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
;
52 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
54 * The master routines are the ones normally used to transmit data to devices
55 * on a bus (or read from them). Apart from two basic transfer functions to
56 * transmit one message at a time, a more complex version can be used to
57 * transmit an arbitrary number of messages without interruption.
58 * @count must be be less than 64k since msg.len is u16.
60 extern int i2c_master_send(const struct i2c_client
*client
, const char *buf
,
62 extern int i2c_master_recv(const struct i2c_client
*client
, char *buf
,
65 /* Transfer num messages.
67 extern int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
70 extern int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
73 /* This is the very generalized SMBus access routine. You probably do not
74 want to use this, though; one of the functions below may be much easier,
75 and probably just as fast.
76 Note that we use i2c_adapter here, because you do not need a specific
77 smbus adapter to call this function. */
78 extern s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
,
79 unsigned short flags
, char read_write
, u8 command
,
80 int size
, union i2c_smbus_data
*data
);
82 /* Now follow the 'nice' access routines. These also document the calling
83 conventions of i2c_smbus_xfer. */
85 extern s32
i2c_smbus_read_byte(const struct i2c_client
*client
);
86 extern s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
);
87 extern s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
,
89 extern s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
,
90 u8 command
, u8 value
);
91 extern s32
i2c_smbus_read_word_data(const struct i2c_client
*client
,
93 extern s32
i2c_smbus_write_word_data(const struct i2c_client
*client
,
94 u8 command
, u16 value
);
97 i2c_smbus_read_word_swapped(const struct i2c_client
*client
, u8 command
)
99 s32 value
= i2c_smbus_read_word_data(client
, command
);
101 return (value
< 0) ? value
: swab16(value
);
105 i2c_smbus_write_word_swapped(const struct i2c_client
*client
,
106 u8 command
, u16 value
)
108 return i2c_smbus_write_word_data(client
, command
, swab16(value
));
111 /* Returns the number of read bytes */
112 extern s32
i2c_smbus_read_block_data(const struct i2c_client
*client
,
113 u8 command
, u8
*values
);
114 extern s32
i2c_smbus_write_block_data(const struct i2c_client
*client
,
115 u8 command
, u8 length
, const u8
*values
);
116 /* Returns the number of read bytes */
117 extern s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
,
118 u8 command
, u8 length
, u8
*values
);
119 extern s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
,
120 u8 command
, u8 length
,
125 * struct i2c_driver - represent an I2C device driver
126 * @class: What kind of i2c device we instantiate (for detect)
127 * @attach_adapter: Callback for bus addition (deprecated)
128 * @detach_adapter: Callback for bus removal (deprecated)
129 * @probe: Callback for device binding
130 * @remove: Callback for device unbinding
131 * @shutdown: Callback for device shutdown
132 * @suspend: Callback for device suspend
133 * @resume: Callback for device resume
134 * @alert: Alert callback, for example for the SMBus alert protocol
135 * @command: Callback for bus-wide signaling (optional)
136 * @driver: Device driver model driver
137 * @id_table: List of I2C devices supported by this driver
138 * @detect: Callback for device detection
139 * @address_list: The I2C addresses to probe (for detect)
140 * @clients: List of detected clients we created (for i2c-core use only)
142 * The driver.owner field should be set to the module owner of this driver.
143 * The driver.name field should be set to the name of this driver.
145 * For automatic device detection, both @detect and @address_list must
146 * be defined. @class should also be set, otherwise only devices forced
147 * with module parameters will be created. The detect function must
148 * fill at least the name field of the i2c_board_info structure it is
149 * handed upon successful detection, and possibly also the flags field.
151 * If @detect is missing, the driver will still work fine for enumerated
152 * devices. Detected devices simply won't be supported. This is expected
153 * for the many I2C/SMBus devices which can't be detected reliably, and
154 * the ones which can always be enumerated in practice.
