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/rtmutex.h> 34 #include <linux/irqdomain.h> /* for Host Notify IRQ */ 35 #include <linux/of.h> /* for struct device_node */ 36 #include <linux/swab.h> /* for swab16 */ 37 #include <uapi/linux/i2c.h> 38 39 extern struct bus_type i2c_bus_type; 40 extern struct device_type i2c_adapter_type; 41 extern struct device_type i2c_client_type; 42 43 /* --- General options ------------------------------------------------ */ 44 45 struct i2c_msg; 46 struct i2c_algorithm; 47 struct i2c_adapter; 48 struct i2c_client; 49 struct i2c_driver; 50 union i2c_smbus_data; 51 struct i2c_board_info; 52 enum i2c_slave_event; 53 typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *); 54 55 struct module; 56 struct property_entry; 57 58 #if IS_ENABLED(CONFIG_I2C) 59 /* 60 * The master routines are the ones normally used to transmit data to devices 61 * on a bus (or read from them). Apart from two basic transfer functions to 62 * transmit one message at a time, a more complex version can be used to 63 * transmit an arbitrary number of messages without interruption. 64 * @count must be be less than 64k since msg.len is u16. 65 */ 66 extern int i2c_transfer_buffer_flags(const struct i2c_client *client, 67 char *buf, int count, u16 flags); 68 69 /** 70 * i2c_master_recv - issue a single I2C message in master receive mode 71 * @client: Handle to slave device 72 * @buf: Where to store data read from slave 73 * @count: How many bytes to read, must be less than 64k since msg.len is u16 74 * 75 * Returns negative errno, or else the number of bytes read. 76 */ 77 static inline int i2c_master_recv(const struct i2c_client *client, 78 char *buf, int count) 79 { 80 return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD); 81 }; 82 83 /** 84 * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode 85 * using a DMA safe buffer 86 * @client: Handle to slave device 87 * @buf: Where to store data read from slave, must be safe to use with DMA 88 * @count: How many bytes to read, must be less than 64k since msg.len is u16 89 * 90 * Returns negative errno, or else the number of bytes read. 91 */ 92 static inline int i2c_master_recv_dmasafe(const struct i2c_client *client, 93 char *buf, int count) 94 { 95 return i2c_transfer_buffer_flags(client, buf, count, 96 I2C_M_RD | I2C_M_DMA_SAFE); 97 }; 98 99 /** 100 * i2c_master_send - issue a single I2C message in master transmit mode 101 * @client: Handle to slave device 102 * @buf: Data that will be written to the slave 103 * @count: How many bytes to write, must be less than 64k since msg.len is u16 104 * 105 * Returns negative errno, or else the number of bytes written. 106 */ 107 static inline int i2c_master_send(const struct i2c_client *client, 108 const char *buf, int count) 109 { 110 return i2c_transfer_buffer_flags(client, (char *)buf, count, 0); 111 }; 112 113 /** 114 * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode 115 * using a DMA safe buffer 116 * @client: Handle to slave device 117 * @buf: Data that will be written to the slave, must be safe to use with DMA 118 * @count: How many bytes to write, must be less than 64k since msg.len is u16 119 * 120 * Returns negative errno, or else the number of bytes written. 121 */ 122 static inline int i2c_master_send_dmasafe(const struct i2c_client *client, 123 const char *buf, int count) 124 { 125 return i2c_transfer_buffer_flags(client, (char *)buf, count, 126 I2C_M_DMA_SAFE); 127 }; 128 129 /* Transfer num messages. 130 */ 131 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 132 int num); 133 /* Unlocked flavor */ 134 extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 135 int num); 136 137 /* This is the very generalized SMBus access routine. You probably do not 138 want to use this, though; one of the functions below may be much easier, 139 and probably just as fast. 140 Note that we use i2c_adapter here, because you do not need a specific 141 smbus adapter to call this function. */ 142 extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, 143 unsigned short flags, char read_write, u8 command, 144 int size, union i2c_smbus_data *data); 145 146 /* Now follow the 'nice' access routines. These