1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * i2c.h - definitions for the Linux i2c bus interface
4 * Copyright (C) 1995-2000 Simon G. Vogl
5 * Copyright (C) 2013-2019 Wolfram Sang <wsa@the-dreams.de>
7 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
8 * Frodo Looijaard <frodol@dds.nl>
13 #include <linux/acpi.h> /* for acpi_handle */
14 #include <linux/mod_devicetable.h>
15 #include <linux/device.h> /* for struct device */
16 #include <linux/sched.h> /* for completion */
17 #include <linux/mutex.h>
18 #include <linux/rtmutex.h>
19 #include <linux/irqdomain.h> /* for Host Notify IRQ */
20 #include <linux/of.h> /* for struct device_node */
21 #include <linux/swab.h> /* for swab16 */
22 #include <uapi/linux/i2c.h>
24 extern struct bus_type i2c_bus_type;
25 extern struct device_type i2c_adapter_type;
26 extern struct device_type i2c_client_type;
28 /* --- General options ------------------------------------------------ */
35 struct i2c_device_identity;
37 struct i2c_board_info;
39 typedef int (*i2c_slave_cb_t)(struct i2c_client *client,
40 enum i2c_slave_event event, u8 *val);
43 struct property_entry;
45 #if IS_ENABLED(CONFIG_I2C)
47 * The master routines are the ones normally used to transmit data to devices
48 * on a bus (or read from them). Apart from two basic transfer functions to
49 * transmit one message at a time, a more complex version can be used to
50 * transmit an arbitrary number of messages without interruption.
51 * @count must be be less than 64k since msg.len is u16.
53 extern int i2c_transfer_buffer_flags(const struct i2c_client *client,
54 char *buf, int count, u16 flags);
57 * i2c_master_recv - issue a single I2C message in master receive mode
58 * @client: Handle to slave device
59 * @buf: Where to store data read from slave
60 * @count: How many bytes to read, must be less than 64k since msg.len is u16
62 * Returns negative errno, or else the number of bytes read.
64 static inline int i2c_master_recv(const struct i2c_client *client,
67 return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
71 * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
72 * using a DMA safe buffer
73 * @client: Handle to slave device
74 * @buf: Where to store data read from slave, must be safe to use with DMA
75 * @count: How many bytes to read, must be less than 64k since msg.len is u16
77 * Returns negative errno, or else the number of bytes read.
79 static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
82 return i2c_transfer_buffer_flags(client, buf, count,
83 I2C_M_RD | I2C_M_DMA_SAFE);
87 * i2c_master_send - issue a single I2C message in master transmit mode
88 * @client: Handle to slave device
89 * @buf: Data that will be written to the slave
90 * @count: How many bytes to write, must be less than 64k since msg.len is u16
92 * Returns negative errno, or else the number of bytes written.
94 static inline int i2c_master_send(const struct i2c_client *client,
95 const char *buf, int count)
97 return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
101 * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
102 * using a DMA safe buffer
103 * @client: Handle to slave device
104 * @buf: Data that will be written to the slave, must be safe to use with DMA
105 * @count: How many bytes to write, must be less than 64k since msg.len is u16
107 * Returns negative errno, or else the number of bytes written.
109 static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
110 const char *buf, int count)
112 return i2c_transfer_buffer_flags(client, (char *)buf, count,
116 /* Transfer num messages.
118 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
120 /* Unlocked flavor */
121 extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
124 /* This is the very generalized SMBus access routine. You probably do not
125 want to use this, though; one of the functions below may be much easier,
126 and probably just as fast.
