1 /* ------------------------------------------------------------------------- */
3 /* i2c.h - definitions for the i2c-bus interface */
5 /* ------------------------------------------------------------------------- */
6 /* Copyright (C) 1995-2000 Simon G. Vogl
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
22 /* ------------------------------------------------------------------------- */
24 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
25 Frodo Looijaard <frodol@dds.nl> */
29 #include <linux/mod_devicetable.h>
30 #include <linux/device.h> /* for struct device */
31 #include <linux/sched.h> /* for completion */
32 #include <linux/mutex.h>
33 #include <linux/of.h> /* for struct device_node */
34 #include <linux/swab.h> /* for swab16 */
35 #include <uapi/linux/i2c.h>
37 extern struct bus_type i2c_bus_type
;
38 extern struct device_type i2c_adapter_type
;
40 /* --- General options ------------------------------------------------ */
48 struct i2c_board_info
;
50 typedef int (*i2c_slave_cb_t
)(struct i2c_client
*, enum i2c_slave_event
, u8
*);
54 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
56 * The master routines are the ones normally used to transmit data to devices
57 * on a bus (or read from them). Apart from two basic transfer functions to
58 * transmit one message at a time, a more complex version can be used to
59 * transmit an arbitrary number of messages without interruption.
60 * @count must be be less than 64k since msg.len is u16.
62 extern int i2c_master_send(const struct i2c_client
*client
, const char *buf
,
64 extern int i2c_master_recv(const struct i2c_client
*client
, char *buf
,
67 /* Transfer num messages.
69 extern int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
72 extern int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
75 /* This is the very generalized SMBus access routine. You probably do not
76 want to use this, though; one of the functions below may be much easier,
77 and probably just as fast.
78 Note that we use i2c_adapter here, because you do not need a specific
79 smbus adapter to call this function. */
80 extern s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
,
81 unsigned short flags
, char read_write
, u8 command
,
82 int size
, union i2c_smbus_data
*data
);
84 /* Now follow the 'nice' access routines. These also document the calling
85 conventions of i2c_smbus_xfer. */
87 extern s32
i2c_smbus_read_byte(const struct i2c_client
*client
);
88 extern s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
);
89 extern s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
,
91 extern s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
,
92 u8 command
, u8 value
);
93 extern s32
i2c_smbus_read_word_data(const struct i2c_client
*client
,
95 extern s32
i2c_smbus_write_word_data(const struct i2c_client
*client
,
96 u8 command
, u16 value
);
99 i2c_smbus_read_word_swapped(const struct i2c_client
*client
, u8 command
)
101 s32 value
= i2c_smbus_read_word_data(client
, command
);
103 return (value
< 0) ? value
: swab16(value
);
107 i2c_smbus_write_word_swapped(const struct i2c_client
*client
,
108 u8 command
, u16 value
)
110 return i2c_smbus_write_word_data(client
, command
, swab16(value
));
113 /* Returns the number of read bytes */
114 extern s32
i2c_smbus_read_block_data(const struct i2c_client
*client
,
115 u8 command
, u8
*values
);
116 extern s32
i2c_smbus_write_block_data(const struct i2c_client
*client
,
117 u8 command
, u8 length
, const u8
*values
);
118 /* Returns the number of read bytes */
119 extern s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
,
120 u8 command
, u8 length
, u8
*values
);
121 extern s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
,
122 u8 command
, u8 length
,
127 * struct i2c_driver - represent an I2C device driver
128 * @class: What kind of i2c device we instantiate (for detect)
129 * @attach_adapter: Callback for bus addition (deprecated)
130 * @probe: Callback for device binding
131 * @remove: Callback for device unbinding
132 * @shutdown: Callback for device shutdown
133 * @alert: Alert callback, for example for the SMBus alert protocol
134 * @command: Callback for bus-wide signaling (optional)
135 * @driver: Device driver model driver
136 * @id_table: List of I2C devices supported by this driver
137 * @detect: Callback for device detection
138 * @address_list: The I2C addresses to probe (for detect)
139 * @clients: List of detected clients we created (for i2c-core use only)
141 * The driver.owner field should be set to the module owner of this driver.
