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 <[email protected]> and 25 Frodo Looijaard <[email protected]> */ 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 37 extern struct bus_type i2c_bus_type; 38 extern struct device_type i2c_adapter_type; 39 40 /* --- General options ------------------------------------------------ */ 41 42 struct i2c_msg; 43 struct i2c_algorithm; 44 struct i2c_adapter; 45 struct i2c_client; 46 struct i2c_driver; 47 union i2c_smbus_data; 48 struct i2c_board_info; 49 enum i2c_slave_event; 50 typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *); 51 52 struct 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 */ 62 extern int i2c_master_send(const struct i2c_client *client, const char *buf, 63 int count); 64 extern int i2c_master_recv(const struct i2c_client *client, char *buf, 65 int count); 66 67 /* Transfer num messages. 68 */ 69 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 70 int num); 71 /* Unlocked flavor */ 72 extern 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. */ 80 extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, 81 unsigned short flags, char read_write, u8 command, 82 int size, union i2c_smbus_data *data); 83 84 /* Now follow the 'nice' access routines. These also document the calling 85 conventions of i2c_smbus_xfer. */ 86 87 extern s32 i2c_smbus_read_byte(const struct i2c_client *client); 88 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value); 89 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client, 90 u8 command); 91 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client, 92 u8 command, u8 value); 93 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client, 94 u8 command); 95 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client, 96 u8 command, u16 value); 97 98 static inline s32 99 i2c_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 } 105 106 static inline s32 107 i2c_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 */ 114 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client, 115 u8 command, u8 *values); 116 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client, 117 u8 command, u8 length, const u8 *values); 118 /* Returns the number of read bytes */ 119 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, 120 u8 command, u8 length, u8 *values); 121 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, 122 u8 command, u8 length, 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 * @suspend: Callback for device suspend 134 * @resume: Callback for device resume 135 * @alert: Alert callback, for example for the SMBus alert protocol 136 * @command: Callback for bus-wide signaling (optional) 137 * @driver: Device driver model driver 138 * @id_table: List of I2C devices supported by this driver 139 * @detect: Callback for device detection 140 * @address_list: The I2C addresses to probe (for detect) 141 * @clients: List of detected clients we created (for i2c-core use only) 142 * 143 * The driver.owner field should be set to the module owner of this driver. 144 * The driver.name field should be set to the name of this driver. 145 * 146 * For automatic device detection, both @detect and @address_list must 147 * be defined. @class should also be set, otherwise only devices forced 148 * with module parameters will be created. The detect function must 149 * fill at least the name field of the i2c_board_info structure it is 150 * handed upon successful detection, and possibly also the flags field. 151 * 152 * If @detect is missing, the driver will still work fine for enumerated 153 * devices. Detected devices simply won't be supported. This is expected 154 * for the many I2C/SMBus devices which can't be detected reliably, and 155 * the ones which can always be enumerated in practice. 156 * 157 * The i2c_client structure which is handed to the @detect callback is 158 * not a real i2c_client. It is initialized just enough so that you can 159 * call i2c_smbus_read_byte_data and friends on it. Don't do anything 160 * else with it. In particular, calling dev_dbg and friends on it is 161 * not allowed. 162 */ 163 struct i2c_driver { 164 unsigned int class; 165 166 /* Notifies the driver that a new bus has appeared. You should avoid 167 * using this, it will be removed in a near future. 