include/linux/i2c.h

   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         struct device *parent = adapter->dev.parent;
 451
 452         if (parent != NULL && parent->type == &i2c_adapter_type)
 453                 return to_i2c_adapter(parent);
 454         else
 455                 return NULL;
 456 }
 457
 458 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 459
 460 /* Adapter locking functions, exported for shared pin cases */
 461 void i2c_lock_adapter(struct i2c_adapter *);
 462 void i2c_unlock_adapter(struct i2c_adapter *);
 463
 464 /*flags for the client struct: */
 465 #define I2C_CLIENT_PEC  0x04            /* Use Packet Error Checking */
 466 #define I2C_CLIENT_TEN  0x10            /* we have a ten bit chip address */
 467                                         /* Must equal I2C_M_TEN below */
 468 #define I2C_CLIENT_WAKE 0x80            /* for board_info; true iff can wake */
 469 #define I2C_CLIENT_SCCB 0x9000          /* Use Omnivision SCCB protocol */
 470                                         /* Must match I2C_M_STOP|IGNORE_NAK */
 471
 472 /* i2c adapter classes (bitmask) */
 473 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
 474 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
 475 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
 476
 477 /* Internal numbers to terminate lists */
 478 #define I2C_CLIENT_END          0xfffeU
 479
 480 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
 481 #define I2C_ADDRS(addr, addrs...) \
 482         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
 483
 484
 485 /* ----- functions exported by i2c.o */
 486
 487 /* administration...
 488  */
 489 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 490 extern int i2c_add_adapter(struct i2c_adapter *);
 491 extern void i2c_del_adapter(struct i2c_adapter *);
 492 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 493
 494 extern int i2c_register_driver(struct module *, struct i2c_driver *);
 495 extern void i2c_del_driver(struct i2c_driver *);
 496
 497 /* use a define to avoid include chaining to get THIS_MODULE */
 498 #define i2c_add_driver(driver) \
 499         i2c_register_driver(THIS_MODULE, driver)
 500
 501 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
 502 extern void i2c_release_client(struct i2c_client *client);
 503
 504 /* call the i2c_client->command() of all attached clients with
 505  * the given arguments */
 506 extern void i2c_clients_command(struct i2c_adapter *adap,
 507                                 unsigned int cmd, void *arg);
 508
 509 extern struct i2c_adapter *i2c_get_adapter(int nr);
 510 extern void i2c_put_adapter(struct i2c_adapter *adap);
 511
 512
 513 /* Return the functionality mask */
 514 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
 515 {
 516         return adap->algo->functionality(adap);
 517 }
 518
 519 /* Return 1 if adapter supports everything we need, 0 if not. */
 520 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 521 {
 522         return (func & i2c_get_functionality(adap)) == func;
 523 }
 524
 525 /* Return the adapter number for a specific adapter */
 526 static inline int i2c_adapter_id(struct i2c_adapter *adap)
 527 {
 528         return adap->nr;
 529 }
 530
 531 /**
 532  * module_i2c_driver() - Helper macro for registering a I2C driver
 533  * @__i2c_driver: i2c_driver struct
 534  *
 535  * Helper macro for I2C drivers which do not do anything special in module
 536  * init/exit. This eliminates a lot of boilerplate. Each module may only
 537  * use this macro once, and calling it replaces module_init() and module_exit()
 538  */
 539 #define module_i2c_driver(__i2c_driver) \
 540         module_driver(__i2c_driver, i2c_add_driver, \
 541                         i2c_del_driver)
 542
 543 #endif /* I2C */
 544
 545 #if IS_ENABLED(CONFIG_ACPI_I2C)
 546 extern void acpi_i2c_register_devices(struct i2c_adapter *adap);
 547 #else
 548 static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
 549 #endif
 550
 551 #endif /* _LINUX_I2C_H */