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TOMOYO Linux Cross Reference
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 
 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 #endif /* I2C */
125 
126 /**
127  * struct i2c_driver - represent an I2C device driver
128  * @class: What kind of i2c device we instantiate (for detect)
129  * @attach_adapter: Callback for bus addition (deprecated)
130  * @probe: Callback for device binding
131  * @remove: Callback for device unbinding
132  * @shutdown: Callback for device shutdown
133  * @alert: Alert callback, for example for the SMBus alert protocol
134  * @command: Callback for bus-wide signaling (optional)
135  * @driver: Device driver model driver
136  * @id_table: List of I2C devices supported by this driver
137  * @detect: Callback for device detection
138  * @address_list: The I2C addresses to probe (for detect)
139  * @clients: List of detected clients we created (for i2c-core use only)
140  *
141  * The driver.owner field should be set to the module owner of this driver.
142  * The driver.name field should be set to the name of this driver.
143  *
144  * For automatic device detection, both @detect and @address_list must
145  * be defined. @class should also be set, otherwise only devices forced
146  * with module parameters will be created. The detect function must
147  * fill at least the name field of the i2c_board_info structure it is
148  * handed upon successful detection, and possibly also the flags field.
149  *
150  * If @detect is missing, the driver will still work fine for enumerated
151  * devices. Detected devices simply won't be supported. This is expected
152  * for the many I2C/SMBus devices which can't be detected reliably, and
153  * the ones which can always be enumerated in practice.
154  *
155  * The i2c_client structure which is handed to the @detect callback is
156  * not a real i2c_client. It is initialized just enough so that you can
157  * call i2c_smbus_read_byte_data and friends on it. Don't do anything
158  * else with it. In particular, calling dev_dbg and friends on it is
159  * not allowed.
160  */
161 struct i2c_driver {
162         unsigned int class;
163 
164         /* Notifies the driver that a new bus has appeared. You should avoid
165          * using this, it will be removed in a near future.
166          */
167         int (*attach_adapter)(struct i2c_adapter *) __deprecated;
168 
169         /* Standard driver model interfaces */
170         int (*probe)(struct i2c_client *, const struct i2c_device_id *);
171         int (*remove)(struct i2c_client *);
172 
173         /* driver model interfaces that don't relate to enumeration  */
174         void (*shutdown)(struct i2c_client *);
175 
176         /* Alert callback, for example for the SMBus alert protocol.
177          * The format and meaning of the data value depends on the protocol.
178          * For the SMBus alert protocol, there is a single bit of data passed
179          * as the alert response's low bit ("event flag").
180          */
181         void (*alert)(struct i2c_client *, unsigned int data);
182 
183         /* a ioctl like command that can be used to perform specific functions
184          * with the device.
185          */
186         int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
187 
188         struct device_driver driver;
189         const struct i2c_device_id *id_table;
190 
191         /* Device detection callback for automatic device creation */
192         int (*detect)(struct i2c_client *, struct i2c_board_info *);
193         const unsigned short *address_list;
194         struct list_head clients;
195 };
196 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
197 
198 /**
199  * struct i2c_client - represent an I2C slave device
200  * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
201  *      I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
202  * @addr: Address used on the I2C bus connected to the parent adapter.
203  * @name: Indicates the type of the device, usually a chip name that's
204  *      generic enough to hide second-sourcing and compatible revisions.
205  * @adapter: manages the bus segment hosting this I2C device
206  * @dev: Driver model device node for the slave.
207  * @irq: indicates the IRQ generated by this device (if any)
208  * @detected: member of an i2c_driver.clients list or i2c-core's
209  *      userspace_devices list
210  * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
211  *      calls it to pass on slave events to the slave driver.
212  *
213  * An i2c_client identifies a single device (i.e. chip) connected to an
214  * i2c bus. The behaviour exposed to Linux is defined by the driver
215  * managing the device.
