i2c.h 21.8 KB
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/* ------------------------------------------------------------------------- */
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/*									     */
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/* i2c.h - definitions for the i2c-bus interface			     */
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/*									     */
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/* ------------------------------------------------------------------------- */
/*   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.		     */
/* ------------------------------------------------------------------------- */

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/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
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   Frodo Looijaard <frodol@dds.nl> */

#ifndef _LINUX_I2C_H
#define _LINUX_I2C_H

#include <linux/types.h>
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#ifdef __KERNEL__
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#include <linux/module.h>
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#include <linux/i2c-id.h>
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#include <linux/mod_devicetable.h>
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#include <linux/device.h>	/* for struct device */
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#include <linux/sched.h>	/* for completion */
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#include <linux/mutex.h>
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extern struct bus_type i2c_bus_type;

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/* --- General options ------------------------------------------------	*/

struct i2c_msg;
struct i2c_algorithm;
struct i2c_adapter;
struct i2c_client;
struct i2c_driver;
union i2c_smbus_data;
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struct i2c_board_info;
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#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
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/*
 * The master routines are the ones normally used to transmit data to devices
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 * 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
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 * transmit an arbitrary number of messages without interruption.
 */
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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);
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/* Transfer num messages.
 */
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extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
			int num);
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/* 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,
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   and probably just as fast.
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   Note that we use i2c_adapter here, because you do not need a specific
   smbus adapter to call this function. */
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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);
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/* Now follow the 'nice' access routines. These also document the calling
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   conventions of i2c_smbus_xfer. */
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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);
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/* Returns the number of read bytes */
extern s32 i2c_smbus_read_block_data(struct i2c_client *client,
				     u8 command, u8 *values);
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extern s32 i2c_smbus_write_block_data(struct i2c_client *client,
				      u8 command, u8 length, const u8 *values);
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/* Returns the number of read bytes */
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extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client,
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					 u8 command, u8 length, u8 *values);
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extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client,
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					  u8 command, u8 length,
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					  const u8 *values);
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#endif /* I2C */
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/**
 * struct i2c_driver - represent an I2C device driver
 * @class: What kind of i2c device we instantiate (for detect)
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 * @attach_adapter: Callback for bus addition (for legacy drivers)
 * @detach_adapter: Callback for bus removal (for legacy drivers)
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 * @probe: Callback for device binding
 * @remove: Callback for device unbinding
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 * @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
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 * @detect: Callback for device detection
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 * @address_list: The I2C addresses to probe (for detect)
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 * @clients: List of detected clients we created (for i2c-core use only)
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 *
 * 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.
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 *
 * 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.
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 */
struct i2c_driver {
	unsigned int class;

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	/* 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.
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	 */
	int (*attach_adapter)(struct i2c_adapter *);
	int (*detach_adapter)(struct i2c_adapter *);

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

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	/* 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);

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	/* a ioctl like command that can be used to perform specific functions
	 * with the device.
	 */
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	int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
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	struct device_driver driver;
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	const struct i2c_device_id *id_table;
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	/* Device detection callback for automatic device creation */
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	int (*detect)(struct i2c_client *, struct i2c_board_info *);
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	const unsigned short *address_list;
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	struct list_head clients;
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};
#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)

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

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

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

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static inline void *i2c_get_clientdata(const struct i2c_client *dev)
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{
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	return dev_get_drvdata(&dev->dev);
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}

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static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
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{
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	dev_set_drvdata(&dev->dev, data);
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}

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/**
 * struct i2c_board_info - template for device creation
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 * @type: chip type, to initialize i2c_client.name
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 * @flags: to initialize i2c_client.flags
 * @addr: stored in i2c_client.addr
 * @platform_data: stored in i2c_client.dev.platform_data
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 * @archdata: copied into i2c_client.dev.archdata
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 * @irq: stored in i2c_client.irq
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 *
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 * 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
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 * 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.
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 */
struct i2c_board_info {
	char		type[I2C_NAME_SIZE];
	unsigned short	flags;
	unsigned short	addr;
	void		*platform_data;
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	struct dev_archdata	*archdata;
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	int		irq;
};

/**
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 * I2C_BOARD_INFO - macro used to list an i2c device and its address
 * @dev_type: identifies the device type
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 * @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
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 * fields (such as associated irq, or device-specific platform_data)
 * are provided using conventional syntax.
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 */
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#define I2C_BOARD_INFO(dev_type, dev_addr) \
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	.type = dev_type, .addr = (dev_addr)
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#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
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/* 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);

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/* 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);

