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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 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_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  */
424 struct 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  */
450 struct 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 
465 int i2c_recover_bus(struct i2c_adapter *adap);
466 
467 /* Generic recovery routines */
468 int i2c_generic_gpio_recovery(struct i2c_adapter *adap);
469 int 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 
492 struct 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  */
519 struct 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 
528         int timeout;                    /* in jiffies */
529         int retries;
530         struct device dev;              /* the adapter device */
531 
532         int nr;
533         char name[48];
534         struct completion dev_released;
535 
536         struct mutex userspace_clients_lock;
537         struct list_head userspace_clients;
538 
539         struct i2c_bus_recovery_info *bus_recovery_info;
540         const struct i2c_adapter_quirks *quirks;
541 };
542 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
543 
544 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
545 {
546         return dev_get_drvdata(&dev->dev);
547 }
548 
549 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
550 {
551         dev_set_drvdata(&dev->dev, data);
552 }
553 
554 static inline struct i2c_adapter *
555 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
556 {
557 #if IS_ENABLED(CONFIG_I2C_MUX)
558         struct device *parent = adapter->dev.parent;
559 
560         if (parent != NULL && parent->type == &i2c_adapter_type)
561                 return to_i2c_adapter(parent);
562         else
563 #endif
564                 return NULL;
565 }
566 
567 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
568 
569 /* Adapter locking functions, exported for shared pin cases */
570 void i2c_lock_adapter(struct i2c_adapter *);
571 void i2c_unlock_adapter(struct i2c_adapter *);
572 
573 /*flags for the client struct: */
574 #define I2C_CLIENT_PEC          0x04    /* Use Packet Error Checking */
575 #define I2C_CLIENT_TEN          0x10    /* we have a ten bit chip address */
576                                         /* Must equal I2C_M_TEN below */
577 #define I2C_CLIENT_SLAVE        0x20    /* we are the slave */
578 #define I2C_CLIENT_WAKE         0x80    /* for board_info; true iff can wake */
579 #define I2C_CLIENT_SCCB         0x9000  /* Use Omnivision SCCB protocol */
580                                         /* Must match I2C_M_STOP|IGNORE_NAK */
581 
582 /* i2c adapter classes (bitmask) */
583 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
584 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
585 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
586 #define I2C_CLASS_DEPRECATED    (1<<8)  /* Warn users that adapter will stop using classes */
587 
588 /* Internal numbers to terminate lists */
589 #define I2C_CLIENT_END          0xfffeU
590 
591 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
592 #define I2C_ADDRS(addr, addrs...) \
593         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
594 
595 
596 /* ----- functions exported by i2c.o */
597 
598 /* administration...
599  */
600 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
601 extern int i2c_add_adapter(struct i2c_adapter *);
602 extern void i2c_del_adapter(struct i2c_adapter *);
603 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
604 
605 extern int i2c_register_driver(struct module *, struct i2c_driver *);
606 extern void i2c_del_driver(struct i2c_driver *);
607 
608 /* use a define to avoid include chaining to get THIS_MODULE */
609 #define i2c_add_driver(driver) \
610         i2c_register_driver(THIS_MODULE, driver)
611 
612 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
613 extern void i2c_release_client(struct i2c_client *client);
614 
615 /* call the i2c_client->command() of all attached clients with
616  * the given arguments */
617 extern void i2c_clients_command(struct i2c_adapter *adap,
618                                 unsigned int cmd, void *arg);
619 
620 extern struct i2c_adapter *i2c_get_adapter(int nr);
621 extern void i2c_put_adapter(struct i2c_adapter *adap);
622 
623 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
624 
625 /* Return the functionality mask */
626 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
627 {
628         return adap->algo->functionality(adap);
629 }
630 
631 /* Return 1 if adapter supports everything we need, 0 if not. */
632 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
633 {
634         return (func & i2c_get_functionality(adap)) == func;
635 }
636 
637 /**
638  * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
639  * @adap: i2c adapter
640  * @quirks: quirk flags
641  *
642  * Return: true if the adapter has all the specified quirk flags, false if not
643  */
644 static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
645 {
646         if (!adap->quirks)
647                 return false;
648         return (adap->quirks->flags & quirks) == quirks;
649 }
650 
651 /* Return the adapter number for a specific adapter */
652 static inline int i2c_adapter_id(struct i2c_adapter *adap)
653 {
654         return adap->nr;
655 }
656 
657 /**
658  * module_i2c_driver() - Helper macro for registering a modular I2C driver
659  * @__i2c_driver: i2c_driver struct
660  *
661  * Helper macro for I2C drivers which do not do anything special in module
662  * init/exit. This eliminates a lot of boilerplate. Each module may only
663  * use this macro once, and calling it replaces module_init() and module_exit()
664  */
665 #define module_i2c_driver(__i2c_driver) \
666         module_driver(__i2c_driver, i2c_add_driver, \
667                         i2c_del_driver)
668 
669 /**
670  * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
671  * @__i2c_driver: i2c_driver struct
672  *
673  * Helper macro for I2C drivers which do not do anything special in their
674  * init. This eliminates a lot of boilerplate. Each driver may only
675  * use this macro once, and calling it replaces device_initcall().
676  */
677 #define builtin_i2c_driver(__i2c_driver) \
678         builtin_driver(__i2c_driver, i2c_add_driver)
679 
680 #endif /* I2C */
681 
682 #if IS_ENABLED(CONFIG_OF)
683 /* must call put_device() when done with returned i2c_client device */
684 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
685 
686 /* must call put_device() when done with returned i2c_adapter device */
687 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
688 
689 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
690 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
691 
692 #else
693 
694 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
695 {
696         return NULL;
697 }
698 
699 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
700 {
701         return NULL;
702 }
703 
704 static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
705 {
706         return NULL;
707 }
708 #endif /* CONFIG_OF */
709 
710 #endif /* _LINUX_I2C_H */
711 

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