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/rtmutex.h>
34 #include <linux/irqdomain.h> /* for Host Notify IRQ */
35 #include <linux/of.h> /* for struct device_node */
36 #include <linux/swab.h> /* for swab16 */
37 #include <uapi/linux/i2c.h>
39 extern struct bus_type i2c_bus_type
;
40 extern struct device_type i2c_adapter_type
;
41 extern struct device_type i2c_client_type
;
43 /* --- General options ------------------------------------------------ */
50 struct i2c_device_identity
;
52 struct i2c_board_info
;
54 typedef int (*i2c_slave_cb_t
)(struct i2c_client
*, enum i2c_slave_event
, u8
*);
57 struct property_entry
;
59 #if IS_ENABLED(CONFIG_I2C)
61 * The master routines are the ones normally used to transmit data to devices
62 * on a bus (or read from them). Apart from two basic transfer functions to
63 * transmit one message at a time, a more complex version can be used to
64 * transmit an arbitrary number of messages without interruption.
65 * @count must be be less than 64k since msg.len is u16.
67 extern int i2c_transfer_buffer_flags(const struct i2c_client
*client
,
68 char *buf
, int count
, u16 flags
);
71 * i2c_master_recv - issue a single I2C message in master receive mode
72 * @client: Handle to slave device
73 * @buf: Where to store data read from slave
74 * @count: How many bytes to read, must be less than 64k since msg.len is u16
76 * Returns negative errno, or else the number of bytes read.
78 static inline int i2c_master_recv(const struct i2c_client
*client
,
81 return i2c_transfer_buffer_flags(client
, buf
, count
, I2C_M_RD
);
85 * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
86 * using a DMA safe buffer
87 * @client: Handle to slave device
88 * @buf: Where to store data read from slave, must be safe to use with DMA
89 * @count: How many bytes to read, must be less than 64k since msg.len is u16
91 * Returns negative errno, or else the number of bytes read.
93 static inline int i2c_master_recv_dmasafe(const struct i2c_client
*client
,
96 return i2c_transfer_buffer_flags(client
, buf
, count
,
97 I2C_M_RD
| I2C_M_DMA_SAFE
);
101 * i2c_master_send - issue a single I2C message in master transmit mode
102 * @client: Handle to slave device
103 * @buf: Data that will be written to the slave
104 * @count: How many bytes to write, must be less than 64k since msg.len is u16
106 * Returns negative errno, or else the number of bytes written.
108 static inline int i2c_master_send(const struct i2c_client
*client
,
109 const char *buf
, int count
)
111 return i2c_transfer_buffer_flags(client
, (char *)buf
, count
, 0);
115 * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
116 * using a DMA safe buffer
117 * @client: Handle to slave device
118 * @buf: Data that will be written to the slave, must be safe to use with DMA
119 * @count: How many bytes to write, must be less than 64k since msg.len is u16
121 * Returns negative errno, or else the number of bytes written.
123 static inline int i2c_master_send_dmasafe(const struct i2c_client
*client
,
124 const char *buf
, int count
)
126 return i2c_transfer_buffer_flags(client
, (char *)buf
, count
,
130 /* Transfer num messages.
132 extern int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
134 /* Unlocked flavor */
135 extern int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
138 /* This is the very generalized SMBus access routine. You probably do not
139 want to use this, though; one of the functions below may be much easier,
140 and probably just as fast.
