patch-2.1.94 linux/drivers/char/i2c.h

• Lines: 167
• Date: Wed Apr 8 17:24:48 1998
• Orig file: v2.1.93/linux/drivers/char/i2c.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.93/linux/drivers/char/i2c.h linux/drivers/char/i2c.h
@@ -0,0 +1,166 @@
+#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.
+ *
+ */
+
+#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_BUSID_BT848		1	/* I2C bus on a BT848 */
+
+/*
+ * 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 */
+
+#define LOCK_I2C_BUS(bus)    spin_lock_irqsave(&(bus->bus_lock),flags);
+#define UNLOCK_I2C_BUS(bus)  spin_unlock_irqrestore(&(bus->bus_lock),flags);
+
+struct i2c_bus 
+{
+	char  name[32];         /* some useful label */
+	int   id;
+	void  *data;            /* free for use by the bus driver */
+
+	spinlock_t bus_lock;
+
+	/* 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);
+
+#endif /* I2C_H */