/*
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2020 embedded brains GmbH & Co. KG
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * The command implemented here has a similar interface like the one from Linux
 * i2c tools. Think of it as a heavily simplified version of them. Instead of
 * the bus number they expect a bus path.
 */

#include <dev/i2c/i2c.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <rtems/shell.h>

static const char rtems_i2cdetect_shell_usage [] =
  "i2cdetect <I2C_BUS>\n"
  "\ttry to detect i2c devices on the given bus\n";

static int rtems_i2cdetect_shell_main(int argc, char *argv[])
{
  int fd;
  int rv;
  const char *bus;
  const uint16_t first = 1;
  const uint16_t last = 0x7f;
  uint16_t current;

  if (argc != 2 || strcmp(argv[1], "-h") == 0) {
    printf(rtems_i2cdetect_shell_usage);
    return 1;
  }

  bus = argv[1];
  fd = open(bus, O_RDWR);
  if (fd < 0) {
    perror("Couldn't open bus");
    return 1;
  }

  printf("    x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF\n"
         "0x    ");
  for (current = first; current <= last; ++current) {
    i2c_msg msg = {
      .addr = current,
      .flags = 0,
      .len = 0,
      .buf = NULL,
    };

    struct i2c_rdwr_ioctl_data payload = {
      .msgs = &msg,
      .nmsgs = 1,
    };

    if ((current & 0x0F) == 0) {
      printf("\n%1xx ", current >> 4);
    }

    rv = ioctl(fd, I2C_RDWR, &payload);
    if (rv < 0) {
      if (errno != EIO) {
        perror("ioctl failed");
      }
      printf(" --");
    } else {
      printf(" %02x", current);
    }
  }
  printf("\n");
  close(fd);

  return 0;
}

rtems_shell_cmd_t rtems_shell_I2CDETECT_Command = {
  .name = "i2cdetect",
  .usage = rtems_i2cdetect_shell_usage,
  .topic = "misc",
  .command = rtems_i2cdetect_shell_main,
};