xref: /openbmc/linux/include/linux/i2c.h (revision ae3473231e77a3f1909d48cd144cebe5e1d049b3)
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/irqdomain.h>		/* for Host Notify IRQ */
34 #include <linux/of.h>		/* for struct device_node */
35 #include <linux/swab.h>		/* for swab16 */
36 #include <uapi/linux/i2c.h>
37 
38 extern struct bus_type i2c_bus_type;
39 extern struct device_type i2c_adapter_type;
40 
41 /* --- General options ------------------------------------------------	*/
42 
43 struct i2c_msg;
44 struct i2c_algorithm;
45 struct i2c_adapter;
46 struct i2c_client;
47 struct i2c_driver;
48 union i2c_smbus_data;
49 struct i2c_board_info;
50 enum i2c_slave_event;
51 typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *);
52 
53 struct module;
54 
55 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
56 /*
57  * The master routines are the ones normally used to transmit data to devices
58  * on a bus (or read from them). Apart from two basic transfer functions to
59  * transmit one message at a time, a more complex version can be used to
60  * transmit an arbitrary number of messages without interruption.
61  * @count must be be less than 64k since msg.len is u16.
62  */
63 extern int i2c_master_send(const struct i2c_client *client, const char *buf,
64 			   int count);
65 extern int i2c_master_recv(const struct i2c_client *client, char *buf,
66 			   int count);
67 
68 /* Transfer num messages.
69  */
70 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
71 			int num);
72 /* Unlocked flavor */
73 extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
74 			  int num);
75 
76 /* This is the very generalized SMBus access routine. You probably do not
77    want to use this, though; one of the functions below may be much easier,
78    and probably just as fast.
79    Note that we use i2c_adapter here, because you do not need a specific
80    smbus adapter to call this function. */
81 extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
82 			  unsigned short flags, char read_write, u8 command,
83 			  int size, union i2c_smbus_data *data);
84 
85 /* Now follow the 'nice' access routines. These also document the calling
86    conventions of i2c_smbus_xfer. */
87 
88 extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
89 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
90 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
91 				    u8 command);
92 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
93 				     u8 command, u8 value);
94 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
95 				    u8 command);
96 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
97 				     u8 command, u16 value);
98 
99 static inline s32
100 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
101 {
102 	s32 value = i2c_smbus_read_word_data(client, command);
103 
104 	return (value < 0) ? value : swab16(value);
105 }
106 
107 static inline s32
108 i2c_smbus_write_word_swapped(const struct i2c_client *client,
109 			     u8 command, u16 value)
110 {
111 	return i2c_smbus_write_word_data(client, command, swab16(value));
112 }
113 
114 /* Returns the number of read bytes */
115 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
116 				     u8 command, u8 *values);
117 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
118 				      u8 command, u8 length, const u8 *values);
119 /* Returns the number of read bytes */
120 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
121 					 u8 command, u8 length, u8 *values);
122 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
123 					  u8 command, u8 length,
124 					  const u8 *values);
125 extern s32
126 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
127 					  u8 command, u8 length, u8 *values);
128 #endif /* I2C */
129 
130 enum i2c_alert_protocol {
131 	I2C_PROTOCOL_SMBUS_ALERT,
132 	I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
133 };
134 
135 /**
136  * struct i2c_driver - represent an I2C device driver
137  * @class: What kind of i2c device we instantiate (for detect)
138  * @attach_adapter: Callback for bus addition (deprecated)
139  * @probe: Callback for device binding - soon to be deprecated
140  * @probe_new: New callback for device binding
141  * @remove: Callback for device unbinding
142  * @shutdown: Callback for device shutdown
143  * @alert: Alert callback, for example for the SMBus alert protocol
144  * @command: Callback for bus-wide signaling (optional)
145  * @driver: Device driver model driver
146  * @id_table: List of I2C devices supported by this driver
147  * @detect: Callback for device detection
148  * @address_list: The I2C addresses to probe (for detect)
149  * @clients: List of detected clients we created (for i2c-core use only)
150  *
151  * The driver.owner field should be set to the module owner of this driver.
