miscutils/i2c_tools.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Minimal i2c-tools implementation for busybox.
   4  * Parts of code ported from i2c-tools:
   5  *              http://www.lm-sensors.org/wiki/I2CTools.
   6  *
   7  * Copyright (C) 2014 by Bartosz Golaszewski <bartekgola@gmail.com>
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10  */
  11
  12 //config:config I2CGET
  13 //config:       bool "i2cget"
  14 //config:       default y
  15 //config:       select PLATFORM_LINUX
  16 //config:       help
  17 //config:         Read from I2C/SMBus chip registers.
  18 //config:
  19 //config:config I2CSET
  20 //config:       bool "i2cset"
  21 //config:       default y
  22 //config:       select PLATFORM_LINUX
  23 //config:       help
  24 //config:         Set I2C registers.
  25 //config:
  26 //config:config I2CDUMP
  27 //config:       bool "i2cdump"
  28 //config:       default y
  29 //config:       select PLATFORM_LINUX
  30 //config:       help
  31 //config:         Examine I2C registers.
  32 //config:
  33 //config:config I2CDETECT
  34 //config:       bool "i2cdetect"
  35 //config:       default y
  36 //config:       select PLATFORM_LINUX
  37 //config:       help
  38 //config:         Detect I2C chips.
  39 //config:
  40
  41 //applet:IF_I2CGET(APPLET(i2cget, BB_DIR_USR_SBIN, BB_SUID_DROP))
  42 //applet:IF_I2CSET(APPLET(i2cset, BB_DIR_USR_SBIN, BB_SUID_DROP))
  43 //applet:IF_I2CDUMP(APPLET(i2cdump, BB_DIR_USR_SBIN, BB_SUID_DROP))
  44 //applet:IF_I2CDETECT(APPLET(i2cdetect, BB_DIR_USR_SBIN, BB_SUID_DROP))
  45
  46 //kbuild:lib-$(CONFIG_I2CGET) += i2c_tools.o
  47 //kbuild:lib-$(CONFIG_I2CSET) += i2c_tools.o
  48 //kbuild:lib-$(CONFIG_I2CDUMP) += i2c_tools.o
  49 //kbuild:lib-$(CONFIG_I2CDETECT) += i2c_tools.o
  50
  51 /*
  52  * Unsupported stuff:
  53  *
  54  * - upstream i2c-tools can also look-up i2c busses by name, we only accept
  55  *   numbers,
  56  * - bank and bankreg parameters for i2cdump are not supported because of
  57  *   their limited usefulness (see i2cdump manual entry for more info),
  58  * - i2cdetect doesn't look for bus info in /proc as it does in upstream, but
  59  *   it shouldn't be a problem in modern kernels.
  60  */
  61
  62 #include "libbb.h"
  63
  64 #include <linux/i2c.h>
  65 #include <linux/i2c-dev.h>
  66
  67 #define I2CDUMP_NUM_REGS                256
  68
  69 #define I2CDETECT_MODE_AUTO             0
  70 #define I2CDETECT_MODE_QUICK            1
  71 #define I2CDETECT_MODE_READ             2
  72
  73 /*
  74  * This is needed for ioctl_or_perror_and_die() since it only accepts pointers.
  75  */
  76 static ALWAYS_INLINE void *itoptr(int i)
  77 {
  78         return (void*)(intptr_t)i;
  79 }
  80
  81 static int32_t i2c_smbus_access(int fd, char read_write, uint8_t cmd,
  82                                 int size, union i2c_smbus_data *data)
  83 {
  84         struct i2c_smbus_ioctl_data args;
  85
  86         args.read_write = read_write;
  87         args.command = cmd;
  88         args.size = size;
  89         args.data = data;
  90
  91         return ioctl(fd, I2C_SMBUS, &args);
  92 }
  93
  94 static int32_t i2c_smbus_read_byte(int fd)
  95 {
  96         union i2c_smbus_data data;
  97         int err;
  98
  99         err = i2c_smbus_access(fd, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data);
 100         if (err < 0)
 101                 return err;
 102
 103         return data.byte;
 104 }
 105
 106 #if ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP
 107 static int32_t i2c_smbus_write_byte(int fd, uint8_t val)
 108 {
 109         return i2c_smbus_access(fd, I2C_SMBUS_WRITE,
 110                                 val, I2C_SMBUS_BYTE, NULL);
 111 }
 112
 113 static int32_t i2c_smbus_read_byte_data(int fd, uint8_t cmd)
 114 {
 115         union i2c_smbus_data data;
 116         int err;
 117
 118         err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
 119                                I2C_SMBUS_BYTE_DATA, &data);
 120         if (err < 0)
 121                 return err;
 122
 123         return data.byte;
 124 }
 125
 126 static int32_t i2c_smbus_read_word_data(int fd, uint8_t cmd)
 127 {
 128         union i2c_smbus_data data;
 129         int err;
 130
 131         err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
 132                                I2C_SMBUS_WORD_DATA, &data);
 133         if (err < 0)
 134                 return err;
 135
 136         return data.word;
 137 }
 138 #endif /* ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP */
 139
 140 #if ENABLE_I2CSET
 141 static int32_t i2c_smbus_write_byte_data(int file,
 142                                          uint8_t cmd, uint8_t value)
 143 {
 144         union i2c_smbus_data data;
 145
 146         data.byte = value;
 147
 148         return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
 149                                 I2C_SMBUS_BYTE_DATA, &data);
 150 }
 151
 152 static int32_t i2c_smbus_write_word_data(int file, uint8_t cmd, uint16_t value)
 153 {
 154         union i2c_smbus_data data;
 155
 156         data.word = value;
 157
 158         return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
 159                                 I2C_SMBUS_WORD_DATA, &data);
 160 }
 161
 162 static int32_t i2c_smbus_write_block_data(int file, uint8_t cmd,
 163                                    uint8_t length, const uint8_t *values)
 164 {
 165         union i2c_smbus_data data;
 166
 167         if (length > I2C_SMBUS_BLOCK_MAX)
 168                 length = I2C_SMBUS_BLOCK_MAX;
 169
 170         memcpy(data.block+1, values, length);
 171         data.block[0] = length;
 172
 173         return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
 174                                 I2C_SMBUS_BLOCK_DATA, &data);
 175 }
 176
 177 static int32_t i2c_smbus_write_i2c_block_data(int file, uint8_t cmd,
 178                                        uint8_t length, const uint8_t *values)
 179 {
 180         union i2c_smbus_data data;
 181
 182         if (length > I2C_SMBUS_BLOCK_MAX)
 183                 length = I2C_SMBUS_BLOCK_MAX;
 184
 185         memcpy(data.block+1, values, length);
 186         data.block[0] = length;
 187
 188         return i2c_smbus_access(file, I2C_SMBUS_WRITE, cmd,
 189                                 I2C_SMBUS_I2C_BLOCK_BROKEN, &data);
 190 }
 191 #endif /* ENABLE_I2CSET */
 192
 193 #if ENABLE_I2CDUMP
 194 /*
 195  * Returns the number of bytes read, vals must hold at
 196  * least I2C_SMBUS_BLOCK_MAX bytes.