also document the calling 147 conventions of i2c_smbus_xfer. */ 148 149 extern s32 i2c_smbus_read_byte(const struct i2c_client *client); 150 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value); 151 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client, 152 u8 command); 153 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client, 154 u8 command, u8 value); 155 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client, 156 u8 command); 157 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client, 158 u8 command, u16 value); 159 160 static inline s32 161 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command) 162 { 163 s32 value = i2c_smbus_read_word_data(client, command); 164 165 return (value < 0) ? value : swab16(value); 166 } 167 168 static inline s32 169 i2c_smbus_write_word_swapped(const struct i2c_client *client, 170 u8 command, u16 value) 171 { 172 return i2c_smbus_write_word_data(client, command, swab16(value)); 173 } 174 175 /* Returns the number of read bytes */ 176 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client, 177 u8 command, u8 *values); 178 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client, 179 u8 command, u8 length, const u8 *values); 180 /* Returns the number of read bytes */ 181 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, 182 u8 command, u8 length, u8 *values); 183 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, 184 u8 command, u8 length, 185 const u8 *values); 186 extern s32 187 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client, 188 u8 command, u8 length, u8 *values); 189 #endif /* I2C */ 190 191 enum i2c_alert_protocol { 192 I2C_PROTOCOL_SMBUS_ALERT, 193 I2C_PROTOCOL_SMBUS_HOST_NOTIFY, 194 }; 195 196 /** 197 * struct i2c_driver - represent an I2C device driver 198 * @class: What kind of i2c device we instantiate (for detect) 199 * @attach_adapter: Callback for bus addition (deprecated) 200 * @probe: Callback for device binding - soon to be deprecated 201 * @probe_new: New callback for device binding 202 * @remove: Callback for device unbinding 203 * @shutdown: Callback for device shutdown 204 * @alert: Alert callback, for example for the SMBus alert protocol 205 * @command: Callback for bus-wide signaling (optional) 206 * @driver: Device driver model driver 207 * @id_table: List of I2C devices supported by this driver 208 * @detect: Callback for device detection 209 * @address_list: The I2C addresses to probe (for detect) 210 * @clients: List of detected clients we created (for i2c-core use only) 211 * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping 212 * 213 * The driver.owner field should be set to the module owner of this driver. 214 * The driver.name field should be set to the name of this driver. 215 * 216 * For automatic device detection, both @detect and @address_list must 217 * be defined. @class should also be set, otherwise only devices forced 218 * with module parameters will be created. The detect function must 219 * fill at least the name field of the i2c_board_info structure it is 220 * handed upon successful detection, and possibly also the flags field. 221 * 222 * If @detect is missing, the driver will still work fine for enumerated 223 * devices. Detected devices simply won't be supported. This is expected 224 * for the many I2C/SMBus devices which can't be detected reliably, and 225 * the ones which can always be enumerated in practice. 226 * 227 * The i2c_client structure which is handed to the @detect callback is 228 * not a real i2c_client. It is initialized just enough so that you can 229 * call i2c_smbus_read_byte_data and friends on it. Don't do anything 230 * else with it. In particular, calling dev_dbg and friends on it is 231 * not allowed. 232 */ 233 struct i2c_driver { 234 unsigned int class; 235 236 /* Notifies the driver that a new bus has appeared. You should avoid 237 * using this, it will be removed in a near future. 238 */ 239 int (*attach_adapter)(struct i2c_adapter *) __deprecated; 240 241 /* Standard driver model interfaces */ 242 int (*probe)(struct i2c_client *, const struct i2c_device_id *); 243 int (*remove)(struct i2c_client *); 244 245 /* New driver model interface to aid the seamless removal of the 246 * current probe()'s, more commonly unused than used second parameter. 