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 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 50 struct module; 51 52 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 53 /* 54 * The master routines are the ones normally used to transmit data to devices 55 * on a bus (or read from them). Apart from two basic transfer functions to 56 * transmit one message at a time, a more complex version can be used to 57 * transmit an arbitrary number of messages without interruption. 58 * @count must be be less than 64k since msg.len is u16. 59 */ 60 extern int i2c_master_send(const struct i2c_client *client, const char *buf, 61 int count); 62 extern int i2c_master_recv(const struct i2c_client *client, char *buf, 63 int count); 64 65 /* Transfer num messages. 66 */ 67 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 68 int num); 69 /* Unlocked flavor */ 70 extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 71 int num); 72 73 /* This is the very generalized SMBus access routine. You probably do not 74 want to use this, though; one of the functions below may be much easier, 75 and probably just as fast. 76 Note that we use i2c_adapter here, because you do not need a specific 77 smbus adapter to call this function. */ 78 extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, 79 unsigned short flags, char read_write, u8 command, 80 int size, union i2c_smbus_data *data); 81 82 /* Now follow the 'nice' access routines. These also document the calling 83 conventions of i2c_smbus_xfer. */ 84 85 extern s32 i2c_smbus_read_byte(const struct i2c_client *client); 86 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value); 87 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client, 88 u8 command); 89 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client, 90 u8 command, u8 value); 91 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client, 92 u8 command); 93 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client, 94 u8 command, u16 value); 95 96 static inline s32 97 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command) 98 { 99 s32 value = i2c_smbus_read_word_data(client, command); 100 101 return (value < 0) ? value : swab16(value); 102 } 103 104 static inline s32 105 i2c_smbus_write_word_swapped(const struct i2c_client *client, 106 u8 command, u16 value) 107 { 108 return i2c_smbus_write_word_data(client, command, swab16(value)); 109 } 110 111 /* Returns the number of read bytes */ 112 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client, 113 u8 command, u8 *values); 114 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client, 115 u8 command, u8 length, const u8 *values); 116 /* Returns the number of read bytes */ 117 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, 118 u8 command, u8 length, u8 *values); 119 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, 120 u8 command, u8 length, 121 const u8 *values); 122 #endif /* I2C */ 123 124 /** 125 * struct i2c_driver - represent an I2C device driver 126 * @class: What kind of i2c device we instantiate (for detect) 127 * @attach_adapter: Callback for bus addition (deprecated) 128 * @probe: Callback for device binding 129 * @remove: Callback for device unbinding 130 * @shutdown: Callback for device shutdown 131 * @suspend: Callback for device suspend 132 * @resume: Callback for device resume 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 */ 161 struct 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 int (*suspend)(struct i2c_client *, pm_message_t mesg); 176 int (*resume)(struct i2c_client *); 177 178 /* Alert callback, for example for the SMBus alert protocol. 179 * The format and meaning of the data value depends on the protocol. 180 * For the SMBus alert protocol, there is a single bit of data passed 181 * as the alert response's low bit ("event flag"). 182 */ 183 void (*alert)(struct i2c_client *, unsigned int data); 184 185 /* a ioctl like command that can be used to perform specific functions 186 * with the device. 187 */ 188 int (*command)(struct i2c_client *client, unsigned int cmd, void *arg); 189 190 struct device_driver driver; 191 const struct i2c_device_id *id_table; 192 193 /* Device detection callback for automatic device creation */ 194 int (*detect)(struct i2c_client *, struct i2c_board_info *); 195 const unsigned short *address_list; 196 struct list_head clients; 197 }; 198 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver) 199 200 /** 201 * struct i2c_client - represent an I2C slave device 202 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address; 203 * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking 204 * @addr: Address used on the I2C bus connected to the parent adapter. 