127 Note that we use i2c_adapter here, because you do not need a specific
128 smbus adapter to call this function. */
129 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
130 unsigned short flags, char read_write, u8 command,
131 int protocol, union i2c_smbus_data *data);
133 /* Unlocked flavor */
134 s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
135 unsigned short flags, char read_write, u8 command,
136 int protocol, union i2c_smbus_data *data);
138 /* Now follow the 'nice' access routines. These also document the calling
139 conventions of i2c_smbus_xfer. */
141 extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
142 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
143 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
145 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
146 u8 command, u8 value);
147 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
149 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
150 u8 command, u16 value);
153 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
155 s32 value = i2c_smbus_read_word_data(client, command);
157 return (value < 0) ? value : swab16(value);
161 i2c_smbus_write_word_swapped(const struct i2c_client *client,
162 u8 command, u16 value)
164 return i2c_smbus_write_word_data(client, command, swab16(value));
167 /* Returns the number of read bytes */
168 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
169 u8 command, u8 *values);
170 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
171 u8 command, u8 length, const u8 *values);
172 /* Returns the number of read bytes */
173 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
174 u8 command, u8 length, u8 *values);
175 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
176 u8 command, u8 length,
179 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
180 u8 command, u8 length, u8 *values);
181 int i2c_get_device_id(const struct i2c_client *client,
182 struct i2c_device_identity *id);
186 * struct i2c_device_identity - i2c client device identification
187 * @manufacturer_id: 0 - 4095, database maintained by NXP
188 * @part_id: 0 - 511, according to manufacturer
189 * @die_revision: 0 - 7, according to manufacturer
191 struct i2c_device_identity {
193 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS 0
194 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1 1
195 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2 2
196 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3 3
197 #define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL 4
198 #define I2C_DEVICE_ID_ANALOG_DEVICES 5
199 #define I2C_DEVICE_ID_STMICROELECTRONICS 6
200 #define I2C_DEVICE_ID_ON_SEMICONDUCTOR 7
201 #define I2C_DEVICE_ID_SPRINTEK_CORPORATION 8
202 #define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG 9
203 #define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR 10
204 #define I2C_DEVICE_ID_FLIR 11
205 #define I2C_DEVICE_ID_O2MICRO 12
206 #define I2C_DEVICE_ID_ATMEL 13
207 #define I2C_DEVICE_ID_NONE 0xffff
212 enum i2c_alert_protocol {
213 I2C_PROTOCOL_SMBUS_ALERT,
214 I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
218 * struct i2c_driver - represent an I2C device driver
219 * @class: What kind of i2c device we instantiate (for detect)
220 * @probe: Callback for device binding - soon to be deprecated
221 * @probe_new: New callback for device binding
222 * @remove: Callback for device unbinding
223 * @shutdown: Callback for device shutdown
224 * @alert: Alert callback, for example for the SMBus alert protocol
225 * @command: Callback for bus-wide signaling (optional)
226 * @driver: Device driver model driver
227 * @id_table: List of I2C devices supported by this driver
228 * @detect: Callback for device detection
229 * @address_list: The I2C addresses to probe (for detect)
230 * @clients: List of detected clients we created (for i2c-core use only)
231 * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
233 * The driver.owner field should be set to the module owner of this driver.
234 * The driver.name field should be set to the name of this driver.
236 * For automatic device detection, both @detect and @address_list must
237 * be defined. @class should also be set, otherwise only devices forced
238 * with module parameters will be created. The detect function must
239 * fill at least the name field of the i2c_board_info structure it is
240 * handed upon successful detection, and possibly also the flags field.
242 * If @detect is missing, the driver will still work fine for enumerated
243 * devices. Detected devices simply won't be supported. This is expected
244 * for the many I2C/SMBus devices which can't be detected reliably, and
245 * the ones which can always be enumerated in practice.
247 * The i2c_client structure which is handed to the @detect callback is
248 * not a real i2c_client. It is initialized just enough so that you can
249 * call i2c_smbus_read_byte_data and friends on it. Don't do anything
250 * else with it. In particular, calling dev_dbg and friends on it is
256 /* Standard driver model interfaces */
257 int (*probe)(struct i2c_client *client, const struct i2c_device_id *id);
258 int (*remove)(struct i2c_client *client);
260 /* New driver model interface to aid the seamless removal of the
261 * current probe()'s, more commonly unused than used second parameter.
263 int (*probe_new)(struct i2c_client *client);
265 /* driver model interfaces that don't relate to enumeration */
266 void (*shutdown)(struct i2c_client *client);
268 /* Alert callback, for example for the SMBus alert protocol.
269 * The format and meaning of the data value depends on the protocol.
270 * For the SMBus alert protocol, there is a single bit of data passed
271 * as the alert response's low bit ("event flag").
272 * For the SMBus Host Notify protocol, the data corresponds to the
273 * 16-bit payload data reported by the slave device acting as master.
275 void (*alert)(struct i2c_client *client, enum i2c_alert_protocol protocol,
278 /* a ioctl like command that can be used to perform specific functions
281 int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
283 struct device_driver driver;
284 const struct i2c_device_id *id_table;
286 /* Device detection callback for automatic device creation */
287 int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
288 const unsigned short *address_list;
289 struct list_head clients;
291 bool disable_i2c_core_irq_mapping;
293 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
296 * struct i2c_client - represent an I2C slave device
297 * @flags: see I2C_CLIENT_* for possible flags
298 * @addr: Address used on the I2C bus connected to the parent adapter.
