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 enum i2c_slave_event;
  50 typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *);
  51
  52 struct module;
  53
  54 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
  55 /*
  56  * The master routines are the ones normally used to transmit data to devices
  57  * on a bus (or read from them). Apart from two basic transfer functions to
  58  * transmit one message at a time, a more complex version can be used to
  59  * transmit an arbitrary number of messages without interruption.
  60  * @count must be be less than 64k since msg.len is u16.
  61  */
  62 extern int i2c_master_send(const struct i2c_client *client, const char *buf,
  63                            int count);
  64 extern int i2c_master_recv(const struct i2c_client *client, char *buf,
  65                            int count);
  66
  67 /* Transfer num messages.
  68  */
  69 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  70                         int num);
  71 /* Unlocked flavor */
  72 extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  73                           int num);
  74
  75 /* This is the very generalized SMBus access routine. You probably do not
  76    want to use this, though; one of the functions below may be much easier,
  77    and probably just as fast.
  78    Note that we use i2c_adapter here, because you do not need a specific
  79    smbus adapter to call this function. */
  80 extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
  81                           unsigned short flags, char read_write, u8 command,
  82                           int size, union i2c_smbus_data *data);
  83
  84 /* Now follow the 'nice' access routines. These also document the calling
  85    conventions of i2c_smbus_xfer. */
  86
  87 extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
  88 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
  89 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
  90                                     u8 command);
  91 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
  92                                      u8 command, u8 value);
  93 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
  94                                     u8 command);
  95 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
  96                                      u8 command, u16 value);
  97
  98 static inline s32
  99 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
 100 {
 101         s32 value = i2c_smbus_read_word_data(client, command);
 102
 103         return (value < 0) ? value : swab16(value);
 104 }
 105
 106 static inline s32
 107 i2c_smbus_write_word_swapped(const struct i2c_client *client,
 108                              u8 command, u16 value)
 109 {
 110         return i2c_smbus_write_word_data(client, command, swab16(value));
 111 }
 112
 113 /* Returns the number of read bytes */
 114 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
 115                                      u8 command, u8 *values);
 116 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
 117                                       u8 command, u8 length, const u8 *values);
 118 /* Returns the number of read bytes */
 119 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
 120                                          u8 command, u8 length, u8 *values);
 121 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
 122                                           u8 command, u8 length,
 123                                           const u8 *values);
 124 extern s32
 125 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
 126                                           u8 command, u8 length, u8 *values);
 127 #endif /* I2C */
 128
 129 /**
 130  * struct i2c_driver - represent an I2C device driver
 131  * @class: What kind of i2c device we instantiate (for detect)
 132  * @attach_adapter: Callback for bus addition (deprecated)
 133  * @probe: Callback for device binding
 134  * @remove: Callback for device unbinding
 135  * @shutdown: Callback for device shutdown
 136  * @alert: Alert callback, for example for the SMBus alert protocol
 137  * @command: Callback for bus-wide signaling (optional)
 138  * @driver: Device driver model driver
 139  * @id_table: List of I2C devices supported by this driver
 140  * @detect: Callback for device detection
 141  * @address_list: The I2C addresses to probe (for detect)
 142  * @clients: List of detected clients we created (for i2c-core use only)
 143  *
 144  * The driver.owner field should be set to the module owner of this driver.
 145  * The driver.name field should be set to the name of this driver.
 146  *
 147  * For automatic device detection, both @detect and @address_list must
 148  * be defined. @class should also be set, otherwise only devices forced
 149  * with module parameters will be created. The detect function must
 150  * fill at least the name field of the i2c_board_info structure it is
 151  * handed upon successful detection, and possibly also the flags field.
 152  *
 153  * If @detect is missing, the driver will still work fine for enumerated
 154  * devices. Detected devices simply won't be supported. This is expected
 155  * for the many I2C/SMBus devices which can't be detected reliably, and
 156  * the ones which can always be enumerated in practice.
 157  *
 158  * The i2c_client structure which is handed to the @detect callback is
 159  * not a real i2c_client. It is initialized just enough so that you can
 160  * call i2c_smbus_read_byte_data and friends on it. Don't do anything
 161  * else with it. In particular, calling dev_dbg and friends on it is
 162  * not allowed.
 163  */
 164 struct i2c_driver {
 165         unsigned int class;
 166
 167         /* Notifies the driver that a new bus has appeared. You should avoid
 168          * using this, it will be removed in a near future.
