在Linux 应用层 基于i2c-dev.h 实现i2c读写

/*
    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.
*/

#ifndef _LINUX_I2C_DEV_H
#define _LINUX_I2C_DEV_H

#include <linux/types.h>
#include <sys/ioctl.h>
#include <stddef.h>

/* -- i2c.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

/* /dev/i2c-X ioctl commands.  The ioctl's parameter is always an
 * unsigned long, except for:
 *	- I2C_FUNCS, takes pointer to an unsigned long
 *	- I2C_RDWR, takes pointer to struct i2c_rdwr_ioctl_data
 *	- I2C_SMBUS, takes pointer to struct i2c_smbus_ioctl_data
 */
#define I2C_RETRIES	0x0701	/* number of times a device address should
				   be polled when not acknowledging */
#define I2C_TIMEOUT	0x0702	/* set timeout in units of 10 ms */

/* NOTE: Slave address is 7 or 10 bits, but 10-bit addresses
 * are NOT supported! (due to code brokenness)
 */
#define I2C_SLAVE	0x0703	/* Use this slave address */
#define I2C_SLAVE_FORCE	0x0706	/* Use this slave address, even if it
				   is already in use by a driver! */
#define I2C_TENBIT	0x0704	/* 0 for 7 bit addrs, != 0 for 10 bit */

#define I2C_FUNCS	0x0705	/* Get the adapter functionality mask */

#define I2C_RDWR	0x0707	/* Combined R/W transfer (one STOP only) */

#define I2C_PEC		0x0708	/* != 0 to use PEC with SMBus */
#define I2C_SMBUS	0x0720	/* SMBus transfer */

/* This is the structure as used in the I2C_SMBUS ioctl call */
struct i2c_smbus_ioctl_data {
	__u8 read_write;
	__u8 command;
	__u32 size;
	union i2c_smbus_data *data;
};

/* This is the structure as used in the I2C_RDWR ioctl call */
struct i2c_rdwr_ioctl_data {
	struct i2c_msg *msgs;	/* pointers to i2c_msgs */
	__u32 nmsgs;			/* number of i2c_msgs */
};

#define  I2C_RDRW_IOCTL_MAX_MSGS	42

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, const __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,
                                                   const __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 /* _LINUX_I2C_DEV_H */