299 * @name: Indicates the type of the device, usually a chip name that's
300 * generic enough to hide second-sourcing and compatible revisions.
301 * @adapter: manages the bus segment hosting this I2C device
302 * @dev: Driver model device node for the slave.
303 * @init_irq: IRQ that was set at initialization
304 * @irq: indicates the IRQ generated by this device (if any)
305 * @detected: member of an i2c_driver.clients list or i2c-core's
306 * userspace_devices list
307 * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
308 * calls it to pass on slave events to the slave driver.
310 * An i2c_client identifies a single device (i.e. chip) connected to an
311 * i2c bus. The behaviour exposed to Linux is defined by the driver
312 * managing the device.
315 unsigned short flags; /* div., see below */
316 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
317 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
318 /* Must equal I2C_M_TEN below */
319 #define I2C_CLIENT_SLAVE 0x20 /* we are the slave */
320 #define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */
321 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
322 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
323 /* Must match I2C_M_STOP|IGNORE_NAK */
325 unsigned short addr; /* chip address - NOTE: 7bit */
326 /* addresses are stored in the */
328 char name[I2C_NAME_SIZE];
329 struct i2c_adapter *adapter; /* the adapter we sit on */
330 struct device dev; /* the device structure */
331 int init_irq; /* irq set at initialization */
332 int irq; /* irq issued by device */
333 struct list_head detected;
334 #if IS_ENABLED(CONFIG_I2C_SLAVE)
335 i2c_slave_cb_t slave_cb; /* callback for slave mode */
338 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
340 extern struct i2c_client *i2c_verify_client(struct device *dev);
341 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
342 extern const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
343 const struct i2c_client *client);
345 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
347 struct device * const dev = container_of(kobj, struct device, kobj);
348 return to_i2c_client(dev);
351 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
353 return dev_get_drvdata(&dev->dev);
356 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
358 dev_set_drvdata(&dev->dev, data);
361 /* I2C slave support */
363 #if IS_ENABLED(CONFIG_I2C_SLAVE)
364 enum i2c_slave_event {
365 I2C_SLAVE_READ_REQUESTED,
366 I2C_SLAVE_WRITE_REQUESTED,
367 I2C_SLAVE_READ_PROCESSED,
368 I2C_SLAVE_WRITE_RECEIVED,
372 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
373 extern int i2c_slave_unregister(struct i2c_client *client);
374 extern bool i2c_detect_slave_mode(struct device *dev);
376 static inline int i2c_slave_event(struct i2c_client *client,
377 enum i2c_slave_event event, u8 *val)
379 return client->slave_cb(client, event, val);
382 static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
386 * struct i2c_board_info - template for device creation
387 * @type: chip type, to initialize i2c_client.name
388 * @flags: to initialize i2c_client.flags
389 * @addr: stored in i2c_client.addr
390 * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
391 * @platform_data: stored in i2c_client.dev.platform_data
392 * @of_node: pointer to OpenFirmware device node
393 * @fwnode: device node supplied by the platform firmware
394 * @properties: additional device properties for the device
395 * @resources: resources associated with the device
396 * @num_resources: number of resources in the @resources array
397 * @irq: stored in i2c_client.irq
399 * I2C doesn't actually support hardware probing, although controllers and
400 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
401 * a device at a given address. Drivers commonly need more information than
402 * that, such as chip type, configuration, associated IRQ, and so on.
404 * i2c_board_info is used to build tables of information listing I2C devices
405 * that are present. This information is used to grow the driver model tree.
406 * For mainboards this is done statically using i2c_register_board_info();
407 * bus numbers identify adapters that aren't yet available. For add-on boards,
408 * i2c_new_device() does this dynamically with the adapter already known.
410 struct i2c_board_info {
411 char type[I2C_NAME_SIZE];
412 unsigned short flags;
414 const char *dev_name;
416 struct device_node *of_node;
417 struct fwnode_handle *fwnode;
418 const struct property_entry *properties;
419 const struct resource *resources;
420 unsigned int num_resources;
425 * I2C_BOARD_INFO - macro used to list an i2c device and its address
426 * @dev_type: identifies the device type
427 * @dev_addr: the device's address on the bus.