168 */ 169 int (*attach_adapter)(struct i2c_adapter *) __deprecated; 170 171 /* Standard driver model interfaces */ 172 int (*probe)(struct i2c_client *, const struct i2c_device_id *); 173 int (*remove)(struct i2c_client *); 174 175 /* driver model interfaces that don't relate to enumeration */ 176 void (*shutdown)(struct i2c_client *); 177 int (*suspend)(struct i2c_client *, pm_message_t mesg); 178 int (*resume)(struct i2c_client *); 179 180 /* Alert callback, for example for the SMBus alert protocol. 181 * The format and meaning of the data value depends on the protocol. 182 * For the SMBus alert protocol, there is a single bit of data passed 183 * as the alert response's low bit ("event flag"). 184 */ 185 void (*alert)(struct i2c_client *, unsigned int data); 186 187 /* a ioctl like command that can be used to perform specific functions 188 * with the device. 189 */ 190 int (*command)(struct i2c_client *client, unsigned int cmd, void *arg); 191 192 struct device_driver driver; 193 const struct i2c_device_id *id_table; 194 195 /* Device detection callback for automatic device creation */ 196 int (*detect)(struct i2c_client *, struct i2c_board_info *); 197 const unsigned short *address_list; 198 struct list_head clients; 199 }; 200 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver) 201 202 /** 203 * struct i2c_client - represent an I2C slave device 204 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address; 205 * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking 206 * @addr: Address used on the I2C bus connected to the parent adapter. 207 * @name: Indicates the type of the device, usually a chip name that's 208 * generic enough to hide second-sourcing and compatible revisions. 209 * @adapter: manages the bus segment hosting this I2C device 210 * @dev: Driver model device node for the slave. 211 * @irq: indicates the IRQ generated by this device (if any) 212 * @detected: member of an i2c_driver.clients list or i2c-core's 213 * userspace_devices list 214 * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter 215 * calls it to pass on slave events to the slave driver. 216 * 217 * An i2c_client identifies a single device (i.e. chip) connected to an 218 * i2c bus. The behaviour exposed to Linux is defined by the driver 219 * managing the device. 220 */ 221 struct i2c_client { 222 unsigned short flags; /* div., see below */ 223 unsigned short addr; /* chip address - NOTE: 7bit */ 224 /* addresses are stored in the */ 225 /* _LOWER_ 7 bits */ 226 char name[I2C_NAME_SIZE]; 227 struct i2c_adapter *adapter; /* the adapter we sit on */ 228 struct device dev; /* the device structure */ 229 int irq; /* irq issued by device */ 230 struct list_head detected; 231 #if IS_ENABLED(CONFIG_I2C_SLAVE) 232 i2c_slave_cb_t slave_cb; /* callback for slave mode */ 233 #endif 234 }; 235 #define to_i2c_client(d) container_of(d, struct i2c_client, dev) 236 237 extern struct i2c_client *i2c_verify_client(struct device *dev); 238 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev); 239 240 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj) 241 { 242 struct device * const dev = container_of(kobj, struct device, kobj); 243 return to_i2c_client(dev); 244 } 245 246 static inline void *i2c_get_clientdata(const struct i2c_client *dev) 247 { 248 return dev_get_drvdata(&dev->dev); 249 } 250 251 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) 252 { 253 dev_set_drvdata(&dev->dev, data); 254 } 255 256 /* I2C slave support */ 257 258 #if IS_ENABLED(CONFIG_I2C_SLAVE) 259 enum i2c_slave_event { 260 I2C_SLAVE_REQ_READ_START, 261 I2C_SLAVE_REQ_READ_END, 262 I2C_SLAVE_REQ_WRITE_START, 263 I2C_SLAVE_REQ_WRITE_END, 264 I2C_SLAVE_STOP, 265 }; 266 267 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb); 268 extern int i2c_slave_unregister(struct i2c_client *client); 269 270 static inline int i2c_slave_event(struct i2c_client *client, 271 enum i2c_slave_event event, u8 *val) 272 { 273 return client->slave_cb(client, event, val); 274 } 275 #endif 276 277 /** 278 * struct i2c_board_info - template for device creation 279 * @type: chip type, to initialize i2c_client.name 280 * @flags: to initialize