[safe/jmp/linux-2.6] / include / linux / i2c.h

/* ------------------------------------------------------------------------- */
/*                                                                           */
/* 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 Kyösti Mälkki <kmalkki@cc.hut.fi> and
   Frodo Looijaard <frodol@dds.nl> */

#ifndef _LINUX_I2C_H
#define _LINUX_I2C_H

#include <linux/types.h>
#ifdef __KERNEL__
#include <linux/module.h>
#include <linux/i2c-id.h>
#include <linux/mod_devicetable.h>
#include <linux/device.h>       /* for struct device */
#include <linux/sched.h>        /* for completion */
#include <linux/mutex.h>

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;
struct i2c_board_info;

#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
/*
 * 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 *client, const char *buf,
                           int count);
extern int i2c_master_recv(struct i2c_client *client, char *buf, int count);

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

/* 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 i2c_smbus_xfer. */

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 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, const u8 *values);
/* Returns the number of read bytes */
extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client,
                                         u8 command, u8 length, u8 *values);
extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client,
                                          u8 command, u8 length,
                                          const u8 *values);
#endif /* I2C */

/**
 * struct i2c_driver - represent an I2C device driver
 * @class: What kind of i2c device we instantiate (for detect)
 * @attach_adapter: Callback for bus addition (for legacy drivers)
 * @detach_adapter: Callback for bus removal (for legacy drivers)
 * @probe: Callback for device binding
 * @remove: Callback for device unbinding
 * @shutdown: Callback for device shutdown
 * @suspend: Callback for device suspend
 * @resume: Callback for device resume
 * @command: Callback for bus-wide signaling (optional)
 * @driver: Device driver model driver
 * @id_table: List of I2C devices supported by this driver
 * @detect: Callback for device detection
 * @address_list: The I2C addresses to probe (for detect)
 * @clients: List of detected clients we created (for i2c-core use only)
 *
 * The driver.owner field should be set to the module owner of this driver.
 * The driver.name field should be set to the name of this driver.
 *
 * For automatic device detection, both @detect and @address_data must
 * be defined. @class should also be set, otherwise only devices forced
 * with module parameters will be created. The detect function must
 * fill at least the name field of the i2c_board_info structure it is
 * handed upon successful detection, and possibly also the flags field.
 *
 * If @detect is missing, the driver will still work fine for enumerated
 * devices. Detected devices simply won't be supported. This is expected
 * for the many I2C/SMBus devices which can't be detected reliably, and
 * the ones which can always be enumerated in practice.
 *
 * The i2c_client structure which is handed to the @detect callback is
 * not a real i2c_client. It is initialized just enough so that you can
 * call i2c_smbus_read_byte_data and friends on it. Don't do anything
 * else with it. In particular, calling dev_dbg and friends on it is
 * not allowed.
 */
struct i2c_driver {
        unsigned int class;

        /* Notifies the driver that a new bus has appeared or is about to be
         * removed. You should avoid using this if you can, it will probably
         * be removed in a near future.
         */
        int (*attach_adapter)(struct i2c_adapter *);
        int (*detach_adapter)(struct i2c_adapter *);

        /* Standard driver model interfaces */
        int (*probe)(struct i2c_client *, const struct i2c_device_id *);
        int (*remove)(struct i2c_client *);

        /* driver model interfaces that don't relate to enumeration  */
        void (*shutdown)(struct i2c_client *);
        int (*suspend)(struct i2c_client *, pm_message_t mesg);
        int (*resume)(struct i2c_client *);

        /* Alert callback, for example for the SMBus alert protocol.
         * The format and meaning of the data value depends on the protocol.
         * For the SMBus alert protocol, there is a single bit of data passed
         * as the alert response's low bit ("event flag").
         */
        void (*alert)(struct i2c_client *, unsigned int data);

        /* 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;
        const struct i2c_device_id *id_table;

        /* Device detection callback for automatic device creation */
        int (*detect)(struct i2c_client *, struct i2c_board_info *);
        const unsigned short *address_list;
        struct list_head clients;
};
#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)

/**
 * struct i2c_client - represent an I2C slave device
 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
 *      I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
 * @addr: Address used on the I2C bus connected to the parent adapter.
 * @name: Indicates the type of the device, usually a chip name that's
 *      generic enough to hide second-sourcing and compatible revisions.
 * @adapter: manages the bus segment hosting this I2C device
 * @driver: device's driver, hence pointer to access routines
 * @dev: Driver model device node for the slave.
 * @irq: indicates the IRQ generated by this device (if any)
 * @detected: member of an i2c_driver.clients list or i2c-core's
 *      userspace_devices list
 *
 * An i2c_client identifies a single device (i.e. chip) connected to an
 * i2c bus. The behaviour exposed to Linux is defined by the driver
 * managing the device.
 */
struct i2c_client {
        unsigned short flags;           /* div., see below              */
        unsigned short addr;            /* chip address - NOTE: 7bit    */
                                        /* addresses are stored in the  */
                                        /* _LOWER_ 7 bits               */
        char name[I2C_NAME_SIZE];
        struct i2c_adapter *adapter;    /* the adapter we sit on        */
        struct i2c_driver *driver;      /* and our access routines      */
        struct device dev;              /* the device structure         */
        int irq;                        /* irq issued by device         */
        struct list_head detected;
};
#define to_i2c_client(d) container_of(d, struct i2c_client, dev)

extern struct i2c_client *i2c_verify_client(struct device *dev);

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

static inline void *i2c_get_clientdata(const 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);
}

