1/* ------------------------------------------------------------------------- */ 2/* */ 3/* i2c.h - definitions for the i2c-bus interface */ 4/* */ 5/* ------------------------------------------------------------------------- */ 6/* Copyright (C) 1995-2000 Simon G. Vogl 7 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. 12 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. 17 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, 21 MA 02110-1301 USA. */ 22/* ------------------------------------------------------------------------- */ 23 24/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and 25 Frodo Looijaard <frodol@dds.nl> */ 26#ifndef _LINUX_I2C_H 27#define _LINUX_I2C_H 28 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> 36 37extern struct bus_type i2c_bus_type; 38extern struct device_type i2c_adapter_type; 39 40/* --- General options ------------------------------------------------ */ 41 42struct i2c_msg; 43struct i2c_algorithm; 44struct i2c_adapter; 45struct i2c_client; 46struct i2c_driver; 47union i2c_smbus_data; 48struct i2c_board_info; 49enum i2c_slave_event; 50typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *); 51 52struct module; 53 54#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 55/* 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. 61 */ 62extern int i2c_master_send(const struct i2c_client *client, const char *buf, 63 int count); 64extern int i2c_master_recv(const struct i2c_client *client, char *buf, 65 int count); 66 67/* Transfer num messages. 68 */ 69extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 70 int num); 71/* Unlocked flavor */ 72extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 73 int num); 74 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. */ 80extern 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); 83 84/* Now follow the 'nice' access routines. These also document the calling 85 conventions of i2c_smbus_xfer. */ 86 87extern s32 i2c_smbus_read_byte(const struct i2c_client *client); 88extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value); 89extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client, 90 u8 command); 91extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client, 92 u8 command, u8 value); 93extern s32 i2c_smbus_read_word_data(const struct i2c_client *client, 94 u8 command); 95extern s32 i2c_smbus_write_word_data(const struct i2c_client *client, 96 u8 command, u16 value); 97 98static inline s32 99i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command) 100{ 101 s32 value = i2c_smbus_read_word_data(client, command); 102 103 return (value < 0) ? value : swab16(value); 104} 105 106static inline s32 107i2c_smbus_write_word_swapped(const struct i2c_client *client, 108 u8 command, u16 value) 109{ 110 return i2c_smbus_write_word_data(client, command, swab16(value)); 111} 112 113/* Returns the number of read bytes */ 114extern s32 i2c_smbus_read_block_data(const struct i2c_client *client, 115 u8 command, u8 *values); 116extern 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 */ 119extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, 120 u8 command, u8 length, u8 *values); 121extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, 122 u8 command, u8 length, 123 const u8 *values); 124#endif /* I2C */ 125 126/** 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) 140 * 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. 143 * 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. 149 * 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. 154 * 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 159 * not allowed. 160 */ 161struct i2c_driver { 162 unsigned int class; 163 164 /* Notifies the driver that a new bus has appeared. You should avoid 165 * using this, it will be removed in a near future. 166 */ 167 int (*attach_adapter)(struct i2c_adapter *) __deprecated; 168 169 /* Standard driver model interfaces */ 170 int (*probe)(struct i2c_client *, const struct i2c_device_id *); 171 int (*remove)(struct i2c_client *); 172 173 /* driver model interfaces that don't relate to enumeration */ 174 void (*shutdown)(struct i2c_client *); 175 176 /* 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"). 180 */ 181 void (*alert)(struct i2c_client *, unsigned int data); 182 183 /* a ioctl like command that can be used to perform specific functions 184 * with the device. 185 */ 186 int (*command)(struct i2c_client *client, unsigned int cmd, void *arg); 187 188 struct device_driver driver; 189 const struct i2c_device_id *id_table; 190 191 /* 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; 195}; 196#define to_i2c_driver(d) container_of(d, struct i2c_driver, driver) 197 198/** 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. 212 * 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. 