141 Note that we use i2c_adapter here, because you do not need a specific
142 smbus adapter to call this function. */
143 extern s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
,
144 unsigned short flags
, char read_write
, u8 command
,
145 int size
, union i2c_smbus_data
*data
);
147 /* Now follow the 'nice' access routines. These also document the calling
148 conventions of i2c_smbus_xfer. */
150 extern s32
i2c_smbus_read_byte(const struct i2c_client
*client
);
151 extern s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
);
152 extern s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
,
154 extern s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
,
155 u8 command
, u8 value
);
156 extern s32
i2c_smbus_read_word_data(const struct i2c_client
*client
,
158 extern s32
i2c_smbus_write_word_data(const struct i2c_client
*client
,
159 u8 command
, u16 value
);
162 i2c_smbus_read_word_swapped(const struct i2c_client
*client
, u8 command
)
164 s32 value
= i2c_smbus_read_word_data(client
, command
);
166 return (value
< 0) ? value
: swab16(value
);
170 i2c_smbus_write_word_swapped(const struct i2c_client
*client
,
171 u8 command
, u16 value
)
173 return i2c_smbus_write_word_data(client
, command
, swab16(value
));
176 /* Returns the number of read bytes */
177 extern s32
i2c_smbus_read_block_data(const struct i2c_client
*client
,
178 u8 command
, u8
*values
);
179 extern s32
i2c_smbus_write_block_data(const struct i2c_client
*client
,
180 u8 command
, u8 length
, const u8
*values
);
181 /* Returns the number of read bytes */
182 extern s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
,
183 u8 command
, u8 length
, u8
*values
);
184 extern s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
,
185 u8 command
, u8 length
,
188 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client
*client
,
189 u8 command
, u8 length
, u8
*values
);
190 int i2c_get_device_id(const struct i2c_client
*client
,
191 struct i2c_device_identity
*id
);
195 * struct i2c_device_identity - i2c client device identification
196 * @manufacturer_id: 0 - 4095, database maintained by NXP
197 * @part_id: 0 - 511, according to manufacturer
198 * @die_revision: 0 - 7, according to manufacturer
200 struct i2c_device_identity
{
202 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS 0
203 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1 1
204 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2 2
205 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3 3
206 #define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL 4
207 #define I2C_DEVICE_ID_ANALOG_DEVICES 5
208 #define I2C_DEVICE_ID_STMICROELECTRONICS 6
209 #define I2C_DEVICE_ID_ON_SEMICONDUCTOR 7
210 #define I2C_DEVICE_ID_SPRINTEK_CORPORATION 8
211 #define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG 9
212 #define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR 10
213 #define I2C_DEVICE_ID_FLIR 11
214 #define I2C_DEVICE_ID_O2MICRO 12
215 #define I2C_DEVICE_ID_ATMEL 13
216 #define I2C_DEVICE_ID_NONE 0xffff
221 enum i2c_alert_protocol
{
222 I2C_PROTOCOL_SMBUS_ALERT
,
223 I2C_PROTOCOL_SMBUS_HOST_NOTIFY
,
227 * struct i2c_driver - represent an I2C device driver
228 * @class: What kind of i2c device we instantiate (for detect)
229 * @attach_adapter: Callback for bus addition (deprecated)
230 * @probe: Callback for device binding - soon to be deprecated
231 * @probe_new: New callback for device binding
232 * @remove: Callback for device unbinding
233 * @shutdown: Callback for device shutdown
234 * @alert: Alert callback, for example for the SMBus alert protocol
235 * @command: Callback for bus-wide signaling (optional)
236 * @driver: Device driver model driver
237 * @id_table: List of I2C devices supported by this driver
238 * @detect: Callback for device detection
239 * @address_list: The I2C addresses to probe (for detect)
240 * @clients: List of detected clients we created (for i2c-core use only)
241 * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
243 * The driver.owner field should be set to the module owner of this driver.
244 * The driver.name field should be set to the name of this driver.
246 * For automatic device detection, both @detect and @address_list must
247 * be defined. @class should also be set, otherwise only devices forced
248 * with module parameters will be created. The detect function must
249 * fill at least the name field of the i2c_board_info structure it is
250 * handed upon successful detection, and possibly also the flags field.
252 * If @detect is missing, the driver will still work fine for enumerated
253 * devices. Detected devices simply won't be supported. This is expected
254 * for the many I2C/SMBus devices which can't be detected reliably, and
255 * the ones which can always be enumerated in practice.