216  */
217 struct i2c_client {
218         unsigned short flags;           /* div., see below              */
219         unsigned short addr;            /* chip address - NOTE: 7bit    */
220                                         /* addresses are stored in the  */
221                                         /* _LOWER_ 7 bits               */
222         char name[I2C_NAME_SIZE];
223         struct i2c_adapter *adapter;    /* the adapter we sit on        */
224         struct device dev;              /* the device structure         */
225         int irq;                        /* irq issued by device         */
226         struct list_head detected;
227 #if IS_ENABLED(CONFIG_I2C_SLAVE)
228         i2c_slave_cb_t slave_cb;        /* callback for slave mode      */
229 #endif
230 };
231 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
232 
233 extern struct i2c_client *i2c_verify_client(struct device *dev);
234 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
235 
236 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
237 {
238         struct device * const dev = container_of(kobj, struct device, kobj);
239         return to_i2c_client(dev);
240 }
241 
242 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
243 {
244         return dev_get_drvdata(&dev->dev);
245 }
246 
247 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
248 {
249         dev_set_drvdata(&dev->dev, data);
250 }
251 
252 /* I2C slave support */
253 
254 #if IS_ENABLED(CONFIG_I2C_SLAVE)
255 enum i2c_slave_event {
256         I2C_SLAVE_READ_REQUESTED,
257         I2C_SLAVE_WRITE_REQUESTED,
258         I2C_SLAVE_READ_PROCESSED,
259         I2C_SLAVE_WRITE_RECEIVED,
260         I2C_SLAVE_STOP,
261 };
262 
263 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
264 extern int i2c_slave_unregister(struct i2c_client *client);
265 
266 static inline int i2c_slave_event(struct i2c_client *client,
267                                   enum i2c_slave_event event, u8 *val)
268 {
269         return client->slave_cb(client, event, val);
270 }
271 #endif
272 
273 /**
274  * struct i2c_board_info - template for device creation
275  * @type: chip type, to initialize i2c_client.name
276  * @flags: to initialize i2c_client.flags
277  * @addr: stored in i2c_client.addr
278  * @platform_data: stored in i2c_client.dev.platform_data
279  * @archdata: copied into i2c_client.dev.archdata
280  * @of_node: pointer to OpenFirmware device node
281  * @fwnode: device node supplied by the platform firmware
282  * @irq: stored in i2c_client.irq
283  *
284  * I2C doesn't actually support hardware probing, although controllers and
285  * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
286  * a device at a given address.  Drivers commonly need more information than
287  * that, such as chip type, configuration, associated IRQ, and so on.
288  *
289  * i2c_board_info is used to build tables of information listing I2C devices
290  * that are present.  This information is used to grow the driver model tree.
291  * For mainboards this is done statically using i2c_register_board_info();
292  * bus numbers identify adapters that aren't yet available.  For add-on boards,
293  * i2c_new_device() does this dynamically with the adapter already known.
294  */
295 struct i2c_board_info {
296         char            type[I2C_NAME_SIZE];
297         unsigned short  flags;
298         unsigned short  addr;
299         void            *platform_data;
300         struct dev_archdata     *archdata;
301         struct device_node *of_node;
302         struct fwnode_handle *fwnode;
303         int             irq;
304 };
305 
306 /**
307  * I2C_BOARD_INFO - macro used to list an i2c device and its address
308  * @dev_type: identifies the device type
309  * @dev_addr: the device's address on the bus.
310  *
311  * This macro initializes essential fields of a struct i2c_board_info,
312  * declaring what has been provided on a particular board.  Optional
313  * fields (such as associated irq, or device-specific platform_data)
314  * are provided using conventional syntax.
315  */
316 #define I2C_BOARD_INFO(dev_type, dev_addr) \
317         .type = dev_type, .addr = (dev_addr)
318 
319 
320 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
321 /* Add-on boards should register/unregister their devices; e.g. a board
322  * with integrated I2C, a config eeprom, sensors, and a codec that's
323  * used in conjunction with the primary hardware.