205 * @name: Indicates the type of the device, usually a chip name that's 206 * generic enough to hide second-sourcing and compatible revisions. 207 * @adapter: manages the bus segment hosting this I2C device 208 * @driver: device's driver, hence pointer to access routines 209 * @dev: Driver model device node for the slave. 210 * @irq: indicates the IRQ generated by this device (if any) 211 * @detected: member of an i2c_driver.clients list or i2c-core's 212 * userspace_devices list 213 * 214 * An i2c_client identifies a single device (i.e. chip) connected to an 215 * i2c bus. The behaviour exposed to Linux is defined by the driver 216 * managing the device. 217 */ 218 struct i2c_client { 219 unsigned short flags; /* div., see below */ 220 unsigned short addr; /* chip address - NOTE: 7bit */ 221 /* addresses are stored in the */ 222 /* _LOWER_ 7 bits */ 223 char name[I2C_NAME_SIZE]; 224 struct i2c_adapter *adapter; /* the adapter we sit on */ 225 struct i2c_driver *driver; /* and our access routines */ 226 struct device dev; /* the device structure */ 227 int irq; /* irq issued by device */ 228 struct list_head detected; 229 }; 230 #define to_i2c_client(d) container_of(d, struct i2c_client, dev) 231 232 extern struct i2c_client *i2c_verify_client(struct device *dev); 233 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev); 234 235 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj) 236 { 237 struct device * const dev = container_of(kobj, struct device, kobj); 238 return to_i2c_client(dev); 239 } 240 241 static inline void *i2c_get_clientdata(const struct i2c_client *dev) 242 { 243 return dev_get_drvdata(&dev->dev); 244 } 245 246 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) 247 { 248 dev_set_drvdata(&dev->dev, data); 249 } 250 251 /** 252 * struct i2c_board_info - template for device creation 253 * @type: chip type, to initialize i2c_client.name 254 * @flags: to initialize i2c_client.flags 255 * @addr: stored in i2c_client.addr 256 * @platform_data: stored in i2c_client.dev.platform_data 257 * @archdata: copied into i2c_client.dev.archdata 258 * @of_node: pointer to OpenFirmware device node 259 * @acpi_node: ACPI device node 260 * @irq: stored in i2c_client.irq 261 * 262 * I2C doesn't actually support hardware probing, although controllers and 263 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's 264 * a device at a given address. Drivers commonly need more information than 265 * that, such as chip type, configuration, associated IRQ, and so on. 266 * 267 * i2c_board_info is used to build tables of information listing I2C devices 268 * that are present. This information is used to grow the driver model tree. 269 * For mainboards this is done statically using i2c_register_board_info(); 270 * bus numbers identify adapters that aren't yet available. For add-on boards, 271 * i2c_new_device() does this dynamically with the adapter already known. 272 */ 273 struct i2c_board_info { 274 char type[I2C_NAME_SIZE]; 275 unsigned short flags; 276 unsigned short addr; 277 void *platform_data; 278 struct dev_archdata *archdata; 279 struct device_node *of_node; 280 struct acpi_dev_node acpi_node; 281 int irq; 282 }; 283 284 /** 285 * I2C_BOARD_INFO - macro used to list an i2c device and its address 286 * @dev_type: identifies the device type 287 * @dev_addr: the device's address on the bus. 288 * 289 * This macro initializes essential fields of a struct i2c_board_info, 290 * declaring what has been provided on a particular board. Optional 291 * fields (such as associated irq, or device-specific platform_data) 292 * are provided using conventional syntax. 293 */ 294 #define I2C_BOARD_INFO(dev_type, dev_addr) \ 295 .type = dev_type, .addr = (dev_addr) 296 297 298 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 299 /* Add-on boards should register/unregister their devices; e.g. a board 300 * with integrated I2C, a config eeprom, sensors, and a codec that's 301 * used in conjunction with the primary hardware. 