247 */ 248 int (*probe_new)(struct i2c_client *); 249 250 /* driver model interfaces that don't relate to enumeration */ 251 void (*shutdown)(struct i2c_client *); 252 253 /* Alert callback, for example for the SMBus alert protocol. 254 * The format and meaning of the data value depends on the protocol. 255 * For the SMBus alert protocol, there is a single bit of data passed 256 * as the alert response's low bit ("event flag"). 257 * For the SMBus Host Notify protocol, the data corresponds to the 258 * 16-bit payload data reported by the slave device acting as master. 259 */ 260 void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol, 261 unsigned int data); 262 263 /* a ioctl like command that can be used to perform specific functions 264 * with the device. 265 */ 266 int (*command)(struct i2c_client *client, unsigned int cmd, void *arg); 267 268 struct device_driver driver; 269 const struct i2c_device_id *id_table; 270 271 /* Device detection callback for automatic device creation */ 272 int (*detect)(struct i2c_client *, struct i2c_board_info *); 273 const unsigned short *address_list; 274 struct list_head clients; 275 276 bool disable_i2c_core_irq_mapping; 277 }; 278 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver) 279 280 /** 281 * struct i2c_client - represent an I2C slave device 282 * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address; 283 * I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking 284 * @addr: Address used on the I2C bus connected to the parent adapter. 285 * @name: Indicates the type of the device, usually a chip name that's 286 * generic enough to hide second-sourcing and compatible revisions. 287 * @adapter: manages the bus segment hosting this I2C device 288 * @dev: Driver model device node for the slave. 289 * @irq: indicates the IRQ generated by this device (if any) 290 * @detected: member of an i2c_driver.clients list or i2c-core's 291 * userspace_devices list 292 * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter 293 * calls it to pass on slave events to the slave driver. 294 * 295 * An i2c_client identifies a single device (i.e. chip) connected to an 296 * i2c bus. The behaviour exposed to Linux is defined by the driver 297 * managing the device. 298 */ 299 struct i2c_client { 300 unsigned short flags; /* div., see below */ 301 unsigned short addr; /* chip address - NOTE: 7bit */ 302 /* addresses are stored in the */ 303 /* _LOWER_ 7 bits */ 304 char name[I2C_NAME_SIZE]; 305 struct i2c_adapter *adapter; /* the adapter we sit on */ 306 struct device dev; /* the device structure */ 307 int irq; /* irq issued by device */ 308 struct list_head detected; 309 #if IS_ENABLED(CONFIG_I2C_SLAVE) 310 i2c_slave_cb_t slave_cb; /* callback for slave mode */ 311 #endif 312 }; 313 #define to_i2c_client(d) container_of(d, struct i2c_client, dev) 314 315 extern struct i2c_client *i2c_verify_client(struct device *dev); 316 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev); 317 extern const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 318 const struct i2c_client *client); 319 320 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj) 321 { 322 struct device * const dev = container_of(kobj, struct device, kobj); 323 return to_i2c_client(dev); 324 } 325 326 static inline void *i2c_get_clientdata(const struct i2c_client *dev) 327 { 328 return dev_get_drvdata(&dev->dev); 329 } 330 331 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data) 332 { 333 dev_set_drvdata(&dev->dev, data); 334 } 335 336 /* I2C slave support */ 337 338 #if IS_ENABLED(CONFIG_I2C_SLAVE) 339 enum i2c_slave_event { 340 I2C_SLAVE_READ_REQUESTED, 341 I2C_SLAVE_WRITE_REQUESTED, 342 I2C_SLAVE_READ_PROCESSED, 343 I2C_SLAVE_WRITE_RECEIVED, 344 I2C_SLAVE_STOP, 345 }; 346 347 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb); 348 extern int i2c_slave_unregister(struct i2c_client *client); 349 extern bool i2c_detect_slave_mode(struct device *dev); 350 351 static inline int i2c_slave_event(struct i2c_client *client, 352 enum i2c_slave_event event, u8 *val) 353 { 354 return client->slave_cb(client, event, val); 