257 * The i2c_client structure which is handed to the @detect callback is
258 * not a real i2c_client. It is initialized just enough so that you can
259 * call i2c_smbus_read_byte_data and friends on it. Don't do anything
260 * else with it. In particular, calling dev_dbg and friends on it is
266 /* Notifies the driver that a new bus has appeared. You should avoid
267 * using this, it will be removed in a near future.
269 int (*attach_adapter
)(struct i2c_adapter
*) __deprecated
;
271 /* Standard driver model interfaces */
272 int (*probe
)(struct i2c_client
*, const struct i2c_device_id
*);
273 int (*remove
)(struct i2c_client
*);
275 /* New driver model interface to aid the seamless removal of the
276 * current probe()'s, more commonly unused than used second parameter.
278 int (*probe_new
)(struct i2c_client
*);
280 /* driver model interfaces that don't relate to enumeration */
281 void (*shutdown
)(struct i2c_client
*);
283 /* Alert callback, for example for the SMBus alert protocol.
284 * The format and meaning of the data value depends on the protocol.
285 * For the SMBus alert protocol, there is a single bit of data passed
286 * as the alert response's low bit ("event flag").
287 * For the SMBus Host Notify protocol, the data corresponds to the
288 * 16-bit payload data reported by the slave device acting as master.
290 void (*alert
)(struct i2c_client
*, enum i2c_alert_protocol protocol
,
293 /* a ioctl like command that can be used to perform specific functions
296 int (*command
)(struct i2c_client
*client
, unsigned int cmd
, void *arg
);
298 struct device_driver driver
;
299 const struct i2c_device_id
*id_table
;
301 /* Device detection callback for automatic device creation */
302 int (*detect
)(struct i2c_client
*, struct i2c_board_info
*);
303 const unsigned short *address_list
;
304 struct list_head clients
;
306 bool disable_i2c_core_irq_mapping
;
308 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
311 * struct i2c_client - represent an I2C slave device
312 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
313 * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
314 * @addr: Address used on the I2C bus connected to the parent adapter.
315 * @name: Indicates the type of the device, usually a chip name that's
316 * generic enough to hide second-sourcing and compatible revisions.
317 * @adapter: manages the bus segment hosting this I2C device
318 * @dev: Driver model device node for the slave.
319 * @irq: indicates the IRQ generated by this device (if any)
320 * @detected: member of an i2c_driver.clients list or i2c-core's
321 * userspace_devices list
322 * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
323 * calls it to pass on slave events to the slave driver.
325 * An i2c_client identifies a single device (i.e. chip) connected to an
326 * i2c bus. The behaviour exposed to Linux is defined by the driver
327 * managing the device.
330 unsigned short flags
; /* div., see below */
331 unsigned short addr
; /* chip address - NOTE: 7bit */
332 /* addresses are stored in the */
334 char name
[I2C_NAME_SIZE
];
335 struct i2c_adapter
*adapter
; /* the adapter we sit on */
336 struct device dev
; /* the device structure */
337 int irq
; /* irq issued by device */
338 struct list_head detected
;
339 #if IS_ENABLED(CONFIG_I2C_SLAVE)
340 i2c_slave_cb_t slave_cb
; /* callback for slave mode */
343 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
345 extern struct i2c_client
*i2c_verify_client(struct device
*dev
);
346 extern struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
);
347 extern const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
348 const struct i2c_client
*client
);
350 static inline struct i2c_client
*kobj_to_i2c_client(struct kobject
*kobj
)
352 struct device
* const dev
= container_of(kobj
, struct device
, kobj
);
353 return to_i2c_client(dev
);
356 static inline void *i2c_get_clientdata(const struct i2c_client
*dev
)
358 return dev_get_drvdata(&dev
->dev
);
361 static inline void i2c_set_clientdata(struct i2c_client
*dev
, void *data
)
363 dev_set_drvdata(&dev
