i2c.h

I2C总线LINUX驱动程序

/* ------------------------------------------------------------------------- */
/* 									     */
/* 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., 675 Mass Ave, Cambridge, MA 02139, USA.		     */
/* ------------------------------------------------------------------------- */

/* With some changes from Ky鰏ti M鋖kki <[e-mail]> and
   Frodo Looijaard <[e-mail]> */

/* $Id: i2c.h,v 1.101 2006/02/15 01:40:46 phil Exp $ */

#ifndef _LINUX_I2C_H
#define _LINUX_I2C_H

#define I2C_DATE "20060214"
#define I2C_VERSION "2.10.0"

/* You can set this to 0 if you patch i2c into your kernel tree
   and have no i2c module that have been compiled using a
   Linux-2.4-compatible i2c.h header file left. 
   As a result, you'll get a different code (can't really
   say whether it's any better, but it's different). */
#define I2C_LINUX_2_4_BINARY_COMPATIBILITY 1

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <asm/semaphore.h>
#include "i2c-id.h"

/* --- General options ------------------------------------------------	*/

#define I2C_ADAP_MAX	16		/* control memory consumption	*/
#define I2C_DRIVER_MAX	16
#define I2C_CLIENT_MAX	32

struct i2c_msg;
struct i2c_algorithm;
struct i2c_adapter;
struct i2c_client;
struct i2c_driver;
struct i2c_client_address_data;
union i2c_smbus_data;

/*
 * The master routines are the ones normally used to transmit data to devices
 * on a bus (or read from them). Apart from two basic transfer functions to 
 * transmit one message at a time, a more complex version can be used to 
 * transmit an arbitrary number of messages without interruption.
 */
extern int i2c_master_send(struct i2c_client *,const char* ,int);
extern int i2c_master_recv(struct i2c_client *,char* ,int);

/* Transfer num messages.
 */
extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg msg[],int num);

/*
 * Some adapter types (i.e. PCF 8584 based ones) may support slave behaviuor. 
 * This is not tested/implemented yet and will change in the future.
 */
extern int i2c_slave_send(struct i2c_client *,char*,int);
extern int i2c_slave_recv(struct i2c_client *,char*,int);



/* This is the very generalized SMBus access routine. You probably do not
   want to use this, though; one of the functions below may be much easier,
   and probably just as fast. 
   Note that we use i2c_adapter here, because you do not need a specific
   smbus adapter to call this function. */
extern s32 i2c_smbus_xfer (struct i2c_adapter * adapter, u16 addr, 
                           unsigned short flags,
                           char read_write, u8 command, int size,
                           union i2c_smbus_data * data);

/* Now follow the 'nice' access routines. These also document the calling
   conventions of smbus_access. */

extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value);
extern s32 i2c_smbus_read_byte(struct i2c_client * client);
extern s32 i2c_smbus_write_byte(struct i2c_client * client, u8 value);
extern s32 i2c_smbus_read_byte_data(struct i2c_client * client, u8 command);
extern s32 i2c_smbus_write_byte_data(struct i2c_client * client,
                                     u8 command, u8 value);
extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);
extern s32 i2c_smbus_write_word_data(struct i2c_client * client,
                                     u8 command, u16 value);
extern s32 i2c_smbus_process_call(struct i2c_client * client,
                                  u8 command, u16 value);
/* Returns the number of read bytes */
extern s32 i2c_smbus_read_block_data(struct i2c_client * client,
                                     u8 command, u8 *values);
extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
                                      u8 command, u8 length,
                                      u8 *values);
/* Returns the number of read bytes */
extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client,
                                         u8 command, u8 *values);
extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client * client,
                                          u8 command, u8 length,
                                          u8 *values);


/*
 * A driver is capable of handling one or more physical devices present on
 * I2C adapters. This information is used to inform the driver of adapter
 * events.
 */

struct i2c_driver {
	char name[32];
	int id;
	unsigned int flags;		/* div., see below		*/

	/* Notifies the driver that a new bus has appeared. This routine
	 * can be used by the driver to test if the bus meets its conditions
	 * & seek for the presence of the chip(s) it supports. If found, it 
	 * registers the client(s) that are on the bus to the i2c admin. via
	 * i2c_attach_client.
	 */
	int (*attach_adapter)(struct i2c_adapter *);

	/* tells the driver that a client is about to be deleted & gives it 
	 * the chance to remove its private data. Also, if the client struct
	 * has been dynamically allocated by the driver in the function above,
	 * it must be freed here.
	 */
	int (*detach_client)(struct i2c_client *);
	
	/* a ioctl like command that can be used to perform specific functions
	 * with the device.
	 */
	int (*command)(struct i2c_client *client,unsigned int cmd, void *arg);
	
