linux/include/linux/i2c.h
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   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
  37extern struct bus_type i2c_bus_type;
  38extern struct device_type i2c_adapter_type;
  39
  40/* --- General options ------------------------------------------------ */
  41
  42struct i2c_msg;
  43struct i2c_algorithm;
  44struct i2c_adapter;
  45struct i2c_client;
  46struct i2c_driver;
  47union i2c_smbus_data;
  48struct i2c_board_info;
  49
  50struct 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 */
  60extern int i2c_master_send(const struct i2c_client *client, const char *buf,
  61                           int count);
  62extern int i2c_master_recv(const struct i2c_client *client, char *buf,
  63                           int count);
  64
  65/* Transfer num messages.
  66 */
  67extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  68                        int num);
  69/* Unlocked flavor */
  70extern 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. */
  78extern 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
  85extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
  86extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
  87extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
  88                                    u8 command);
  89extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
  90                                     u8 command, u8 value);
  91extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
  92                                    u8 command);
  93extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
  94                                     u8 command, u16 value);
  95
  96static inline s32
  97i2c_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
 104static inline s32
 105i2c_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 */
 112extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
 113                                     u8 command, u8 *values);
 114extern 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 */
 117extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
 118                                         u8 command, u8 length, u8 *values);
 119extern 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 */
 162struct 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 */
 221struct 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
 235extern struct i2c_client *i2c_verify_client(struct device *dev);
 236extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
 237
 238static 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
 244static inline void *i2c_get_clientdata(const struct i2c_client *dev)
 245{
 246        return dev_get_drvdata(&dev->dev);
 247}
 248
 249static 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 * @acpi_node: ACPI device node
 263 * @irq: stored in i2c_client.irq
 264 *
 265 * I2C doesn't actually support hardware probing, although controllers and
 266 * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
 267 * a device at a given address.  Drivers commonly need more information than
 268 * that, such as chip type, configuration, associated IRQ, and so on.
 269 *
 270 * i2c_board_info is used to build tables of information listing I2C devices
 271 * that are present.  This information is used to grow the driver model tree.
 272 * For mainboards this is done statically using i2c_register_board_info();
 273 * bus numbers identify adapters that aren't yet available.  For add-on boards,
 274 * i2c_new_device() does this dynamically with the adapter already known.
 275 */
 276struct i2c_board_info {
 277        char            type[I2C_NAME_SIZE];
 278        unsigned short  flags;
 279        unsigned short  addr;
 280        void            *platform_data;
 281        struct dev_archdata     *archdata;
 282        struct device_node *of_node;
 283        struct acpi_dev_node acpi_node;
 284        int             irq;
 285};
 286
 287/**
 288 * I2C_BOARD_INFO - macro used to list an i2c device and its address
 289 * @dev_type: identifies the device type
 290 * @dev_addr: the device's address on the bus.
 291 *
 292 * This macro initializes essential fields of a struct i2c_board_info,
 293 * declaring what has been provided on a particular board.  Optional
 294 * fields (such as associated irq, or device-specific platform_data)
 295 * are provided using conventional syntax.
 296 */
 297#define I2C_BOARD_INFO(dev_type, dev_addr) \
 298        .type = dev_type, .addr = (dev_addr)
 299
 300
 301#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 302/* Add-on boards should register/unregister their devices; e.g. a board
 303 * with integrated I2C, a config eeprom, sensors, and a codec that's
 304 * used in conjunction with the primary hardware.
 305 */
 306extern struct i2c_client *
 307i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
 308
 309/* If you don't know the exact address of an I2C device, use this variant
 310 * instead, which can probe for device presence in a list of possible
 311 * addresses. The "probe" callback function is optional. If it is provided,
 312 * it must return 1 on successful probe, 0 otherwise. If it is not provided,
 313 * a default probing method is used.
 314 */
 315extern struct i2c_client *
 316i2c_new_probed_device(struct i2c_adapter *adap,
 317                      struct i2c_board_info *info,
 318                      unsigned short const *addr_list,
 319                      int (*probe)(struct i2c_adapter *, unsigned short addr));
 320
 321/* Common custom probe functions */
 322extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
 323
 324/* For devices that use several addresses, use i2c_new_dummy() to make
 325 * client handles for the extra addresses.
 326 */
 327extern struct i2c_client *
 328i2c_new_dummy(struct i2c_adapter *adap, u16 address);
 329
 330extern void i2c_unregister_device(struct i2c_client *);
 331#endif /* I2C */
 332
 333/* Mainboard arch_initcall() code should register all its I2C devices.
 334 * This is done at arch_initcall time, before declaring any i2c adapters.
 335 * Modules for add-on boards must use other calls.
 336 */
 337#ifdef CONFIG_I2C_BOARDINFO
 338extern int
 339i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 340                        unsigned n);
 341#else
 342static inline int
 343i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 344                        unsigned n)
 345{
 346        return 0;
 347}
 348#endif /* I2C_BOARDINFO */
 349
 350/*
 351 * The following structs are for those who like to implement new bus drivers:
 352 * i2c_algorithm is the interface to a class of hardware solutions which can
 353 * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
 354 * to name two of the most common.