->dev
, data
);
366 /* I2C slave support */
368 #if IS_ENABLED(CONFIG_I2C_SLAVE)
369 enum i2c_slave_event
{
370 I2C_SLAVE_READ_REQUESTED
,
371 I2C_SLAVE_WRITE_REQUESTED
,
372 I2C_SLAVE_READ_PROCESSED
,
373 I2C_SLAVE_WRITE_RECEIVED
,
377 extern int i2c_slave_register(struct i2c_client
*client
, i2c_slave_cb_t slave_cb
);
378 extern int i2c_slave_unregister(struct i2c_client
*client
);
379 extern bool i2c_detect_slave_mode(struct device
*dev
);
381 static inline int i2c_slave_event(struct i2c_client
*client
,
382 enum i2c_slave_event event
, u8
*val
)
384 return client
->slave_cb(client
, event
, val
);
387 static inline bool i2c_detect_slave_mode(struct device
*dev
) { return false; }
391 * struct i2c_board_info - template for device creation
392 * @type: chip type, to initialize i2c_client.name
393 * @flags: to initialize i2c_client.flags
394 * @addr: stored in i2c_client.addr
395 * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
396 * @platform_data: stored in i2c_client.dev.platform_data
397 * @archdata: copied into i2c_client.dev.archdata
398 * @of_node: pointer to OpenFirmware device node
399 * @fwnode: device node supplied by the platform firmware
400 * @properties: additional device properties for the device
401 * @resources: resources associated with the device
402 * @num_resources: number of resources in the @resources array
403 * @irq: stored in i2c_client.irq
405 * I2C doesn't actually support hardware probing, although controllers and
406 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
407 * a device at a given address. Drivers commonly need more information than
408 * that, such as chip type, configuration, associated IRQ, and so on.
410 * i2c_board_info is used to build tables of information listing I2C devices
411 * that are present. This information is used to grow the driver model tree.
412 * For mainboards this is done statically using i2c_register_board_info();
413 * bus numbers identify adapters that aren't yet available. For add-on boards,
414 * i2c_new_device() does this dynamically with the adapter already known.
416 struct i2c_board_info
{
417 char type
[I2C_NAME_SIZE
];
418 unsigned short flags
;
420 const char *dev_name
;
422 struct dev_archdata
*archdata
;
423 struct device_node
*of_node
;
424 struct fwnode_handle
*fwnode
;
425 const struct property_entry
*properties
;
426 const struct resource
*resources
;
427 unsigned int num_resources
;
432 * I2C_BOARD_INFO - macro used to list an i2c device and its address
433 * @dev_type: identifies the device type
434 * @dev_addr: the device's address on the bus.
436 * This macro initializes essential fields of a struct i2c_board_info,
437 * declaring what has been provided on a particular board. Optional
438 * fields (such as associated irq, or device-specific platform_data)
439 * are provided using conventional syntax.
441 #define I2C_BOARD_INFO(dev_type, dev_addr) \
442 .type = dev_type, .addr = (dev_addr)
445 #if IS_ENABLED(CONFIG_I2C)
446 /* Add-on boards should register/unregister their devices; e.g. a board
447 * with integrated I2C, a config eeprom, sensors, and a codec that's
448 * used in conjunction with the primary hardware.
450 extern struct i2c_client
*
451 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
);
453 /* If you don't know the exact address of an I2C device, use this variant
454 * instead, which can probe for device presence in a list of possible
455 * addresses. The "probe" callback function is optional. If it is provided,
456 * it must return 1 on successful probe, 0 otherwise. If it is not provided,
457 * a default probing method is used.
459 extern struct i2c_client
*
460 i2c_new_probed_device(struct i2c_adapter
*adap
,
461 struct i2c_board_info
*info
,
462 unsigned short const *addr_list
,
463 int (*probe
)(struct i2c_adapter
*, unsigned short addr
));
465 /* Common custom probe functions */
466 extern int i2c_probe_func_quick_read(struct i2c_adapter
*, unsigned short addr
);
468 /* For devices that use several addresses, use i2c_new_dummy() to make
469 * client handles for the extra addresses.