429 * This macro initializes essential fields of a struct i2c_board_info,
430 * declaring what has been provided on a particular board. Optional
431 * fields (such as associated irq, or device-specific platform_data)
432 * are provided using conventional syntax.
434 #define I2C_BOARD_INFO(dev_type, dev_addr) \
435 .type = dev_type, .addr = (dev_addr)
438 #if IS_ENABLED(CONFIG_I2C)
439 /* Add-on boards should register/unregister their devices; e.g. a board
440 * with integrated I2C, a config eeprom, sensors, and a codec that's
441 * used in conjunction with the primary hardware.
443 extern struct i2c_client *
444 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
446 extern struct i2c_client *
447 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
449 /* If you don't know the exact address of an I2C device, use this variant
450 * instead, which can probe for device presence in a list of possible
451 * addresses. The "probe" callback function is optional. If it is provided,
452 * it must return 1 on successful probe, 0 otherwise. If it is not provided,
453 * a default probing method is used.
455 extern struct i2c_client *
456 i2c_new_scanned_device(struct i2c_adapter *adap,
457 struct i2c_board_info *info,
458 unsigned short const *addr_list,
459 int (*probe)(struct i2c_adapter *adap, unsigned short addr));
461 extern struct i2c_client *
462 i2c_new_probed_device(struct i2c_adapter *adap,
463 struct i2c_board_info *info,
464 unsigned short const *addr_list,
465 int (*probe)(struct i2c_adapter *adap, unsigned short addr));
467 /* Common custom probe functions */
468 extern int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr);
470 extern struct i2c_client *
471 i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address);
473 extern struct i2c_client *
474 devm_i2c_new_dummy_device(struct device *dev, struct i2c_adapter *adap, u16 address);
476 extern struct i2c_client *
477 i2c_new_ancillary_device(struct i2c_client *client,
481 extern void i2c_unregister_device(struct i2c_client *client);
484 /* Mainboard arch_initcall() code should register all its I2C devices.
485 * This is done at arch_initcall time, before declaring any i2c adapters.
486 * Modules for add-on boards must use other calls.
488 #ifdef CONFIG_I2C_BOARDINFO
490 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
494 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
499 #endif /* I2C_BOARDINFO */
502 * struct i2c_algorithm - represent I2C transfer method
503 * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
504 * defined by the msgs array, with num messages available to transfer via
505 * the adapter specified by adap.
506 * @master_xfer_atomic: same as @master_xfer. Yet, only using atomic context
507 * so e.g. PMICs can be accessed very late before shutdown. Optional.
508 * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
509 * is not present, then the bus layer will try and convert the SMBus calls
510 * into I2C transfers instead.
511 * @smbus_xfer_atomic: same as @smbus_xfer. Yet, only using atomic context
512 * so e.g. PMICs can be accessed very late before shutdown. Optional.
513 * @functionality: Return the flags that this algorithm/adapter pair supports
514 * from the I2C_FUNC_* flags.
515 * @reg_slave: Register given client to I2C slave mode of this adapter
516 * @unreg_slave: Unregister given client from I2C slave mode of this adapter
518 * The following structs are for those who like to implement new bus drivers:
519 * i2c_algorithm is the interface to a class of hardware solutions which can
520 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
521 * to name two of the most common.
523 * The return codes from the @master_xfer{_atomic} fields should indicate the
524 * type of error code that occurred during the transfer, as documented in the
525 * Kernel Documentation file Documentation/i2c/fault-codes.rst.
527 struct i2c_algorithm {
529 * If an adapter algorithm can't do I2C-level access, set master_xfer
530 * to NULL. If an adapter algorithm can do SMBus access, set
531 * smbus_xfer. If set to NULL, the SMBus protocol is simulated
532 * using common I2C messages.
