i2c.h

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/* ------------------------------------------------------------------------- */
/* 									     */
/* 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 1.68 2003/01/21 08:08:16 kmalkki Exp $ */

#ifndef _LINUX_I2C_H
#define _LINUX_I2C_H

#include <linux/module.h>
#include <linux/types.h>
#include <linux/i2c-id.h>
#include <linux/device.h>	/* for struct device */
#include <asm/semaphore.h>

/* --- For i2c-isa ---------------------------------------------------- */

extern void i2c_adapter_dev_release(struct device *dev);
extern struct device_driver i2c_adapter_driver;
extern struct class i2c_adapter_class;
extern struct bus_type i2c_bus_type;

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

struct i2c_msg;
struct i2c_algorithm;
struct i2c_adapter;
struct i2c_client;
struct i2c_driver;
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 *msgs, 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);
/* Returns the number of bytes transferred */
extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
				      u8 command, u8 length,
				      u8 *values);
extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client,
					 u8 command, 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 {
	struct module *owner;
	char name[32];
	int id;
	unsigned int class;
	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 *);
	int (*detach_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);

	struct device_driver driver;
	struct list_head list;
};
#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)

#define I2C_NAME_SIZE	50

/*
 * 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 {
	unsigned int flags;		/* div., see below		*/
	unsigned short addr;		/* chip address - NOTE: 7bit 	*/
					/* addresses are stored in the	*/
					/* _LOWER_ 7 bits		*/
	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
	struct i2c_driver *driver;	/* and our access routines	*/
	int usage_count;		/* How many accesses currently  */
					/* to the client		*/
	struct device dev;		/* the device structure		*/
	struct list_head list;
	char name[I2C_NAME_SIZE];
	struct completion released;
};
#define to_i2c_client(d) container_of(d, struct i2c_client, dev)

static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
{
	return to_i2c_client(container_of(kobj, struct device, kobj));
}

static inline void *i2c_get_clientdata (struct i2c_client *dev)
{
	return dev_get_drvdata (&dev->dev);
}

static inline void i2c_set_clientdata (struct i2c_client *dev, void *data)
{
	dev_set_drvdata (&dev->dev, data);
}

/*
 * 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 {
	/* 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 {
	struct module *owner;
	unsigned int id;
	unsigned int class;
	struct i2c_algorithm *algo;/* the algorithm to access the bus	*/
	void *algo_data;

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

	/* data fields that are valid for all devices	*/
	struct semaphore bus_lock;
	struct semaphore clist_lock;

	int timeout;
	int retries;
	struct device dev;		/* the adapter device */
	struct class_device class_dev;	/* the class device */

	int nr;
	struct list_head clients;
	struct list_head list;
	char name[I2C_NAME_SIZE];
	struct completion dev_released;
	struct completion class_dev_released;
};
#define dev_to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
#define class_dev_to_i2c_adapter(d) container_of(d, struct i2c_adapter, class_dev)

static inline void *i2c_get_adapdata (struct i2c_adapter *dev)
{
	return dev_get_drvdata (&dev->dev);
}

static inline void i2c_set_adapdata (struct i2c_adapter *dev, void *data)
{
	dev_set_drvdata (&dev->dev, data);
}

/*flags for the driver struct: */
#define I2C_DF_NOTIFY	0x01		/* notify on bus (de/a)ttaches 	*/
#if 0
/* this flag is gone -- there is a (optional) driver->detach_adapter
 * callback now which can be used instead */
# define I2C_DF_DUMMY	0x02
#endif

/*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 adapter classes (bitmask) */
#define I2C_CLASS_HWMON		(1<<0)	/* lm_sensors, ... */
#define I2C_CLASS_TV_ANALOG	(1<<1)	/* bttv + friends */
#define I2C_CLASS_TV_DIGITAL	(1<<2)	/* dvb cards */
#define I2C_CLASS_DDC		(1<<3)	/* i2c-matroxfb ? */
#define I2C_CLASS_CAM_ANALOG	(1<<4)	/* camera with analog CCD */
#define I2C_CLASS_CAM_DIGITAL	(1<<5)	/* most webcams */
#define I2C_CLASS_SOUND		(1<<6)	/* sound devices */
#define I2C_CLASS_ALL		(UINT_MAX) /* all of the above */

/* i2c_client_address_data is the struct for holding default client
 * addresses for a driver and for the parameters supplied on the
 * command line
 */
struct i2c_client_address_data {
	unsigned short *normal_i2c;
	unsigned short *probe;
	unsigned short *ignore;
	unsigned short **forces;
};

/* Internal numbers to terminate lists */
#define I2C_CLIENT_END		0xfffeU

/* The numbers to use to set I2C bus address */
#define ANY_I2C_BUS		0xffff
#define ANY_I2C_ISA_BUS		9191


/* ----- functions exported by i2c.o */

/* administration...
 */
extern int i2c_add_adapter(struct i2c_adapter *);
extern int i2c_del_adapter(struct i2c_adapter *);

extern int i2c_add_driver(struct i2c_driver *);
extern int i2c_del_driver(struct i2c_driver *);

extern int i2c_attach_client(struct i2c_client *);
extern int i2c_detach_client(struct i2c_client *);

/* New function: This is to get an i2c_client-struct for controlling the 
   client either by using i2c_control-function or having the 
   client-module export functions that can be used with the i2c_client
   -struct. */
extern struct i2c_client *i2c_get_client(int driver_id, int adapter_id, 
					struct i2c_client *prev);

/* Should be used with new function
   extern struct i2c_client *i2c_get_client(int,int,struct i2c_client *);
   to make sure that client-struct is valid and that it is okay to access
   the i2c-client. 
   returns -EACCES if client doesn't allow use (default)
   returns -EBUSY if client doesn't allow multiple use (default) and 
   usage_count >0 */
extern int i2c_use_client(struct i2c_client *);
extern int i2c_release_client(struct i2c_client *);

/* call the i2c_client->command() of all attached clients with
 * the given arguments */
extern void i2c_clients_command(struct i2c_adapter *adap,
				unsigned int cmd, void *arg);

/* returns -EBUSY if address has been taken, 0 if not. Note that the only
   other place at which this is called is within i2c_attach_client; so
   you can cheat by simply not registering. Not recommended, of course! */
extern int i2c_check_addr (struct i2c_adapter *adapter, int addr);

/* Detect function. It iterates over all possible addresses itself.
 * It will only call found_proc if some client is connected at the
 * specific address (unless a 'force' matched);
 */
extern int i2c_probe(struct i2c_adapter *adapter, 
		struct i2c_client_address_data *address_data,
		int (*found_proc) (struct i2c_adapter *, int, int));

/* An ioctl like call to set div. parameters of the adapter.
 */