216 */ 217struct i2c_client { 218 unsigned short flags; /* div., see below */ 219 unsigned short addr; /* chip address - NOTE: 7bit */ 220 /* addresses are stored in the */ 221 /* _LOWER_ 7 bits */ 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 */ 229#endif 230}; 231#define to_i2c_client(d) container_of(d, struct i2c_client, dev) 232 233extern struct i2c_client *i2c_verify_client(struct device *dev); 234extern struct i2c_adapter *i2c_verify_adapter(struct device *dev); 235 236static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj) 237{ 238 struct device * const dev = container_of(kobj, struct device, kobj); 239 return to_i2c_client(dev); 240} 241 242static inline void *i2c_get_clientdata(const struct i2c_client *dev) 243{ 244 return dev_get_drvdata(&dev->dev); 245} 246 247static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) 248{ 249 dev_set_drvdata(&dev->dev, data); 250} 251 252/* I2C slave support */ 253 254#if IS_ENABLED(CONFIG_I2C_SLAVE) 255enum i2c_slave_event { 256 I2C_SLAVE_READ_REQUESTED, 257 I2C_SLAVE_WRITE_REQUESTED, 258 I2C_SLAVE_READ_PROCESSED, 259 I2C_SLAVE_WRITE_RECEIVED, 260 I2C_SLAVE_STOP, 261}; 262 263extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb); 264extern int i2c_slave_unregister(struct i2c_client *client); 265 266static inline int i2c_slave_event(struct i2c_client *client, 267 enum i2c_slave_event event, u8 *val) 268{ 269 return client->slave_cb(client, event, val); 270} 271#endif 272 273/** 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 * @fwnode: device node supplied by the platform firmware 282 * @irq: stored in i2c_client.irq 283 * 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. 288 * 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. 294 */ 295struct i2c_board_info { 296 char type[I2C_NAME_SIZE]; 297 unsigned short flags; 298 unsigned short addr; 299 void *platform_data; 300 struct dev_archdata *archdata; 301 struct device_node *of_node; 302 struct fwnode_handle *fwnode; 303 int irq; 304}; 305 306/** 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. 310 * 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. 315 */ 316#define I2C_BOARD_INFO(dev_type, dev_addr) \ 317 .type = dev_type, .addr = (dev_addr) 318 319 320#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. 324 */ 325extern struct i2c_client * 326i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); 327 328/* 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. 333 */ 334extern struct i2c_client * 335i2c_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)); 339 340/* Common custom probe functions */ 341extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); 342 343/* For devices that use several addresses, use i2c_new_dummy() to make 344 * client handles for the extra addresses. 345 */ 346extern struct i2c_client * 347i2c_new_dummy(struct i2c_adapter *adap, u16 address); 348 349extern void i2c_unregister_device(struct i2c_client *); 350#endif /* I2C */ 351 352/* 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. 355 */ 356#ifdef CONFIG_I2C_BOARDINFO 357extern int 358i2c_register_board_info(int busnum, struct i2c_board_info const *info, 359 unsigned n); 360#else 361static inline int 362i2c_register_board_info(int busnum, struct i2c_board_info const *info, 363 unsigned n) 364{ 365 return 0; 366} 367#endif /* I2C_BOARDINFO */ 368 369/** 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 381 * 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. 386 * 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. 390 */ 391struct 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, 399 int num); 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); 403 404 /* To determine what the adapter supports */ 405 u32 (*functionality) (struct i2c_adapter *); 406 407#if IS_ENABLED(CONFIG_I2C_SLAVE) 408 int (*reg_slave)(struct i2c_client *client); 409 int (*unreg_slave)(struct i2c_client *client); 410#endif 411}; 412 413/** 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 423 * recovery. 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. 430 */ 431struct i2c_bus_recovery_info { 432 int (*recover_bus)(struct i2c_adapter *); 433 434 int (*get_scl)(struct i2c_adapter *); 435 void (*set_scl)(struct i2c_adapter *, int val); 436 int (*get_sda)(struct i2c_adapter *); 437 438 void (*prepare_recovery)(struct i2c_adapter *); 439 void (*unprepare_recovery)(struct i2c_adapter *); 440 441 /* gpio recovery */ 442 int scl_gpio; 443 int sda_gpio; 444}; 445 446int i2c_recover_bus(struct i2c_adapter *adap); 447 448/* Generic recovery routines */ 449int i2c_generic_gpio_recovery(struct i2c_adapter *adap); 450int i2c_generic_scl_recovery(struct i2c_adapter *adap); 451 452/** 453 * struct i2c_adapter_quirks - describe flaws of an i2c adapter 454 * @flags: see I2C_AQ_* for possible flags and read below 455 * @max_num_msgs: maximum number of messages per transfer 456 * @max_write_len: maximum length of a write message 457 * @max_read_len: maximum length of a read message 458 * @max_comb_1st_msg_len: maximum length of the first msg in a combined message 459 * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message 460 * 461 * Note about combined messages: Some I2C controllers can only send one message 462 * per transfer, plus something called combined message or write-then-read. 463 * This is (usually) a small write message followed by a read message and 464 * barely enough to access register based devices like EEPROMs. There is a flag 465 * to support this mode. It implies max_num_msg = 2 and does the length checks 466 * with max_comb_*_len because combined message mode usually has its own 467 * limitations. Because of HW implementations, some controllers can actually do 468 * write-then-anything or other variants. To support that, write-then-read has 469 * been broken out into smaller bits like write-first and read-second which can 470 * be combined as needed. 