142 * The driver.name field should be set to the name of this driver.
144 * For automatic device detection, both @detect and @address_list must
145 * be defined. @class should also be set, otherwise only devices forced
146 * with module parameters will be created. The detect function must
147 * fill at least the name field of the i2c_board_info structure it is
148 * handed upon successful detection, and possibly also the flags field.
150 * If @detect is missing, the driver will still work fine for enumerated
151 * devices. Detected devices simply won't be supported. This is expected
152 * for the many I2C/SMBus devices which can't be detected reliably, and
153 * the ones which can always be enumerated in practice.
155 * The i2c_client structure which is handed to the @detect callback is
156 * not a real i2c_client. It is initialized just enough so that you can
157 * call i2c_smbus_read_byte_data and friends on it. Don't do anything
158 * else with it. In particular, calling dev_dbg and friends on it is
164 /* Notifies the driver that a new bus has appeared. You should avoid
165 * using this, it will be removed in a near future.
167 int (*attach_adapter
)(struct i2c_adapter
*) __deprecated
;
169 /* Standard driver model interfaces */
170 int (*probe
)(struct i2c_client
*, const struct i2c_device_id
*);
171 int (*remove
)(struct i2c_client
*);
173 /* driver model interfaces that don't relate to enumeration */
174 void (*shutdown
)(struct i2c_client
*);
176 /* Alert callback, for example for the SMBus alert protocol.
177 * The format and meaning of the data value depends on the protocol.
178 * For the SMBus alert protocol, there is a single bit of data passed
179 * as the alert response's low bit ("event flag").
181 void (*alert
)(struct i2c_client
*, unsigned int data
);
183 /* a ioctl like command that can be used to perform specific functions
186 int (*command
)(struct i2c_client
*client
, unsigned int cmd
, void *arg
);
188 struct device_driver driver
;
189 const struct i2c_device_id
*id_table
;
191 /* Device detection callback for automatic device creation */
192 int (*detect
)(struct i2c_client
*, struct i2c_board_info
*);
193 const unsigned short *address_list
;
194 struct list_head clients
;
196 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
199 * struct i2c_client - represent an I2C slave device
200 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
201 * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
202 * @addr: Address used on the I2C bus connected to the parent adapter.
203 * @name: Indicates the type of the device, usually a chip name that's
204 * generic enough to hide second-sourcing and compatible revisions.
205 * @adapter: manages the bus segment hosting this I2C device
206 * @dev: Driver model device node for the slave.
207 * @irq: indicates the IRQ generated by this device (if any)
208 * @detected: member of an i2c_driver.clients list or i2c-core's
209 * userspace_devices list
210 * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
211 * calls it to pass on slave events to the slave driver.
213 * An i2c_client identifies a single device (i.e. chip) connected to an
214 * i2c bus. The behaviour exposed to Linux is defined by the driver
215 * managing the device.
