usr.sbin/i2cscan/i2cscan.c

   1 /* $NetBSD: i2cscan.c,v 1.4 2013/07/10 15:18:54 tcort Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2011, 2013 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Paul Goyette and Jared McNeill
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __RCSID("$NetBSD: i2cscan.c,v 1.4 2013/07/10 15:18:54 tcort Exp $");
  34
  35 #include <sys/types.h>
  36 #include <sys/ioctl.h>
  37
  38 #include <err.h>
  39 #include <errno.h>
  40 #include <fcntl.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <unistd.h>
  44
  45 #include <dev/i2c/i2c_io.h>
  46
  47 #define MODE_DEFAULT 0
  48 #define MODE_READ 1
  49
  50 __dead static void
  51 usage(void)
  52 {
  53         fprintf(stderr, "usage: %s [-r] <i2cdev>\n", getprogname());
  54         exit(EXIT_FAILURE);
  55 }
  56
  57 static int
  58 iic_smbus_quick_write(int fd, i2c_addr_t addr, int flags)
  59 {
  60         i2c_ioctl_exec_t iie;
  61
  62         iie.iie_op = I2C_OP_WRITE_WITH_STOP;
  63         iie.iie_addr = addr;
  64         iie.iie_cmd = NULL;
  65         iie.iie_cmdlen = 0;
  66         iie.iie_buf = NULL;
  67         iie.iie_buflen = 0;
  68
  69         if (ioctl(fd, I2C_IOCTL_EXEC, &iie) == -1)
  70                 return errno;
  71         return 0;
  72 }
  73
  74 static int
  75 iic_smbus_receive_byte(int fd, i2c_addr_t addr, uint8_t *valp, int flags)
  76 {
  77         i2c_ioctl_exec_t iie;
  78
  79         iie.iie_op = I2C_OP_READ_WITH_STOP;
  80         iie.iie_addr = addr;
  81         iie.iie_cmd = NULL;
  82         iie.iie_cmdlen = 0;
  83         iie.iie_buf = valp;
  84         iie.iie_buflen = 1;
  85
  86         if (ioctl(fd, I2C_IOCTL_EXEC, &iie) == -1)
  87                 return errno;
  88         return 0;
  89
  90 }
  91
  92 static void
  93 do_i2c_scan(const char *dname, int fd, int mode)
  94 {
  95         int error;
  96         int found = 0;
  97         i2c_addr_t addr;
  98         uint8_t val;
  99
 100         for (addr = 0x09; addr < 0x78; addr++) {
 101                 /*
 102                  * Skip certain i2c addresses:
 103                  *      0x00            General Call / START
 104                  *      0x01            CBUS Address
 105                  *      0x02            Different Bus format
 106                  *      0x03 - 0x07     Reserved
 107                  *      0x08            Host Address
 108                  *      0x0c            Alert Response Address
 109                  *      0x28            ACCESS.Bus host
 110                  *      0x37            ACCESS.Bus default address
 111                  *      0x48 - 0x4b     Prototypes
 112                  *      0x61            Device Default Address
 113                  *      0x78 - 0x7b     10-bit addresses
 114                  *      0x7c - 0x7f     Reserved
 115                  *
 116                  * Some of these are skipped by judicious selection
 117                  * of the range of the above for (;;) statement.
 118                  *
 119                  * if (addr <= 0x08 || addr >= 0x78)
 120                  *      continue;
 121                  */
 122                 if (addr == 0x0c || addr == 0x28 || addr == 0x37 ||
 123                     addr == 0x61 || (addr & 0x7c) == 0x48)
 124                         continue;
 125
 126                 /*
 127                  * Use SMBus quick_write command to detect most
 128                  * addresses;  should avoid hanging the bus on
 129                  * some write-only devices (like clocks that show
 130                  * up at address 0x69)
 131                  *
 132                  * XXX The quick_write() is allegedly known to
 133                  * XXX corrupt the Atmel AT24RF08 EEPROM found
 134                  * XXX on some IBM Thinkpads!
 135                  */
 136                 printf("\r%s: scanning 0x%02x", dname, addr);
 137                 fflush(stdout);
 138                 if ((addr & 0xf8) == 0x30 ||
 139                     (addr & 0xf0) == 0x50 ||
 140                     mode == MODE_READ)
 141                         error = iic_smbus_receive_byte(fd, addr, &val, 0);
 142                 else
 143                         error = iic_smbus_quick_write(fd, addr, 0);
 144                 if (error == 0) {
 145                         printf("\r%s: found device at 0x%02x\n",
 146                             dname, addr);
 147                         ++found;
 148                 }
 149         }
 150         if (found == 0)
 151                 printf("\r%s: no devices found\n", dname);
 152         else
 153                 printf("\r%s: %d devices found\n", dname, found);
 154 }
 155
 156 int
 157 main(int argc, char *argv[])
 158 {
 159         int fd;
 160         int ch, rflag;
 161         int mode;
 162
 163         setprogname(*argv);
 164
 165         rflag = 0;
 166
 167         while ((ch = getopt(argc, argv, "r")) != -1)
 168                 switch (ch) {
 169                 case 'r':
 170                         rflag = 1;
 171                         break;
 172                 default:
 173                         break;
 174                 }
 175         argv += optind;
 176         argc -= optind;
 177
 178         if (rflag)
 179                 mode = MODE_READ;
 180         else
 181                 mode = MODE_DEFAULT;
 182
 183         if (*argv == NULL)
 184                 usage();
 185
 186         fd = open(*argv, O_RDWR);
 187         if (fd == -1)
 188                 err(EXIT_FAILURE, "couldn't open %s", *argv);
 189
 190         do_i2c_scan(*argv, fd, mode);
 191
 192         close(fd);
 193
 194         return EXIT_SUCCESS;
 195 }