471 */ 472 473struct i2c_adapter_quirks { 474 u64 flags; 475 int max_num_msgs; 476 u16 max_write_len; 477 u16 max_read_len; 478 u16 max_comb_1st_msg_len; 479 u16 max_comb_2nd_msg_len; 480}; 481 482/* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */ 483#define I2C_AQ_COMB BIT(0) 484/* first combined message must be write */ 485#define I2C_AQ_COMB_WRITE_FIRST BIT(1) 486/* second combined message must be read */ 487#define I2C_AQ_COMB_READ_SECOND BIT(2) 488/* both combined messages must have the same target address */ 489#define I2C_AQ_COMB_SAME_ADDR BIT(3) 490/* convenience macro for typical write-then read case */ 491#define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \ 492 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR) 493 494/* 495 * i2c_adapter is the structure used to identify a physical i2c bus along 496 * with the access algorithms necessary to access it. 497 */ 498struct i2c_adapter { 499 struct module *owner; 500 unsigned int class; /* classes to allow probing for */ 501 const struct i2c_algorithm *algo; /* the algorithm to access the bus */ 502 void *algo_data; 503 504 /* data fields that are valid for all devices */ 505 struct rt_mutex bus_lock; 506 507 int timeout; /* in jiffies */ 508 int retries; 509 struct device dev; /* the adapter device */ 510 511 int nr; 512 char name[48]; 513 struct completion dev_released; 514 515 struct mutex userspace_clients_lock; 516 struct list_head userspace_clients; 517 518 struct i2c_bus_recovery_info *bus_recovery_info; 519 const struct i2c_adapter_quirks *quirks; 520}; 521#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) 522 523static inline void *i2c_get_adapdata(const struct i2c_adapter *dev) 524{ 525 return dev_get_drvdata(&dev->dev); 526} 527 528static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) 529{ 530 dev_set_drvdata(&dev->dev, data); 531} 532 533static inline struct i2c_adapter * 534i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter) 535{ 536#if IS_ENABLED(CONFIG_I2C_MUX) 537 struct device *parent = adapter->dev.parent; 538 539 if (parent != NULL && parent->type == &i2c_adapter_type) 540 return to_i2c_adapter(parent); 541 else 542#endif 543 return NULL; 544} 545 546int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)); 547 548/* Adapter locking functions, exported for shared pin cases */ 549void i2c_lock_adapter(struct i2c_adapter *); 550void i2c_unlock_adapter(struct i2c_adapter *); 551 552/*flags for the client struct: */ 553#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ 554#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ 555 /* Must equal I2C_M_TEN below */ 556#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ 557#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ 558 /* Must match I2C_M_STOP|IGNORE_NAK */ 559 560/* i2c adapter classes (bitmask) */ 561#define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ 562#define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */ 563#define I2C_CLASS_SPD (1<<7) /* Memory modules */ 564#define I2C_CLASS_DEPRECATED (1<<8) /* Warn users that adapter will stop using classes */ 565 566/* Internal numbers to terminate lists */ 567#define I2C_CLIENT_END 0xfffeU 568 569/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */ 570#define I2C_ADDRS(addr, addrs...) \ 571 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END }) 572 573 574/* ----- functions exported by i2c.o */ 575 576/* administration... 577 */ 578#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 579extern int i2c_add_adapter(struct i2c_adapter *); 580extern void i2c_del_adapter(struct i2c_adapter *); 581extern int i2c_add_numbered_adapter(struct i2c_adapter *); 582 583extern int i2c_register_driver(struct module *, struct i2c_driver *); 584extern void i2c_del_driver(struct i2c_driver *); 585 586/* use a define to avoid include chaining to get THIS_MODULE */ 587#define i2c_add_driver(driver) \ 588 i2c_register_driver(THIS_MODULE, driver) 589 590extern struct i2c_client *i2c_use_client(struct i2c_client *client); 591extern void i2c_release_client(struct i2c_client *client); 592 593/* call the i2c_client->command() of all attached clients with 594 * the given arguments */ 595extern void i2c_clients_command(struct i2c_adapter *adap, 596 unsigned int cmd, void *arg); 597 598extern struct i2c_adapter *i2c_get_adapter(int nr); 599extern void i2c_put_adapter(struct i2c_adapter *adap); 600 601 602/* Return the functionality mask */ 603static inline u32 i2c_get_functionality(struct i2c_adapter *adap) 604{ 605 return adap->algo->functionality(adap); 606} 607 608/* Return 1 if adapter supports everything we need, 0 if not. */ 609static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func) 610{ 611 return (func & i2c_get_functionality(adap)) == func; 612} 613 614/* Return the adapter number for a specific adapter */ 615static inline int i2c_adapter_id(struct i2c_adapter *adap) 616{ 617 return adap->nr; 618} 619 620/** 621 * module_i2c_driver() - Helper macro for registering a I2C driver 622 * @__i2c_driver: i2c_driver struct 623 * 624 * Helper macro for I2C drivers which do not do anything special in module 625 * init/exit. This eliminates a lot of boilerplate. Each module may only 626 * use this macro once, and calling it replaces module_init() and module_exit() 627 */ 628#define module_i2c_driver(__i2c_driver) \ 629 module_driver(__i2c_driver, i2c_add_driver, \ 630 i2c_del_driver) 631 632#endif /* I2C */ 633 634#if IS_ENABLED(CONFIG_OF) 635/* must call put_device() when done with returned i2c_client device */ 636extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node); 637 638/* must call put_device() when done with returned i2c_adapter device */ 639extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node); 640 641#else 642 643static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) 644{ 645 return NULL; 646} 647 648static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) 649{ 650 return NULL; 651} 652#endif /* CONFIG_OF */ 653 654#endif /* _LINUX_I2C_H */ 655