 197  */
 198 static int32_t i2c_smbus_read_block_data(int fd, uint8_t cmd, uint8_t *vals)
 199 {
 200         union i2c_smbus_data data;
 201         int i, err;
 202
 203         err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
 204                                I2C_SMBUS_BLOCK_DATA, &data);
 205         if (err < 0)
 206                 return err;
 207
 208         for (i = 1; i <= data.block[0]; i++)
 209                 *vals++ = data.block[i];
 210         return data.block[0];
 211 }
 212
 213 static int32_t i2c_smbus_read_i2c_block_data(int fd, uint8_t cmd,
 214                                              uint8_t len, uint8_t *vals)
 215 {
 216         union i2c_smbus_data data;
 217         int i, err;
 218
 219         if (len > I2C_SMBUS_BLOCK_MAX)
 220                 len = I2C_SMBUS_BLOCK_MAX;
 221         data.block[0] = len;
 222
 223         err = i2c_smbus_access(fd, I2C_SMBUS_READ, cmd,
 224                                len == 32 ? I2C_SMBUS_I2C_BLOCK_BROKEN :
 225                                            I2C_SMBUS_I2C_BLOCK_DATA, &data);
 226         if (err < 0)
 227                 return err;
 228
 229         for (i = 1; i <= data.block[0]; i++)
 230                 *vals++ = data.block[i];
 231         return data.block[0];
 232 }
 233 #endif /* ENABLE_I2CDUMP */
 234
 235 #if ENABLE_I2CDETECT
 236 static int32_t i2c_smbus_write_quick(int fd, uint8_t val)
 237 {
 238         return i2c_smbus_access(fd, val, 0, I2C_SMBUS_QUICK, NULL);
 239 }
 240 #endif /* ENABLE_I2CDETECT */
 241
 242 static int i2c_bus_lookup(const char *bus_str)
 243 {
 244         return xstrtou_range(bus_str, 10, 0, 0xfffff);
 245 }
 246
 247 #if ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP
 248 static int i2c_parse_bus_addr(const char *addr_str)
 249 {
 250         /* Slave address must be in range 0x03 - 0x77. */
 251         return xstrtou_range(addr_str, 16, 0x03, 0x77);
 252 }
 253
 254 static void i2c_set_pec(int fd, int pec)
 255 {
 256         ioctl_or_perror_and_die(fd, I2C_PEC,
 257                                 itoptr(pec ? 1 : 0),
 258                                 "can't set PEC");
 259 }
 260
 261 static void i2c_set_slave_addr(int fd, int addr, int force)
 262 {
 263         ioctl_or_perror_and_die(fd, force ? I2C_SLAVE_FORCE : I2C_SLAVE,
 264                                 itoptr(addr),
 265                                 "can't set address to 0x%02x", addr);
 266 }
 267 #endif /* ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP */
 268
 269 #if ENABLE_I2CGET || ENABLE_I2CSET
 270 static int i2c_parse_data_addr(const char *data_addr)
 271 {
 272         /* Data address must be an 8 bit integer. */
 273         return xstrtou_range(data_addr, 16, 0, 0xff);
 274 }
 275 #endif /* ENABLE_I2CGET || ENABLE_I2CSET */
 276
 277 /*
 278  * Opens the device file associated with given i2c bus.
 279  *
 280  * Upstream i2c-tools also support opening devices by i2c bus name
 281  * but we drop it here for size reduction.
 282  */
 283 static int i2c_dev_open(int i2cbus)
 284 {
 285         char filename[sizeof("/dev/i2c-%d") + sizeof(int)*3];
 286         int fd;
 287
 288         sprintf(filename, "/dev/i2c-%d", i2cbus);
 289         fd = open(filename, O_RDWR);
 290         if (fd < 0) {
 291                 if (errno == ENOENT) {
 292                         filename[8] = '/'; /* change to "/dev/i2c/%d" */
 293                         fd = xopen(filename, O_RDWR);
 294                 } else {
 295                         bb_perror_msg_and_die("can't open '%s'", filename);
 296                 }
 297         }
 298
 299         return fd;
 300 }
 301
 302 /* Size reducing helpers for xxx_check_funcs(). */
 303 static void get_funcs_matrix(int fd, unsigned long *funcs)
 304 {
 305         ioctl_or_perror_and_die(fd, I2C_FUNCS, funcs,
 306                         "can't get adapter functionality matrix");
 307 }
 308
 309 #if ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP
 310 static void check_funcs_test_end(int funcs, int pec, const char *err)
 311 {
 312         if (pec && !(funcs & (I2C_FUNC_SMBUS_PEC | I2C_FUNC_I2C)))
 313                 bb_error_msg("warning: adapter does not support PEC");
 314
 315         if (err)
 316                 bb_error_msg_and_die(
 317                         "adapter has no %s capability", err);
 318 }
 319 #endif /* ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP */
 320
 321 /*
 322  * The below functions emit an error message and exit if the adapter doesn't
 323  * support desired functionalities.