534 * master_xfer should return the number of messages successfully
535 * processed, or a negative value on error
537 int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
539 int (*master_xfer_atomic)(struct i2c_adapter *adap,
540 struct i2c_msg *msgs, int num);
541 int (*smbus_xfer)(struct i2c_adapter *adap, u16 addr,
542 unsigned short flags, char read_write,
543 u8 command, int size, union i2c_smbus_data *data);
544 int (*smbus_xfer_atomic)(struct i2c_adapter *adap, u16 addr,
545 unsigned short flags, char read_write,
546 u8 command, int size, union i2c_smbus_data *data);
548 /* To determine what the adapter supports */
549 u32 (*functionality)(struct i2c_adapter *adap);
551 #if IS_ENABLED(CONFIG_I2C_SLAVE)
552 int (*reg_slave)(struct i2c_client *client);
553 int (*unreg_slave)(struct i2c_client *client);
558 * struct i2c_lock_operations - represent I2C locking operations
559 * @lock_bus: Get exclusive access to an I2C bus segment
560 * @trylock_bus: Try to get exclusive access to an I2C bus segment
561 * @unlock_bus: Release exclusive access to an I2C bus segment
563 * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
565 struct i2c_lock_operations {
566 void (*lock_bus)(struct i2c_adapter *adapter, unsigned int flags);
567 int (*trylock_bus)(struct i2c_adapter *adapter, unsigned int flags);
568 void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags);
572 * struct i2c_timings - I2C timing information
573 * @bus_freq_hz: the bus frequency in Hz
574 * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
575 * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
576 * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
577 * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
578 * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
579 * @digital_filter_width_ns: width in ns of spikes on i2c lines that the IP core
580 * digital filter can filter out
581 * @analog_filter_cutoff_freq_hz: threshold frequency for the low pass IP core
588 u32 scl_int_delay_ns;
591 u32 digital_filter_width_ns;
592 u32 analog_filter_cutoff_freq_hz;
596 * struct i2c_bus_recovery_info - I2C bus recovery information
597 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
598 * i2c_generic_scl_recovery().
599 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
600 * recovery. Populated internally for generic GPIO recovery.
601 * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
602 * Populated internally for generic GPIO recovery.
603 * @get_sda: This gets current value of SDA line. This or set_sda() is mandatory
604 * for generic SCL recovery. Populated internally, if sda_gpio is a valid
605 * GPIO, for generic GPIO recovery.
606 * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for
607 * generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO,
608 * for generic GPIO recovery.
609 * @get_bus_free: Returns the bus free state as seen from the IP core in case it
610 * has a more complex internal logic than just reading SDA. Optional.
611 * @prepare_recovery: This will be called before starting recovery. Platform may
612 * configure padmux here for SDA/SCL line or something else they want.
613 * @unprepare_recovery: This will be called after completing recovery. Platform
614 * may configure padmux here for SDA/SCL line or something else they want.
615 * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
616 * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
618 struct i2c_bus_recovery_info {
619 int (*recover_bus)(struct i2c_adapter *adap);
621 int (*get_scl)(struct i2c_adapter *adap);
622 void (*set_scl)(struct i2c_adapter *adap, int val);
623 int (*get_sda)(struct i2c_adapter *adap);
624 void (*set_sda)(struct i2c_adapter *adap, int val);
625 int (*get_bus_free)(struct i2c_adapter *adap);
627 void (*prepare_recovery)(struct i2c_adapter *adap);
628 void (*unprepare_recovery)(struct i2c_adapter *adap);
631 struct gpio_desc *scl_gpiod;
632 struct gpio_desc *sda_gpiod;
635 int i2c_recover_bus(struct i2c_adapter *adap);
637 /* Generic recovery routines */
638 int i2c_generic_scl_recovery(struct i2c_adapter *adap);
641 * struct i2c_adapter_quirks - describe flaws of an i2c adapter
642 * @flags: see I2C_AQ_* for possible flags and read below
643 * @max_num_msgs: maximum number of messages per transfer
644 * @max_write_len: maximum length of a write message
645 * @max_read_len: maximum length of a read message
646 * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
647 * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
649 * Note about combined messages: Some I2C controllers can only send one message
650 * per transfer, plus something called combined message or write-then-read.
651 * This is (usually) a small write message followed by a read message and
652 * barely enough to access register based devices like EEPROMs. There is a flag
653 * to support this mode. It implies max_num_msg = 2 and does the length checks
654 * with max_comb_*_len because combined message mode usually has its own
655 * limitations. Because of HW implementations, some controllers can actually do
656 * write-then-anything or other variants. To support that, write-then-read has
657 * been broken out into smaller bits like write-first and read-second which can
658 * be combined as needed.