i2c_client.flags 281 * @addr: stored in i2c_client.addr 282 * @platform_data: stored in i2c_client.dev.platform_data 283 * @archdata: copied into i2c_client.dev.archdata 284 * @of_node: pointer to OpenFirmware device node 285 * @acpi_node: ACPI device node 286 * @irq: stored in i2c_client.irq 287 * 288 * I2C doesn't actually support hardware probing, although controllers and 289 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's 290 * a device at a given address. Drivers commonly need more information than 291 * that, such as chip type, configuration, associated IRQ, and so on. 292 * 293 * i2c_board_info is used to build tables of information listing I2C devices 294 * that are present. This information is used to grow the driver model tree. 295 * For mainboards this is done statically using i2c_register_board_info(); 296 * bus numbers identify adapters that aren't yet available. For add-on boards, 297 * i2c_new_device() does this dynamically with the adapter already known. 298 */ 299 struct i2c_board_info { 300 char type[I2C_NAME_SIZE]; 301 unsigned short flags; 302 unsigned short addr; 303 void *platform_data; 304 struct dev_archdata *archdata; 305 struct device_node *of_node; 306 struct acpi_dev_node acpi_node; 307 int irq; 308 }; 309 310 /** 311 * I2C_BOARD_INFO - macro used to list an i2c device and its address 312 * @dev_type: identifies the device type 313 * @dev_addr: the device's address on the bus. 314 * 315 * This macro initializes essential fields of a struct i2c_board_info, 316 * declaring what has been provided on a particular board. Optional 317 * fields (such as associated irq, or device-specific platform_data) 318 * are provided using conventional syntax. 319 */ 320 #define I2C_BOARD_INFO(dev_type, dev_addr) \ 321 .type = dev_type, .addr = (dev_addr) 322 323 324 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 325 /* Add-on boards should register/unregister their devices; e.g. a board 326 * with integrated I2C, a config eeprom, sensors, and a codec that's 327 * used in conjunction with the primary hardware. 328 */ 329 extern struct i2c_client * 330 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); 331 332 /* If you don't know the exact address of an I2C device, use this variant 333 * instead, which can probe for device presence in a list of possible 334 * addresses. The "probe" callback function is optional. If it is provided, 335 * it must return 1 on successful probe, 0 otherwise. If it is not provided, 336 * a default probing method is used. 337 */ 338 extern struct i2c_client * 339 i2c_new_probed_device(struct i2c_adapter *adap, 340 struct i2c_board_info *info, 341 unsigned short const *addr_list, 342 int (*probe)(struct i2c_adapter *, unsigned short addr)); 343 344 /* Common custom probe functions */ 345 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); 346 347 /* For devices that use several addresses, use i2c_new_dummy() to make 348 * client handles for the extra addresses. 349 */ 350 extern struct i2c_client * 351 i2c_new_dummy(struct i2c_adapter *adap, u16 address); 352 353 extern void i2c_unregister_device(struct i2c_client *); 354 #endif /* I2C */ 355 356 /* Mainboard arch_initcall() code should register all its I2C devices. 357 * This is done at arch_initcall time, before declaring any i2c adapters. 358 * Modules for add-on boards must use other calls. 359 */ 360 #ifdef CONFIG_I2C_BOARDINFO 361 extern int 362 i2c_register_board_info(int busnum, struct i2c_board_info const *info, 363 unsigned n); 364 #else 365 static inline int 366 i2c_register_board_info(int busnum, struct i2c_board_info const *info, 367 unsigned n) 368 { 369 return 0; 370 } 371 #endif /* I2C_BOARDINFO */ 372 373 /** 374 * struct i2c_algorithm - represent I2C transfer method 375 * @master_xfer: Issue a set of i2c transactions to the given I2C adapter 376 * defined by the msgs array, with num messages available to transfer via 377 * the adapter specified by adap. 378 * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this 379 * is not present, then the bus layer will try and convert the SMBus calls 380 * into I2C transfers instead. 381 * @functionality: Return the flags that this algorithm/adapter pair supports 382 * from the I2C_FUNC_* flags. 