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/* For devices that use several addresses, use i2c_new_dummy() to make
 * client handles for the extra addresses.
 */
extern struct i2c_client *
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i2c_new_dummy(struct i2c_adapter *adap, u16 address);
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extern void i2c_unregister_device(struct i2c_client *);
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#endif /* I2C */
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/* 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.
 */
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#ifdef CONFIG_I2C_BOARDINFO
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extern int
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i2c_register_board_info(int busnum, struct i2c_board_info const *info,
			unsigned n);
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#else
static inline int
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i2c_register_board_info(int busnum, struct i2c_board_info const *info,
			unsigned n)
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{
	return 0;
}
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#endif /* I2C_BOARDINFO */
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/*
 * 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
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	   to NULL. If an adapter algorithm can do SMBus access, set
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	   smbus_xfer. If set to NULL, the SMBus protocol is simulated
	   using common I2C messages */
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	/* master_xfer should return the number of messages successfully
	   processed, or a negative value on error */
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	int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
			   int num);
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	int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
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			   unsigned short flags, char read_write,
			   u8 command, int size, union i2c_smbus_data *data);
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	/* 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;
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	unsigned int id;
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	unsigned int class;		  /* classes to allow probing for */
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	const struct i2c_algorithm *algo; /* the algorithm to access the bus */
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	void *algo_data;

	/* data fields that are valid for all devices	*/
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	struct rt_mutex bus_lock;
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	int timeout;			/* in jiffies */
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	int retries;
	struct device dev;		/* the adapter device */

	int nr;
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	char name[48];
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	struct completion dev_released;
};
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#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
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static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
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{
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	return dev_get_drvdata(&dev->dev);
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}

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static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
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{
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	dev_set_drvdata(&dev->dev, data);
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}

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/**
 * 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)
{
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	rt_mutex_lock(&adapter->bus_lock);
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}

/**
 * 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)
{
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	rt_mutex_unlock(&adapter->bus_lock);
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}

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/*flags for the client struct: */
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#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 */
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/* 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 */
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#define I2C_CLASS_DDC		(1<<3)	/* DDC bus on graphics adapters */
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#define I2C_CLASS_SPD		(1<<7)	/* SPD EEPROMs and similar */
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/* Internal numbers to terminate lists */
#define I2C_CLIENT_END		0xfffeU

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

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

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

/* administration...
 */
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#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
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extern int i2c_add_adapter(struct i2c_adapter *);
extern int i2c_del_adapter(struct i2c_adapter *);
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extern int i2c_add_numbered_adapter(struct i2c_adapter *);
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extern int i2c_register_driver(struct module *, struct i2c_driver *);
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extern void i2c_del_driver(struct i2c_driver *);
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static inline int i2c_add_driver(struct i2c_driver *driver)
{
	return i2c_register_driver(THIS_MODULE, driver);
}

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

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extern struct i2c_adapter *i2c_get_adapter(int id);
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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;
}

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/* Return the adapter number for a specific adapter */
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static inline int i2c_adapter_id(struct i2c_adapter *adap)
{
	return adap->nr;
}
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#endif /* I2C */
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#endif /* __KERNEL__ */
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/**
 * 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).
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 */
struct i2c_msg {
	__u16 addr;	/* slave address			*/
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	__u16 flags;
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#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 */
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	__u16 len;		/* msg length				*/
	__u8 *buf;		/* pointer to msg data			*/
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};

/* To determine what functionality is present */

#define I2C_FUNC_I2C			0x00000001
#define I2C_FUNC_10BIT_ADDR		0x00000002
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#define I2C_FUNC_PROTOCOL_MANGLING	0x00000004 /* I2C_M_NOSTART etc. */
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#define I2C_FUNC_SMBUS_PEC		0x00000008
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#define I2C_FUNC_SMBUS_BLOCK_PROC_CALL	0x00008000 /* SMBus 2.0 */
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#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
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#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. */

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#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)
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/*
 * Data for SMBus Messages
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 */
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#define I2C_SMBUS_BLOCK_MAX	32	/* As specified in SMBus standard */
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union i2c_smbus_data {
	__u8 byte;
	__u16 word;
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	__u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
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			       /* and one more for user-space compatibility */
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};

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/* i2c_smbus_xfer read or write markers */
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#define I2C_SMBUS_READ	1
#define I2C_SMBUS_WRITE	0

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/* SMBus transaction types (size parameter in the above functions)
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   Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
#define I2C_SMBUS_QUICK		    0
#define I2C_SMBUS_BYTE		    1
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#define I2C_SMBUS_BYTE_DATA	    2
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#define I2C_SMBUS_WORD_DATA	    3
#define I2C_SMBUS_PROC_CALL	    4
#define I2C_SMBUS_BLOCK_DATA	    5
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#define I2C_SMBUS_I2C_BLOCK_BROKEN  6
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#define I2C_SMBUS_BLOCK_PROC_CALL   7		/* SMBus 2.0 */
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#define I2C_SMBUS_I2C_BLOCK_DATA    8
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#endif /* _LINUX_I2C_H */