661 struct i2c_adapter_quirks {
666 u16 max_comb_1st_msg_len;
667 u16 max_comb_2nd_msg_len;
670 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
671 #define I2C_AQ_COMB BIT(0)
672 /* first combined message must be write */
673 #define I2C_AQ_COMB_WRITE_FIRST BIT(1)
674 /* second combined message must be read */
675 #define I2C_AQ_COMB_READ_SECOND BIT(2)
676 /* both combined messages must have the same target address */
677 #define I2C_AQ_COMB_SAME_ADDR BIT(3)
678 /* convenience macro for typical write-then read case */
679 #define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
680 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
681 /* clock stretching is not supported */
682 #define I2C_AQ_NO_CLK_STRETCH BIT(4)
683 /* message cannot have length of 0 */
684 #define I2C_AQ_NO_ZERO_LEN_READ BIT(5)
685 #define I2C_AQ_NO_ZERO_LEN_WRITE BIT(6)
686 #define I2C_AQ_NO_ZERO_LEN (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
689 * i2c_adapter is the structure used to identify a physical i2c bus along
690 * with the access algorithms necessary to access it.
693 struct module *owner;
694 unsigned int class; /* classes to allow probing for */
695 const struct i2c_algorithm *algo; /* the algorithm to access the bus */
698 /* data fields that are valid for all devices */
699 const struct i2c_lock_operations *lock_ops;
700 struct rt_mutex bus_lock;
701 struct rt_mutex mux_lock;
703 int timeout; /* in jiffies */
705 struct device dev; /* the adapter device */
706 unsigned long locked_flags; /* owned by the I2C core */
707 #define I2C_ALF_IS_SUSPENDED 0
708 #define I2C_ALF_SUSPEND_REPORTED 1
712 struct completion dev_released;
714 struct mutex userspace_clients_lock;
715 struct list_head userspace_clients;
717 struct i2c_bus_recovery_info *bus_recovery_info;
718 const struct i2c_adapter_quirks *quirks;
720 struct irq_domain *host_notify_domain;
722 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
724 static inline void *i2c_get_adapdata(const struct i2c_adapter *adap)
726 return dev_get_drvdata(&adap->dev);
729 static inline void i2c_set_adapdata(struct i2c_adapter *adap, void *data)
731 dev_set_drvdata(&adap->dev, data);
734 static inline struct i2c_adapter *
735 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
737 #if IS_ENABLED(CONFIG_I2C_MUX)
738 struct device *parent = adapter->dev.parent;
740 if (parent != NULL && parent->type == &i2c_adapter_type)
741 return to_i2c_adapter(parent);
747 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data));
749 /* Adapter locking functions, exported for shared pin cases */
750 #define I2C_LOCK_ROOT_ADAPTER BIT(0)
751 #define I2C_LOCK_SEGMENT BIT(1)
754 * i2c_lock_bus - Get exclusive access to an I2C bus segment
755 * @adapter: Target I2C bus segment
756 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
757 * locks only this branch in the adapter tree
760 i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
762 adapter->lock_ops->lock_bus(adapter, flags);
766 * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
767 * @adapter: Target I2C bus segment
768 * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
769 * I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
771 * Return: true if the I2C bus segment is locked, false otherwise
774 i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
776 return adapter->lock_ops->trylock_bus(adapter, flags);
780 * i2c_unlock_bus - Release exclusive access to an I2C bus segment
781 * @adapter: Target I2C bus segment
782 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
783 * unlocks only this branch in the adapter tree
786 i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
788 adapter->lock_ops->unlock_bus(adapter, flags);
792 * i2c_mark_adapter_suspended - Report suspended state of the adapter to the core
793 * @adap: Adapter to mark as suspended
795 * When using this helper to mark an adapter as suspended, the core will reject
796 * further transfers to this adapter. The usage of this helper is optional but
797 * recommended for devices having distinct handlers for system suspend and
798 * runtime suspend. More complex devices are free to implement custom solutions
799 * to reject transfers when suspended.
801 static inline void i2c_mark_adapter_suspended(struct i2c_adapter *adap)
803 i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
804 set_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
805 i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
809 * i2c_mark_adapter_resumed - Report resumed state of the adapter to the core
810 * @adap: Adapter to mark as resumed
812 * When using this helper to mark an adapter as resumed, the core will allow
813 * further transfers to this adapter. See also further notes to
814 * @i2c_mark_adapter_suspended().