302 */ 303 extern struct i2c_client * 304 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); 305 306 /* If you don't know the exact address of an I2C device, use this variant 307 * instead, which can probe for device presence in a list of possible 308 * addresses. The "probe" callback function is optional. If it is provided, 309 * it must return 1 on successful probe, 0 otherwise. If it is not provided, 310 * a default probing method is used. 311 */ 312 extern struct i2c_client * 313 i2c_new_probed_device(struct i2c_adapter *adap, 314 struct i2c_board_info *info, 315 unsigned short const *addr_list, 316 int (*probe)(struct i2c_adapter *, unsigned short addr)); 317 318 /* Common custom probe functions */ 319 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); 320 321 /* For devices that use several addresses, use i2c_new_dummy() to make 322 * client handles for the extra addresses. 323 */ 324 extern struct i2c_client * 325 i2c_new_dummy(struct i2c_adapter *adap, u16 address); 326 327 extern void i2c_unregister_device(struct i2c_client *); 328 #endif /* I2C */ 329 330 /* Mainboard arch_initcall() code should register all its I2C devices. 331 * This is done at arch_initcall time, before declaring any i2c adapters. 332 * Modules for add-on boards must use other calls. 333 */ 334 #ifdef CONFIG_I2C_BOARDINFO 335 extern int 336 i2c_register_board_info(int busnum, struct i2c_board_info const *info, 337 unsigned n); 338 #else 339 static inline int 340 i2c_register_board_info(int busnum, struct i2c_board_info const *info, 341 unsigned n) 342 { 343 return 0; 344 } 345 #endif /* I2C_BOARDINFO */ 346 347 /* 348 * The following structs are for those who like to implement new bus drivers: 349 * i2c_algorithm is the interface to a class of hardware solutions which can 350 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584 351 * to name two of the most common. 352 */ 353 struct i2c_algorithm { 354 /* If an adapter algorithm can't do I2C-level access, set master_xfer 355 to NULL. If an adapter algorithm can do SMBus access, set 356 smbus_xfer. If set to NULL, the SMBus protocol is simulated 357 using common I2C messages */ 358 /* master_xfer should return the number of messages successfully 359 processed, or a negative value on error */ 360 int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, 361 int num); 362 int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr, 363 unsigned short flags, char read_write, 364 u8 command, int size, union i2c_smbus_data *data); 365 366 /* To determine what the adapter supports */ 367 u32 (*functionality) (struct i2c_adapter *); 368 }; 369 370 /** 371 * struct i2c_bus_recovery_info - I2C bus recovery information 372 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or 373 * i2c_generic_scl_recovery() or i2c_generic_gpio_recovery(). 374 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL 375 * recovery. Used internally for generic GPIO recovery. 376 * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used 377 * internally for generic GPIO recovery. 378 * @get_sda: This gets current value of SDA line. Optional for generic SCL 379 * recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO 380 * recovery. 381 * @prepare_recovery: This will be called before starting recovery. Platform may 382 * configure padmux here for SDA/SCL line or something else they want. 383 * @unprepare_recovery: This will be called after completing recovery. Platform 384 * may configure padmux here for SDA/SCL line or something else they want. 385 * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery. 386 * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery. 387 */ 388 struct i2c_bus_recovery_info { 389 int (*recover_bus)(struct i2c_adapter *); 390 391 int (*get_scl)(struct i2c_adapter *); 392 void (*set_scl)(struct i2c_adapter *, int val); 393 int (*get_sda)(struct i2c_adapter *); 394 395 void (*prepare_recovery)(struct i2c_bus_recovery_info *bri); 396 void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri); 397 398 /* gpio recovery */ 399 int scl_gpio; 400 int sda_gpio; 401 }; 402 403 int i2c_recover_bus(struct i2c_adapter *adap); 404 405 /* Generic recovery routines */ 406 int i2c_generic_gpio_recovery(struct i2c_adapter *adap); 407 int i2c_generic_scl_recovery(struct i2c_adapter *adap); 408 409 /* 410 * i2c_adapter is the structure used to identify a physical i2c bus along 411 * with the access algorithms necessary to access it. 412 */ 413 struct i2c_adapter { 414 struct module *owner; 415 unsigned int class; /* classes to allow probing for */ 416 const struct i2c_algorithm *algo; /* the algorithm to access the bus */ 417 void *algo_data; 418 419 /* data fields that are valid for all devices */ 420 struct rt_mutex bus_lock; 421 422 int timeout; /* in jiffies */ 423 int retries; 424 struct device dev; /* the adapter device */ 425 426 int nr; 427 char name[48]; 428 struct completion