324  */
325 extern struct i2c_client *
326 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
327 
328 /* If you don't know the exact address of an I2C device, use this variant
329  * instead, which can probe for device presence in a list of possible
330  * addresses. The "probe" callback function is optional. If it is provided,
331  * it must return 1 on successful probe, 0 otherwise. If it is not provided,
332  * a default probing method is used.
333  */
334 extern struct i2c_client *
335 i2c_new_probed_device(struct i2c_adapter *adap,
336                       struct i2c_board_info *info,
337                       unsigned short const *addr_list,
338                       int (*probe)(struct i2c_adapter *, unsigned short addr));
339 
340 /* Common custom probe functions */
341 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
342 
343 /* For devices that use several addresses, use i2c_new_dummy() to make
344  * client handles for the extra addresses.
345  */
346 extern struct i2c_client *
347 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
348 
349 extern void i2c_unregister_device(struct i2c_client *);
350 #endif /* I2C */
351 
352 /* Mainboard arch_initcall() code should register all its I2C devices.
353  * This is done at arch_initcall time, before declaring any i2c adapters.
354  * Modules for add-on boards must use other calls.
355  */
356 #ifdef CONFIG_I2C_BOARDINFO
357 extern int
358 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
359                         unsigned n);
360 #else
361 static inline int
362 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
363                         unsigned n)
364 {
365         return 0;
366 }
367 #endif /* I2C_BOARDINFO */
368 
369 /**
370  * struct i2c_algorithm - represent I2C transfer method
371  * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
372  *   defined by the msgs array, with num messages available to transfer via
373  *   the adapter specified by adap.
374  * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
375  *   is not present, then the bus layer will try and convert the SMBus calls
376  *   into I2C transfers instead.
377  * @functionality: Return the flags that this algorithm/adapter pair supports
378  *   from the I2C_FUNC_* flags.
379  * @reg_slave: Register given client to I2C slave mode of this adapter
380  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
381  *
382  * The following structs are for those who like to implement new bus drivers:
383  * i2c_algorithm is the interface to a class of hardware solutions which can
384  * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
385  * to name two of the most common.
386  *
387  * The return codes from the @master_xfer field should indicate the type of
388  * error code that occurred during the transfer, as documented in the kernel
389  * Documentation file Documentation/i2c/fault-codes.
390  */
391 struct i2c_algorithm {
392         /* If an adapter algorithm can't do I2C-level access, set master_xfer
393            to NULL. If an adapter algorithm can do SMBus access, set
394            smbus_xfer. If set to NULL, the SMBus protocol is simulated
395            using common I2C messages */
396         /* master_xfer should return the number of messages successfully
397            processed, or a negative value on error */
398         int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
399                            int num);
400         int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
401                            unsigned short flags, char read_write,
402                            u8 command, int size, union i2c_smbus_data *data);
403 
404         /* To determine what the adapter supports */
405         u32 (*functionality) (struct i2c_adapter *);
406 
407 #if IS_ENABLED(CONFIG_I2C_SLAVE)
408         int (*reg_slave)(struct i2c_client *client);
409         int (*unreg_slave)(struct i2c_client *client);
410 #endif
411 };
412 
413 /**
414  * struct i2c_bus_recovery_info - I2C bus recovery information
415  * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
416  *      i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
417  * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
418  *      recovery. Used internally for generic GPIO recovery.
419  * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used
420  *      internally for generic GPIO recovery.
421  * @get_sda: This gets current value of SDA line. Optional for generic SCL
422  *      recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO
423  *      recovery.
424  * @prepare_recovery: This will be called before starting recovery. Platform may
425  *      configure padmux here for SDA/SCL line or something else they want.
426  * @unprepare_recovery: This will be called after completing recovery. Platform
427  *      may configure padmux here for SDA/SCL line or something else they want.
