name, fd);
 150 
 151         if (msglen)
 152                 do_msg(fd, msglen);
 153 
 154         if (readcount)
 155                 do_read(fd, readcount);
 156 
 157         close(fd);
 158         return 0;
 159 }