 324  */
 325 #if ENABLE_I2CGET || ENABLE_I2CDUMP
 326 static void check_read_funcs(int fd, int mode, int data_addr, int pec)
 327 {
 328         unsigned long funcs;
 329         const char *err = NULL;
 330
 331         get_funcs_matrix(fd, &funcs);
 332         switch (mode) {
 333         case I2C_SMBUS_BYTE:
 334                 if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
 335                         err = "SMBus receive byte";
 336                         break;
 337                 }
 338                 if (data_addr >= 0 && !(funcs & I2C_FUNC_SMBUS_WRITE_BYTE))
 339                         err = "SMBus send byte";
 340                 break;
 341         case I2C_SMBUS_BYTE_DATA:
 342                 if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE_DATA))
 343                         err = "SMBus read byte";
 344                 break;
 345         case I2C_SMBUS_WORD_DATA:
 346                 if (!(funcs & I2C_FUNC_SMBUS_READ_WORD_DATA))
 347                         err = "SMBus read word";
 348                 break;
 349 #if ENABLE_I2CDUMP
 350         case I2C_SMBUS_BLOCK_DATA:
 351                 if (!(funcs & I2C_FUNC_SMBUS_READ_BLOCK_DATA))
 352                         err = "SMBus block read";
 353                 break;
 354
 355         case I2C_SMBUS_I2C_BLOCK_DATA:
 356                 if (!(funcs & I2C_FUNC_SMBUS_READ_I2C_BLOCK))
 357                         err = "I2C block read";
 358                 break;
 359 #endif /* ENABLE_I2CDUMP */
 360         default:
 361                 bb_error_msg_and_die("internal error");
 362         }
 363         check_funcs_test_end(funcs, pec, err);
 364 }
 365 #endif /* ENABLE_I2CGET || ENABLE_I2CDUMP */
 366
 367 #if ENABLE_I2CSET
 368 static void check_write_funcs(int fd, int mode, int pec)
 369 {
 370         unsigned long funcs;
 371         const char *err = NULL;
 372
 373         get_funcs_matrix(fd, &funcs);
 374         switch (mode) {
 375         case I2C_SMBUS_BYTE:
 376                 if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE))
 377                         err = "SMBus send byte";
 378                 break;
 379
 380         case I2C_SMBUS_BYTE_DATA:
 381                 if (!(funcs & I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 382                         err = "SMBus write byte";
 383                 break;
 384
 385         case I2C_SMBUS_WORD_DATA:
 386                 if (!(funcs & I2C_FUNC_SMBUS_WRITE_WORD_DATA))
 387                         err = "SMBus write word";
 388                 break;
 389
 390         case I2C_SMBUS_BLOCK_DATA:
 391                 if (!(funcs & I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
 392                         err = "SMBus block write";
 393                 break;
 394         case I2C_SMBUS_I2C_BLOCK_DATA:
 395                 if (!(funcs & I2C_FUNC_SMBUS_WRITE_I2C_BLOCK))
 396                         err = "I2C block write";
 397                 break;
 398         }
 399         check_funcs_test_end(funcs, pec, err);
 400 }
 401 #endif /* ENABLE_I2CSET */
 402
 403 static void confirm_or_abort(void)
 404 {
 405         fprintf(stderr, "Continue? [y/N] ");
 406         fflush_all();
 407         if (!bb_ask_confirmation())
 408                 bb_error_msg_and_die("aborting");
 409 }
 410
 411 /*
 412  * Return only if user confirms the action, abort otherwise.
 413  *
 414  * The messages displayed here are much less elaborate than their i2c-tools
 415  * counterparts - this is done for size reduction.
 416  */
 417 static void confirm_action(int bus_addr, int mode, int data_addr, int pec)
 418 {
 419         bb_error_msg("WARNING! This program can confuse your I2C bus");
 420
 421         /* Don't let the user break his/her EEPROMs */
 422         if (bus_addr >= 0x50 && bus_addr <= 0x57 && pec) {
 423                 bb_error_msg_and_die("this is I2C not smbus - using PEC on I2C "
 424                         "devices may result in data loss, aborting");
 425         }
 426
 427         if (mode == I2C_SMBUS_BYTE && data_addr >= 0 && pec)
 428                 bb_error_msg("WARNING! May interpret a write byte command "
 429                         "with PEC as a write byte data command");
 430
 431         if (pec)
 432                 bb_error_msg("PEC checking enabled");
 433
 434         confirm_or_abort();
 435 }
 436
 437 #if ENABLE_I2CGET
 438 //usage:#define i2cget_trivial_usage
 439 //usage:       "[-f] [-y] BUS CHIP-ADDRESS [DATA-ADDRESS [MODE]]"
 440 //usage:#define i2cget_full_usage "\n\n"
 441 //usage:       "Read from I2C/SMBus chip registers\n"
 442 //usage:     "\n        I2CBUS  i2c bus number"
 443 //usage:     "\n        ADDRESS 0x03 - 0x77"
 444 //usage:     "\nMODE is:"
 445 //usage:     "\n        b       read byte data (default)"
 446 //usage:     "\n        w       read word data"
 447 //usage:     "\n        c       write byte/read byte"
 448 //usage:     "\n        Append p for SMBus PEC"
 449 //usage:     "\n"
 450 //usage:     "\n        -f      force access"
 451 //usage:     "\n        -y      disable interactive mode"
 452 int i2cget_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 453 int i2cget_main(int argc UNUSED_PARAM, char **argv)
 454 {
 455         const unsigned opt_f = (1 << 0), opt_y = (1 << 1);
 456         const char *const optstr = "fy";
 457
 458         int bus_num, bus_addr, data_addr = -1, status;
 459         int mode = I2C_SMBUS_BYTE, pec = 0, fd;
 460         unsigned opts;
 461
 462         opt_complementary = "-2:?4"; /* from 2 to 4 args */
 463         opts = getopt32(argv, optstr);
 464         argv += optind;
 465
 466         bus_num = i2c_bus_lookup(argv[0]);
 467         bus_addr = i2c_parse_bus_addr(argv[1]);
 468
 469         if (argv[2]) {
 470                 data_addr = i2c_parse_data_addr(argv[2]);
 471                 mode = I2C_SMBUS_BYTE_DATA;
 472                 if (argv[3]) {
 473                         switch (argv[3][0]) {
 474                         case 'b':       /* Already set */               break;
 475                         case 'w':       mode = I2C_SMBUS_WORD_DATA;     break;
 476                         case 'c':       mode = I2C_SMBUS_BYTE;          break;
 477                         default:
 478                                 bb_error_msg("invalid mode");
 479                                 bb_show_usage();