218 unsigned short flags
; /* div., see below */
219 unsigned short addr
; /* chip address - NOTE: 7bit */
220 /* addresses are stored in the */
222 char name
[I2C_NAME_SIZE
];
223 struct i2c_adapter
*adapter
; /* the adapter we sit on */
224 struct device dev
; /* the device structure */
225 int irq
; /* irq issued by device */
226 struct list_head detected
;
227 #if IS_ENABLED(CONFIG_I2C_SLAVE)
228 i2c_slave_cb_t slave_cb
; /* callback for slave mode */
231 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
233 extern struct i2c_client
*i2c_verify_client(struct device
*dev
);
234 extern struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
);
236 static inline struct i2c_client
*kobj_to_i2c_client(struct kobject
*kobj
)
238 struct device
* const dev
= container_of(kobj
, struct device
, kobj
);
239 return to_i2c_client(dev
);
242 static inline void *i2c_get_clientdata(const struct i2c_client
*dev
)
244 return dev_get_drvdata(&dev
->dev
);
247 static inline void i2c_set_clientdata(struct i2c_client
*dev
, void *data
)
249 dev_set_drvdata(&dev
->dev
, data
);
252 /* I2C slave support */
254 #if IS_ENABLED(CONFIG_I2C_SLAVE)
255 enum i2c_slave_event
{
256 I2C_SLAVE_REQ_READ_START
,
257 I2C_SLAVE_REQ_READ_END
,
258 I2C_SLAVE_REQ_WRITE_START
,
259 I2C_SLAVE_REQ_WRITE_END
,
263 extern int i2c_slave_register(struct i2c_client
*client
, i2c_slave_cb_t slave_cb
);
264 extern int i2c_slave_unregister(struct i2c_client
*client
);
266 static inline int i2c_slave_event(struct i2c_client
*client
,
267 enum i2c_slave_event event
, u8
*val
)
269 return client
->slave_cb(client
, event
, val
);
274 * struct i2c_board_info - template for device creation
275 * @type: chip type, to initialize i2c_client.name
276 * @flags: to initialize i2c_client.flags
277 * @addr: stored in i2c_client.addr
278 * @platform_data: stored in i2c_client.dev.platform_data
279 * @archdata: copied into i2c_client.dev.archdata
280 * @of_node: pointer to OpenFirmware device node
281 * @acpi_node: ACPI device node
282 * @irq: stored in i2c_client.irq
284 * I2C doesn't actually support hardware probing, although controllers and
285 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
286 * a device at a given address. Drivers commonly need more information than
287 * that, such as chip type, configuration, associated IRQ, and so on.
289 * i2c_board_info is used to build tables of information listing I2C devices
290 * that are present. This information is used to grow the driver model tree.
291 * For mainboards this is done statically using i2c_register_board_info();
292 * bus numbers identify adapters that aren't yet available. For add-on boards,
293 * i2c_new_device() does this dynamically with the adapter already known.
295 struct i2c_board_info
{
296 char type
[I2C_NAME_SIZE
];
297 unsigned short flags
;
300 struct dev_archdata
*archdata
;
301 struct device_node
*of_node
;
302 struct acpi_dev_node acpi_node
;
307 * I2C_BOARD_INFO - macro used to list an i2c device and its address
308 * @dev_type: identifies the device type
309 * @dev_addr: the device's address on the bus.
311 * This macro initializes essential fields of a struct i2c_board_info,
312 * declaring what has been provided on a particular board. Optional
313 * fields (such as associated irq, or device-specific platform_data)
314 * are provided using conventional syntax.
316 #define I2C_BOARD_INFO(dev_type, dev_addr) \
317 .type = dev_type, .addr = (dev_addr)
320 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
321 /* Add-on boards should register/unregister their devices; e.g. a board
322 * with integrated I2C, a config eeprom, sensors, and a codec that's
323 * used in conjunction with the primary hardware.
325 extern struct i2c_client
*
326 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
);
328 /* If you don't know the exact address of an I2C device, use this variant
329 * instead, which can probe for device presence in a list of possible
330 * addresses. The "probe" callback function is optional. If it is provided,
331 * it must return 1 on successful probe, 0 otherwise. If it is not provided,
332 * a default probing method is used.
334 extern struct i2c_client
*
335 i2c_new_probed_device(struct i2c_adapter
*adap
,
336 struct i2c_board_info
*info
,
337 unsigned short const *addr_list
,
338 int (*probe
)(struct i2c_adapter
*, unsigned short addr
));
340 /* Common custom probe functions */
341 extern int i2c_probe_func_quick_read(struct i2c_adapter
*, unsigned short addr
);
343 /* For devices that use several addresses, use i2c_new_dummy() to make
344 * client handles for the extra addresses.
346 extern struct i2c_client
*
347 i2c_new_dummy(struct i2c_adapter
*adap
, u16 address
);
349 extern void i2c_unregister_device(struct i2c_client
*);
352 /* Mainboard arch_initcall() code should register all its I2C devices.
353 * This is done at arch_initcall time, before declaring any i2c adapters.
354 * Modules for add-on boards must use other calls.