/**
 * struct i2c_board_info - template for device creation
 * @type: chip type, to initialize i2c_client.name
 * @flags: to initialize i2c_client.flags
 * @addr: stored in i2c_client.addr
 * @platform_data: stored in i2c_client.dev.platform_data
 * @archdata: copied into i2c_client.dev.archdata
 * @irq: stored in i2c_client.irq
 *
 * I2C doesn't actually support hardware probing, although controllers and
 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
 * a device at a given address.  Drivers commonly need more information than
 * that, such as chip type, configuration, associated IRQ, and so on.
 *
 * i2c_board_info is used to build tables of information listing I2C devices
 * that are present.  This information is used to grow the driver model tree.
 * For mainboards this is done statically using i2c_register_board_info();
 * bus numbers identify adapters that aren't yet available.  For add-on boards,
 * i2c_new_device() does this dynamically with the adapter already known.
 */
struct i2c_board_info {
        char            type[I2C_NAME_SIZE];
        unsigned short  flags;
        unsigned short  addr;
        void            *platform_data;
        struct dev_archdata     *archdata;
        int             irq;
};

/**
 * I2C_BOARD_INFO - macro used to list an i2c device and its address
 * @dev_type: identifies the device type
 * @dev_addr: the device's address on the bus.
 *
 * This macro initializes essential fields of a struct i2c_board_info,
 * declaring what has been provided on a particular board.  Optional
 * fields (such as associated irq, or device-specific platform_data)
 * are provided using conventional syntax.
 */
#define I2C_BOARD_INFO(dev_type, dev_addr) \
        .type = dev_type, .addr = (dev_addr)


#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
/* Add-on boards should register/unregister their devices; e.g. a board
 * with integrated I2C, a config eeprom, sensors, and a codec that's
 * used in conjunction with the primary hardware.
 */
extern struct i2c_client *
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);

/* If you don't know the exact address of an I2C device, use this variant
 * instead, which can probe for device presence in a list of possible
 * addresses.
 */
extern struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
                      struct i2c_board_info *info,
                      unsigned short const *addr_list);

/* For devices that use several addresses, use i2c_new_dummy() to make
 * client handles for the extra addresses.
 */
extern struct i2c_client *
i2c_new_dummy(struct i2c_adapter *adap, u16 address);

extern void i2c_unregister_device(struct i2c_client *);
#endif /* I2C */

/* Mainboard arch_initcall() code should register all its I2C devices.
 * This is done at arch_initcall time, before declaring any i2c adapters.
 * Modules for add-on boards must use other calls.
 */
#ifdef CONFIG_I2C_BOARDINFO
extern int
i2c_register_board_info(int busnum, struct i2c_board_info const *info,
                        unsigned n);
#else
static inline int
i2c_register_board_info(int busnum, struct i2c_board_info const *info,
                        unsigned n)
{
        return 0;
}
#endif /* I2C_BOARDINFO */

/*
 * 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 */
        /* master_xfer should return the number of messages successfully
           processed, or a negative value on error */
        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);

        /* 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;               /* classes to allow probing for */
        const struct i2c_algorithm *algo; /* the algorithm to access the bus */
        void *algo_data;

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

        int timeout;                    /* in jiffies */
        int retries;
        struct device dev;              /* the adapter device */

        int nr;
        char name[48];
        struct completion dev_released;
};
#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)

static inline void *i2c_get_adapdata(const 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);
}

/**
 * i2c_lock_adapter - Prevent access to an I2C bus segment
 * @adapter: Target I2C bus segment
 */
static inline void i2c_lock_adapter(struct i2c_adapter *adapter)
{
        rt_mutex_lock(&adapter->bus_lock);
}

/**
 * i2c_unlock_adapter - Reauthorize access to an I2C bus segment
 * @adapter: Target I2C bus segment
 */
static inline void i2c_unlock_adapter(struct i2c_adapter *adapter)
{
        rt_mutex_unlock(&adapter->bus_lock);
}

/*flags for the client struct: */
#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 */
#define I2C_CLIENT_WAKE 0x80            /* for board_info; true iff can wake */

/* 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)  /* DDC bus on graphics adapters */
#define I2C_CLASS_SPD           (1<<7)  /* SPD EEPROMs and similar */

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

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

/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
#define I2C_ADDRS(addr, addrs...) \
        ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })


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

/* administration...
 */
#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
extern int i2c_add_adapter(struct i2c_adapter *);
extern int i2c_del_adapter(struct i2c_adapter *);
extern int i2c_add_numbered_adapter(struct i2c_adapter *);

extern int i2c_register_driver(struct module *, struct i2c_driver *);
extern void i2c_del_driver(struct i2c_driver *);

static inline int i2c_add_driver(struct i2c_driver *driver)
{
        return i2c_register_driver(THIS_MODULE, driver);
}

extern struct i2c_client *i2c_use_client(struct i2c_client *client);
extern void i2c_release_client(struct i2c_client *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);

extern struct i2c_adapter *i2c_get_adapter(int id);
extern void i2c_put_adapter(struct i2c_adapter *adap);


/* Return the functionality mask */
static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
{
        return adap->algo->functionality(adap);
}

/* Return 1 if adapter supports everything we need, 0 if not. */
static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
{
        return (func & i2c_get_functionality(adap)) == func;
}

/* Return the adapter number for a specific adapter */
static inline int i2c_adapter_id(struct i2c_adapter *adap)
{
        return adap->nr;
}
#endif /* I2C */
#endif /* __KERNEL__ */

/**
 * 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_NOSTART           0x4000  /* if I2C_FUNC_PROTOCOL_MANGLING */
#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_NOSTART etc. */
#define I2C_FUNC_SMBUS_PEC              0x00000008
#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 */