428  * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery.
429  * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery.
430  */
431 struct i2c_bus_recovery_info {
432         int (*recover_bus)(struct i2c_adapter *);
433 
434         int (*get_scl)(struct i2c_adapter *);
435         void (*set_scl)(struct i2c_adapter *, int val);
436         int (*get_sda)(struct i2c_adapter *);
437 
438         void (*prepare_recovery)(struct i2c_adapter *);
439         void (*unprepare_recovery)(struct i2c_adapter *);
440 
441         /* gpio recovery */
442         int scl_gpio;
443         int sda_gpio;
444 };
445 
446 int i2c_recover_bus(struct i2c_adapter *adap);
447 
448 /* Generic recovery routines */
449 int i2c_generic_gpio_recovery(struct i2c_adapter *adap);
450 int i2c_generic_scl_recovery(struct i2c_adapter *adap);
451 
452 /**
453  * struct i2c_adapter_quirks - describe flaws of an i2c adapter
454  * @flags: see I2C_AQ_* for possible flags and read below
455  * @max_num_msgs: maximum number of messages per transfer
456  * @max_write_len: maximum length of a write message
457  * @max_read_len: maximum length of a read message
458  * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
459  * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
460  *
461  * Note about combined messages: Some I2C controllers can only send one message
462  * per transfer, plus something called combined message or write-then-read.
463  * This is (usually) a small write message followed by a read message and
464  * barely enough to access register based devices like EEPROMs. There is a flag
465  * to support this mode. It implies max_num_msg = 2 and does the length checks
466  * with max_comb_*_len because combined message mode usually has its own
467  * limitations. Because of HW implementations, some controllers can actually do
468  * write-then-anything or other variants. To support that, write-then-read has
469  * been broken out into smaller bits like write-first and read-second which can
470  * be combined as needed.
471  */
472 
473 struct i2c_adapter_quirks {
474         u64 flags;
475         int max_num_msgs;
476         u16 max_write_len;
477         u16 max_read_len;
478         u16 max_comb_1st_msg_len;
479         u16 max_comb_2nd_msg_len;
480 };
481 
482 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
483 #define I2C_AQ_COMB                     BIT(0)
484 /* first combined message must be write */
485 #define I2C_AQ_COMB_WRITE_FIRST         BIT(1)
486 /* second combined message must be read */
487 #define I2C_AQ_COMB_READ_SECOND         BIT(2)
488 /* both combined messages must have the same target address */
489 #define I2C_AQ_COMB_SAME_ADDR           BIT(3)
490 /* convenience macro for typical write-then read case */
491 #define I2C_AQ_COMB_WRITE_THEN_READ     (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
492                                          I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
493 
494 /*
495  * i2c_adapter is the structure used to identify a physical i2c bus along
496  * with the access algorithms necessary to access it.