	/* These two are used for bookkeeping & dynamic unloading of 
	 * kernel modules. inc_use tells the driver that a client is being  
	 * used by another module & that it should increase its ref. counter.
	 * dec_use is the inverse operation.
	 * NB: Make sure you have no circular dependencies, or else you get a 
	 * deadlock when trying to unload the modules.
	 * You should use the i2c_{inc,dec}_use_client functions instead of
	 * calling this function directly.
	 * Note that most clients won't need to implement these, only those
	 * which have users inside the kernel (as opposed to only in
	 * user-space through i2c-proc).
	 */
	void (*inc_use)(struct i2c_client *client);
	void (*dec_use)(struct i2c_client *client);
};

/*
 * i2c_client identifies a single device (i.e. chip) that is connected to an 
 * i2c bus. The behaviour is defined by the routines of the driver. This
 * function is mainly used for lookup & other admin. functions.
 */
struct i2c_client {
	char name[32];
	int id;
	unsigned int flags;		/* div., see below		*/
	unsigned int addr;		/* chip address - NOTE: 7bit 	*/
					/* addresses are stored in the	*/
					/* _LOWER_ 7 bits of this char	*/
	/* addr: unsigned int to make lm_sensors i2c-isa adapter work
	  more cleanly. It does not take any more memory space, due to
	  alignment considerations */
	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
	struct i2c_driver *driver;	/* and our access routines	*/
	void *data;			/* for the clients		*/
	int usage_count;		/* How many accesses currently  */
					/* to the client		*/
};


/*
 * The following structs are for those who like to implement new bus drivers:
 * i2c_algorithm is the interface to a class of hardware solutions which can
 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
 * to name two of the most common.
 */
struct i2c_algorithm {
	char name[32];				/* textual description 	*/
	unsigned int id;

	/* If an adapter algorithm can't do I2C-level access, set master_xfer
	   to NULL. If an adapter algorithm can do SMBus access, set 
	   smbus_xfer. If set to NULL, the SMBus protocol is simulated
	   using common I2C messages */
	int (*master_xfer)(struct i2c_adapter *adap,struct i2c_msg msgs[], 
	                   int num);
	int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr, 
	                   unsigned short flags, char read_write,
	                   u8 command, int size, union i2c_smbus_data * data);

	/* --- these optional/future use for some adapter types.*/
	int (*slave_send)(struct i2c_adapter *,char*,int);
	int (*slave_recv)(struct i2c_adapter *,char*,int);

	/* --- ioctl like call to set div. parameters. */
	int (*algo_control)(struct i2c_adapter *, unsigned int, unsigned long);

	/* To determine what the adapter supports */
	u32 (*functionality) (struct i2c_adapter *);
};

/*
 * i2c_adapter is the structure used to identify a physical i2c bus along
 * with the access algorithms necessary to access it.
 */
struct i2c_adapter {
	char name[32];	/* some useful name to identify the adapter	*/
	unsigned int id;/* == is algo->id | hwdep.struct->id, 		*/
			/* for registered values see below		*/
	struct i2c_algorithm *algo;/* the algorithm to access the bus	*/
	void *algo_data;

	/* --- These may be NULL, but should increase the module use count */
	void (*inc_use)(struct i2c_adapter *);
	void (*dec_use)(struct i2c_adapter *);

	/* --- administration stuff. */
	int (*client_register)(struct i2c_client *);
	int (*client_unregister)(struct i2c_client *);

	void *data;	/* private data for the adapter			*/
			/* some data fields that are used by all types	*/
			/* these data fields are readonly to the public	*/
			/* and can be set via the i2c_ioctl call	*/

			/* data fields that are valid for all devices	*/
	struct semaphore bus;
#if !I2C_LINUX_2_4_BINARY_COMPATIBILITY
	struct semaphore list;  
#endif
	unsigned int flags;/* flags specifying div. data		*/

	struct i2c_client *clients[I2C_CLIENT_MAX];
#if I2C_LINUX_2_4_BINARY_COMPATIBILITY
	int client_count; /* not used anywhere */
#endif

	int timeout;
	int retries;

#ifdef CONFIG_PROC_FS 
	/* No need to set this when you initialize the adapter          */
	int inode;
#endif /* def CONFIG_PROC_FS */
};

/*flags for the driver struct: */
#define I2C_DF_NOTIFY	0x01		/* notify on bus (de/a)ttaches 	*/
#define I2C_DF_DUMMY	0x02		/* do not connect any clients */

/*flags for the client struct: */
#define I2C_CLIENT_ALLOW_USE		0x01	/* Client allows access */
#define I2C_CLIENT_ALLOW_MULTIPLE_USE 	0x02  	/* Allow multiple access-locks */
						/* on an i2c_client */
#define I2C_CLIENT_PEC  0x04			/* Use Packet Error Checking */
#define I2C_CLIENT_TEN	0x10			/* we have a ten bit chip address	*/
						/* Must equal I2C_M_TEN below */

/* i2c_client_address_data is the struct for holding default client
 * addresses for a driver and for the parameters supplied on the
 * command line
 */