blob: ddfa04108baf14ade92a85d3a3f909ca9ab30589 [file] [log] [blame]
/* ------------------------------------------------------------------------- */
/* */
/* 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
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., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301 USA. */
/* ------------------------------------------------------------------------- */
/* With some changes from Kyösti Mälkki <> and
Frodo Looijaard <> */
#ifndef _LINUX_I2C_H
#define _LINUX_I2C_H
#include <linux/types.h>
#ifdef __KERNEL__
#include <linux/mod_devicetable.h>
#include <linux/device.h> /* for struct device */
#include <linux/sched.h> /* for completion */
#include <linux/mutex.h>
#include <linux/of.h> /* for struct device_node */
#include <linux/swab.h> /* for swab16 */
extern struct bus_type i2c_bus_type;
extern struct device_type i2c_adapter_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;
struct module;
#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.
* @count must be be less than 64k since msg.len is u16.
extern int i2c_master_send(const struct i2c_client *client, const char *buf,
int count);
extern int i2c_master_recv(const 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(const struct i2c_client *client);
extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
u8 command);
extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
u8 command, u8 value);
extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
u8 command);
extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
u8 command, u16 value);
static inline s32
i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
s32 value = i2c_smbus_read_word_data(client, command);
return (value < 0) ? value : swab16(value);
static inline s32
i2c_smbus_write_word_swapped(const struct i2c_client *client,
u8 command, u16 value)
return i2c_smbus_write_word_data(client, command, swab16(value));
/* Returns the number of read bytes */
extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
u8 command, u8 *values);
extern s32 i2c_smbus_write_block_data(const 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(const struct i2c_client *client,
u8 command, u8 length, u8 *values);
extern s32 i2c_smbus_write_i2c_block_data(const 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 (deprecated)
* @detach_adapter: Callback for bus removal (deprecated)
* @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
* @alert: Alert callback, for example for the SMBus alert protocol
* @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 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, it will be removed in a
* near future.
int (*attach_adapter)(struct i2c_adapter *) __deprecated;
int (*detach_adapter)(struct i2c_adapter *) __deprecated;
/* 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);
extern struct i2c_adapter *i2c_verify_adapter(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
* @flags: to initialize i2c_client.flags
* @addr: stored in i2c_client.addr
* @platform_data: stored in
* @archdata: copied into
* @of_node: pointer to OpenFirmware device node
* @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;
struct device_node *of_node;
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. The "probe" callback function is optional. If it is provided,
* it must return 1 on successful probe, 0 otherwise. If it is not provided,
* a default probing method is used.
extern struct i2c_client *
i2c_new_probed_device(struct i2c_adapter *adap,
struct i2c_board_info *info,
unsigned short const *addr_list,
int (*probe)(struct i2c_adapter *, unsigned short addr));
/* Common custom probe functions */
extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
/* 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.
extern int
i2c_register_board_info(int busnum, struct i2c_board_info const *info,
unsigned n);
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 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;
struct mutex userspace_clients_lock;
struct list_head userspace_clients;
#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);
static inline struct i2c_adapter *
i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
struct device *parent = adapter->dev.parent;
if (parent != NULL && parent->type == &i2c_adapter_type)
return to_i2c_adapter(parent);
return NULL;
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
/* Adapter locking functions, exported for shared pin cases */
void i2c_lock_adapter(struct i2c_adapter *);
void i2c_unlock_adapter(struct i2c_adapter *);
/*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_DDC (1<<3) /* DDC bus on graphics adapters */
#define I2C_CLASS_SPD (1<<7) /* Memory modules */
/* Internal numbers to terminate lists */
#define I2C_CLIENT_END 0xfffeU
/* 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 *);
/* use a define to avoid include chaining to get THIS_MODULE */
#define i2c_add_driver(driver) \
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 nr);
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;
* module_i2c_driver() - Helper macro for registering a I2C driver
* @__i2c_driver: i2c_driver struct
* Helper macro for I2C drivers which do not do anything special in module
* init/exit. This eliminates a lot of boilerplate. Each module may only
* use this macro once, and calling it replaces module_init() and module_exit()
#define module_i2c_driver(__i2c_driver) \
module_driver(__i2c_driver, i2c_add_driver, \
#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_NOSTART */
#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_IGNORE_NAK etc. */
#define I2C_FUNC_SMBUS_PEC 0x00000008
#define I2C_FUNC_NOSTART 0x00000010 /* I2C_M_NOSTART */
#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. */
* 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_BLOCK_PROC_CALL 7 /* SMBus 2.0 */
#endif /* _LINUX_I2C_H */