i2c_smbus.h

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/*
 * i2c-dev.h - i2c-bus driver, char device interface
 *
 * Copyright (C) 1995-97 Simon G. Vogl
 * Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA.
 */

/* $Id: i2c-dev.h 5361 2008-10-19 09:47:02Z khali $ */

#ifndef LIB_I2CDEV_H
#define LIB_I2CDEV_H

#include <linux/types.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>

/*
 * I2C Message - used for pure i2c transaction, also from /dev interface
 */
struct i2c_msg {
  __u16 addr;  /* slave address      */
  unsigned short flags;
#define I2C_M_TEN           0x10  /* we have a ten bit chip address  */
#define I2C_M_RD            0x01
#define I2C_M_NOSTART       0x4000
#define I2C_M_REV_DIR_ADDR  0x2000
#define I2C_M_IGNORE_NAK    0x1000
#define I2C_M_NO_RD_ACK     0x0800
  short len;    /* msg length        */
  char *buf;    /* pointer to msg data      */
};

/* To determine what functionality is present */

#define I2C_FUNC_I2C                    0x00000001
#define I2C_FUNC_10BIT_ADDR             0x00000002
#define I2C_FUNC_PROTOCOL_MANGLING      0x00000004 /* I2C_M_{REV_DIR_ADDR,NOSTART,..} */
#define I2C_FUNC_SMBUS_PEC              0x00000008
#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL  0x00008000 /* SMBus 2.0 */
#define I2C_FUNC_SMBUS_QUICK            0x00010000
#define I2C_FUNC_SMBUS_READ_BYTE        0x00020000
#define I2C_FUNC_SMBUS_WRITE_BYTE       0x00040000
#define I2C_FUNC_SMBUS_READ_BYTE_DATA   0x00080000
#define I2C_FUNC_SMBUS_WRITE_BYTE_DATA  0x00100000
#define I2C_FUNC_SMBUS_READ_WORD_DATA   0x00200000
#define I2C_FUNC_SMBUS_WRITE_WORD_DATA  0x00400000
#define I2C_FUNC_SMBUS_PROC_CALL        0x00800000
#define I2C_FUNC_SMBUS_READ_BLOCK_DATA  0x01000000
#define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
#define I2C_FUNC_SMBUS_READ_I2C_BLOCK   0x04000000 /* I2C-like block xfer  */
#define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK  0x08000000 /* w/ 1-byte reg. addr. */

#define I2C_FUNC_SMBUS_BYTE (I2C_FUNC_SMBUS_READ_BYTE | \
                             I2C_FUNC_SMBUS_WRITE_BYTE)
#define I2C_FUNC_SMBUS_BYTE_DATA (I2C_FUNC_SMBUS_READ_BYTE_DATA | \
                                  I2C_FUNC_SMBUS_WRITE_BYTE_DATA)
#define I2C_FUNC_SMBUS_WORD_DATA (I2C_FUNC_SMBUS_READ_WORD_DATA | \
                                  I2C_FUNC_SMBUS_WRITE_WORD_DATA)
#define I2C_FUNC_SMBUS_BLOCK_DATA (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
                                   I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)
#define I2C_FUNC_SMBUS_I2C_BLOCK (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \
                                  I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)

/* Old name, for compatibility */
#define I2C_FUNC_SMBUS_HWPEC_CALC  I2C_FUNC_SMBUS_PEC

/*
 * Data for SMBus Messages
 */
#define I2C_SMBUS_BLOCK_MAX  32  /* As specified in SMBus standard */
#define I2C_SMBUS_I2C_BLOCK_MAX  32  /* Not specified but we use same structure */
union i2c_smbus_data {
  __u8 byte;
  __u16 word;
  __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
  /* and one more for PEC */
};

/* smbus_access read or write markers */
#define I2C_SMBUS_READ  1
#define I2C_SMBUS_WRITE  0

/* SMBus transaction types (size parameter in the above functions)
   Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
#define I2C_SMBUS_QUICK             0
#define I2C_SMBUS_BYTE              1
#define I2C_SMBUS_BYTE_DATA         2
#define I2C_SMBUS_WORD_DATA         3
#define I2C_SMBUS_PROC_CALL         4
#define I2C_SMBUS_BLOCK_DATA        5
#define I2C_SMBUS_I2C_BLOCK_BROKEN  6
#define I2C_SMBUS_BLOCK_PROC_CALL   7    /* SMBus 2.0 */
#define I2C_SMBUS_I2C_BLOCK_DATA    8


/* ----- commands for the ioctl like i2c_command call:
 * note that additional calls are defined in the algorithm and hw
 *  dependent layers - these can be listed here, or see the
 *  corresponding header files.
 */
/* -> bit-adapter specific ioctls  */
#define I2C_RETRIES  0x0701  /* number of times a device address      */
/* should be polled when not            */
/* acknowledging       */
#define I2C_TIMEOUT  0x0702  /* set timeout - call with int     */


/* this is for i2c-dev.c  */
#define I2C_SLAVE    0x0703  /* Change slave address      */
/* Attn.: Slave address is 7 or 10 bits */
#define I2C_SLAVE_FORCE  0x0706  /* Change slave address      */
/* Attn.: Slave address is 7 or 10 bits */
/* This changes the address, even if it */
/* is already taken!      */
#define I2C_TENBIT   0x0704  /* 0 for 7 bit addrs, != 0 for 10 bit  */