356 #ifdef CONFIG_I2C_BOARDINFO
358 i2c_register_board_info(int busnum
, struct i2c_board_info
const *info
,
362 i2c_register_board_info(int busnum
, struct i2c_board_info
const *info
,
367 #endif /* I2C_BOARDINFO */
370 * struct i2c_algorithm - represent I2C transfer method
371 * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
372 * defined by the msgs array, with num messages available to transfer via
373 * the adapter specified by adap.
374 * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
375 * is not present, then the bus layer will try and convert the SMBus calls
376 * into I2C transfers instead.
377 * @functionality: Return the flags that this algorithm/adapter pair supports
378 * from the I2C_FUNC_* flags.
379 * @reg_slave: Register given client to I2C slave mode of this adapter
380 * @unreg_slave: Unregister given client from I2C slave mode of this adapter
382 * The following structs are for those who like to implement new bus drivers:
383 * i2c_algorithm is the interface to a class of hardware solutions which can
384 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
385 * to name two of the most common.
387 * The return codes from the @master_xfer field should indicate the type of
388 * error code that occurred during the transfer, as documented in the kernel
389 * Documentation file Documentation/i2c/fault-codes.
391 struct i2c_algorithm
{
392 /* If an adapter algorithm can't do I2C-level access, set master_xfer
393 to NULL. If an adapter algorithm can do SMBus access, set
394 smbus_xfer. If set to NULL, the SMBus protocol is simulated
395 using common I2C messages */
396 /* master_xfer should return the number of messages successfully
397 processed, or a negative value on error */
398 int (*master_xfer
)(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
400 int (*smbus_xfer
) (struct i2c_adapter
*adap
, u16 addr
,
401 unsigned short flags
, char read_write
,
402 u8 command
, int size
, union i2c_smbus_data
*data
);
404 /* To determine what the adapter supports */
405 u32 (*functionality
) (struct i2c_adapter
*);
407 #if IS_ENABLED(CONFIG_I2C_SLAVE)
408 int (*reg_slave
)(struct i2c_client
*client
);
409 int (*unreg_slave
)(struct i2c_client
*client
);
414 * struct i2c_bus_recovery_info - I2C bus recovery information
415 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
416 * i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
417 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
418 * recovery. Used internally for generic GPIO recovery.
419 * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used
420 * internally for generic GPIO recovery.
421 * @get_sda: This gets current value of SDA line. Optional for generic SCL
422 * recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO
424 * @prepare_recovery: This will be called before starting recovery. Platform may
425 * configure padmux here for SDA/SCL line or something else they want.
426 * @unprepare_recovery: This will be called after completing recovery. Platform
427 * may configure padmux here for SDA/SCL line or something else they want.
428 * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery.
429 * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery.
431 struct i2c_bus_recovery_info
{
432 int (*recover_bus
)(struct i2c_adapter
*);
434 int (*get_scl
)(struct i2c_adapter
*);
435 void (*set_scl
)(struct i2c_adapter
*, int val
);
436 int (*get_sda
)(struct i2c_adapter
*);
438 void (*prepare_recovery
)(struct i2c_bus_recovery_info
*bri
);
439 void (*unprepare_recovery
)(struct i2c_bus_recovery_info
*bri
);
446 int i2c_recover_bus(struct i2c_adapter
*adap
);
448 /* Generic recovery routines */
449 int i2c_generic_gpio_recovery(struct i2c_adapter
*adap
);
450 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
);
453 * i2c_adapter is the structure used to identify a physical i2c bus along
454 * with the access algorithms necessary to access it.