 169          */
 170         int (*attach_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
 179         /* Alert callback, for example for the SMBus alert protocol.
 180          * The format and meaning of the data value depends on the protocol.
 181          * For the SMBus alert protocol, there is a single bit of data passed
 182          * as the alert response's low bit ("event flag").
 183          */
 184         void (*alert)(struct i2c_client *, unsigned int data);
 185
 186         /* a ioctl like command that can be used to perform specific functions
 187          * with the device.
 188          */
 189         int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
 190
 191         struct device_driver driver;
 192         const struct i2c_device_id *id_table;
 193
 194         /* Device detection callback for automatic device creation */
 195         int (*detect)(struct i2c_client *, struct i2c_board_info *);
 196         const unsigned short *address_list;
 197         struct list_head clients;
 198 };
 199 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 200
 201 /**
 202  * struct i2c_client - represent an I2C slave device
 203  * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
 204  *      I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
 205  * @addr: Address used on the I2C bus connected to the parent adapter.
 206  * @name: Indicates the type of the device, usually a chip name that's
 207  *      generic enough to hide second-sourcing and compatible revisions.
 208  * @adapter: manages the bus segment hosting this I2C device
 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  * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
 214  *      calls it to pass on slave events to the slave driver.
 215  *
 216  * An i2c_client identifies a single device (i.e. chip) connected to an
 217  * i2c bus. The behaviour exposed to Linux is defined by the driver
 218  * managing the device.
 219  */
 220 struct i2c_client {
 221         unsigned short flags;           /* div., see below              */
 222         unsigned short addr;            /* chip address - NOTE: 7bit    */
 223                                         /* addresses are stored in the  */
 224                                         /* _LOWER_ 7 bits               */
 225         char name[I2C_NAME_SIZE];
 226         struct i2c_adapter *adapter;    /* the adapter we sit on        */
 227         struct device dev;              /* the device structure         */
 228         int irq;                        /* irq issued by device         */
 229         struct list_head detected;
 230 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 231         i2c_slave_cb_t slave_cb;        /* callback for slave mode      */
 232 #endif
 233 };
 234 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
 235
 236 extern struct i2c_client *i2c_verify_client(struct device *dev);
 237 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
 238
 239 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
 240 {
 241         struct device * const dev = container_of(kobj, struct device, kobj);
 242         return to_i2c_client(dev);
 243 }
 244
 245 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
 246 {
 247         return dev_get_drvdata(&dev->dev);
 248 }
 249
 250 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
 251 {
 252         dev_set_drvdata(&dev->dev, data);
 253 }
 254
 255 /* I2C slave support */
 256
 257 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 258 enum i2c_slave_event {
 259         I2C_SLAVE_READ_REQUESTED,
 260         I2C_SLAVE_WRITE_REQUESTED,
 261         I2C_SLAVE_READ_PROCESSED,
 262         I2C_SLAVE_WRITE_RECEIVED,
 263         I2C_SLAVE_STOP,
 264 };
 265
 266 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
 267 extern int i2c_slave_unregister(struct i2c_client *client);
 268
 269 static inline int i2c_slave_event(struct i2c_client *client,
 270                                   enum i2c_slave_event event, u8 *val)
 271 {
 272         return client->slave_cb(client, event, val);
 273 }
 274 #endif
 275
 276 /**
 277  * struct i2c_board_info - template for device creation
 278  * @type: chip type, to initialize i2c_client.name
 279  * @flags: to initialize i2c_client.flags
 280  * @addr: stored in i2c_client.addr
 281  * @platform_data: stored in i2c_client.dev.platform_data
 282  * @archdata: copied into i2c_client.dev.archdata
 283  * @of_node: pointer to OpenFirmware device node
 284  * @fwnode: device node supplied by the platform firmware
 285  * @irq: stored in i2c_client.irq
 286  *
 287  * I2C doesn't actually support hardware probing, although controllers and
 288  * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
 289  * a device at a given address.  Drivers commonly need more information than
 290  * that, such as chip type, configuration, associated IRQ, and so on.
 291  *
 292  * i2c_board_info is used to build tables of information listing I2C devices
 293  * that are present.  This information is used to grow the driver model tree.
 294  * For mainboards this is done statically using i2c_register_board_info();
 295  * bus numbers identify adapters that aren't yet available.  For add-on boards,
 296  * i2c_new_device() does this dynamically with the adapter already known.