355 } 356 #else 357 static inline bool i2c_detect_slave_mode(struct device *dev) { return false; } 358 #endif 359 360 /** 361 * struct i2c_board_info - template for device creation 362 * @type: chip type, to initialize i2c_client.name 363 * @flags: to initialize i2c_client.flags 364 * @addr: stored in i2c_client.addr 365 * @dev_name: Overrides the default <busnr>-<addr> dev_name if set 366 * @platform_data: stored in i2c_client.dev.platform_data 367 * @archdata: copied into i2c_client.dev.archdata 368 * @of_node: pointer to OpenFirmware device node 369 * @fwnode: device node supplied by the platform firmware 370 * @properties: additional device properties for the device 371 * @resources: resources associated with the device 372 * @num_resources: number of resources in the @resources array 373 * @irq: stored in i2c_client.irq 374 * 375 * I2C doesn't actually support hardware probing, although controllers and 376 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's 377 * a device at a given address. Drivers commonly need more information than 378 * that, such as chip type, configuration, associated IRQ, and so on. 379 * 380 * i2c_board_info is used to build tables of information listing I2C devices 381 * that are present. This information is used to grow the driver model tree. 382 * For mainboards this is done statically using i2c_register_board_info(); 383 * bus numbers identify adapters that aren't yet available. For add-on boards, 384 * i2c_new_device() does this dynamically with the adapter already known. 385 */ 386 struct i2c_board_info { 387 char type[I2C_NAME_SIZE]; 388 unsigned short flags; 389 unsigned short addr; 390 const char *dev_name; 391 void *platform_data; 392 struct dev_archdata *archdata; 393 struct device_node *of_node; 394 struct fwnode_handle *fwnode; 395 const struct property_entry *properties; 396 const struct resource *resources; 397 unsigned int num_resources; 398 int irq; 399 }; 400 401 /** 402 * I2C_BOARD_INFO - macro used to list an i2c device and its address 403 * @dev_type: identifies the device type 404 * @dev_addr: the device's address on the bus. 405 * 406 * This macro initializes essential fields of a struct i2c_board_info, 407 * declaring what has been provided on a particular board. Optional 408 * fields (such as associated irq, or device-specific platform_data) 409 * are provided using conventional syntax. 410 */ 411 #define I2C_BOARD_INFO(dev_type, dev_addr) \ 412 .type = dev_type, .addr = (dev_addr) 413 414 415 #if IS_ENABLED(CONFIG_I2C) 416 /* Add-on boards should register/unregister their devices; e.g. a board 417 * with integrated I2C, a config eeprom, sensors, and a codec that's 418 * used in conjunction with the primary hardware. 419 */ 420 extern struct i2c_client * 421 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info); 422 423 /* If you don't know the exact address of an I2C device, use this variant 424 * instead, which can probe for device presence in a list of possible 425 * addresses. The "probe" callback function is optional. If it is provided, 426 * it must return 1 on successful probe, 0 otherwise. If it is not provided, 427 * a default probing method is used. 428 */ 429 extern struct i2c_client * 430 i2c_new_probed_device(struct i2c_adapter *adap, 431 struct i2c_board_info *info, 432 unsigned short const *addr_list, 433 int (*probe)(struct i2c_adapter *, unsigned short addr)); 434 435 /* Common custom probe functions */ 436 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr); 437 438 /* For devices that use several addresses, use i2c_new_dummy() to make 439 * client handles for the extra addresses. 440 */ 441 extern struct i2c_client * 442 i2c_new_dummy(struct i2c_adapter *adap, u16 address); 443 444 extern struct i2c_client * 445 i2c_new_secondary_device(struct i2c_client *client, 446 const char *name, 447 u16 default_addr); 448 449 extern void i2c_unregister_device(struct i2c_client *); 450 #endif /* I2C */ 451 452 /* Mainboard arch_initcall() code should register all its I2C devices. 453 * This is done at arch_initcall time, before declaring any i2c adapters. 454 * Modules for add-on boards must use other calls. 