471 extern struct i2c_client
*
472 i2c_new_dummy(struct i2c_adapter
*adap
, u16 address
);
474 extern struct i2c_client
*
475 i2c_new_secondary_device(struct i2c_client
*client
,
479 extern void i2c_unregister_device(struct i2c_client
*);
482 /* Mainboard arch_initcall() code should register all its I2C devices.
483 * This is done at arch_initcall time, before declaring any i2c adapters.
484 * Modules for add-on boards must use other calls.
486 #ifdef CONFIG_I2C_BOARDINFO
488 i2c_register_board_info(int busnum
, struct i2c_board_info
const *info
,
492 i2c_register_board_info(int busnum
, struct i2c_board_info
const *info
,
497 #endif /* I2C_BOARDINFO */
500 * struct i2c_algorithm - represent I2C transfer method
501 * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
502 * defined by the msgs array, with num messages available to transfer via
503 * the adapter specified by adap.
504 * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
505 * is not present, then the bus layer will try and convert the SMBus calls
506 * into I2C transfers instead.
507 * @functionality: Return the flags that this algorithm/adapter pair supports
508 * from the I2C_FUNC_* flags.
509 * @reg_slave: Register given client to I2C slave mode of this adapter
510 * @unreg_slave: Unregister given client from I2C slave mode of this adapter
512 * The following structs are for those who like to implement new bus drivers:
513 * i2c_algorithm is the interface to a class of hardware solutions which can
514 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
515 * to name two of the most common.
517 * The return codes from the @master_xfer field should indicate the type of
518 * error code that occurred during the transfer, as documented in the kernel
519 * Documentation file Documentation/i2c/fault-codes.
521 struct i2c_algorithm
{
522 /* If an adapter algorithm can't do I2C-level access, set master_xfer
523 to NULL. If an adapter algorithm can do SMBus access, set
524 smbus_xfer. If set to NULL, the SMBus protocol is simulated
525 using common I2C messages */
526 /* master_xfer should return the number of messages successfully
527 processed, or a negative value on error */
528 int (*master_xfer
)(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
,
530 int (*smbus_xfer
) (struct i2c_adapter
*adap
, u16 addr
,
531 unsigned short flags
, char read_write
,
532 u8 command
, int size
, union i2c_smbus_data
*data
);
534 /* To determine what the adapter supports */
535 u32 (*functionality
) (struct i2c_adapter
*);
537 #if IS_ENABLED(CONFIG_I2C_SLAVE)
538 int (*reg_slave
)(struct i2c_client
*client
);
539 int (*unreg_slave
)(struct i2c_client
*client
);
544 * struct i2c_lock_operations - represent I2C locking operations
545 * @lock_bus: Get exclusive access to an I2C bus segment
546 * @trylock_bus: Try to get exclusive access to an I2C bus segment
547 * @unlock_bus: Release exclusive access to an I2C bus segment
549 * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
551 struct i2c_lock_operations
{
552 void (*lock_bus
)(struct i2c_adapter
*, unsigned int flags
);
553 int (*trylock_bus
)(struct i2c_adapter
*, unsigned int flags
);
554 void (*unlock_bus
)(struct i2c_adapter
*, unsigned int flags
);
558 * struct i2c_timings - I2C timing information
559 * @bus_freq_hz: the bus frequency in Hz
560 * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
561 * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
562 * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
563 * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
569 u32 scl_int_delay_ns
;
574 * struct i2c_bus_recovery_info - I2C bus recovery information
575 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
576 * i2c_generic_scl_recovery().
577 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
578 * recovery. Populated internally for generic GPIO recovery.
579 * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
580 * Populated internally for generic GPIO recovery.
581 * @get_sda: This gets current value of SDA line. Optional for generic SCL
582 * recovery. Populated internally, if sda_gpio is a valid GPIO, for generic
584 * @set_sda: This sets/clears the SDA line. Optional for generic SCL recovery.