 480                         }
 481                         pec = argv[3][1] == 'p';
 482                 }
 483         }
 484
 485         fd = i2c_dev_open(bus_num);
 486         check_read_funcs(fd, mode, data_addr, pec);
 487         i2c_set_slave_addr(fd, bus_addr, opts & opt_f);
 488
 489         if (!(opts & opt_y))
 490                 confirm_action(bus_addr, mode, data_addr, pec);
 491
 492         if (pec)
 493                 i2c_set_pec(fd, 1);
 494
 495         switch (mode) {
 496         case I2C_SMBUS_BYTE:
 497                 if (data_addr >= 0) {
 498                         status = i2c_smbus_write_byte(fd, data_addr);
 499                         if (status < 0)
 500                                 bb_error_msg("warning - write failed");
 501                 }
 502                 status = i2c_smbus_read_byte(fd);
 503                 break;
 504         case I2C_SMBUS_WORD_DATA:
 505                 status = i2c_smbus_read_word_data(fd, data_addr);
 506                 break;
 507         default: /* I2C_SMBUS_BYTE_DATA */
 508                 status = i2c_smbus_read_byte_data(fd, data_addr);
 509         }
 510         close(fd);
 511
 512         if (status < 0)
 513                 bb_perror_msg_and_die("read failed");
 514
 515         printf("0x%0*x\n", mode == I2C_SMBUS_WORD_DATA ? 4 : 2, status);
 516
 517         return 0;
 518 }
 519 #endif /* ENABLE_I2CGET */
 520
 521 #if ENABLE_I2CSET
 522 //usage:#define i2cset_trivial_usage
 523 //usage:       "[-f] [-y] [-m MASK] BUS CHIP-ADDR DATA-ADDR [VALUE] ... [MODE]"
 524 //usage:#define i2cset_full_usage "\n\n"
 525 //usage:       "Set I2C registers\n"
 526 //usage:     "\n        I2CBUS  i2c bus number"
 527 //usage:     "\n        ADDRESS 0x03 - 0x77"
 528 //usage:     "\nMODE is:"
 529 //usage:     "\n        c       byte, no value"
 530 //usage:     "\n        b       byte data (default)"
 531 //usage:     "\n        w       word data"
 532 //usage:     "\n        i       I2C block data"
 533 //usage:     "\n        s       SMBus block data"
 534 //usage:     "\n        Append p for SMBus PEC"
 535 //usage:     "\n"
 536 //usage:     "\n        -f      force access"
 537 //usage:     "\n        -y      disable interactive mode"
 538 //usage:     "\n        -r      read back and compare the result"
 539 //usage:     "\n        -m MASK mask specifying which bits to write"
 540 int i2cset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 541 int i2cset_main(int argc, char **argv)
 542 {
 543         const unsigned opt_f = (1 << 0), opt_y = (1 << 1),
 544                               opt_m = (1 << 2), opt_r = (1 << 3);
 545         const char *const optstr = "fym:r";
 546
 547         int bus_num, bus_addr, data_addr, mode = I2C_SMBUS_BYTE, pec = 0;
 548         int val, blen = 0, mask = 0, fd, status;
 549         unsigned char block[I2C_SMBUS_BLOCK_MAX];
 550         char *opt_m_arg = NULL;
 551         unsigned opts;
 552
 553         opt_complementary = "-3"; /* from 3 to ? args */
 554         opts = getopt32(argv, optstr, &opt_m_arg);
 555         argv += optind;
 556         argc -= optind;
 557
 558         bus_num = i2c_bus_lookup(argv[0]);
 559         bus_addr = i2c_parse_bus_addr(argv[1]);
 560         data_addr = i2c_parse_data_addr(argv[2]);
 561
 562         if (argv[3]) {
 563                 if (!argv[4] && argv[3][0] != 'c') {
 564                         mode = I2C_SMBUS_BYTE_DATA; /* Implicit b */
 565                 } else {
 566                         switch (argv[argc-1][0]) {
 567                         case 'c': /* Already set */                     break;
 568                         case 'b': mode = I2C_SMBUS_BYTE_DATA;           break;
 569                         case 'w': mode = I2C_SMBUS_WORD_DATA;           break;
 570                         case 's': mode = I2C_SMBUS_BLOCK_DATA;          break;
 571                         case 'i': mode = I2C_SMBUS_I2C_BLOCK_DATA;      break;
 572                         default:
 573                                 bb_error_msg("invalid mode");
 574                                 bb_show_usage();
 575                         }
 576
 577                         pec = argv[argc-1][1] == 'p';
 578                         if (mode == I2C_SMBUS_BLOCK_DATA ||
 579                                         mode == I2C_SMBUS_I2C_BLOCK_DATA) {
 580                                 if (pec && mode == I2C_SMBUS_I2C_BLOCK_DATA)
 581                                         bb_error_msg_and_die(
 582                                                 "PEC not supported for I2C "
 583                                                 "block writes");
 584                                 if (opts & opt_m)
 585                                         bb_error_msg_and_die(
 586                                                 "mask not supported for block "
 587                                                 "writes");
 588                         }
 589                 }
 590         }
 591
 592         /* Prepare the value(s) to be written according to current mode. */
 593         switch (mode) {
 594         case I2C_SMBUS_BYTE_DATA:
 595                 val = xstrtou_range(argv[3], 0, 0, 0xff);
 596                 break;
 597         case I2C_SMBUS_WORD_DATA:
 598                 val = xstrtou_range(argv[3], 0, 0, 0xffff);
 599                 break;
 600         case I2C_SMBUS_BLOCK_DATA:
 601         case I2C_SMBUS_I2C_BLOCK_DATA:
 602                 for (blen = 3; blen < (argc - 1); blen++)
 603                         block[blen] = xstrtou_range(argv[blen], 0, 0, 0xff);
 604                 val = -1;
 605                 break;
 606         default:
 607                 val = -1;
 608                 break;
 609         }
 610
 611         if (opts & opt_m) {
 612                 mask = xstrtou_range(opt_m_arg, 0, 0,
 613                                 (mode == I2C_SMBUS_BYTE ||
 614                                  mode == I2C_SMBUS_BYTE_DATA) ? 0xff : 0xffff);
 615         }
 616
 617         fd = i2c_dev_open(bus_num);
 618         check_write_funcs(fd, mode, pec);
 619         i2c_set_slave_addr(fd, bus_addr, opts & opt_f);
 620
 621         if (!(opts & opt_y))
 622                 confirm_action(bus_addr, mode, data_addr, pec);
 623
 624         /*
 625          * If we're using mask - read the current value here and adjust the
 626          * value to be written.