455 */ 456 #ifdef CONFIG_I2C_BOARDINFO 457 extern int 458 i2c_register_board_info(int busnum, struct i2c_board_info const *info, 459 unsigned n); 460 #else 461 static inline int 462 i2c_register_board_info(int busnum, struct i2c_board_info const *info, 463 unsigned n) 464 { 465 return 0; 466 } 467 #endif /* I2C_BOARDINFO */ 468 469 /** 470 * struct i2c_algorithm - represent I2C transfer method 471 * @master_xfer: Issue a set of i2c transactions to the given I2C adapter 472 * defined by the msgs array, with num messages available to transfer via 473 * the adapter specified by adap. 474 * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this 475 * is not present, then the bus layer will try and convert the SMBus calls 476 * into I2C transfers instead. 477 * @functionality: Return the flags that this algorithm/adapter pair supports 478 * from the I2C_FUNC_* flags. 479 * @reg_slave: Register given client to I2C slave mode of this adapter 480 * @unreg_slave: Unregister given client from I2C slave mode of this adapter 481 * 482 * The following structs are for those who like to implement new bus drivers: 483 * i2c_algorithm is the interface to a class of hardware solutions which can 484 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584 485 * to name two of the most common. 486 * 487 * The return codes from the @master_xfer field should indicate the type of 488 * error code that occurred during the transfer, as documented in the kernel 489 * Documentation file Documentation/i2c/fault-codes. 490 */ 491 struct i2c_algorithm { 492 /* If an adapter algorithm can't do I2C-level access, set master_xfer 493 to NULL. If an adapter algorithm can do SMBus access, set 494 smbus_xfer. If set to NULL, the SMBus protocol is simulated 495 using common I2C messages */ 496 /* master_xfer should return the number of messages successfully 497 processed, or a negative value on error */ 498 int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, 499 int num); 500 int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr, 501 unsigned short flags, char read_write, 502 u8 command, int size, union i2c_smbus_data *data); 503 504 /* To determine what the adapter supports */ 505 u32 (*functionality) (struct i2c_adapter *); 506 507 #if IS_ENABLED(CONFIG_I2C_SLAVE) 508 int (*reg_slave)(struct i2c_client *client); 509 int (*unreg_slave)(struct i2c_client *client); 510 #endif 511 }; 512 513 /** 514 * struct i2c_lock_operations - represent I2C locking operations 515 * @lock_bus: Get exclusive access to an I2C bus segment 516 * @trylock_bus: Try to get exclusive access to an I2C bus segment 517 * @unlock_bus: Release exclusive access to an I2C bus segment 518 * 519 * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus. 520 */ 521 struct i2c_lock_operations { 522 void (*lock_bus)(struct i2c_adapter *, unsigned int flags); 523 int (*trylock_bus)(struct i2c_adapter *, unsigned int flags); 524 void (*unlock_bus)(struct i2c_adapter *, unsigned int flags); 525 }; 526 527 /** 528 * struct i2c_timings - I2C timing information 529 * @bus_freq_hz: the bus frequency in Hz 530 * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification 531 * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification 532 * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns 533 * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification 534 */ 535 struct i2c_timings { 536 u32 bus_freq_hz; 537 u32 scl_rise_ns; 538 u32 scl_fall_ns; 539 u32 scl_int_delay_ns; 540 u32 sda_fall_ns; 541 }; 542 543 /** 544 * struct i2c_bus_recovery_info - I2C bus recovery information 545 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or 546 * i2c_generic_scl_recovery(). 547 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL 548 * recovery. Populated internally for generic GPIO recovery. 549 * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery. 550 * Populated internally for generic GPIO recovery. 551 * @get_sda: This gets current value of SDA line. Optional for generic SCL 552 * recovery. Populated internally, if sda_gpio is a valid GPIO, for generic 553 * GPIO recovery. 554 * @set_sda: This sets/clears the SDA line. Optional for generic SCL recovery. 555 * Populated internally, if sda_gpio is a valid GPIO, for generic GPIO 556 * recovery. 