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;
  49enum i2c_slave_event;
  50typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *);
  51
  52struct 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 */
  62extern int i2c_master_send(const struct i2c_client *client, const char *buf,
  63                           int count);
  64extern int i2c_master_recv(const struct i2c_client *client, char *buf,
  65                           int count);
  66
  67/* Transfer num messages.
  68 */
  69extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  70                        int num);
  71/* Unlocked flavor */
  72extern 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. */
  80extern 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
  87extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
  88extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
  89extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
  90                                    u8 command);
  91extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
  92                                     u8 command, u8 value);
  93extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
  94                                    u8 command);
  95extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
  96                                     u8 command, u16 value);
  97
  98static inline s32
  99i2c_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
 106static inline s32
 107i2c_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 */
 114extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
 115                                     u8 command, u8 *values);
 116extern 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 */
 119extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
 120                                         u8 command, u8 length, u8 *values);
 121extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
 122                                          u8 command, u8 length,
 123                                          const u8 *values);
 124extern s32
 125i2c_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 */
 164struct 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 */
 220struct 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
 236extern struct i2c_client *i2c_verify_client(struct device *dev);
 237extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
 238
 239static 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
 245static inline void *i2c_get_clientdata(const struct i2c_client *dev)
 246{
 247        return dev_get_drvdata(&dev->dev);
 248}
 249
 250static 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)
 258enum 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
 266extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
 267extern int i2c_slave_unregister(struct i2c_client *client);
 268
 269static 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 */
 298struct 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 */
 328extern struct i2c_client *
 329i2c_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 */
 337extern struct i2c_client *
 338i2c_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 */
 344extern 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 */
 349extern struct i2c_client *
 350i2c_new_dummy(struct i2c_adapter *adap, u16 address);
 351
 352extern 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
 360extern int
 361i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 362                        unsigned n);
 363#else
 364static inline int
 365i2c_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 */
 394struct 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_timings - I2C timing information
 418 * @bus_freq_hz: the bus frequency in Hz
 419 * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
 420 * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
 421 * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
 422 * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
 423 */
 424struct i2c_timings {
 425        u32 bus_freq_hz;
 426        u32 scl_rise_ns;
 427        u32 scl_fall_ns;
 428        u32 scl_int_delay_ns;
 429        u32 sda_fall_ns;
 430};
 431
 432/**
 433 * struct i2c_bus_recovery_info - I2C bus recovery information
 434 * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
 435 *      i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
 436 * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
 437 *      recovery. Used internally for generic GPIO recovery.
 438 * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used
 439 *      internally for generic GPIO recovery.
 440 * @get_sda: This gets current value of SDA line. Optional for generic SCL
 441 *      recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO
 442 *      recovery.
 443 * @prepare_recovery: This will be called before starting recovery. Platform may
 444 *      configure padmux here for SDA/SCL line or something else they want.
 445 * @unprepare_recovery: This will be called after completing recovery. Platform
 446 *      may configure padmux here for SDA/SCL line or something else they want.
 447 * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery.
 448 * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery.
 449 */
 450struct i2c_bus_recovery_info {
 451        int (*recover_bus)(struct i2c_adapter *);
 452
 453        int (*get_scl)(struct i2c_adapter *);
 454        void (*set_scl)(struct i2c_adapter *, int val);
 455        int (*get_sda)(struct i2c_adapter *);
 456
 457        void (*prepare_recovery)(struct i2c_adapter *);
 458        void (*unprepare_recovery)(struct i2c_adapter *);
 459
 460        /* gpio recovery */
 461        int scl_gpio;
 462        int sda_gpio;
 463};
 464
 465int i2c_recover_bus(struct i2c_adapter *adap);
 466
 467/* Generic recovery routines */
 468int i2c_generic_gpio_recovery(struct i2c_adapter *adap);
 469int i2c_generic_scl_recovery(struct i2c_adapter *adap);
 470
 471/**
 472 * struct i2c_adapter_quirks - describe flaws of an i2c adapter
 473 * @flags: see I2C_AQ_* for possible flags and read below
 474 * @max_num_msgs: maximum number of messages per transfer
 475 * @max_write_len: maximum length of a write message
 476 * @max_read_len: maximum length of a read message
 477 * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
 478 * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
 479 *
 480 * Note about combined messages: Some I2C controllers can only send one message
 481 * per transfer, plus something called combined message or write-then-read.