457 struct module
*owner
;
458 unsigned int class; /* classes to allow probing for */
459 const struct i2c_algorithm
*algo
; /* the algorithm to access the bus */
462 /* data fields that are valid for all devices */
463 struct rt_mutex bus_lock
;
465 int timeout
; /* in jiffies */
467 struct device dev
; /* the adapter device */
471 struct completion dev_released
;
473 struct mutex userspace_clients_lock
;
474 struct list_head userspace_clients
;
476 struct i2c_bus_recovery_info
*bus_recovery_info
;
478 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
480 static inline void *i2c_get_adapdata(const struct i2c_adapter
*dev
)
482 return dev_get_drvdata(&dev
->dev
);
485 static inline void i2c_set_adapdata(struct i2c_adapter
*dev
, void *data
)
487 dev_set_drvdata(&dev
->dev
, data
);
490 static inline struct i2c_adapter
*
491 i2c_parent_is_i2c_adapter(const struct i2c_adapter
*adapter
)
493 #if IS_ENABLED(CONFIG_I2C_MUX)
494 struct device
*parent
= adapter
->dev
.parent
;
496 if (parent
!= NULL
&& parent
->type
== &i2c_adapter_type
)
497 return to_i2c_adapter(parent
);
503 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *));
505 /* Adapter locking functions, exported for shared pin cases */
506 void i2c_lock_adapter(struct i2c_adapter
*);
507 void i2c_unlock_adapter(struct i2c_adapter
*);
509 /*flags for the client struct: */
510 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
511 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
512 /* Must equal I2C_M_TEN below */
513 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
514 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
515 /* Must match I2C_M_STOP|IGNORE_NAK */
517 /* i2c adapter classes (bitmask) */
518 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
519 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
520 #define I2C_CLASS_SPD (1<<7) /* Memory modules */
521 #define I2C_CLASS_DEPRECATED (1<<8) /* Warn users that adapter will stop using classes */
523 /* Internal numbers to terminate lists */
524 #define I2C_CLIENT_END 0xfffeU
526 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
527 #define I2C_ADDRS(addr, addrs...) \
528 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
531 /* ----- functions exported by i2c.o */
535 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
536 extern int i2c_add_adapter(struct i2c_adapter
*);
537 extern void i2c_del_adapter(struct i2c_adapter
*);
538 extern int i2c_add_numbered_adapter(struct i2c_adapter
*);
540 extern int i2c_register_driver(struct module
*, struct i2c_driver
*);
541 extern void i2c_del_driver(struct i2c_driver
*);
543 /* use a define to avoid include chaining to get THIS_MODULE */
544 #define i2c_add_driver(driver) \
545 i2c_register_driver(THIS_MODULE, driver)
547 extern struct i2c_client
*i2c_use_client(struct i2c_client
*client
);
548 extern void i2c_release_client(struct i2c_client
*client
);
550 /* call the i2c_client->command() of all attached clients with
551 * the given arguments */
552 extern void i2c_clients_command(struct i2c_adapter
*adap
,
553 unsigned int cmd
, void *arg
);
555 extern struct i2c_adapter
*i2c_get_adapter(int nr
);
556 extern void i2c_put_adapter(struct i2c_adapter
*adap
);
559 /* Return the functionality mask */
560 static inline u32
i2c_get_functionality(struct i2c_adapter
*adap
)
562 return adap
->algo
->functionality(adap
);
565 /* Return 1 if adapter supports everything we need, 0 if not. */
566 static inline int i2c_check_functionality(struct i2c_adapter
*adap
, u32 func
)
568 return (func
& i2c_get_functionality(adap
)) == func
;
571 /* Return the adapter number for a specific adapter */
572 static inline int i2c_adapter_id(struct i2c_adapter
*adap
)
578 * module_i2c_driver() - Helper macro for registering a I2C driver
579 * @__i2c_driver: i2c_driver struct
581 * Helper macro for I2C drivers which do not do anything special in module
582 * init/exit. This eliminates a lot of boilerplate. Each module may only
583 * use this macro once, and calling it replaces module_init() and module_exit()
585 #define module_i2c_driver(__i2c_driver) \
586 module_driver(__i2c_driver, i2c_add_driver, \
591 #if IS_ENABLED(CONFIG_OF)
592 /* must call put_device() when done with returned i2c_client device */
593 extern struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
);
595 /* must call put_device() when done with returned i2c_adapter device */
596 extern struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
);
600 static inline struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
605 static inline struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
609 #endif /* CONFIG_OF */
611 #endif /* _LINUX_I2C_H */