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  * @detach_adapter: Callback for bus removal (deprecated)
 129  * @probe: Callback for device binding
 130  * @remove: Callback for device unbinding
 131  * @shutdown: Callback for device shutdown
 132  * @suspend: Callback for device suspend
 133  * @resume: Callback for device resume
 134  * @alert: Alert callback, for example for the SMBus alert protocol
 135  * @command: Callback for bus-wide signaling (optional)
 136  * @driver: Device driver model driver
 137  * @id_table: List of I2C devices supported by this driver
 138  * @detect: Callback for device detection
 139  * @address_list: The I2C addresses to probe (for detect)
 140  * @clients: List of detected clients we created (for i2c-core use only)
 141  *
 142  * The driver.owner field should be set to the module owner of this driver.
 143  * The driver.name field should be set to the name of this driver.
 144  *
 145  * For automatic device detection, both @detect and @address_list must
 146  * be defined. @class should also be set, otherwise only devices forced
 147  * with module parameters will be created. The detect function must
 148  * fill at least the name field of the i2c_board_info structure it is
 149  * handed upon successful detection, and possibly also the flags field.
 150  *
 151  * If @detect is missing, the driver will still work fine for enumerated
 152  * devices. Detected devices simply won't be supported. This is expected
 153  * for the many I2C/SMBus devices which can't be detected reliably, and
 154  * the ones which can always be enumerated in practice.
 155  *
 156  * The i2c_client structure which is handed to the @detect callback is
 157  * not a real i2c_client. It is initialized just enough so that you can
 158  * call i2c_smbus_read_byte_data and friends on it. Don't do anything
 159  * else with it. In particular, calling dev_dbg and friends on it is
 160  * not allowed.
 161  */
 162 struct i2c_driver {
 163         unsigned int class;
 164
 165         /* Notifies the driver that a new bus has appeared or is about to be
 166          * removed. You should avoid using this, it will be removed in a
 167          * near future.
 168          */
 169         int (*attach_adapter)(struct i2c_adapter *) __deprecated;
 170         int (*detach_adapter)(struct i2c_adapter *) __deprecated;
 171
 172         /* Standard driver model interfaces */
 173         int (*probe)(struct i2c_client *, const struct i2c_device_id *);
 174         int (*remove)(struct i2c_client *);
 175
 176         /* driver model interfaces that don't relate to enumeration  */
 177         void (*shutdown)(struct i2c_client *);
 178         int (*suspend)(struct i2c_client *, pm_message_t mesg);
 179         int (*resume)(struct i2c_client *);
 180
 181         /* Alert callback, for example for the SMBus alert protocol.
 182          * The format and meaning of the data value depends on the protocol.
 183          * For the SMBus alert protocol, there is a single bit of data passed
 184          * as the alert response's low bit ("event flag").
 185          */
 186         void (*alert)(struct i2c_client *, unsigned int data);
 187
 188         /* a ioctl like command that can be used to perform specific functions
 189          * with the device.
 190          */
 191         int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
 192
 193         struct device_driver driver;
 194         const struct i2c_device_id *id_table;
 195
 196         /* Device detection callback for automatic device creation */
 197         int (*detect)(struct i2c_client *, struct i2c_board_info *);
 198         const unsigned short *address_list;
 199         struct list_head clients;
 200 };
 201 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 202
 203 /**
 204  * struct i2c_client - represent an I2C slave device
 205  * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
 206  *      I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
 207  * @addr: Address used on the I2C bus connected to the parent adapter.
 208  * @name: Indicates the type of the device, usually a chip name that's
 209  *      generic enough to hide second-sourcing and compatible revisions.
 210  * @adapter: manages the bus segment hosting this I2C device
 211  * @driver: device's driver, hence pointer to access routines
 212  * @dev: Driver model device node for the slave.
 213  * @irq: indicates the IRQ generated by this device (if any)
 214  * @detected: member of an i2c_driver.clients list or i2c-core's
 215  *      userspace_devices list
 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 i2c_driver *driver;      /* and our access routines      */
 229         struct device dev;              /* the device structure         */
 230         int irq;                        /* irq issued by device         */
 231         struct list_head detected;
 232 };
 233 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
 234
 235 extern struct i2c_client *i2c_verify_client(struct device *dev);
 236 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
 237
 238 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
 239 {
 240         struct device * const dev = container_of(kobj, struct device, kobj);
 241         return to_i2c_client(dev);
 242 }
 243
 244 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
 245 {
 246         return dev_get_drvdata(&dev->dev);
 247 }
 248
 249 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
 250 {
 251         dev_set_drvdata(&dev->dev, data);
 252 }
 253
 254 /**
 255  * struct i2c_board_info - template for device creation
 256  * @type: chip type, to initialize i2c_client.name
 257  * @flags: to initialize i2c_client.flags
 258  * @addr: stored in i2c_client.addr
 259  * @platform_data: stored in i2c_client.dev.platform_data
 260  * @archdata: copied into i2c_client.dev.archdata
 261  * @of_node: pointer to OpenFirmware device node
 262  * @irq: stored in i2c_client.irq
 263  *
 264  * I2C doesn't actually support hardware probing, although controllers and
 265  * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
 266  * a device at a given address.  Drivers commonly need more information than
 267  * that, such as chip type, configuration, associated IRQ, and so on.