557 * @prepare_recovery: This will be called before starting recovery. Platform may 558 * configure padmux here for SDA/SCL line or something else they want. 559 * @unprepare_recovery: This will be called after completing recovery. Platform 560 * may configure padmux here for SDA/SCL line or something else they want. 561 * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery. 562 * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery. 563 */ 564 struct i2c_bus_recovery_info { 565 int (*recover_bus)(struct i2c_adapter *adap); 566 567 int (*get_scl)(struct i2c_adapter *adap); 568 void (*set_scl)(struct i2c_adapter *adap, int val); 569 int (*get_sda)(struct i2c_adapter *adap); 570 void (*set_sda)(struct i2c_adapter *adap, int val); 571 572 void (*prepare_recovery)(struct i2c_adapter *adap); 573 void (*unprepare_recovery)(struct i2c_adapter *adap); 574 575 /* gpio recovery */ 576 struct gpio_desc *scl_gpiod; 577 struct gpio_desc *sda_gpiod; 578 }; 579 580 int i2c_recover_bus(struct i2c_adapter *adap); 581 582 /* Generic recovery routines */ 583 int i2c_generic_scl_recovery(struct i2c_adapter *adap); 584 585 /** 586 * struct i2c_adapter_quirks - describe flaws of an i2c adapter 587 * @flags: see I2C_AQ_* for possible flags and read below 588 * @max_num_msgs: maximum number of messages per transfer 589 * @max_write_len: maximum length of a write message 590 * @max_read_len: maximum length of a read message 591 * @max_comb_1st_msg_len: maximum length of the first msg in a combined message 592 * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message 593 * 594 * Note about combined messages: Some I2C controllers can only send one message 595 * per transfer, plus something called combined message or write-then-read. 596 * This is (usually) a small write message followed by a read message and 597 * barely enough to access register based devices like EEPROMs. There is a flag 598 * to support this mode. It implies max_num_msg = 2 and does the length checks 599 * with max_comb_*_len because combined message mode usually has its own 600 * limitations. Because of HW implementations, some controllers can actually do 601 * write-then-anything or other variants. To support that, write-then-read has 602 * been broken out into smaller bits like write-first and read-second which can 603 * be combined as needed. 604 */ 605 606 struct i2c_adapter_quirks { 607 u64 flags; 608 int max_num_msgs; 609 u16 max_write_len; 610 u16 max_read_len; 611 u16 max_comb_1st_msg_len; 612 u16 max_comb_2nd_msg_len; 613 }; 614 615 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */ 616 #define I2C_AQ_COMB BIT(0) 617 /* first combined message must be write */ 618 #define I2C_AQ_COMB_WRITE_FIRST BIT(1) 619 /* second combined message must be read */ 620 #define I2C_AQ_COMB_READ_SECOND BIT(2) 621 /* both combined messages must have the same target address */ 622 #define I2C_AQ_COMB_SAME_ADDR BIT(3) 623 /* convenience macro for typical write-then read case */ 624 #define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \ 625 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR) 626 /* clock stretching is not supported */ 627 #define I2C_AQ_NO_CLK_STRETCH BIT(4) 628 629 /* 630 * i2c_adapter is the structure used to identify a physical i2c bus along 631 * with the access algorithms necessary to access it. 632 */ 633 struct i2c_adapter { 634 struct module *owner; 635 unsigned int class; /* classes to allow probing for */ 636 const struct i2c_algorithm *algo; /* the algorithm to access the bus */ 637 void *algo_data; 638 639 /* data fields that are valid for all devices */ 640 const struct i2c_lock_operations *lock_ops; 641 struct rt_mutex bus_lock; 642 struct rt_mutex mux_lock; 643 644 int timeout; /* in jiffies */ 645 int retries; 646 struct device dev; /* the adapter device */ 647 648 int nr; 649 char name[48]; 650 struct completion dev_released; 651 652 struct mutex userspace_clients_lock; 653 struct list_head userspace_clients; 654 655 struct i2c_bus_recovery_info *bus_recovery_info; 656 const struct i2c_adapter_quirks *quirks; 657 658 struct irq_domain *host_notify_domain; 659 }; 660 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev) 