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#ifndef I2C_H
#define I2C_H
/*
* linux i2c interface. Works a little bit like the scsi subsystem.
* There are:
*
* i2c the basic control module (like scsi_mod)
* bus driver a driver with a i2c bus (hostadapter driver)
* chip driver a driver for a chip connected
* to a i2c bus (cdrom/hd driver)
*
* A device will be attached to one bus and one chip driver. Every chip
* driver gets a unique ID.
*
* A chip driver can provide a ioctl-like callback for the
* communication with other parts of the kernel (not every i2c chip is
* useful without other devices, a TV card tuner for example).
*
* "i2c internal" parts of the structs: only the i2c module is allowed to
* write to them, for others they are read-only.
*
*/
#include <linux/version.h>
#define I2C_BUS_MAX 4 /* max # of bus drivers */
#define I2C_DRIVER_MAX 8 /* max # of chip drivers */
#define I2C_DEVICE_MAX 8 /* max # if devices per bus/driver */
struct i2c_bus;
struct i2c_driver;
struct i2c_device;
#define I2C_DRIVERID_MSP3400 1
#define I2C_DRIVERID_TUNER 2
#define I2C_DRIVERID_VIDEOTEXT 3
#define I2C_DRIVERID_VIDEODECODER 4
#define I2C_DRIVERID_VIDEOENCODER 5
#define I2C_BUSID_BT848 1 /* I2C bus on a BT848 */
#define I2C_BUSID_PARPORT 2 /* Bit banging on a parallel port */
#define I2C_BUSID_BUZ 3
#define I2C_BUSID_ZORAN 4
#define I2C_BUSID_CYBER2000 5
/*
* struct for a driver for a i2c chip (tuner, soundprocessor,
* videotext, ... ).
*
* a driver will register within the i2c module. The i2c module will
* callback the driver (i2c_attach) for every device it finds on a i2c
* bus at the specified address. If the driver decides to "accept"
* the, device, it must return a struct i2c_device, and NULL
* otherwise.
*
* i2c_detach = i2c_attach ** -1
*
* i2c_command will be used to pass commands to the driver in a
* ioctl-line manner.
*
*/
struct i2c_driver
{
char name[32]; /* some useful label */
int id; /* device type ID */
unsigned char addr_l, addr_h; /* address range of the chip */
int (*attach)(struct i2c_device *device);
int (*detach)(struct i2c_device *device);
int (*command)(struct i2c_device *device,unsigned int cmd, void *arg);
/* i2c internal */
struct i2c_device *devices[I2C_DEVICE_MAX];
int devcount;
};
/*
* this holds the informations about a i2c bus available in the system.
*
* a chip with a i2c bus interface (like bt848) registers the bus within
* the i2c module. This struct provides functions to access the i2c bus.
*
* One must hold the spinlock to access the i2c bus (XXX: is the irqsave
* required? Maybe better use a semaphore?).
* [-AC-] having a spinlock_irqsave is only needed if we have drivers wishing
* to bang their i2c bus from an interrupt.
*
* attach/detach_inform is a callback to inform the bus driver about
* attached chip drivers.
*
*/
/* needed: unsigned long flags */
#if LINUX_VERSION_CODE >= 0x020100
# if 0
# define LOCK_FLAGS unsigned long flags;
# define LOCK_I2C_BUS(bus) spin_lock_irqsave(&(bus->bus_lock),flags);
# define UNLOCK_I2C_BUS(bus) spin_unlock_irqrestore(&(bus->bus_lock),flags);
# else
# define LOCK_FLAGS
# define LOCK_I2C_BUS(bus) spin_lock(&(bus->bus_lock));
# define UNLOCK_I2C_BUS(bus) spin_unlock(&(bus->bus_lock));
# endif
#else
# define LOCK_FLAGS unsigned long flags;
# define LOCK_I2C_BUS(bus) { save_flags(flags); cli(); }
# define UNLOCK_I2C_BUS(bus) { restore_flags(flags); }
#endif
struct i2c_bus
{
char name[32]; /* some useful label */
int id;
void *data; /* free for use by the bus driver */
#if LINUX_VERSION_CODE >= 0x020100
spinlock_t bus_lock;
#endif
/* attach/detach inform callbacks */
void (*attach_inform)(struct i2c_bus *bus, int id);
void (*detach_inform)(struct i2c_bus *bus, int id);
/* Software I2C */
void (*i2c_setlines)(struct i2c_bus *bus, int ctrl, int data);
int (*i2c_getdataline)(struct i2c_bus *bus);
/* Hardware I2C */
int (*i2c_read)(struct i2c_bus *bus, unsigned char addr);
int (*i2c_write)(struct i2c_bus *bus, unsigned char addr,
unsigned char b1, unsigned char b2, int both);
/* internal data for i2c module */
struct i2c_device *devices[I2C_DEVICE_MAX];
int devcount;
};
/*
* This holds per-device data for a i2c device
*/
struct i2c_device
{
char name[32]; /* some useful label */
void *data; /* free for use by the chip driver */
unsigned char addr; /* chip addr */
/* i2c internal */
struct i2c_bus *bus;
struct i2c_driver *driver;
};
/* ------------------------------------------------------------------- */
/* i2c module functions */
/* register/unregister a i2c bus */
int i2c_register_bus(struct i2c_bus *bus);
int i2c_unregister_bus(struct i2c_bus *bus);
/* register/unregister a chip driver */
int i2c_register_driver(struct i2c_driver *driver);
int i2c_unregister_driver(struct i2c_driver *driver);
/* send a command to a chip using the ioctl-like callback interface */
int i2c_control_device(struct i2c_bus *bus, int id,
unsigned int cmd, void *arg);
/* i2c bus access functions */
void i2c_start(struct i2c_bus *bus);
void i2c_stop(struct i2c_bus *bus);
void i2c_one(struct i2c_bus *bus);
void i2c_zero(struct i2c_bus *bus);
int i2c_ack(struct i2c_bus *bus);
int i2c_sendbyte(struct i2c_bus *bus,unsigned char data,int wait_for_ack);
unsigned char i2c_readbyte(struct i2c_bus *bus,int last);
/* i2c (maybe) hardware functions */
int i2c_read(struct i2c_bus *bus, unsigned char addr);
int i2c_write(struct i2c_bus *bus, unsigned char addr,
unsigned char b1, unsigned char b2, int both);
int i2c_init(void);
#endif /* I2C_H */
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