585 * Populated internally, if sda_gpio is a valid GPIO, for generic GPIO
587 * @prepare_recovery: This will be called before starting recovery. Platform may
588 * configure padmux here for SDA/SCL line or something else they want.
589 * @unprepare_recovery: This will be called after completing recovery. Platform
590 * may configure padmux here for SDA/SCL line or something else they want.
591 * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
592 * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
594 struct i2c_bus_recovery_info
{
595 int (*recover_bus
)(struct i2c_adapter
*adap
);
597 int (*get_scl
)(struct i2c_adapter
*adap
);
598 void (*set_scl
)(struct i2c_adapter
*adap
, int val
);
599 int (*get_sda
)(struct i2c_adapter
*adap
);
600 void (*set_sda
)(struct i2c_adapter
*adap
, int val
);
602 void (*prepare_recovery
)(struct i2c_adapter
*adap
);
603 void (*unprepare_recovery
)(struct i2c_adapter
*adap
);
606 struct gpio_desc
*scl_gpiod
;
607 struct gpio_desc
*sda_gpiod
;
610 int i2c_recover_bus(struct i2c_adapter
*adap
);
612 /* Generic recovery routines */
613 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
);
616 * struct i2c_adapter_quirks - describe flaws of an i2c adapter
617 * @flags: see I2C_AQ_* for possible flags and read below
618 * @max_num_msgs: maximum number of messages per transfer
619 * @max_write_len: maximum length of a write message
620 * @max_read_len: maximum length of a read message
621 * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
622 * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
624 * Note about combined messages: Some I2C controllers can only send one message
625 * per transfer, plus something called combined message or write-then-read.
626 * This is (usually) a small write message followed by a read message and
627 * barely enough to access register based devices like EEPROMs. There is a flag
628 * to support this mode. It implies max_num_msg = 2 and does the length checks
629 * with max_comb_*_len because combined message mode usually has its own
630 * limitations. Because of HW implementations, some controllers can actually do
631 * write-then-anything or other variants. To support that, write-then-read has
632 * been broken out into smaller bits like write-first and read-second which can
633 * be combined as needed.
636 struct i2c_adapter_quirks
{
641 u16 max_comb_1st_msg_len
;
642 u16 max_comb_2nd_msg_len
;
645 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
646 #define I2C_AQ_COMB BIT(0)
647 /* first combined message must be write */
648 #define I2C_AQ_COMB_WRITE_FIRST BIT(1)
649 /* second combined message must be read */
650 #define I2C_AQ_COMB_READ_SECOND BIT(2)
651 /* both combined messages must have the same target address */
652 #define I2C_AQ_COMB_SAME_ADDR BIT(3)
653 /* convenience macro for typical write-then read case */
654 #define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
655 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
656 /* clock stretching is not supported */
657 #define I2C_AQ_NO_CLK_STRETCH BIT(4)
660 * i2c_adapter is the structure used to identify a physical i2c bus along
661 * with the access algorithms necessary to access it.