 627          */
 628         if (opts & opt_m) {
 629                 int tmpval;
 630
 631                 switch (mode) {
 632                 case I2C_SMBUS_BYTE:
 633                         tmpval = i2c_smbus_read_byte(fd);
 634                         break;
 635                 case I2C_SMBUS_WORD_DATA:
 636                         tmpval = i2c_smbus_read_word_data(fd, data_addr);
 637                         break;
 638                 default:
 639                         tmpval = i2c_smbus_read_byte_data(fd, data_addr);
 640                 }
 641
 642                 if (tmpval < 0)
 643                         bb_perror_msg_and_die("can't read old value");
 644
 645                 val = (val & mask) | (tmpval & ~mask);
 646
 647                 if (!(opts & opt_y)) {
 648                         bb_error_msg("old value 0x%0*x, write mask "
 649                                 "0x%0*x, will write 0x%0*x to register "
 650                                 "0x%02x",
 651                                 mode == I2C_SMBUS_WORD_DATA ? 4 : 2, tmpval,
 652                                 mode == I2C_SMBUS_WORD_DATA ? 4 : 2, mask,
 653                                 mode == I2C_SMBUS_WORD_DATA ? 4 : 2, val,
 654                                 data_addr);
 655                         confirm_or_abort();
 656                 }
 657         }
 658
 659         if (pec)
 660                 i2c_set_pec(fd, 1);
 661
 662         switch (mode) {
 663         case I2C_SMBUS_BYTE:
 664                 status = i2c_smbus_write_byte(fd, data_addr);
 665                 break;
 666         case I2C_SMBUS_WORD_DATA:
 667                 status = i2c_smbus_write_word_data(fd, data_addr, val);
 668                 break;
 669         case I2C_SMBUS_BLOCK_DATA:
 670                 status = i2c_smbus_write_block_data(fd, data_addr,
 671                                                     blen, block);
 672                 break;
 673         case I2C_SMBUS_I2C_BLOCK_DATA:
 674                 status = i2c_smbus_write_i2c_block_data(fd, data_addr,
 675                                                         blen, block);
 676                 break;
 677         default: /* I2C_SMBUS_BYTE_DATA */
 678                 status = i2c_smbus_write_byte_data(fd, data_addr, val);
 679                 break;
 680         }
 681         if (status < 0)
 682                 bb_perror_msg_and_die("write failed");
 683
 684         if (pec)
 685                 i2c_set_pec(fd, 0); /* Clear PEC. */
 686
 687         /* No readback required - we're done. */
 688         if (!(opts & opt_r))
 689                 return 0;
 690
 691         switch (mode) {
 692         case I2C_SMBUS_BYTE:
 693                 status = i2c_smbus_read_byte(fd);
 694                 val = data_addr;
 695                 break;
 696         case I2C_SMBUS_WORD_DATA:
 697                 status = i2c_smbus_read_word_data(fd, data_addr);
 698                 break;
 699         default: /* I2C_SMBUS_BYTE_DATA */
 700                 status = i2c_smbus_read_byte_data(fd, data_addr);
 701         }
 702
 703         if (status < 0) {
 704                 puts("Warning - readback failed");
 705         } else
 706         if (status != val) {
 707                 printf("Warning - data mismatch - wrote "
 708                        "0x%0*x, read back 0x%0*x\n",
 709                        mode == I2C_SMBUS_WORD_DATA ? 4 : 2, val,
 710                        mode == I2C_SMBUS_WORD_DATA ? 4 : 2, status);
 711         } else {
 712                 printf("Value 0x%0*x written, readback matched\n",
 713                        mode == I2C_SMBUS_WORD_DATA ? 4 : 2, val);
 714         }
 715
 716         return 0;
 717 }
 718 #endif /* ENABLE_I2CSET */
 719
 720 #if ENABLE_I2CDUMP
 721 static int read_block_data(int buf_fd, int mode, int *block)
 722 {
 723         uint8_t cblock[I2C_SMBUS_BLOCK_MAX + I2CDUMP_NUM_REGS];
 724         int res, blen = 0, tmp, i;
 725
 726         if (mode == I2C_SMBUS_BLOCK_DATA) {
 727                 blen = i2c_smbus_read_block_data(buf_fd, 0, cblock);
 728                 if (blen <= 0)
 729                         goto fail;
 730         } else {
 731                 for (res = 0; res < I2CDUMP_NUM_REGS; res += tmp) {
 732                         tmp = i2c_smbus_read_i2c_block_data(
 733                                         buf_fd, res, I2C_SMBUS_BLOCK_MAX,
 734                                         cblock + res);
 735                         if (tmp <= 0)
 736                                 goto fail;
 737                 }
 738
 739                 if (res >= I2CDUMP_NUM_REGS)
 740                         res = I2CDUMP_NUM_REGS;
 741
 742                 for (i = 0; i < res; i++)
 743                         block[i] = cblock[i];
 744
 745                 if (mode != I2C_SMBUS_BLOCK_DATA)
 746                         for (i = res; i < I2CDUMP_NUM_REGS; i++)
 747                                 block[i] = -1;
 748         }
 749
 750         return blen;
 751
 752  fail:
 753         bb_error_msg_and_die("block read failed");
 754 }
 755
 756 /* Dump all but word data. */
 757 static void dump_data(int bus_fd, int mode, unsigned first,
 758                       unsigned last, int *block, int blen)
 759 {
 760         int i, j, res;
 761
 762         puts("     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f"
 763              "    0123456789abcdef");
 764
 765         for (i = 0; i < I2CDUMP_NUM_REGS; i += 0x10) {
 766                 if (mode == I2C_SMBUS_BLOCK_DATA && i >= blen)
 767                         break;
 768                 if (i/16 < first/16)
 769                         continue;
 770                 if (i/16 > last/16)
 771                         break;
 772
 773                 printf("%02x: ", i);
 774                 for (j = 0; j < 16; j++) {
 775                         fflush_all();
 776                         /* Skip unwanted registers */
 777                         if (i+j < first || i+j > last) {
 778                                 printf("   ");
 779                                 if (mode == I2C_SMBUS_WORD_DATA) {
 780                                         printf("   ");
 781                                         j++;
 782                                 }
 783                                 continue;
 784                         }
 785
 786                         switch (mode) {
 787                         case I2C_SMBUS_BYTE_DATA:
 788                                 res = i2c_smbus_read_byte_data(bus_fd, i+j);
 789                                 block[i+j] = res;
 790                                 break;
 791                         case I2C_SMBUS_WORD_DATA:
 792                                 res = i2c_smbus_read_word_data(bus_fd, i+j);
 793                                 if (res < 0) {
 794                                         block[i+j] = res;
 795                                         block[i+j+1] = res;
 796                                 } else {
 797                                         block[i+j] = res & 0xff;