156 * The i2c_client structure which is handed to the @detect callback is
157 * not a real i2c_client. It is initialized just enough so that you can
158 * call i2c_smbus_read_byte_data and friends on it. Don't do anything
159 * else with it. In particular, calling dev_dbg and friends on it is
165 /* Notifies the driver that a new bus has appeared or is about to be
166 * removed. You should avoid using this, it will be removed in a
169 int (*attach_adapter
)(struct i2c_adapter
*) __deprecated
;
170 int (*detach_adapter
)(struct i2c_adapter
*) __deprecated
;
172 /* Standard driver model interfaces */
173 int (*probe
)(struct i2c_client
*, const struct i2c_device_id
*);
174 int (*remove
)(struct i2c_client
*);
176 /* driver model interfaces that don't relate to enumeration */
177 void (*shutdown
)(struct i2c_client
*);
178 int (*suspend
)(struct i2c_client
*, pm_message_t mesg
);
179 int (*resume
)(struct i2c_client
*);
181 /* Alert callback, for example for the SMBus alert protocol.
182 * The format and meaning of the data value depends on the protocol.
183 * For the SMBus alert protocol, there is a single bit of data passed
184 * as the alert response's low bit ("event flag").
186 void (*alert
)(struct i2c_client
*, unsigned int data
);
188 /* a ioctl like command that can be used to perform specific functions
191 int (*command
)(struct i2c_client
*client
, unsigned int cmd
, void *arg
);
193 struct device_driver driver
;
194 const struct i2c_device_id
*id_table
;
196 /* Device detection callback for automatic device creation */
197 int (*detect
)(struct i2c_client
*, struct i2c_board_info
*);
198 const unsigned short *address_list
;
199 struct list_head clients
;
201 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
204 * struct i2c_client - represent an I2C slave device
205 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
206 * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
207 * @addr: Address used on the I2C bus connected to the parent adapter.
208 * @name: Indicates the type of the device, usually a chip name that's
209 * generic enough to hide second-sourcing and compatible revisions.
210 * @adapter: manages the bus segment hosting this I2C device
211 * @driver: device's driver, hence pointer to access routines
212 * @dev: Driver model device node for the slave.
213 * @irq: indicates the IRQ generated by this device (if any)
214 * @detected: member of an i2c_driver.clients list or i2c-core's
215 * userspace_devices list
217 * An i2c_client identifies a single device (i.e. chip) connected to an
218 * i2c bus. The behaviour exposed to Linux is defined by the driver
219 * managing the device.
222 unsigned short flags
; /* div., see below */
223 unsigned short addr
; /* chip address - NOTE: 7bit */
224 /* addresses are stored in the */
226 char name
[I2C_NAME_SIZE
];
227 struct i2c_adapter
*adapter
; /* the adapter we sit on */
228 struct i2c_driver
*driver
; /* and our access routines */
229 struct device dev
; /* the device structure */
230 int irq
; /* irq issued by device */
231 struct list_head detected
;
233 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
235 extern struct i2c_client
*i2c_verify_client(struct device
*dev
);
236 extern struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
);
238 static inline struct i2c_client
*kobj_to_i2c_client(struct kobject
*kobj
)
240 struct device
* const dev
= container_of(kobj
, struct device
, kobj
);
241 return to_i2c_client(dev
);
244 static inline void *i2c_get_clientdata(const struct i2c_client
*dev
)
246 return dev_get_drvdata(&dev
->dev
);
249 static inline void i2c_set_clientdata(struct i2c_client
*dev
, void *data
)
251 dev_set_drvdata(&dev
->dev
, data
);
255 * struct i2c_board_info - template for device creation
256 * @type: chip type, to initialize i2c_client.name
257 * @flags: to initialize i2c_client.flags
258 * @addr: stored in i2c_client.addr
259 * @platform_data: stored in i2c_client.dev.platform_data
260 * @archdata: copied into i2c_client.dev.archdata
261 * @of_node: pointer to OpenFirmware device node
262 * @acpi_node: ACPI device node
263 * @irq: stored in i2c_client.irq
265 * I2C doesn't actually support hardware probing, although controllers and
266 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
267 * a device at a given address. Drivers commonly need more information than
268 * that, such as chip type, configuration, associated IRQ, and so on.