664 struct module
*owner
;
665 unsigned int class; /* classes to allow probing for */
666 const struct i2c_algorithm
*algo
; /* the algorithm to access the bus */
669 /* data fields that are valid for all devices */
670 const struct i2c_lock_operations
*lock_ops
;
671 struct rt_mutex bus_lock
;
672 struct rt_mutex mux_lock
;
674 int timeout
; /* in jiffies */
676 struct device dev
; /* the adapter device */
680 struct completion dev_released
;
682 struct mutex userspace_clients_lock
;
683 struct list_head userspace_clients
;
685 struct i2c_bus_recovery_info
*bus_recovery_info
;
686 const struct i2c_adapter_quirks
*quirks
;
688 struct irq_domain
*host_notify_domain
;
690 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
692 static inline void *i2c_get_adapdata(const struct i2c_adapter
*dev
)
694 return dev_get_drvdata(&dev
->dev
);
697 static inline void i2c_set_adapdata(struct i2c_adapter
*dev
, void *data
)
699 dev_set_drvdata(&dev
->dev
, data
);
702 static inline struct i2c_adapter
*
703 i2c_parent_is_i2c_adapter(const struct i2c_adapter
*adapter
)
705 #if IS_ENABLED(CONFIG_I2C_MUX)
706 struct device
*parent
= adapter
->dev
.parent
;
708 if (parent
!= NULL
&& parent
->type
== &i2c_adapter_type
)
709 return to_i2c_adapter(parent
);
715 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *));
717 /* Adapter locking functions, exported for shared pin cases */
718 #define I2C_LOCK_ROOT_ADAPTER BIT(0)
719 #define I2C_LOCK_SEGMENT BIT(1)
722 * i2c_lock_bus - Get exclusive access to an I2C bus segment
723 * @adapter: Target I2C bus segment
724 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
725 * locks only this branch in the adapter tree
728 i2c_lock_bus(struct i2c_adapter
*adapter
, unsigned int flags
)
730 adapter
->lock_ops
->lock_bus(adapter
, flags
);
734 * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
735 * @adapter: Target I2C bus segment
736 * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
737 * I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
739 * Return: true if the I2C bus segment is locked, false otherwise
742 i2c_trylock_bus(struct i2c_adapter
*adapter
, unsigned int flags
)
744 return adapter
->lock_ops
->trylock_bus(adapter
, flags
);
748 * i2c_unlock_bus - Release exclusive access to an I2C bus segment
749 * @adapter: Target I2C bus segment
750 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
751 * unlocks only this branch in the adapter tree
754 i2c_unlock_bus(struct i2c_adapter
*adapter
, unsigned int flags
)
756 adapter
->lock_ops
->unlock_bus(adapter
, flags
);
760 i2c_lock_adapter(struct i2c_adapter
*adapter
)
762 i2c_lock_bus(adapter
, I2C_LOCK_ROOT_ADAPTER
);
766 i2c_unlock_adapter(struct i2c_adapter
*adapter
)
768 i2c_unlock_bus(adapter
, I2C_LOCK_ROOT_ADAPTER
);
771 /*flags for the client struct: */
772 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
773 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
774 /* Must equal I2C_M_TEN below */
775 #define I2C_CLIENT_SLAVE 0x20 /* we are the slave */
776 #define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */
777 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
778 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
779 /* Must match I2C_M_STOP|IGNORE_NAK */
781 /* i2c adapter classes (bitmask) */
782 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
783 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
784 #define I2C_CLASS_SPD (1<<7) /* Memory modules */
785 /* Warn users that the adapter doesn't support classes anymore */
786 #define I2C_CLASS_DEPRECATED (1<<8)
788 /* Internal numbers to terminate lists */
789 #define I2C_CLIENT_END 0xfffeU
791 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
792 #define I2C_ADDRS(addr, addrs...) \
793 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
796 /* ----- functions exported by i2c.o */
800 #if IS_ENABLED(CONFIG_I2C)
801 extern int i2c_add_adapter(struct i2c_adapter
*);
802 extern void i2c_del_adapter(struct i2c_adapter
*);
803 extern int i2c_add_numbered_adapter(struct i2c_adapter
*);
805 extern int i2c_register_driver(struct module
*, struct i2c_driver
*);
806 extern void i2c_del_driver(struct i2c_driver
*);
808 /* use a define to avoid include chaining to get THIS_MODULE */
