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