383 * @reg_slave: Register given client to I2C slave mode of this adapter 384 * @unreg_slave: Unregister given client from I2C slave mode of this adapter 385 * 386 * The following structs are for those who like to implement new bus drivers: 387 * i2c_algorithm is the interface to a class of hardware solutions which can 388 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584 389 * to name two of the most common. 390 * 391 * The return codes from the @master_xfer field should indicate the type of 392 * error code that occurred during the transfer, as documented in the kernel 393 * Documentation file Documentation/i2c/fault-codes. 394 */ 395 struct i2c_algorithm { 396 /* If an adapter algorithm can't do I2C-level access, set master_xfer 397 to NULL. If an adapter algorithm can do SMBus access, set 398 smbus_xfer. If set to NULL, the SMBus protocol is simulated 399 using common I2C messages */ 400 /* master_xfer should return the number of messages successfully 401 processed, or a negative value on error */ 402 int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, 403 int num); 404 int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr, 405 unsigned short flags, char read_write, 406 u8 command, int size, union i2c_smbus_data *data); 407 408 /* To determine what the adapter supports */ 409 u32 (*functionality) (struct i2c_adapter *); 410 411 #if IS_ENABLED(CONFIG_I2C_SLAVE) 412 int (*reg_slave)(struct i2c_client *client); 413 int (*unreg_slave)(struct i2c_client *client); 414 #endif 415 }; 416 417 /** 418 * struct i2c_bus_recovery_info - I2C bus recovery information 419 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or 420 * i2c_generic_scl_recovery() or i2c_generic_gpio_recovery(). 421 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL 422 * recovery. Used internally for generic GPIO recovery. 423 * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used 424 * internally for generic GPIO recovery. 425 * @get_sda: This gets current value of SDA line. Optional for generic SCL 426 * recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO 427 * recovery. 428 * @prepare_recovery: This will be called before starting recovery. Platform may 429 * configure padmux here for SDA/SCL line or something else they want. 430 * @unprepare_recovery: This will be called after completing recovery. Platform 431 * may configure padmux here for SDA/SCL line or something else they want. 432 * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery. 433 * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery. 434 */ 435 struct i2c_bus_recovery_info { 436 int (*recover_bus)(struct i2c_adapter *); 437 438 int (*get_scl)(struct i2c_adapter *); 439 void (*set_scl)(struct i2c_adapter *, int val); 440 int (*get_sda)(struct i2c_adapter *); 441 442 void (*prepare_recovery)(struct i2c_bus_recovery_info *bri); 443 void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri); 444 445 /* gpio recovery */ 446 int scl_gpio; 447 int sda_gpio; 448 }; 449 450 int i2c_recover_bus(struct i2c_adapter *adap); 451 452 /* Generic recovery routines */ 453 int i2c_generic_gpio_recovery(struct i2c_adapter *adap); 454 int i2c_generic_scl_recovery(struct i2c_adapter *adap); 455 456 /* 457 * i2c_adapter is the structure used to identify a physical i2c bus along 458 * with the access algorithms necessary to access it. 459 */ 460 struct i2c_adapter { 461 struct module *owner; 462 unsigned int class; /* classes to allow probing for */ 463 const struct i2c_algorithm *algo; /* the algorithm to access the bus */ 464 void *algo_data; 465 466 /* data fields that are valid for all devices */ 467 struct rt_mutex bus_lock; 468 469 int timeout; /* in jiffies */ 470 int retries; 471 struct device dev; /* the adapter device */ 472 473 int nr; 474 char name[48]; 475 struct completion dev_released; 476 477 struct mutex userspace_clients_lock; 478 struct list_head userspace_clients; 479 480 struct i2c_bus_recovery_info *bus_recovery_info; 481 }; 482 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) 483 484 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev) 485 { 486 return dev_get_drvdata(&dev->dev); 487 } 488 489 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) 