809 #define i2c_add_driver(driver) \
810 i2c_register_driver(THIS_MODULE, driver)
812 extern struct i2c_client
*i2c_use_client(struct i2c_client
*client
);
813 extern void i2c_release_client(struct i2c_client
*client
);
815 /* call the i2c_client->command() of all attached clients with
816 * the given arguments */
817 extern void i2c_clients_command(struct i2c_adapter
*adap
,
818 unsigned int cmd
, void *arg
);
820 extern struct i2c_adapter
*i2c_get_adapter(int nr
);
821 extern void i2c_put_adapter(struct i2c_adapter
*adap
);
822 extern unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
);
824 void i2c_parse_fw_timings(struct device
*dev
, struct i2c_timings
*t
, bool use_defaults
);
826 /* Return the functionality mask */
827 static inline u32
i2c_get_functionality(struct i2c_adapter
*adap
)
829 return adap
->algo
->functionality(adap
);
832 /* Return 1 if adapter supports everything we need, 0 if not. */
833 static inline int i2c_check_functionality(struct i2c_adapter
*adap
, u32 func
)
835 return (func
& i2c_get_functionality(adap
)) == func
;
839 * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
841 * @quirks: quirk flags
843 * Return: true if the adapter has all the specified quirk flags, false if not
845 static inline bool i2c_check_quirks(struct i2c_adapter
*adap
, u64 quirks
)
849 return (adap
->quirks
->flags
& quirks
) == quirks
;
852 /* Return the adapter number for a specific adapter */
853 static inline int i2c_adapter_id(struct i2c_adapter
*adap
)
858 static inline u8
i2c_8bit_addr_from_msg(const struct i2c_msg
*msg
)
860 return (msg
->addr
<< 1) | (msg
->flags
& I2C_M_RD
? 1 : 0);
863 u8
*i2c_get_dma_safe_msg_buf(struct i2c_msg
*msg
, unsigned int threshold
);
864 void i2c_release_dma_safe_msg_buf(struct i2c_msg
*msg
, u8
*buf
);
866 int i2c_handle_smbus_host_notify(struct i2c_adapter
*adap
, unsigned short addr
);
868 * module_i2c_driver() - Helper macro for registering a modular I2C driver
869 * @__i2c_driver: i2c_driver struct
871 * Helper macro for I2C drivers which do not do anything special in module
872 * init/exit. This eliminates a lot of boilerplate. Each module may only
873 * use this macro once, and calling it replaces module_init() and module_exit()
875 #define module_i2c_driver(__i2c_driver) \
876 module_driver(__i2c_driver, i2c_add_driver, \
880 * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
881 * @__i2c_driver: i2c_driver struct
883 * Helper macro for I2C drivers which do not do anything special in their
884 * init. This eliminates a lot of boilerplate. Each driver may only
885 * use this macro once, and calling it replaces device_initcall().
887 #define builtin_i2c_driver(__i2c_driver) \
888 builtin_driver(__i2c_driver, i2c_add_driver)
892 #if IS_ENABLED(CONFIG_OF)
893 /* must call put_device() when done with returned i2c_client device */
894 extern struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
);
896 /* must call put_device() when done with returned i2c_adapter device */
897 extern struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
);
899 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
900 struct i2c_adapter
*of_get_i2c_adapter_by_node(struct device_node
*node
);
902 extern const struct of_device_id
903 *i2c_of_match_device(const struct of_device_id
*matches
,
904 struct i2c_client
*client
);
908 static inline struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
913 static inline struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
918 static inline struct i2c_adapter
*of_get_i2c_adapter_by_node(struct device_node
*node
)
923 static inline const struct of_device_id
924 *i2c_of_match_device(const struct of_device_id
*matches
,
925 struct i2c_client
*client
)
930 #endif /* CONFIG_OF */
932 #if IS_ENABLED(CONFIG_ACPI)
933 u32
i2c_acpi_find_bus_speed(struct device
*dev
);
934 struct i2c_client
*i2c_acpi_new_device(struct device
*dev
, int index
,
935 struct i2c_board_info
*info
);
937 static inline u32
i2c_acpi_find_bus_speed(struct device
*dev
)
941 static inline struct i2c_client
*i2c_acpi_new_device(struct device
*dev
,
942 int index
, struct i2c_board_info
*info
)
946 #endif /* CONFIG_ACPI */
948 #endif /* _LINUX_I2C_H */