 798                                         block[i+j+1] = res >> 8;
 799                                 }
 800                                 break;
 801                         case I2C_SMBUS_BYTE:
 802                                 res = i2c_smbus_read_byte(bus_fd);
 803                                 block[i+j] = res;
 804                                 break;
 805                         default:
 806                                 res = block[i+j];
 807                         }
 808
 809                         if (mode == I2C_SMBUS_BLOCK_DATA &&
 810                             i+j >= blen) {
 811                                 printf("   ");
 812                         } else if (res < 0) {
 813                                 printf("XX ");
 814                                 if (mode == I2C_SMBUS_WORD_DATA)
 815                                         printf("XX ");
 816                         } else {
 817                                 printf("%02x ", block[i+j]);
 818                                 if (mode == I2C_SMBUS_WORD_DATA)
 819                                         printf("%02x ", block[i+j+1]);
 820                         }
 821
 822                         if (mode == I2C_SMBUS_WORD_DATA)
 823                                 j++;
 824                 }
 825                 printf("   ");
 826
 827                 for (j = 0; j < 16; j++) {
 828                         if (mode == I2C_SMBUS_BLOCK_DATA && i+j >= blen)
 829                                 break;
 830                         /* Skip unwanted registers */
 831                         if (i+j < first || i+j > last) {
 832                                 bb_putchar(' ');
 833                                 continue;
 834                         }
 835
 836                         res = block[i+j];
 837                         if (res < 0) {
 838                                 bb_putchar('X');
 839                         } else if (res == 0x00 || res == 0xff) {
 840                                 bb_putchar('.');
 841                         } else if (res < 32 || res >= 127) {
 842                                 bb_putchar('?');
 843                         } else {
 844                                 bb_putchar(res);
 845                         }
 846                 }
 847                 bb_putchar('\n');
 848         }
 849 }
 850
 851 static void dump_word_data(int bus_fd, unsigned first, unsigned last)
 852 {
 853         int i, j, rv;
 854
 855         /* Word data. */
 856         puts("     0,8  1,9  2,a  3,b  4,c  5,d  6,e  7,f");
 857         for (i = 0; i < 256; i += 8) {
 858                 if (i/8 < first/8)
 859                         continue;
 860                 if (i/8 > last/8)
 861                         break;
 862
 863                 printf("%02x: ", i);
 864                 for (j = 0; j < 8; j++) {
 865                         /* Skip unwanted registers. */
 866                         if (i+j < first || i+j > last) {
 867                                 printf("     ");
 868                                 continue;
 869                         }
 870
 871                         rv = i2c_smbus_read_word_data(bus_fd, i+j);
 872                         if (rv < 0)
 873                                 printf("XXXX ");
 874                         else
 875                                 printf("%04x ", rv & 0xffff);
 876                 }
 877                 bb_putchar('\n');
 878         }
 879 }
 880
 881 //usage:#define i2cdump_trivial_usage
 882 //usage:       "[-f] [-r FIRST-LAST] [-y] BUS ADDR [MODE]"
 883 //usage:#define i2cdump_full_usage "\n\n"
 884 //usage:       "Examine I2C registers\n"
 885 //usage:     "\n        I2CBUS  i2c bus number"
 886 //usage:     "\n        ADDRESS 0x03 - 0x77"
 887 //usage:     "\nMODE is:"
 888 //usage:     "\n        b       byte (default)"
 889 //usage:     "\n        w       word"
 890 //usage:     "\n        W       word on even register addresses"
 891 //usage:     "\n        i       I2C block"
 892 //usage:     "\n        s       SMBus block"
 893 //usage:     "\n        c       consecutive byte"
 894 //usage:     "\n        Append p for SMBus PEC"
 895 //usage:     "\n"
 896 //usage:     "\n        -f      force access"
 897 //usage:     "\n        -y      disable interactive mode"
 898 //usage:     "\n        -r      limit the number of registers being accessed"
 899 int i2cdump_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 900 int i2cdump_main(int argc UNUSED_PARAM, char **argv)
 901 {
 902         const unsigned opt_f = (1 << 0), opt_y = (1 << 1),
 903                               opt_r = (1 << 2);
 904         const char *const optstr = "fyr:";
 905
 906         int bus_num, bus_addr, mode = I2C_SMBUS_BYTE_DATA, even = 0, pec = 0;
 907         unsigned first = 0x00, last = 0xff, opts;
 908         int *block = (int *)bb_common_bufsiz1;
 909         char *opt_r_str, *dash;
 910         int fd, res, blen;
 911
 912         opt_complementary = "-2:?3"; /* from 2 to 3 args */
 913         opts = getopt32(argv, optstr, &opt_r_str);
 914         argv += optind;
 915
 916         bus_num = i2c_bus_lookup(argv[0]);
 917         bus_addr = i2c_parse_bus_addr(argv[1]);
 918
 919         if (argv[2]) {
 920                 switch (argv[2][0]) {
 921                 case 'b': /* Already set. */                    break;
 922                 case 'c': mode = I2C_SMBUS_BYTE;                break;
 923                 case 'w': mode = I2C_SMBUS_WORD_DATA;           break;
 924                 case 'W':
 925                         mode = I2C_SMBUS_WORD_DATA;
 926                         even = 1;
 927                         break;
 928                 case 's': mode = I2C_SMBUS_BLOCK_DATA;          break;
 929                 case 'i': mode = I2C_SMBUS_I2C_BLOCK_DATA;      break;
 930                 default:
 931                         bb_error_msg_and_die("invalid mode");
 932                 }
 933
 934                 if (argv[2][1] == 'p') {
 935                         if (argv[2][0] == 'W' || argv[2][0] == 'i') {
 936                                 bb_error_msg_and_die(
 937                                         "pec not supported for -W and -i");
 938                         } else {
 939                                 pec = 1;
 940                         }
 941                 }
 942         }
 943
 944         if (opts & opt_r) {
 945                 first = strtol(opt_r_str, &dash, 0);
 946                 if (dash == opt_r_str || *dash != '-' || first > 0xff)
 947                         bb_error_msg_and_die("invalid range");
 948                 last = xstrtou_range(++dash, 0, first, 0xff);
 949
 950                 /* Range is not available for every mode. */
 951                 switch (mode) {
 952                 case I2C_SMBUS_BYTE:
 953                 case I2C_SMBUS_BYTE_DATA:
 954                         break;
 955                 case I2C_SMBUS_WORD_DATA:
 956                         if (!even || (!(first % 2) && last % 2))
 957                                 break;