661 662 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev) 663 { 664 return dev_get_drvdata(&dev->dev); 665 } 666 667 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data) 668 { 669 dev_set_drvdata(&dev->dev, data); 670 } 671 672 static inline struct i2c_adapter * 673 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter) 674 { 675 #if IS_ENABLED(CONFIG_I2C_MUX) 676 struct device *parent = adapter->dev.parent; 677 678 if (parent != NULL && parent->type == &i2c_adapter_type) 679 return to_i2c_adapter(parent); 680 else 681 #endif 682 return NULL; 683 } 684 685 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)); 686 687 /* Adapter locking functions, exported for shared pin cases */ 688 #define I2C_LOCK_ROOT_ADAPTER BIT(0) 689 #define I2C_LOCK_SEGMENT BIT(1) 690 691 /** 692 * i2c_lock_bus - Get exclusive access to an I2C bus segment 693 * @adapter: Target I2C bus segment 694 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT 695 * locks only this branch in the adapter tree 696 */ 697 static inline void 698 i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags) 699 { 700 adapter->lock_ops->lock_bus(adapter, flags); 701 } 702 703 /** 704 * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment 705 * @adapter: Target I2C bus segment 706 * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter, 707 * I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree 708 * 709 * Return: true if the I2C bus segment is locked, false otherwise 710 */ 711 static inline int 712 i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags) 713 { 714 return adapter->lock_ops->trylock_bus(adapter, flags); 715 } 716 717 /** 718 * i2c_unlock_bus - Release exclusive access to an I2C bus segment 719 * @adapter: Target I2C bus segment 720 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT 721 * unlocks only this branch in the adapter tree 722 */ 723 static inline void 724 i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags) 725 { 726 adapter->lock_ops->unlock_bus(adapter, flags); 727 } 728 729 static inline void 730 i2c_lock_adapter(struct i2c_adapter *adapter) 731 { 732 i2c_lock_bus(adapter, I2C_LOCK_ROOT_ADAPTER); 733 } 734 735 static inline void 736 i2c_unlock_adapter(struct i2c_adapter *adapter) 737 { 738 i2c_unlock_bus(adapter, I2C_LOCK_ROOT_ADAPTER); 739 } 740 741 /*flags for the client struct: */ 742 #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */ 743 #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ 744 /* Must equal I2C_M_TEN below */ 745 #define I2C_CLIENT_SLAVE 0x20 /* we are the slave */ 746 #define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */ 747 #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ 748 #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ 749 /* Must match I2C_M_STOP|IGNORE_NAK */ 750 751 /* i2c adapter classes (bitmask) */ 752 #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ 753 #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */ 754 #define I2C_CLASS_SPD (1<<7) /* Memory modules */ 755 /* Warn users that the adapter doesn't support classes anymore */ 756 #define I2C_CLASS_DEPRECATED (1<<8) 757 758 /* Internal numbers to terminate lists */ 759 #define I2C_CLIENT_END 0xfffeU 760 761 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */ 762 #define I2C_ADDRS(addr, addrs...) \ 763 ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END }) 764 765 766 /* ----- functions exported by i2c.o */ 767 768 /* administration... 769 */ 770 #if IS_ENABLED(CONFIG_I2C) 771 extern int i2c_add_adapter(struct i2c_adapter *); 772 extern void i2c_del_adapter(struct i2c_adapter *); 773 extern int i2c_add_numbered_adapter(struct i2c_adapter *); 774 775 extern int i2c_register_driver(struct module *, struct i2c_driver *); 776 extern void i2c_del_driver(struct i2c_driver *); 777 778 /* use a define to avoid include chaining to get THIS_MODULE */ 779 #define i2c_add_driver(driver) \ 780 i2c_register_driver(THIS_MODULE, driver) 781 782 extern struct i2c_client *i2c_use_client(struct i2c_client *client); 783 extern void i2c_release_client(struct i2c_client *client); 784 785 /* call the i2c_client->command() of all attached clients with 786 * the given