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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 */