497  */
498 struct i2c_adapter {
499         struct module *owner;
500         unsigned int class;               /* classes to allow probing for */
501         const struct i2c_algorithm *algo; /* the algorithm to access the bus */
502         void *algo_data;
503 
504         /* data fields that are valid for all devices   */
505         struct rt_mutex bus_lock;
506 
507         int timeout;                    /* in jiffies */
508         int retries;
509         struct device dev;              /* the adapter device */
510 
511         int nr;
512         char name[48];
513         struct completion dev_released;
514 
515         struct mutex userspace_clients_lock;
516         struct list_head userspace_clients;
517 
518         struct i2c_bus_recovery_info *bus_recovery_info;
519         const struct i2c_adapter_quirks *quirks;
520 };
521 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
522 
523 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
524 {
525         return dev_get_drvdata(&dev->dev);
526 }
527 
528 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
529 {
530         dev_set_drvdata(&dev->dev, data);
531 }
532 
533 static inline struct i2c_adapter *
534 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
535 {
536 #if IS_ENABLED(CONFIG_I2C_MUX)
537         struct device *parent = adapter->dev.parent;
538 
539         if (parent != NULL && parent->type == &i2c_adapter_type)
540                 return to_i2c_adapter(parent);
541         else
542 #endif
543                 return NULL;
544 }
545 
546 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
547 
548 /* Adapter locking functions, exported for shared pin cases */
549 void i2c_lock_adapter(struct i2c_adapter *);
550 void i2c_unlock_adapter(struct i2c_adapter *);
551 
552 /*flags for the client struct: */
553 #define I2C_CLIENT_PEC  0x04            /* Use Packet Error Checking */
554 #define I2C_CLIENT_TEN  0x10            /* we have a ten bit chip address */
555                                         /* Must equal I2C_M_TEN below */
556 #define I2C_CLIENT_WAKE 0x80            /* for board_info; true iff can wake */
557 #define I2C_CLIENT_SCCB 0x9000          /* Use Omnivision SCCB protocol */
558                                         /* Must match I2C_M_STOP|IGNORE_NAK */
559 
560 /* i2c adapter classes (bitmask) */
561 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
562 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
563 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
564 #define I2C_CLASS_DEPRECATED    (1<<8)  /* Warn users that adapter will stop using classes */
565 
566 /* Internal numbers to terminate lists */
567 #define I2C_CLIENT_END          0xfffeU
568 
569 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
570 #define I2C_ADDRS(addr, addrs...) \
571         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
572 
573 
574 /* ----- functions exported by i2c.o */
575 
576 /* administration...
577  */
578 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
579 extern int i2c_add_adapter(struct i2c_adapter *);
580 extern void i2c_del_adapter(struct i2c_adapter *);
581 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
582 
583 extern int i2c_register_driver(struct module *, struct i2c_driver *);
584 extern void i2c_del_driver(struct i2c_driver *);
585 
586 /* use a define to avoid include chaining to get THIS_MODULE */
587 #define i2c_add_driver(driver) \
588         i2c_register_driver(THIS_MODULE, driver)
589 
590 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
591 extern void i2c_release_client(struct i2c_client *client);
592 
593 /* call the i2c_client->command() of all attached clients with
594  * the given arguments */
595 extern void i2c_clients_command(struct i2c_adapter *adap,
596                                 unsigned int cmd, void *arg);
597 
598 extern struct i2c_adapter *i2c_get_adapter(int nr);
599 extern void i2c_put_adapter(struct i2c_adapter *adap);
600 
601 
602 /* Return the functionality mask */
603 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
604 {
605         return adap->algo->functionality(adap);
606 }
607 
608 /* Return 1 if adapter supports everything we need, 0 if not. */
609 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
610 {
611         return (func & i2c_get_functionality(adap)) == func;
612 }
613 
614 /* Return the adapter number for a specific adapter */
615 static inline int i2c_adapter_id(struct i2c_adapter *adap)
616 {
617         return adap->nr;
618 }
619 
620 /**
621  * module_i2c_driver() - Helper macro for registering a I2C driver
622  * @__i2c_driver: i2c_driver struct
623  *
624  * Helper macro for I2C drivers which do not do anything special in module
625  * init/exit. This eliminates a lot of boilerplate. Each module may only
626  * use this macro once, and calling it replaces module_init() and module_exit()
627  */
628 #define module_i2c_driver(__i2c_driver) \
629         module_driver(__i2c_driver, i2c_add_driver, \
630                         i2c_del_driver)
631 
632 #endif /* I2C */
633 
634 #if IS_ENABLED(CONFIG_OF)
635 /* must call put_device() when done with returned i2c_client device */
636 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
637 
638 /* must call put_device() when done with returned i2c_adapter device */
639 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
640 
641 #else
642 
643 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
644 {
645         return NULL;
646 }
647 
648 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
649 {
650         return NULL;
651 }
652 #endif /* CONFIG_OF */
653 
654 #endif /* _LINUX_I2C_H */
655 

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