490 { 491 dev_set_drvdata(&dev->dev, data); 492 } 493 494 static inline struct i2c_adapter * 495 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter) 496 { 497 #if IS_ENABLED(CONFIG_I2C_MUX) 498 struct device *parent = adapter->dev.parent; 499 500 if (parent != NULL && parent->type == &i2c_adapter_type) 501 return to_i2c_adapter(parent); 502 else 503 #endif 504 return NULL; 505 } 506 507 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)); 508 509 /* Adapter locking functions, exported for shared pin cases */ 510 void i2c_lock_adapter(struct i2c_adapter *); 511 void i2c_unlock_adapter(struct i2c_adapter *); 512 513 /*flags for the client struct: */ 514 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ 515 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ 516 /* Must equal I2C_M_TEN below */ 517 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ 518 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ 519 /* Must match I2C_M_STOP|IGNORE_NAK */ 520 521 /* i2c adapter classes (bitmask) */ 522 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ 523 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */ 524 #define I2C_CLASS_SPD (1<<7) /* Memory modules */ 525 #define I2C_CLASS_DEPRECATED (1<<8) /* Warn users that adapter will stop using classes */ 526 527 /* Internal numbers to terminate lists */ 528 #define I2C_CLIENT_END 0xfffeU 529 530 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */ 531 #define I2C_ADDRS(addr, addrs...) \ 532 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END }) 533 534 535 /* ----- functions exported by i2c.o */ 536 537 /* administration... 538 */ 539 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 540 extern int i2c_add_adapter(struct i2c_adapter *); 541 extern void i2c_del_adapter(struct i2c_adapter *); 542 extern int i2c_add_numbered_adapter(struct i2c_adapter *); 543 544 extern int i2c_register_driver(struct module *, struct i2c_driver *); 545 extern void i2c_del_driver(struct i2c_driver *); 546 547 /* use a define to avoid include chaining to get THIS_MODULE */ 548 #define i2c_add_driver(driver) \ 549 i2c_register_driver(THIS_MODULE, driver) 550 551 extern struct i2c_client *i2c_use_client(struct i2c_client *client); 552 extern void i2c_release_client(struct i2c_client *client); 553 554 /* call the i2c_client->command() of all attached clients with 555 * the given arguments */ 556 extern void i2c_clients_command(struct i2c_adapter *adap, 557 unsigned int cmd, void *arg); 558 559 extern struct i2c_adapter *i2c_get_adapter(int nr); 560 extern void i2c_put_adapter(struct i2c_adapter *adap); 561 562 563 /* Return the functionality mask */ 564 static inline u32 i2c_get_functionality(struct i2c_adapter *adap) 565 { 566 return adap->algo->functionality(adap); 567 } 568 569 /* Return 1 if adapter supports everything we need, 0 if not. */ 570 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func) 571 { 572 return (func & i2c_get_functionality(adap)) == func; 573 } 574 575 /* Return the adapter number for a specific adapter */ 576 static inline int i2c_adapter_id(struct i2c_adapter *adap) 577 { 578 return adap->nr; 579 } 580 581 /** 582 * module_i2c_driver() - Helper macro for registering a I2C driver 583 * @__i2c_driver: i2c_driver struct 584 * 585 * Helper macro for I2C drivers which do not do anything special in module 586 * init/exit. This eliminates a lot of boilerplate. Each module may only 587 * use this macro once, and calling it replaces module_init() and module_exit() 588 */ 589 #define module_i2c_driver(__i2c_driver) \ 590 module_driver(__i2c_driver, i2c_add_driver, \ 591 i2c_del_driver) 592 593 #endif /* I2C */ 594 595 #if IS_ENABLED(CONFIG_OF) 596 /* must call put_device() when done with returned i2c_client device */ 597 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node); 598 599 /* must call put_device() when done with returned i2c_adapter device */ 600 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node); 601 602 #else 603 604 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) 605 { 606 return NULL; 607 } 608 609 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) 610 { 611 return NULL; 612 } 613 #endif /* CONFIG_OF */ 614 615 #endif /* _LINUX_I2C_H */ 616