 482 * This is (usually) a small write message followed by a read message and
 483 * barely enough to access register based devices like EEPROMs. There is a flag
 484 * to support this mode. It implies max_num_msg = 2 and does the length checks
 485 * with max_comb_*_len because combined message mode usually has its own
 486 * limitations. Because of HW implementations, some controllers can actually do
 487 * write-then-anything or other variants. To support that, write-then-read has
 488 * been broken out into smaller bits like write-first and read-second which can
 489 * be combined as needed.
 490 */
 491
 492struct i2c_adapter_quirks {
 493        u64 flags;
 494        int max_num_msgs;
 495        u16 max_write_len;
 496        u16 max_read_len;
 497        u16 max_comb_1st_msg_len;
 498        u16 max_comb_2nd_msg_len;
 499};
 500
 501/* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
 502#define I2C_AQ_COMB                     BIT(0)
 503/* first combined message must be write */
 504#define I2C_AQ_COMB_WRITE_FIRST         BIT(1)
 505/* second combined message must be read */
 506#define I2C_AQ_COMB_READ_SECOND         BIT(2)
 507/* both combined messages must have the same target address */
 508#define I2C_AQ_COMB_SAME_ADDR           BIT(3)
 509/* convenience macro for typical write-then read case */
 510#define I2C_AQ_COMB_WRITE_THEN_READ     (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
 511                                         I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
 512/* clock stretching is not supported */
 513#define I2C_AQ_NO_CLK_STRETCH           BIT(4)
 514
 515/*
 516 * i2c_adapter is the structure used to identify a physical i2c bus along
 517 * with the access algorithms necessary to access it.
 518 */
 519struct i2c_adapter {
 520        struct module *owner;
 521        unsigned int class;               /* classes to allow probing for */
 522        const struct i2c_algorithm *algo; /* the algorithm to access the bus */
 523        void *algo_data;
 524
 525        /* data fields that are valid for all devices   */
 526        struct rt_mutex bus_lock;
 527        struct rt_mutex mux_lock;
 528
 529        int timeout;                    /* in jiffies */
 530        int retries;
 531        struct device dev;              /* the adapter device */
 532
 533        int nr;
 534        char name[48];
 535        struct completion dev_released;
 536
 537        struct mutex userspace_clients_lock;
 538        struct list_head userspace_clients;
 539
 540        struct i2c_bus_recovery_info *bus_recovery_info;
 541        const struct i2c_adapter_quirks *quirks;
 542
 543        void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
 544        int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
 545        void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
 546};
 547#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 548
 549static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
 550{
 551        return dev_get_drvdata(&dev->dev);
 552}
 553
 554static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
 555{
 556        dev_set_drvdata(&dev->dev, data);
 557}
 558
 559static inline struct i2c_adapter *
 560i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 561{
 562#if IS_ENABLED(CONFIG_I2C_MUX)
 563        struct device *parent = adapter->dev.parent;
 564
 565        if (parent != NULL && parent->type == &i2c_adapter_type)
 566                return to_i2c_adapter(parent);
 567        else
 568#endif
 569                return NULL;
 570}
 571
 572int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 573
 574/* Adapter locking functions, exported for shared pin cases */
 575#define I2C_LOCK_ROOT_ADAPTER BIT(0)
 576#define I2C_LOCK_SEGMENT      BIT(1)
 577
 578/**
 579 * i2c_lock_bus - Get exclusive access to an I2C bus segment
 580 * @adapter: Target I2C bus segment
 581 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 582 *      locks only this branch in the adapter tree
 583 */
 584static inline void
 585i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
 586{
 587        adapter->lock_bus(adapter, flags);
 588}
 589
 590/**
 591 * i2c_unlock_bus - Release exclusive access to an I2C bus segment
 592 * @adapter: Target I2C bus segment
 593 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 594 *      unlocks only this branch in the adapter tree
 595 */
 596static inline void
 597i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
 598{
 599        adapter->unlock_bus(adapter, flags);
 600}
 601
 602static inline void
 603i2c_lock_adapter(struct i2c_adapter *adapter)
 604{
 605        i2c_lock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
 606}
 607
 608static inline void
 609i2c_unlock_adapter(struct i2c_adapter *adapter)
 610{
 611        i2c_unlock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
 612}
 613
 614/*flags for the client struct: */
 615#define I2C_CLIENT_PEC          0x04    /* Use Packet Error Checking */
 616#define I2C_CLIENT_TEN          0x10    /* we have a ten bit chip address */
 617                                        /* Must equal I2C_M_TEN below */
 618#define I2C_CLIENT_SLAVE        0x20    /* we are the slave */
 619#define I2C_CLIENT_WAKE         0x80    /* for board_info; true iff can wake */
 620#define I2C_CLIENT_SCCB         0x9000  /* Use Omnivision SCCB protocol */
 621                                        /* Must match I2C_M_STOP|IGNORE_NAK */
 622
 623/* i2c adapter classes (bitmask) */
 624#define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
 625#define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
 626#define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
 627#define I2C_CLASS_DEPRECATED    (1<<8)  /* Warn users that adapter will stop using classes */
 628
 629/* Internal numbers to terminate lists */
 630#define I2C_CLIENT_END          0xfffeU
 631
 632/* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
 633#define I2C_ADDRS(addr, addrs...) \
 634        ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
 635
 636
 637/* ----- functions exported by i2c.o */
 638
 639/* administration...