 958                         /* Fall through */
 959                 default:
 960                         bb_error_msg_and_die(
 961                                 "range not compatible with selected mode");
 962                 }
 963         }
 964
 965         fd = i2c_dev_open(bus_num);
 966         check_read_funcs(fd, mode, -1 /* data_addr */, pec);
 967         i2c_set_slave_addr(fd, bus_addr, opts & opt_f);
 968
 969         if (pec)
 970                 i2c_set_pec(fd, 1);
 971
 972         if (!(opts & opt_y))
 973                 confirm_action(bus_addr, mode, -1 /* data_addr */, pec);
 974
 975         /* All but word data. */
 976         if (mode != I2C_SMBUS_WORD_DATA || even) {
 977                 if (mode == I2C_SMBUS_BLOCK_DATA || mode == I2C_SMBUS_I2C_BLOCK_DATA)
 978                         blen = read_block_data(fd, mode, block);
 979
 980                 if (mode == I2C_SMBUS_BYTE) {
 981                         res = i2c_smbus_write_byte(fd, first);
 982                         if (res < 0)
 983                                 bb_perror_msg_and_die("write start address");
 984                 }
 985
 986                 dump_data(fd, mode, first, last, block, blen);
 987         } else {
 988                 dump_word_data(fd, first, last);
 989         }
 990
 991         return 0;
 992 }
 993 #endif /* ENABLE_I2CDUMP */
 994
 995 #if ENABLE_I2CDETECT
 996 enum adapter_type {
 997         ADT_DUMMY = 0,
 998         ADT_ISA,
 999         ADT_I2C,
1000         ADT_SMBUS,
1001 };
1002
1003 struct adap_desc {
1004         const char *funcs;
1005         const char *algo;
1006 };
1007
1008 static const struct adap_desc adap_descs[] = {
1009         { .funcs        = "dummy",
1010           .algo         = "Dummy bus", },
1011         { .funcs        = "isa",
1012           .algo         = "ISA bus", },
1013         { .funcs        = "i2c",
1014           .algo         = "I2C adapter", },
1015         { .funcs        = "smbus",
1016           .algo         = "SMBus adapter", },
1017 };
1018
1019 struct i2c_func
1020 {
1021         long value;
1022         const char* name;
1023 };
1024
1025 static const struct i2c_func i2c_funcs_tab[] = {
1026         { .value = I2C_FUNC_I2C,
1027           .name = "I2C" },
1028         { .value = I2C_FUNC_SMBUS_QUICK,
1029           .name = "SMBus quick command" },
1030         { .value = I2C_FUNC_SMBUS_WRITE_BYTE,
1031           .name = "SMBus send byte" },
1032         { .value = I2C_FUNC_SMBUS_READ_BYTE,
1033           .name = "SMBus receive byte" },
1034         { .value = I2C_FUNC_SMBUS_WRITE_BYTE_DATA,
1035           .name = "SMBus write byte" },
1036         { .value = I2C_FUNC_SMBUS_READ_BYTE_DATA,
1037           .name = "SMBus read byte" },
1038         { .value = I2C_FUNC_SMBUS_WRITE_WORD_DATA,
1039           .name = "SMBus write word" },
1040         { .value = I2C_FUNC_SMBUS_READ_WORD_DATA,
1041           .name = "SMBus read word" },
1042         { .value = I2C_FUNC_SMBUS_PROC_CALL,
1043           .name = "SMBus process call" },
1044         { .value = I2C_FUNC_SMBUS_WRITE_BLOCK_DATA,
1045           .name = "SMBus block write" },
1046         { .value = I2C_FUNC_SMBUS_READ_BLOCK_DATA,
1047           .name = "SMBus block read" },
1048         { .value = I2C_FUNC_SMBUS_BLOCK_PROC_CALL,
1049           .name = "SMBus block process call" },
1050         { .value = I2C_FUNC_SMBUS_PEC,
1051           .name = "SMBus PEC" },
1052         { .value = I2C_FUNC_SMBUS_WRITE_I2C_BLOCK,
1053           .name = "I2C block write" },
1054         { .value = I2C_FUNC_SMBUS_READ_I2C_BLOCK,
1055           .name = "I2C block read" },
1056         { .value = 0, .name = NULL }
1057 };
1058
1059 static enum adapter_type i2cdetect_get_funcs(int bus)
1060 {
1061         enum adapter_type ret;
1062         unsigned long funcs;
1063         int fd;
1064
1065         fd = i2c_dev_open(bus);
1066
1067         get_funcs_matrix(fd, &funcs);
1068         if (funcs & I2C_FUNC_I2C)
1069                 ret = ADT_I2C;
1070         else if (funcs & (I2C_FUNC_SMBUS_BYTE |
1071                           I2C_FUNC_SMBUS_BYTE_DATA |
1072                           I2C_FUNC_SMBUS_WORD_DATA))
1073                 ret = ADT_SMBUS;
1074         else
1075                 ret = ADT_DUMMY;
1076
1077         close(fd);
1078
1079         return ret;
1080 }
1081
1082 static void NORETURN list_i2c_busses_and_exit(void)
1083 {
1084         const char *const i2cdev_path = "/sys/class/i2c-dev";
1085
1086         char path[NAME_MAX], name[128];
1087         struct dirent *de, *subde;
1088         enum adapter_type adt;
1089         DIR *dir, *subdir;
1090         int rv, bus;
1091         char *pos;
1092         FILE *fp;
1093
1094         /*
1095          * XXX Upstream i2cdetect also looks for i2c bus info in /proc/bus/i2c,
1096          * but we won't bother since it's only useful on older kernels (before
1097          * 2.6.5). We expect sysfs to be present and mounted at /sys/.
1098          */
1099
1100         dir = xopendir(i2cdev_path);
1101         while ((de = readdir(dir))) {
1102                 if (de->d_name[0] == '.')
1103                         continue;
1104
1105                 /* Simple version for ISA chips. */
1106                 snprintf(path, NAME_MAX, "%s/%s/name",
1107                          i2cdev_path, de->d_name);
1108                 fp = fopen(path, "r");
1109                 if (fp == NULL) {
1110                         snprintf(path, NAME_MAX,
1111                                  "%s/%s/device/name",
1112                                  i2cdev_path, de->d_name);
1113                         fp = fopen(path, "r");
1114                 }
1115
1116                 /* Non-ISA chips require the hard-way. */
1117                 if (fp == NULL) {
1118                         snprintf(path, NAME_MAX,
1119                                  "%s/%s/device/name",
1120                                  i2cdev_path, de->d_name);
1121                         subdir = opendir(path);
1122                         if (subdir == NULL)
1123                                 continue;
1124
1125                         while ((subde = readdir(subdir))) {
1126                                 if (subde->d_name[0] == '.')
1127                                         continue;
1128
1129                                 if (is_prefixed_with(subde->d_name, "i2c-")) {
1130                                         snprintf(path, NAME_MAX,
1131                                                  "%s/%s/device/%s/name",
1132                                                  i2cdev_path, de->d_name,
1133                                                  subde->d_name);
1134                                         fp = fopen(path, "r");
1135                                         break;
1136                                 }
1137                         }
1138                 }
1139
1140                 if (fp != NULL) {
1141                         /*
1142                          * Get the rest of the info and display a line
1143                          * for a single bus.