270 * i2c_board_info is used to build tables of information listing I2C devices
271 * that are present. This information is used to grow the driver model tree.
272 * For mainboards this is done statically using i2c_register_board_info();
273 * bus numbers identify adapters that aren't yet available. For add-on boards,
274 * i2c_new_device() does this dynamically with the adapter already known.
276 struct i2c_board_info
{
277 char type
[I2C_NAME_SIZE
];
278 unsigned short flags
;
281 struct dev_archdata
*archdata
;
282 struct device_node
*of_node
;
283 struct acpi_dev_node acpi_node
;
288 * I2C_BOARD_INFO - macro used to list an i2c device and its address
289 * @dev_type: identifies the device type
290 * @dev_addr: the device's address on the bus.
292 * This macro initializes essential fields of a struct i2c_board_info,
293 * declaring what has been provided on a particular board. Optional
294 * fields (such as associated irq, or device-specific platform_data)
295 * are provided using conventional syntax.
297 #define I2C_BOARD_INFO(dev_type, dev_addr) \
298 .type = dev_type, .addr = (dev_addr)
301 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
302 /* Add-on boards should register/unregister their devices; e.g. a board
303 * with integrated I2C, a config eeprom, sensors, and a codec that's
304 * used in conjunction with the primary hardware.
306 extern struct i2c_client
*
307 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
);
309 /* If you don't know the exact address of an I2C device, use this variant
310 * instead, which can probe for device presence in a list of possible
311 * addresses. The "probe" callback function is optional. If it is provided,
312 * it must return 1 on successful probe, 0 otherwise. If it is not provided,
313 * a default probing method is used.
315 extern struct i2c_client
*
316 i2c_new_probed_device(struct i2c_adapter
*adap
,
317 struct i2c_board_info
*info
,
318 unsigned short const *addr_list
,
319 int (*probe
)(struct i2c_adapter
*, unsigned short addr
));
321 /* Common custom probe functions */
322 extern int i2c_probe_func_quick_read(struct i2c_adapter
*, unsigned short addr
);
324 /* For devices that use several addresses, use i2c_new_dummy() to make
325 * client handles for the extra addresses.
327 extern struct i2c_client
*
328 i2c_new_dummy(struct i2c_adapter
*adap
, u16 address
);
330 extern void i2c_unregister_device(struct i2c_client
*);
333 /* Mainboard arch_initcall() code should register all its I2C devices.
334 * This is done at arch_initcall time, before declaring any i2c adapters.
335 * Modules for add-on boards must use other calls.
337 #ifdef CONFIG_I2C_BOARDINFO
339 i2c_register_board_info(int busnum
, struct i2c_board_info
const *info
,
343 i2c_register_board_info(int busnum
, struct i2c_board_info
const *info
,
348 #endif /* I2C_BOARDINFO */
351 * The following structs are for those who like to implement new bus drivers:
352 * i2c_algorithm is the interface to a class of hardware solutions which can
353 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
354 * to name two of the most common.
356 struct i2c_algorithm
{
357 /* If an adapter algorithm can't do I2C-level access, set master_xfer
358 to NULL. If an adapter algorithm can do SMBus access, set
359 smbus_xfer. If set to NULL, the SMBus protocol is simulated
360 using common I2C messages */
361 /* master_xfer should return the number of messages successfully
362 processed, or a negative value on error */
363 int (*master_xfer
)(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
365 int (*smbus_xfer
) (struct i2c_adapter
*adap
, u16 addr
,
366 unsigned short flags
, char read_write
,
367 u8 command
, int size
, union i2c_smbus_data
*data
);
369 /* To determine what the adapter supports */
370 u32 (*functionality
) (struct i2c_adapter
*);
374 * i2c_adapter is the structure used to identify a physical i2c bus along
375 * with the access algorithms necessary to access it.