816 static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap)
818 i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
819 clear_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
820 i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
823 /* i2c adapter classes (bitmask) */
824 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
825 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
826 #define I2C_CLASS_SPD (1<<7) /* Memory modules */
827 /* Warn users that the adapter doesn't support classes anymore */
828 #define I2C_CLASS_DEPRECATED (1<<8)
830 /* Internal numbers to terminate lists */
831 #define I2C_CLIENT_END 0xfffeU
833 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
834 #define I2C_ADDRS(addr, addrs...) \
835 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
838 /* ----- functions exported by i2c.o */
842 #if IS_ENABLED(CONFIG_I2C)
843 extern int i2c_add_adapter(struct i2c_adapter *adap);
844 extern void i2c_del_adapter(struct i2c_adapter *adap);
845 extern int i2c_add_numbered_adapter(struct i2c_adapter *adap);
847 extern int i2c_register_driver(struct module *owner, struct i2c_driver *driver);
848 extern void i2c_del_driver(struct i2c_driver *driver);
850 /* use a define to avoid include chaining to get THIS_MODULE */
851 #define i2c_add_driver(driver) \
852 i2c_register_driver(THIS_MODULE, driver)
854 static inline bool i2c_client_has_driver(struct i2c_client *client)
856 return !IS_ERR_OR_NULL(client) && client->dev.driver;
859 /* call the i2c_client->command() of all attached clients with
860 * the given arguments */
861 extern void i2c_clients_command(struct i2c_adapter *adap,
862 unsigned int cmd, void *arg);
864 extern struct i2c_adapter *i2c_get_adapter(int nr);
865 extern void i2c_put_adapter(struct i2c_adapter *adap);
866 extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
868 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
870 /* Return the functionality mask */
871 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
873 return adap->algo->functionality(adap);
876 /* Return 1 if adapter supports everything we need, 0 if not. */
877 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
879 return (func & i2c_get_functionality(adap)) == func;
883 * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
885 * @quirks: quirk flags
887 * Return: true if the adapter has all the specified quirk flags, false if not
889 static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
893 return (adap->quirks->flags & quirks) == quirks;
896 /* Return the adapter number for a specific adapter */
897 static inline int i2c_adapter_id(struct i2c_adapter *adap)
902 static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
904 return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
907 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
908 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
910 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
912 * module_i2c_driver() - Helper macro for registering a modular I2C driver
913 * @__i2c_driver: i2c_driver struct
915 * Helper macro for I2C drivers which do not do anything special in module
916 * init/exit. This eliminates a lot of boilerplate. Each module may only
917 * use this macro once, and calling it replaces module_init() and module_exit()
919 #define module_i2c_driver(__i2c_driver) \
920 module_driver(__i2c_driver, i2c_add_driver, \
924 * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
925 * @__i2c_driver: i2c_driver struct
927 * Helper macro for I2C drivers which do not do anything special in their
928 * init. This eliminates a lot of boilerplate. Each driver may only
929 * use this macro once, and calling it replaces device_initcall().
931 #define builtin_i2c_driver(__i2c_driver) \
932 builtin_driver(__i2c_driver, i2c_add_driver)
936 #if IS_ENABLED(CONFIG_OF)
937 /* must call put_device() when done with returned i2c_client device */
938 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
940 /* must call put_device() when done with returned i2c_adapter device */
941 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
943 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
944 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
946 extern const struct of_device_id
947 *i2c_of_match_device(const struct of_device_id *matches,
948 struct i2c_client *client);
950 int of_i2c_get_board_info(struct device *dev, struct device_node *node,
951 struct i2c_board_info *info);
955 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
960 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
965 static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
970 static inline const struct of_device_id
971 *i2c_of_match_device(const struct of_device_id *matches,
972 struct i2c_client *client)
977 static inline int of_i2c_get_board_info(struct device *dev,
978 struct device_node *node,
979 struct i2c_board_info *info)
984 #endif /* CONFIG_OF */
986 struct acpi_resource;
987 struct acpi_resource_i2c_serialbus;
989 #if IS_ENABLED(CONFIG_ACPI)
990 bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
991 struct acpi_resource_i2c_serialbus **i2c);
992 u32 i2c_acpi_find_bus_speed(struct device *dev);
993 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
994 struct i2c_board_info *info);
995 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
997 static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
998 struct acpi_resource_i2c_serialbus **i2c)
1002 static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
1006 static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
1007 int index, struct i2c_board_info *info)
1011 static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
1015 #endif /* CONFIG_ACPI */
1017 #endif /* _LINUX_I2C_H */