text: /* ------------------------------------------------------------------------- */
  /*									     */
  /* i2c.h - definitions for the i2c-bus interface			     */
  /*									     */
  /* ------------------------------------------------------------------------- */
  /*   Copyright (C) 1995-2000 Simon G. Vogl
  
      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.							     */
  /* ------------------------------------------------------------------------- */
  
  /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
     Frodo Looijaard <frodol@dds.nl> */
  
  #ifndef _LINUX_I2C_H
  #define _LINUX_I2C_H
  
  #include <linux/types.h>
  
  /**
   * struct i2c_msg - an I2C transaction segment beginning with START
   * @addr: Slave address, either seven or ten bits.  When this is a ten
   *	bit address, I2C_M_TEN must be set in @flags and the adapter
   *	must support I2C_FUNC_10BIT_ADDR.
   * @flags: I2C_M_RD is handled by all adapters.  No other flags may be
   *	provided unless the adapter exported the relevant I2C_FUNC_*
   *	flags through i2c_check_functionality().
   * @len: Number of data bytes in @buf being read from or written to the
   *	I2C slave address.  For read transactions where I2C_M_RECV_LEN
   *	is set, the caller guarantees that this buffer can hold up to
   *	32 bytes in addition to the initial length byte sent by the
   *	slave (plus, if used, the SMBus PEC); and this value will be
   *	incremented by the number of block data bytes received.
   * @buf: The buffer into which data is read, or from which it's written.
   *
   * An i2c_msg is the low level representation of one segment of an I2C
   * transaction.  It is visible to drivers in the @i2c_transfer() procedure,
   * to userspace from i2c-dev, and to I2C adapter drivers through the
   * @i2c_adapter.@master_xfer() method.
   *
   * Except when I2C "protocol mangling" is used, all I2C adapters implement
   * the standard rules for I2C transactions.  Each transaction begins with a
   * START.  That is followed by the slave address, and a bit encoding read
   * versus write.  Then follow all the data bytes, possibly including a byte
   * with SMBus PEC.  The transfer terminates with a NAK, or when all those
   * bytes have been transferred and ACKed.  If this is the last message in a
   * group, it is followed by a STOP.  Otherwise it is followed by the next
   * @i2c_msg transaction segment, beginning with a (repeated) START.
   *
   * Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then
   * passing certain @flags may have changed those standard protocol behaviors.
   * Those flags are only for use with broken/nonconforming slaves, and with
   * adapters which are known to support the specific mangling options they
   * need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR).
   */
  struct i2c_msg {
  	__u16 addr;	/* slave address			*/
  	__u16 flags;
  #define I2C_M_TEN		0x0010	/* this is a ten bit chip address */
  #define I2C_M_RD		0x0001	/* read data, from slave to master */
  #define I2C_M_STOP		0x8000	/* if I2C_FUNC_PROTOCOL_MANGLING */
  #define I2C_M_NOSTART		0x4000	/* if I2C_FUNC_NOSTART */
  #define I2C_M_REV_DIR_ADDR	0x2000	/* if I2C_FUNC_PROTOCOL_MANGLING */
  #define I2C_M_IGNORE_NAK	0x1000	/* if I2C_FUNC_PROTOCOL_MANGLING */
  #define I2C_M_NO_RD_ACK		0x0800	/* if I2C_FUNC_PROTOCOL_MANGLING */
  #define I2C_M_RECV_LEN		0x0400	/* length will be first received byte */
  	__u16 len;		/* msg length				*/
  	__u8 *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_IGNORE_NAK etc. */
  #define I2C_FUNC_SMBUS_PEC		0x00000008
  #define I2C_FUNC_NOSTART		0x00000010 /* I2C_M_NOSTART */
  #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)
  
  #define I2C_FUNC_SMBUS_EMUL		(I2C_FUNC_SMBUS_QUICK | \
  					 I2C_FUNC_SMBUS_BYTE | \
  					 I2C_FUNC_SMBUS_BYTE_DATA | \
  					 I2C_FUNC_SMBUS_WORD_DATA | \
  					 I2C_FUNC_SMBUS_PROC_CALL | \
  					 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
  					 I2C_FUNC_SMBUS_I2C_BLOCK | \
  					 I2C_FUNC_SMBUS_PEC)
  
  /*
   * Data for SMBus Messages
   */
  #define I2C_SMBUS_BLOCK_MAX	32	/* As specified in SMBus standard */
  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 user-space compatibility */
  };
  
  /* i2c_smbus_xfer 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
  
  #endif /* _LINUX_I2C_H */
  