 297  */
 298 struct i2c_board_info {
 299         char            type[I2C_NAME_SIZE];
 300         unsigned short  flags;
 301         unsigned short  addr;
 302         void            *platform_data;
 303         struct dev_archdata     *archdata;
 304         struct device_node *of_node;
 305         struct fwnode_handle *fwnode;
 306         int             irq;
 307 };
 308
 309 /**
 310  * I2C_BOARD_INFO - macro used to list an i2c device and its address
 311  * @dev_type: identifies the device type
 312  * @dev_addr: the device's address on the bus.
 313  *
 314  * This macro initializes essential fields of a struct i2c_board_info,
 315  * declaring what has been provided on a particular board.  Optional
 316  * fields (such as associated irq, or device-specific platform_data)
 317  * are provided using conventional syntax.
 318  */
 319 #define I2C_BOARD_INFO(dev_type, dev_addr) \
 320         .type = dev_type, .addr = (dev_addr)
 321
 322
 323 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 324 /* Add-on boards should register/unregister their devices; e.g. a board
 325  * with integrated I2C, a config eeprom, sensors, and a codec that's
 326  * used in conjunction with the primary hardware.
 327  */
 328 extern struct i2c_client *
 329 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
 330
 331 /* If you don't know the exact address of an I2C device, use this variant
 332  * instead, which can probe for device presence in a list of possible
 333  * addresses. The "probe" callback function is optional. If it is provided,
 334  * it must return 1 on successful probe, 0 otherwise. If it is not provided,
 335  * a default probing method is used.
 336  */
 337 extern struct i2c_client *
 338 i2c_new_probed_device(struct i2c_adapter *adap,
 339                       struct i2c_board_info *info,
 340                       unsigned short const *addr_list,
 341                       int (*probe)(struct i2c_adapter *, unsigned short addr));
 342
 343 /* Common custom probe functions */
 344 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
 345
 346 /* For devices that use several addresses, use i2c_new_dummy() to make
 347  * client handles for the extra addresses.
 348  */
 349 extern struct i2c_client *
 350 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
 351
 352 extern void i2c_unregister_device(struct i2c_client *);
 353 #endif /* I2C */
 354
 355 /* Mainboard arch_initcall() code should register all its I2C devices.
 356  * This is done at arch_initcall time, before declaring any i2c adapters.
 357  * Modules for add-on boards must use other calls.
 358  */
 359 #ifdef CONFIG_I2C_BOARDINFO
 360 extern int
 361 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 362                         unsigned n);
 363 #else
 364 static inline int
 365 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 366                         unsigned n)
 367 {
 368         return 0;
 369 }
 370 #endif /* I2C_BOARDINFO */
 371
 372 /**
 373  * struct i2c_algorithm - represent I2C transfer method
 374  * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
 375  *   defined by the msgs array, with num messages available to transfer via
 376  *   the adapter specified by adap.
 377  * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
 378  *   is not present, then the bus layer will try and convert the SMBus calls
 379  *   into I2C transfers instead.
 380  * @functionality: Return the flags that this algorithm/adapter pair supports
 381  *   from the I2C_FUNC_* flags.
 382  * @reg_slave: Register given client to I2C slave mode of this adapter
 383  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
 384  *
 385  * The following structs are for those who like to implement new bus drivers:
 386  * i2c_algorithm is the interface to a class of hardware solutions which can
 387  * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
 388  * to name two of the most common.
 389  *
 390  * The return codes from the @master_xfer field should indicate the type of
 391  * error code that occurred during the transfer, as documented in the kernel
 392  * Documentation file Documentation/i2c/fault-codes.
 393  */
 394 struct i2c_algorithm {
 395         /* If an adapter algorithm can't do I2C-level access, set master_xfer
 396            to NULL. If an adapter algorithm can do SMBus access, set
 397            smbus_xfer. If set to NULL, the SMBus protocol is simulated
 398            using common I2C messages */
 399         /* master_xfer should return the number of messages successfully
 400            processed, or a negative value on error */
 401         int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
 402                            int num);
 403         int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
 404                            unsigned short flags, char read_write,
 405                            u8 command, int size, union i2c_smbus_data *data);
 406
 407         /* To determine what the adapter supports */
 408         u32 (*functionality) (struct i2c_adapter *);
 409
 410 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 411         int (*reg_slave)(struct i2c_client *client);
 412         int (*unreg_slave)(struct i2c_client *client);
 413 #endif
 414 };
 415
 416 /**
 417  * struct i2c_bus_recovery_info - I2C bus recovery information
 418  * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
 419  *      i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
 420  * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
 421  *      recovery. Used internally for generic GPIO recovery.