#define I2C_FUNCS    0x0705  /* Get the adapter functionality */
#define I2C_RDWR     0x0707  /* Combined R/W transfer (one stop only)*/
#define I2C_PEC      0x0708  /* != 0 for SMBus PEC                   */

#define I2C_SMBUS    0x0720  /* SMBus-level access */

/* -- i2c.h -- */


/* Note: 10-bit addresses are NOT supported! */


static inline __s32 i2c_smbus_access(int file, char read_write, __u8 command,
                                     int size, union i2c_smbus_data *data)
{
  struct i2c_smbus_ioctl_data args;

  args.read_write = read_write;
  args.command = command;
  args.size = size;
  args.data = data;
  return ioctl(file, I2C_SMBUS, &args);
}


static inline __s32 i2c_smbus_write_quick(int file, __u8 value)
{
  return i2c_smbus_access(file, value, 0, I2C_SMBUS_QUICK, NULL);
}

static inline __s32 i2c_smbus_read_byte(int file)
{
  union i2c_smbus_data data;
  if (i2c_smbus_access(file, I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data)) {
    return -1;
  } else {
    return 0x0FF & data.byte;
  }
}

static inline __s32 i2c_smbus_write_byte(int file, __u8 value)
{
  return i2c_smbus_access(file, I2C_SMBUS_WRITE, value,
                          I2C_SMBUS_BYTE, NULL);
}

static inline __s32 i2c_smbus_read_byte_data(int file, __u8 command)
{
  union i2c_smbus_data data;
  if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
                       I2C_SMBUS_BYTE_DATA, &data)) {
    return -1;
  } else {
    return 0x0FF & data.byte;
  }
}

static inline __s32 i2c_smbus_write_byte_data(int file, __u8 command,
    __u8 value)
{
  union i2c_smbus_data data;
  data.byte = value;
  return i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_BYTE_DATA, &data);
}

static inline __s32 i2c_smbus_read_word_data(int file, __u8 command)
{
  union i2c_smbus_data data;
  if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
                       I2C_SMBUS_WORD_DATA, &data)) {
    return -1;
  } else {
    return 0x0FFFF & data.word;
  }
}

static inline __s32 i2c_smbus_write_word_data(int file, __u8 command,
    __u16 value)
{
  union i2c_smbus_data data;
  data.word = value;
  return i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_WORD_DATA, &data);
}

static inline __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value)
{
  union i2c_smbus_data data;
  data.word = value;
  if (i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
                       I2C_SMBUS_PROC_CALL, &data)) {
    return -1;
  } else {
    return 0x0FFFF & data.word;
  }
}


/* Returns the number of read bytes */
static inline __s32 i2c_smbus_read_block_data(int file, __u8 command,
    __u8 *values)
{
  union i2c_smbus_data data;
  int i;
  if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
                       I2C_SMBUS_BLOCK_DATA, &data)) {
    return -1;
  } else {
    for (i = 1; i <= data.block[0]; i++) {
      values[i - 1] = data.block[i];
    }
    return data.block[0];
  }
}

static inline __s32 i2c_smbus_write_block_data(int file, __u8 command,
    __u8 length, __u8 *values)
{
  union i2c_smbus_data data;
  int i;
  if (length > 32) {
    length = 32;
  }
  for (i = 1; i <= length; i++) {
    data.block[i] = values[i - 1];
  }
  data.block[0] = length;
  return i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_BLOCK_DATA, &data);
}

/* Returns the number of read bytes */
/* Until kernel 2.6.22, the length is hardcoded to 32 bytes. If you
   ask for less than 32 bytes, your code will only work with kernels
   2.6.23 and later. */
static inline __s32 i2c_smbus_read_i2c_block_data(int file, __u8 command,
    __u8 length, __u8 *values)
{
  union i2c_smbus_data data;
  int i;

  if (length > 32) {
    length = 32;
  }
  data.block[0] = length;
  if (i2c_smbus_access(file, I2C_SMBUS_READ, command,
                       length == 32 ? I2C_SMBUS_I2C_BLOCK_BROKEN :
                       I2C_SMBUS_I2C_BLOCK_DATA, &data)) {
    return -1;
  } else {
    for (i = 1; i <= data.block[0]; i++) {
      values[i - 1] = data.block[i];
    }
    return data.block[0];
  }
}

static inline __s32 i2c_smbus_write_i2c_block_data(int file, __u8 command,
    __u8 length, __u8 *values)
{
  union i2c_smbus_data data;
  int i;
  if (length > 32) {
    length = 32;
  }
  for (i = 1; i <= length; i++) {
    data.block[i] = values[i - 1];
  }
  data.block[0] = length;
  return i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
                          I2C_SMBUS_I2C_BLOCK_BROKEN, &data);
}

/* Returns the number of read bytes */
static inline __s32 i2c_smbus_block_process_call(int file, __u8 command,
    __u8 length, __u8 *values)
{
  union i2c_smbus_data data;
  int i;
  if (length > 32) {
    length = 32;
  }
  for (i = 1; i <= length; i++) {
    data.block[i] = values[i - 1];
  }
  data.block[0] = length;
  if (i2c_smbus_access(file, I2C_SMBUS_WRITE, command,
                       I2C_SMBUS_BLOCK_PROC_CALL, &data)) {
    return -1;
  } else {
    for (i = 1; i <= data.block[0]; i++) {
      values[i - 1] = data.block[i];
    }
    return data.block[0];
  }
}


#endif /* LIB_I2CDEV_H */