 268  *
 269  * i2c_board_info is used to build tables of information listing I2C devices
 270  * that are present.  This information is used to grow the driver model tree.
 271  * For mainboards this is done statically using i2c_register_board_info();
 272  * bus numbers identify adapters that aren't yet available.  For add-on boards,
 273  * i2c_new_device() does this dynamically with the adapter already known.
 274  */
 275 struct i2c_board_info {
 276         char            type[I2C_NAME_SIZE];
 277         unsigned short  flags;
 278         unsigned short  addr;
 279         void            *platform_data;
 280         struct dev_archdata     *archdata;
 281         struct device_node *of_node;
 282         int             irq;
 283 };
 284
 285 /**
 286  * I2C_BOARD_INFO - macro used to list an i2c device and its address
 287  * @dev_type: identifies the device type
 288  * @dev_addr: the device's address on the bus.
 289  *
 290  * This macro initializes essential fields of a struct i2c_board_info,
 291  * declaring what has been provided on a particular board.  Optional
 292  * fields (such as associated irq, or device-specific platform_data)
 293  * are provided using conventional syntax.
 294  */
 295 #define I2C_BOARD_INFO(dev_type, dev_addr) \
 296         .type = dev_type, .addr = (dev_addr)
 297
 298
 299 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 300 /* Add-on boards should register/unregister their devices; e.g. a board
 301  * with integrated I2C, a config eeprom, sensors, and a codec that's
 302  * used in conjunction with the primary hardware.
 303  */
 304 extern struct i2c_client *
 305 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
 306
 307 /* If you don't know the exact address of an I2C device, use this variant
 308  * instead, which can probe for device presence in a list of possible
 309  * addresses. The "probe" callback function is optional. If it is provided,
 310  * it must return 1 on successful probe, 0 otherwise. If it is not provided,
 311  * a default probing method is used.
 312  */
 313 extern struct i2c_client *
 314 i2c_new_probed_device(struct i2c_adapter *adap,
 315                       struct i2c_board_info *info,
 316                       unsigned short const *addr_list,
 317                       int (*probe)(struct i2c_adapter *, unsigned short addr));
 318
 319 /* Common custom probe functions */
 320 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
 321
 322 /* For devices that use several addresses, use i2c_new_dummy() to make
 323  * client handles for the extra addresses.
 324  */
 325 extern struct i2c_client *
 326 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
 327
 328 extern void i2c_unregister_device(struct i2c_client *);
 329 #endif /* I2C */
 330
 331 /* Mainboard arch_initcall() code should register all its I2C devices.
 332  * This is done at arch_initcall time, before declaring any i2c adapters.
 333  * Modules for add-on boards must use other calls.
 334  */
 335 #ifdef CONFIG_I2C_BOARDINFO
 336 extern int
 337 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 338                         unsigned n);
 339 #else
 340 static inline int
 341 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 342                         unsigned n)
 343 {
 344         return 0;
 345 }
 346 #endif /* I2C_BOARDINFO */
 347
 348 /*
 349  * The following structs are for those who like to implement new bus drivers:
 350  * i2c_algorithm is the interface to a class of hardware solutions which can
 351  * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
 352  * to name two of the most common.
 353  */
 354 struct i2c_algorithm {
 355         /* If an adapter algorithm can't do I2C-level access, set master_xfer
 356            to NULL. If an adapter algorithm can do SMBus access, set
 357            smbus_xfer. If set to NULL, the SMBus protocol is simulated
 358            using common I2C messages */
 359         /* master_xfer should return the number of messages successfully
 360            processed, or a negative value on error */
 361         int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
 362                            int num);
 363         int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
 364                            unsigned short flags, char read_write,
 365                            u8 command, int size, union i2c_smbus_data *data);
 366
 367         /* To determine what the adapter supports */
 368         u32 (*functionality) (struct i2c_adapter *);
 369 };
 370
 371 /*
 372  * i2c_adapter is the structure used to identify a physical i2c bus along
 373  * with the access algorithms necessary to access it.