 640 */
 641#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 642extern int i2c_add_adapter(struct i2c_adapter *);
 643extern void i2c_del_adapter(struct i2c_adapter *);
 644extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 645
 646extern int i2c_register_driver(struct module *, struct i2c_driver *);
 647extern void i2c_del_driver(struct i2c_driver *);
 648
 649/* use a define to avoid include chaining to get THIS_MODULE */
 650#define i2c_add_driver(driver) \
 651        i2c_register_driver(THIS_MODULE, driver)
 652
 653extern struct i2c_client *i2c_use_client(struct i2c_client *client);
 654extern void i2c_release_client(struct i2c_client *client);
 655
 656/* call the i2c_client->command() of all attached clients with
 657 * the given arguments */
 658extern void i2c_clients_command(struct i2c_adapter *adap,
 659                                unsigned int cmd, void *arg);
 660
 661extern struct i2c_adapter *i2c_get_adapter(int nr);
 662extern void i2c_put_adapter(struct i2c_adapter *adap);
 663
 664void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
 665
 666/* Return the functionality mask */
 667static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
 668{
 669        return adap->algo->functionality(adap);
 670}
 671
 672/* Return 1 if adapter supports everything we need, 0 if not. */
 673static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 674{
 675        return (func & i2c_get_functionality(adap)) == func;
 676}
 677
 678/**
 679 * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
 680 * @adap: i2c adapter
 681 * @quirks: quirk flags
 682 *
 683 * Return: true if the adapter has all the specified quirk flags, false if not
 684 */
 685static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
 686{
 687        if (!adap->quirks)
 688                return false;
 689        return (adap->quirks->flags & quirks) == quirks;
 690}
 691
 692/* Return the adapter number for a specific adapter */
 693static inline int i2c_adapter_id(struct i2c_adapter *adap)
 694{
 695        return adap->nr;
 696}
 697
 698static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
 699{
 700        return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
 701}
 702
 703/**
 704 * module_i2c_driver() - Helper macro for registering a modular I2C driver
 705 * @__i2c_driver: i2c_driver struct
 706 *
 707 * Helper macro for I2C drivers which do not do anything special in module
 708 * init/exit. This eliminates a lot of boilerplate. Each module may only
 709 * use this macro once, and calling it replaces module_init() and module_exit()
 710 */
 711#define module_i2c_driver(__i2c_driver) \
 712        module_driver(__i2c_driver, i2c_add_driver, \
 713                        i2c_del_driver)
 714
 715/**
 716 * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
 717 * @__i2c_driver: i2c_driver struct
 718 *
 719 * Helper macro for I2C drivers which do not do anything special in their
 720 * init. This eliminates a lot of boilerplate. Each driver may only
 721 * use this macro once, and calling it replaces device_initcall().
 722 */
 723#define builtin_i2c_driver(__i2c_driver) \
 724        builtin_driver(__i2c_driver, i2c_add_driver)
 725
 726#endif /* I2C */
 727
 728#if IS_ENABLED(CONFIG_OF)
 729/* must call put_device() when done with returned i2c_client device */
 730extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
 731
 732/* must call put_device() when done with returned i2c_adapter device */
 733extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
 734
 735/* must call i2c_put_adapter() when done with returned i2c_adapter device */
 736struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
 737
 738#else
 739
 740static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 741{
 742        return NULL;
 743}
 744
 745static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 746{
 747        return NULL;
 748}
 749
 750static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 751{
 752        return NULL;
 753}
 754#endif /* CONFIG_OF */
 755
 756#endif /* _LINUX_I2C_H */
 757