378 struct module
*owner
;
379 unsigned int class; /* classes to allow probing for */
380 const struct i2c_algorithm
*algo
; /* the algorithm to access the bus */
383 /* data fields that are valid for all devices */
384 struct rt_mutex bus_lock
;
386 int timeout
; /* in jiffies */
388 struct device dev
; /* the adapter device */
392 struct completion dev_released
;
394 struct mutex userspace_clients_lock
;
395 struct list_head userspace_clients
;
397 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
399 static inline void *i2c_get_adapdata(const struct i2c_adapter
*dev
)
401 return dev_get_drvdata(&dev
->dev
);
404 static inline void i2c_set_adapdata(struct i2c_adapter
*dev
, void *data
)
406 dev_set_drvdata(&dev
->dev
, data
);
409 static inline struct i2c_adapter
*
410 i2c_parent_is_i2c_adapter(const struct i2c_adapter
*adapter
)
412 struct device
*parent
= adapter
->dev
.parent
;
414 if (parent
!= NULL
&& parent
->type
== &i2c_adapter_type
)
415 return to_i2c_adapter(parent
);
420 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *));
422 /* Adapter locking functions, exported for shared pin cases */
423 void i2c_lock_adapter(struct i2c_adapter
*);
424 void i2c_unlock_adapter(struct i2c_adapter
*);
426 /*flags for the client struct: */
427 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
428 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
429 /* Must equal I2C_M_TEN below */
430 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
431 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
432 /* Must match I2C_M_STOP|IGNORE_NAK */
434 /* i2c adapter classes (bitmask) */
435 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
436 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
437 #define I2C_CLASS_SPD (1<<7) /* Memory modules */
439 /* Internal numbers to terminate lists */
440 #define I2C_CLIENT_END 0xfffeU
442 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
443 #define I2C_ADDRS(addr, addrs...) \
444 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
447 /* ----- functions exported by i2c.o */
451 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
452 extern int i2c_add_adapter(struct i2c_adapter
*);
453 extern int i2c_del_adapter(struct i2c_adapter
*);
454 extern int i2c_add_numbered_adapter(struct i2c_adapter
*);
456 extern int i2c_register_driver(struct module
*, struct i2c_driver
*);
457 extern void i2c_del_driver(struct i2c_driver
*);
459 /* use a define to avoid include chaining to get THIS_MODULE */
460 #define i2c_add_driver(driver) \
461 i2c_register_driver(THIS_MODULE, driver)
463 extern struct i2c_client
*i2c_use_client(struct i2c_client
*client
);
464 extern void i2c_release_client(struct i2c_client
*client
);
466 /* call the i2c_client->command() of all attached clients with
467 * the given arguments */
468 extern void i2c_clients_command(struct i2c_adapter
*adap
,
469 unsigned int cmd
, void *arg
);
471 extern struct i2c_adapter
*i2c_get_adapter(int nr
);
472 extern void i2c_put_adapter(struct i2c_adapter
*adap
);
475 /* Return the functionality mask */
476 static inline u32
i2c_get_functionality(struct i2c_adapter
*adap
)
478 return adap
->algo
->functionality(adap
);
481 /* Return 1 if adapter supports everything we need, 0 if not. */
482 static inline int i2c_check_functionality(struct i2c_adapter
*adap
, u32 func
)
484 return (func
& i2c_get_functionality(adap
)) == func
;
487 /* Return the adapter number for a specific adapter */
488 static inline int i2c_adapter_id(struct i2c_adapter
*adap
)
494 * module_i2c_driver() - Helper macro for registering a I2C driver
495 * @__i2c_driver: i2c_driver struct
497 * Helper macro for I2C drivers which do not do anything special in module
498 * init/exit. This eliminates a lot of boilerplate. Each module may only
499 * use this macro once, and calling it replaces module_init() and module_exit()
501 #define module_i2c_driver(__i2c_driver) \
502 module_driver(__i2c_driver, i2c_add_driver, \
507 #if IS_ENABLED(CONFIG_ACPI_I2C)
508 extern void acpi_i2c_register_devices(struct i2c_adapter
*adap
);
510 static inline void acpi_i2c_register_devices(struct i2c_adapter
*adap
) {}
513 #endif /* _LINUX_I2C_H */