 374  */
 375 struct i2c_adapter {
 376         struct module *owner;
 377         unsigned int class;               /* classes to allow probing for */
 378         const struct i2c_algorithm *algo; /* the algorithm to access the bus */
 379         void *algo_data;
 380
 381         /* data fields that are valid for all devices   */
 382         struct rt_mutex bus_lock;
 383
 384         int timeout;                    /* in jiffies */
 385         int retries;
 386         struct device dev;              /* the adapter device */
 387
 388         int nr;
 389         char name[48];
 390         struct completion dev_released;
 391
 392         struct mutex userspace_clients_lock;
 393         struct list_head userspace_clients;
 394 };
 395 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 396
 397 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
 398 {
 399         return dev_get_drvdata(&dev->dev);
 400 }
 401
 402 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
 403 {
 404         dev_set_drvdata(&dev->dev, data);
 405 }
 406
 407 static inline struct i2c_adapter *
 408 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 409 {
 410         struct device *parent = adapter->dev.parent;
 411
 412         if (parent != NULL && parent->type == &i2c_adapter_type)
 413                 return to_i2c_adapter(parent);
 414         else
 415                 return NULL;
 416 }
 417
 418 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 419
 420 /* Adapter locking functions, exported for shared pin cases */
 421 void i2c_lock_adapter(struct i2c_adapter *);
 422 void i2c_unlock_adapter(struct i2c_adapter *);
 423
 424 /*flags for the client struct: */
 425 #define I2C_CLIENT_PEC  0x04            /* Use Packet Error Checking */
 426 #define I2C_CLIENT_TEN  0x10            /* we have a ten bit chip address */
 427                                         /* Must equal I2C_M_TEN below */
 428 #define I2C_CLIENT_WAKE 0x80            /* for board_info; true iff can wake */
 429 #define I2C_CLIENT_SCCB 0x9000          /* Use Omnivision SCCB protocol */
 430                                         /* Must match I2C_M_STOP|IGNORE_NAK */
 431
 432 /* i2c adapter classes (bitmask) */
 433 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
 434 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
 435 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
 436
 437 /* Internal numbers to terminate lists */
 438 #define I2C_CLIENT_END          0xfffeU
 439
 440 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
 441 #define I2C_ADDRS(addr, addrs...) \
 442         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
 443
 444
 445 /* ----- functions exported by i2c.o */
 446
 447 /* administration...
 448  */
 449 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 450 extern int i2c_add_adapter(struct i2c_adapter *);
 451 extern int i2c_del_adapter(struct i2c_adapter *);
 452 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 453
 454 extern int i2c_register_driver(struct module *, struct i2c_driver *);
 455 extern void i2c_del_driver(struct i2c_driver *);
 456
 457 /* use a define to avoid include chaining to get THIS_MODULE */
 458 #define i2c_add_driver(driver) \
 459         i2c_register_driver(THIS_MODULE, driver)
 460
 461 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
 462 extern void i2c_release_client(struct i2c_client *client);
 463
 464 /* call the i2c_client->command() of all attached clients with
 465  * the given arguments */
 466 extern void i2c_clients_command(struct i2c_adapter *adap,
 467                                 unsigned int cmd, void *arg);
 468
 469 extern struct i2c_adapter *i2c_get_adapter(int nr);
 470 extern void i2c_put_adapter(struct i2c_adapter *adap);
 471
 472
 473 /* Return the functionality mask */
 474 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
 475 {
 476         return adap->algo->functionality(adap);
 477 }
 478
 479 /* Return 1 if adapter supports everything we need, 0 if not. */
 480 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 481 {
 482         return (func & i2c_get_functionality(adap)) == func;
 483 }
 484
 485 /* Return the adapter number for a specific adapter */
 486 static inline int i2c_adapter_id(struct i2c_adapter *adap)
 487 {
 488         return adap->nr;
 489 }
 490
 491 /**
 492  * module_i2c_driver() - Helper macro for registering a I2C driver
 493  * @__i2c_driver: i2c_driver struct
 494  *
 495  * Helper macro for I2C drivers which do not do anything special in module
 496  * init/exit. This eliminates a lot of boilerplate. Each module may only
 497  * use this macro once, and calling it replaces module_init() and module_exit()
 498  */
 499 #define module_i2c_driver(__i2c_driver) \
 500         module_driver(__i2c_driver, i2c_add_driver, \
 501                         i2c_del_driver)
 502
 503 #endif /* I2C */
 504 #endif /* _LINUX_I2C_H */