1144                          */
1145                         memset(name, 0, sizeof(name));
1146                         pos = fgets(name, sizeof(name), fp);
1147                         fclose(fp);
1148                         if (pos == NULL)
1149                                 continue;
1150
1151                         pos = strchr(name, '\n');
1152                         if (pos != NULL)
1153                                 *pos = '\0';
1154
1155                         rv = sscanf(de->d_name, "i2c-%d", &bus);
1156                         if (rv != 1)
1157                                 continue;
1158
1159                         if (is_prefixed_with(name, "ISA"))
1160                                 adt = ADT_ISA;
1161                         else
1162                                 adt = i2cdetect_get_funcs(bus);
1163
1164                         printf(
1165                                 "i2c-%d\t%-10s\t%-32s\t%s\n",
1166                                 bus, adap_descs[adt].funcs,
1167                                 name, adap_descs[adt].algo);
1168                 }
1169         }
1170
1171         exit(EXIT_SUCCESS);
1172 }
1173
1174 static void NORETURN no_support(const char *cmd)
1175 {
1176         bb_error_msg_and_die("bus doesn't support %s", cmd);
1177 }
1178
1179 static void will_skip(const char *cmd)
1180 {
1181         bb_error_msg(
1182                 "warning: can't use %s command, "
1183                 "will skip some addresses", cmd);
1184 }
1185
1186 //usage:#define i2cdetect_trivial_usage
1187 //usage:       "[-F I2CBUS] [-l] [-y] [-a] [-q|-r] I2CBUS [FIRST LAST]"
1188 //usage:#define i2cdetect_full_usage "\n\n"
1189 //usage:       "Detect I2C chips.\n"
1190 //usage:     "\n        I2CBUS  i2c bus number"
1191 //usage:     "\n        FIRST and LAST limit the probing range"
1192 //usage:     "\n"
1193 //usage:     "\n        -l      output list of installed busses"
1194 //usage:     "\n        -y      disable interactive mode"
1195 //usage:     "\n        -a      force scanning of non-regular addresses"
1196 //usage:     "\n        -q      use smbus quick write commands for probing (default)"
1197 //usage:     "\n        -r      use smbus read byte commands for probing"
1198 //usage:     "\n        -F      display list of functionalities"
1199 int i2cdetect_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1200 int i2cdetect_main(int argc UNUSED_PARAM, char **argv)
1201 {
1202         const unsigned opt_y = (1 << 0), opt_a = (1 << 1),
1203                               opt_q = (1 << 2), opt_r = (1 << 3),
1204                               opt_F = (1 << 4), opt_l = (1 << 5);
1205         const char *const optstr = "yaqrFl";
1206
1207         int fd, bus_num, i, j, mode = I2CDETECT_MODE_AUTO, status, cmd;
1208         unsigned first = 0x03, last = 0x77, opts;
1209         unsigned long funcs;
1210
1211         opt_complementary = "q--r:r--q:" /* mutually exclusive */
1212                         "?3"; /* up to 3 args */
1213         opts = getopt32(argv, optstr);
1214         argv += optind;
1215
1216         if (opts & opt_l)
1217                 list_i2c_busses_and_exit();
1218
1219         if (!argv[0])
1220                 bb_show_usage();
1221
1222         bus_num = i2c_bus_lookup(argv[0]);
1223         fd = i2c_dev_open(bus_num);
1224         get_funcs_matrix(fd, &funcs);
1225
1226         if (opts & opt_F) {
1227                 /* Only list the functionalities. */
1228                 printf("Functionalities implemented by bus #%d\n", bus_num);
1229                 for (i = 0; i2c_funcs_tab[i].value; i++) {
1230                         printf("%-32s %s\n", i2c_funcs_tab[i].name,
1231                                funcs & i2c_funcs_tab[i].value ? "yes" : "no");
1232                 }
1233
1234                 return EXIT_SUCCESS;
1235         }
1236
1237         if (opts & opt_r)
1238                 mode = I2CDETECT_MODE_READ;
1239         else if (opts & opt_q)
1240                 mode = I2CDETECT_MODE_QUICK;
1241
1242         if (opts & opt_a) {
1243                 first = 0x00;
1244                 last = 0x7f;
1245         }
1246
1247         /* Read address range. */
1248         if (argv[1]) {
1249                 first = xstrtou_range(argv[1], 16, first, last);
1250                 if (argv[2])
1251                         last = xstrtou_range(argv[2], 16, first, last);
1252         }
1253
1254         if (!(funcs & (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_READ_BYTE))) {
1255                 no_support("detection commands");
1256         } else
1257         if (mode == I2CDETECT_MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_QUICK)) {
1258                 no_support("SMBus quick write");
1259         } else
1260         if (mode == I2CDETECT_MODE_READ && !(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
1261                 no_support("SMBus receive byte");
1262         }
1263
1264         if (mode == I2CDETECT_MODE_AUTO) {
1265                 if (!(funcs & I2C_FUNC_SMBUS_QUICK))
1266                         will_skip("SMBus quick write");
1267                 if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE))
1268                         will_skip("SMBus receive byte");
1269         }
1270
1271         if (!(opts & opt_y))
1272                 confirm_action(-1, -1, -1, 0);
1273
1274         puts("     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f");
1275         for (i = 0; i < 128; i += 16) {
1276                 printf("%02x: ", i);
1277                 for (j = 0; j < 16; j++) {
1278                         fflush_all();
1279
1280                         cmd = mode;
1281                         if (mode == I2CDETECT_MODE_AUTO) {
1282                                 if ((i+j >= 0x30 && i+j <= 0x37) ||
1283                                     (i+j >= 0x50 && i+j <= 0x5F))
1284                                         cmd = I2CDETECT_MODE_READ;
1285                                 else
1286                                         cmd = I2CDETECT_MODE_QUICK;
1287                         }
1288
1289                         /* Skip unwanted addresses. */
1290                         if (i+j < first
1291                          || i+j > last
1292                          || (cmd == I2CDETECT_MODE_READ && !(funcs & I2C_FUNC_SMBUS_READ_BYTE))
1293                          || (cmd == I2CDETECT_MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_QUICK)))
1294                         {
1295                                 printf("   ");
1296                                 continue;
1297                         }
1298
1299                         status = ioctl(fd, I2C_SLAVE, itoptr(i + j));
1300                         if (status < 0) {
1301                                 if (errno == EBUSY) {
1302                                         printf("UU ");
1303                                         continue;
1304                                 }
1305
1306                                 bb_perror_msg_and_die(
1307                                         "can't set address to 0x%02x", i + j);
1308                         }
1309
1310                         switch (cmd) {
1311                         case I2CDETECT_MODE_READ:
1312                                 /*
1313                                  * This is known to lock SMBus on various
1314                                  * write-only chips (mainly clock chips).
1315                                  */
1316                                 status = i2c_smbus_read_byte(fd);
1317                                 break;
1318                         default: /* I2CDETECT_MODE_QUICK: */
1319                                 /*
1320                                  * This is known to corrupt the Atmel
1321                                  * AT24RF08 EEPROM.
1322                                  */
1323                                 status = i2c_smbus_write_quick(fd,
1324                                                                I2C_SMBUS_WRITE);
1325                                 break;
1326                         }
1327
1328                         if (status < 0)
1329                                 printf("-- ");
1330                         else
1331                                 printf("%02x ", i+j);
1332                 }
1333                 bb_putchar('\n');
1334         }
1335
1336         return 0;
1337 }
1338 #endif /* ENABLE_I2CDETECT */