 422  * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used
 423  *      internally for generic GPIO recovery.
 424  * @get_sda: This gets current value of SDA line. Optional for generic SCL
 425  *      recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO
 426  *      recovery.
 427  * @prepare_recovery: This will be called before starting recovery. Platform may
 428  *      configure padmux here for SDA/SCL line or something else they want.
 429  * @unprepare_recovery: This will be called after completing recovery. Platform
 430  *      may configure padmux here for SDA/SCL line or something else they want.
 431  * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery.
 432  * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery.
 433  */
 434 struct i2c_bus_recovery_info {
 435         int (*recover_bus)(struct i2c_adapter *);
 436
 437         int (*get_scl)(struct i2c_adapter *);
 438         void (*set_scl)(struct i2c_adapter *, int val);
 439         int (*get_sda)(struct i2c_adapter *);
 440
 441         void (*prepare_recovery)(struct i2c_adapter *);
 442         void (*unprepare_recovery)(struct i2c_adapter *);
 443
 444         /* gpio recovery */
 445         int scl_gpio;
 446         int sda_gpio;
 447 };
 448
 449 int i2c_recover_bus(struct i2c_adapter *adap);
 450
 451 /* Generic recovery routines */
 452 int i2c_generic_gpio_recovery(struct i2c_adapter *adap);
 453 int i2c_generic_scl_recovery(struct i2c_adapter *adap);
 454
 455 /**
 456  * struct i2c_adapter_quirks - describe flaws of an i2c adapter
 457  * @flags: see I2C_AQ_* for possible flags and read below
 458  * @max_num_msgs: maximum number of messages per transfer
 459  * @max_write_len: maximum length of a write message
 460  * @max_read_len: maximum length of a read message
 461  * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
 462  * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
 463  *
 464  * Note about combined messages: Some I2C controllers can only send one message
 465  * per transfer, plus something called combined message or write-then-read.
 466  * This is (usually) a small write message followed by a read message and
 467  * barely enough to access register based devices like EEPROMs. There is a flag
 468  * to support this mode. It implies max_num_msg = 2 and does the length checks
 469  * with max_comb_*_len because combined message mode usually has its own
 470  * limitations. Because of HW implementations, some controllers can actually do
 471  * write-then-anything or other variants. To support that, write-then-read has
 472  * been broken out into smaller bits like write-first and read-second which can
 473  * be combined as needed.
 474  */
 475
 476 struct i2c_adapter_quirks {
 477         u64 flags;
 478         int max_num_msgs;
 479         u16 max_write_len;
 480         u16 max_read_len;
 481         u16 max_comb_1st_msg_len;
 482         u16 max_comb_2nd_msg_len;
 483 };
 484
 485 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
 486 #define I2C_AQ_COMB                     BIT(0)
 487 /* first combined message must be write */
 488 #define I2C_AQ_COMB_WRITE_FIRST         BIT(1)
 489 /* second combined message must be read */
 490 #define I2C_AQ_COMB_READ_SECOND         BIT(2)
 491 /* both combined messages must have the same target address */
 492 #define I2C_AQ_COMB_SAME_ADDR           BIT(3)
 493 /* convenience macro for typical write-then read case */
 494 #define I2C_AQ_COMB_WRITE_THEN_READ     (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
 495                                          I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
 496
 497 /*
 498  * i2c_adapter is the structure used to identify a physical i2c bus along
 499  * with the access algorithms necessary to access it.