dev_released; 429 430 struct mutex userspace_clients_lock; 431 struct list_head userspace_clients; 432 433 struct i2c_bus_recovery_info *bus_recovery_info; 434 }; 435 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) 436 437 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev) 438 { 439 return dev_get_drvdata(&dev->dev); 440 } 441 442 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) 443 { 444 dev_set_drvdata(&dev->dev, data); 445 } 446 447 static inline struct i2c_adapter * 448 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter) 449 { 450 #if IS_ENABLED(I2C_MUX) 451 struct device *parent = adapter->dev.parent; 452 453 if (parent != NULL && parent->type == &i2c_adapter_type) 454 return to_i2c_adapter(parent); 455 else 456 #endif 457 return NULL; 458 } 459 460 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)); 461 462 /* Adapter locking functions, exported for shared pin cases */ 463 void i2c_lock_adapter(struct i2c_adapter *); 464 void i2c_unlock_adapter(struct i2c_adapter *); 465 466 /*flags for the client struct: */ 467 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ 468 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ 469 /* Must equal I2C_M_TEN below */ 470 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ 471 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ 472 /* Must match I2C_M_STOP|IGNORE_NAK */ 473 474 /* i2c adapter classes (bitmask) */ 475 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ 476 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */ 477 #define I2C_CLASS_SPD (1<<7) /* Memory modules */ 478 479 /* Internal numbers to terminate lists */ 480 #define I2C_CLIENT_END 0xfffeU 481 482 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */ 483 #define I2C_ADDRS(addr, addrs...) \ 484 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END }) 485 486 487 /* ----- functions exported by i2c.o */ 488 489 /* administration... 490 */ 491 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE) 492 extern int i2c_add_adapter(struct i2c_adapter *); 493 extern void i2c_del_adapter(struct i2c_adapter *); 494 extern int i2c_add_numbered_adapter(struct i2c_adapter *); 495 496 extern int i2c_register_driver(struct module *, struct i2c_driver *); 497 extern void i2c_del_driver(struct i2c_driver *); 498 499 /* use a define to avoid include chaining to get THIS_MODULE */ 500 #define i2c_add_driver(driver) \ 501 i2c_register_driver(THIS_MODULE, driver) 502 503 extern struct i2c_client *i2c_use_client(struct i2c_client *client); 504 extern void i2c_release_client(struct i2c_client *client); 505 506 /* call the i2c_client->command() of all attached clients with 507 * the given arguments */ 508 extern void i2c_clients_command(struct i2c_adapter *adap, 509 unsigned int cmd, void *arg); 510 511 extern struct i2c_adapter *i2c_get_adapter(int nr); 512 extern void i2c_put_adapter(struct i2c_adapter *adap); 513 514 515 /* Return the functionality mask */ 516 static inline u32 i2c_get_functionality(struct i2c_adapter *adap) 517 { 518 return adap->algo->functionality(adap); 519 } 520 521 /* Return 1 if adapter supports everything we need, 0 if not. */ 522 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func) 523 { 524 return (func & i2c_get_functionality(adap)) == func; 525 } 526 527 /* Return the adapter number for a specific adapter */ 528 static inline int i2c_adapter_id(struct i2c_adapter *adap) 529 { 530 return adap->nr; 531 } 532 533 /** 534 * module_i2c_driver() - Helper macro for registering a I2C driver 535 * @__i2c_driver: i2c_driver struct 536 * 537 * Helper macro for I2C drivers which do not do anything special in module 538 * init/exit. This eliminates a lot of boilerplate. Each module may only 539 * use this macro once, and calling it replaces module_init() and module_exit() 540 */ 541 #define module_i2c_driver(__i2c_driver) \ 542 module_driver(__i2c_driver, i2c_add_driver, \ 543 i2c_del_driver) 544 545 #endif /* I2C */ 546 547 #if IS_ENABLED(CONFIG_OF) 548 /* must call put_device() when done with returned i2c_client device */ 549 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node); 550 551 /* must call put_device() when done with returned i2c_adapter device */ 552 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node); 553 554 #else 555 556 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) 557 { 558 return NULL; 559 } 560 561 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) 562 { 563 return NULL; 564 } 565 #endif /* CONFIG_OF */ 566 567 #endif /* _LINUX_I2C_H */ 568