 355 */
 356struct i2c_algorithm {
 357        /* If an adapter algorithm can't do I2C-level access, set master_xfer
 358           to NULL. If an adapter algorithm can do SMBus access, set
 359           smbus_xfer. If set to NULL, the SMBus protocol is simulated
 360           using common I2C messages */
 361        /* master_xfer should return the number of messages successfully
 362           processed, or a negative value on error */
 363        int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
 364                           int num);
 365        int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
 366                           unsigned short flags, char read_write,
 367                           u8 command, int size, union i2c_smbus_data *data);
 368
 369        /* To determine what the adapter supports */
 370        u32 (*functionality) (struct i2c_adapter *);
 371};
 372
 373/*
 374 * i2c_adapter is the structure used to identify a physical i2c bus along
 375 * with the access algorithms necessary to access it.
 376 */
 377struct i2c_adapter {
 378        struct module *owner;
 379        unsigned int class;               /* classes to allow probing for */
 380        const struct i2c_algorithm *algo; /* the algorithm to access the bus */
 381        void *algo_data;
 382
 383        /* data fields that are valid for all devices   */
 384        struct rt_mutex bus_lock;
 385
 386        int timeout;                    /* in jiffies */
 387        int retries;
 388        struct device dev;              /* the adapter device */
 389
 390        int nr;
 391        char name[48];
 392        struct completion dev_released;
 393
 394        struct mutex userspace_clients_lock;
 395        struct list_head userspace_clients;
 396};
 397#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 398
 399static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
 400{
 401        return dev_get_drvdata(&dev->dev);
 402}
 403
 404static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
 405{
 406        dev_set_drvdata(&dev->dev, data);
 407}
 408
 409static inline struct i2c_adapter *
 410i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 411{
 412        struct device *parent = adapter->dev.parent;
 413
 414        if (parent != NULL && parent->type == &i2c_adapter_type)
 415                return to_i2c_adapter(parent);
 416        else
 417                return NULL;
 418}
 419
 420int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 421
 422/* Adapter locking functions, exported for shared pin cases */
 423void i2c_lock_adapter(struct i2c_adapter *);
 424void i2c_unlock_adapter(struct i2c_adapter *);
 425
 426/*flags for the client struct: */
 427#define I2C_CLIENT_PEC  0x04            /* Use Packet Error Checking */
 428#define I2C_CLIENT_TEN  0x10            /* we have a ten bit chip address */
 429                                        /* Must equal I2C_M_TEN below */
 430#define I2C_CLIENT_WAKE 0x80            /* for board_info; true iff can wake */
 431#define I2C_CLIENT_SCCB 0x9000          /* Use Omnivision SCCB protocol */
 432                                        /* Must match I2C_M_STOP|IGNORE_NAK */
 433
 434/* i2c adapter classes (bitmask) */
 435#define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
 436#define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
 437#define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
 438
 439/* Internal numbers to terminate lists */
 440#define I2C_CLIENT_END          0xfffeU
 441
 442/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
 443#define I2C_ADDRS(addr, addrs...) \
 444        ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
 445
 446
 447/* ----- functions exported by i2c.o */
 448
 449/* administration...
 450 */
 451#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 452extern int i2c_add_adapter(struct i2c_adapter *);
 453extern int i2c_del_adapter(struct i2c_adapter *);
 454extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 455
 456extern int i2c_register_driver(struct module *, struct i2c_driver *);
 457extern void i2c_del_driver(struct i2c_driver *);
 458
 459/* use a define to avoid include chaining to get THIS_MODULE */
 460#define i2c_add_driver(driver) \
 461        i2c_register_driver(THIS_MODULE, driver)
 462
 463extern struct i2c_client *i2c_use_client(struct i2c_client *client);
 464extern void i2c_release_client(struct i2c_client *client);
 465
 466/* call the i2c_client->command() of all attached clients with
 467 * the given arguments */
 468extern void i2c_clients_command(struct i2c_adapter *adap,
 469                                unsigned int cmd, void *arg);
 470
 471extern struct i2c_adapter *i2c_get_adapter(int nr);
 472extern void i2c_put_adapter(struct i2c_adapter *adap);
 473
 474
 475/* Return the functionality mask */
 476static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
 477{
 478        return adap->algo->functionality(adap);
 479}
 480
 481/* Return 1 if adapter supports everything we need, 0 if not. */
 482static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 483{
 484        return (func & i2c_get_functionality(adap)) == func;
 485}
 486
 487/* Return the adapter number for a specific adapter */
 488static inline int i2c_adapter_id(struct i2c_adapter *adap)
 489{
 490        return adap->nr;
 491}
 492
 493/**
 494 * module_i2c_driver() - Helper macro for registering a I2C driver
 495 * @__i2c_driver: i2c_driver struct
 496 *
 497 * Helper macro for I2C drivers which do not do anything special in module
 498 * init/exit. This eliminates a lot of boilerplate. Each module may only
 499 * use this macro once, and calling it replaces module_init() and module_exit()
 500 */
 501#define module_i2c_driver(__i2c_driver) \
 502        module_driver(__i2c_driver, i2c_add_driver, \
 503                        i2c_del_driver)
 504
 505#endif /* I2C */
 506
 507#if IS_ENABLED(CONFIG_ACPI_I2C)
 508extern void acpi_i2c_register_devices(struct i2c_adapter *adap);
 509#else
 510static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
 511#endif
 512
 513#endif /* _LINUX_I2C_H */
 514
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