 500  */
 501 struct i2c_adapter {
 502         struct module *owner;
 503         unsigned int class;               /* classes to allow probing for */
 504         const struct i2c_algorithm *algo; /* the algorithm to access the bus */
 505         void *algo_data;
 506
 507         /* data fields that are valid for all devices   */
 508         struct rt_mutex bus_lock;
 509
 510         int timeout;                    /* in jiffies */
 511         int retries;
 512         struct device dev;              /* the adapter device */
 513
 514         int nr;
 515         char name[48];
 516         struct completion dev_released;
 517
 518         struct mutex userspace_clients_lock;
 519         struct list_head userspace_clients;
 520
 521         struct i2c_bus_recovery_info *bus_recovery_info;
 522         const struct i2c_adapter_quirks *quirks;
 523 };
 524 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 525
 526 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
 527 {
 528         return dev_get_drvdata(&dev->dev);
 529 }
 530
 531 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
 532 {
 533         dev_set_drvdata(&dev->dev, data);
 534 }
 535
 536 static inline struct i2c_adapter *
 537 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 538 {
 539 #if IS_ENABLED(CONFIG_I2C_MUX)
 540         struct device *parent = adapter->dev.parent;
 541
 542         if (parent != NULL && parent->type == &i2c_adapter_type)
 543                 return to_i2c_adapter(parent);
 544         else
 545 #endif
 546                 return NULL;
 547 }
 548
 549 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 550
 551 /* Adapter locking functions, exported for shared pin cases */
 552 void i2c_lock_adapter(struct i2c_adapter *);
 553 void i2c_unlock_adapter(struct i2c_adapter *);
 554
 555 /*flags for the client struct: */
 556 #define I2C_CLIENT_PEC          0x04    /* Use Packet Error Checking */
 557 #define I2C_CLIENT_TEN          0x10    /* we have a ten bit chip address */
 558                                         /* Must equal I2C_M_TEN below */
 559 #define I2C_CLIENT_SLAVE        0x20    /* we are the slave */
 560 #define I2C_CLIENT_WAKE         0x80    /* for board_info; true iff can wake */
 561 #define I2C_CLIENT_SCCB         0x9000  /* Use Omnivision SCCB protocol */
 562                                         /* Must match I2C_M_STOP|IGNORE_NAK */
 563
 564 /* i2c adapter classes (bitmask) */
 565 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
 566 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
 567 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
 568 #define I2C_CLASS_DEPRECATED    (1<<8)  /* Warn users that adapter will stop using classes */
 569
 570 /* Internal numbers to terminate lists */
 571 #define I2C_CLIENT_END          0xfffeU
 572
 573 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
 574 #define I2C_ADDRS(addr, addrs...) \
 575         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
 576
 577
 578 /* ----- functions exported by i2c.o */
 579
 580 /* administration...
 581  */
 582 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 583 extern int i2c_add_adapter(struct i2c_adapter *);
 584 extern void i2c_del_adapter(struct i2c_adapter *);
 585 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 586
 587 extern int i2c_register_driver(struct module *, struct i2c_driver *);
 588 extern void i2c_del_driver(struct i2c_driver *);
 589
 590 /* use a define to avoid include chaining to get THIS_MODULE */
 591 #define i2c_add_driver(driver) \
 592         i2c_register_driver(THIS_MODULE, driver)
 593
 594 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
 595 extern void i2c_release_client(struct i2c_client *client);
 596
 597 /* call the i2c_client->command() of all attached clients with
 598  * the given arguments */
 599 extern void i2c_clients_command(struct i2c_adapter *adap,
 600                                 unsigned int cmd, void *arg);
 601
 602 extern struct i2c_adapter *i2c_get_adapter(int nr);
 603 extern void i2c_put_adapter(struct i2c_adapter *adap);
 604
 605
 606 /* Return the functionality mask */
 607 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
 608 {
 609         return adap->algo->functionality(adap);
 610 }
 611
 612 /* Return 1 if adapter supports everything we need, 0 if not. */
 613 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 614 {
 615         return (func & i2c_get_functionality(adap)) == func;
 616 }
 617
 618 /* Return the adapter number for a specific adapter */
 619 static inline int i2c_adapter_id(struct i2c_adapter *adap)
 620 {
 621         return adap->nr;
 622 }
 623
 624 /**
 625  * module_i2c_driver() - Helper macro for registering a I2C driver
 626  * @__i2c_driver: i2c_driver struct
 627  *
 628  * Helper macro for I2C drivers which do not do anything special in module
 629  * init/exit. This eliminates a lot of boilerplate. Each module may only
 630  * use this macro once, and calling it replaces module_init() and module_exit()
 631  */
 632 #define module_i2c_driver(__i2c_driver) \
 633         module_driver(__i2c_driver, i2c_add_driver, \
 634                         i2c_del_driver)
 635
 636 #endif /* I2C */
 637
 638 #if IS_ENABLED(CONFIG_OF)
 639 /* must call put_device() when done with returned i2c_client device */
 640 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
 641
 642 /* must call put_device() when done with returned i2c_adapter device */
 643 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
 644
 645 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 646 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
 647 #else
 648
 649 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 650 {
 651         return NULL;
 652 }
 653
 654 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 655 {
 656         return NULL;
 657 }
 658
 659 static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 660 {
 661         return NULL;
 662 }
 663 #endif /* CONFIG_OF */
 664
 665 #endif /* _LINUX_I2C_H */