arguments */ 787 extern void i2c_clients_command(struct i2c_adapter *adap, 788 unsigned int cmd, void *arg); 789 790 extern struct i2c_adapter *i2c_get_adapter(int nr); 791 extern void i2c_put_adapter(struct i2c_adapter *adap); 792 extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter); 793 794 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults); 795 796 /* Return the functionality mask */ 797 static inline u32 i2c_get_functionality(struct i2c_adapter *adap) 798 { 799 return adap->algo->functionality(adap); 800 } 801 802 /* Return 1 if adapter supports everything we need, 0 if not. */ 803 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func) 804 { 805 return (func & i2c_get_functionality(adap)) == func; 806 } 807 808 /** 809 * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter 810 * @adap: i2c adapter 811 * @quirks: quirk flags 812 * 813 * Return: true if the adapter has all the specified quirk flags, false if not 814 */ 815 static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks) 816 { 817 if (!adap->quirks) 818 return false; 819 return (adap->quirks->flags & quirks) == quirks; 820 } 821 822 /* Return the adapter number for a specific adapter */ 823 static inline int i2c_adapter_id(struct i2c_adapter *adap) 824 { 825 return adap->nr; 826 } 827 828 static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg) 829 { 830 return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0); 831 } 832 833 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold); 834 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf); 835 836 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr); 837 /** 838 * module_i2c_driver() - Helper macro for registering a modular I2C driver 839 * @__i2c_driver: i2c_driver struct 840 * 841 * Helper macro for I2C drivers which do not do anything special in module 842 * init/exit. This eliminates a lot of boilerplate. Each module may only 843 * use this macro once, and calling it replaces module_init() and module_exit() 844 */ 845 #define module_i2c_driver(__i2c_driver) \ 846 module_driver(__i2c_driver, i2c_add_driver, \ 847 i2c_del_driver) 848 849 /** 850 * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver 851 * @__i2c_driver: i2c_driver struct 852 * 853 * Helper macro for I2C drivers which do not do anything special in their 854 * init. This eliminates a lot of boilerplate. Each driver may only 855 * use this macro once, and calling it replaces device_initcall(). 856 */ 857 #define builtin_i2c_driver(__i2c_driver) \ 858 builtin_driver(__i2c_driver, i2c_add_driver) 859 860 #endif /* I2C */ 861 862 #if IS_ENABLED(CONFIG_OF) 863 /* must call put_device() when done with returned i2c_client device */ 864 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node); 865 866 /* must call put_device() when done with returned i2c_adapter device */ 867 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node); 868 869 /* must call i2c_put_adapter() when done with returned i2c_adapter device */ 870 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node); 871 872 extern const struct of_device_id 873 *i2c_of_match_device(const struct of_device_id *matches, 874 struct i2c_client *client); 875 876 #else 877 878 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node) 879 { 880 return NULL; 881 } 882 883 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node) 884 { 885 return NULL; 886 } 887 888 static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node) 889 { 890 return NULL; 891 } 892 893 static inline const struct of_device_id 894 *i2c_of_match_device(const struct of_device_id *matches, 895 struct i2c_client *client) 896 { 897 return NULL; 898 } 899 900 #endif /* CONFIG_OF */ 901 902 #if IS_ENABLED(CONFIG_ACPI) 903 u32 i2c_acpi_find_bus_speed(struct device *dev); 904 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index, 905 struct i2c_board_info *info); 906 #else 907 static inline u32 i2c_acpi_find_bus_speed(struct device *dev) 908 { 909 return 0; 910 } 911 static inline struct i2c_client *i2c_acpi_new_device(struct device *dev, 912 int index, struct i2c_board_info *info) 913 { 914 return NULL; 915 } 916 #endif /* CONFIG_ACPI */ 917 918 #endif /* _LINUX_I2C_H */ 919