152  * The driver.name field should be set to the name of this driver.
153  *
154  * For automatic device detection, both @detect and @address_list must
155  * be defined. @class should also be set, otherwise only devices forced
156  * with module parameters will be created. The detect function must
157  * fill at least the name field of the i2c_board_info structure it is
158  * handed upon successful detection, and possibly also the flags field.
159  *
160  * If @detect is missing, the driver will still work fine for enumerated
161  * devices. Detected devices simply won't be supported. This is expected
162  * for the many I2C/SMBus devices which can't be detected reliably, and
163  * the ones which can always be enumerated in practice.
164  *
165  * The i2c_client structure which is handed to the @detect callback is
166  * not a real i2c_client. It is initialized just enough so that you can
167  * call i2c_smbus_read_byte_data and friends on it. Don't do anything
168  * else with it. In particular, calling dev_dbg and friends on it is
169  * not allowed.
170  */
171 struct i2c_driver {
172 	unsigned int class;
173 
174 	/* Notifies the driver that a new bus has appeared. You should avoid
175 	 * using this, it will be removed in a near future.
176 	 */
177 	int (*attach_adapter)(struct i2c_adapter *) __deprecated;
178 
179 	/* Standard driver model interfaces */
180 	int (*probe)(struct i2c_client *, const struct i2c_device_id *);
181 	int (*remove)(struct i2c_client *);
182 
183 	/* New driver model interface to aid the seamless removal of the
184 	 * current probe()'s, more commonly unused than used second parameter.
185 	 */
186 	int (*probe_new)(struct i2c_client *);
187 
188 	/* driver model interfaces that don't relate to enumeration  */
189 	void (*shutdown)(struct i2c_client *);
190 
191 	/* Alert callback, for example for the SMBus alert protocol.
192 	 * The format and meaning of the data value depends on the protocol.
193 	 * For the SMBus alert protocol, there is a single bit of data passed
194 	 * as the alert response's low bit ("event flag").
195 	 * For the SMBus Host Notify protocol, the data corresponds to the
196 	 * 16-bit payload data reported by the slave device acting as master.
197 	 */
198 	void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
199 		      unsigned int data);
200 
201 	/* a ioctl like command that can be used to perform specific functions
202 	 * with the device.
203 	 */
204 	int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
205 
206 	struct device_driver driver;
207 	const struct i2c_device_id *id_table;
208 
209 	/* Device detection callback for automatic device creation */
210 	int (*detect)(struct i2c_client *, struct i2c_board_info *);
211 	const unsigned short *address_list;
212 	struct list_head clients;
213 };
214 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
215 
216 /**
217  * struct i2c_client - represent an I2C slave device
218  * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
219  *	I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
220  * @addr: Address used on the I2C bus connected to the parent adapter.
221  * @name: Indicates the type of the device, usually a chip name that's
222  *	generic enough to hide second-sourcing and compatible revisions.
223  * @adapter: manages the bus segment hosting this I2C device
224  * @dev: Driver model device node for the slave.
225  * @irq: indicates the IRQ generated by this device (if any)
226  * @detected: member of an i2c_driver.clients list or i2c-core's
227  *	userspace_devices list
228  * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
229  *	calls it to pass on slave events to the slave driver.
230  *
231  * An i2c_client identifies a single device (i.e. chip) connected to an
232  * i2c bus. The behaviour exposed to Linux is defined by the driver
233  * managing the device.
234  */
235 struct i2c_client {
236 	unsigned short flags;		/* div., see below		*/
237 	unsigned short addr;		/* chip address - NOTE: 7bit	*/
238 					/* addresses are stored in the	*/
239 					/* _LOWER_ 7 bits		*/
240 	char name[I2C_NAME_SIZE];
241 	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
242 	struct device dev;		/* the device structure		*/
243 	int irq;			/* irq issued by device		*/
244 	struct list_head detected;
245 #if IS_ENABLED(CONFIG_I2C_SLAVE)
246 	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
247 #endif
248 };
249 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
250 
251 extern struct i2c_client *i2c_verify_client(struct device *dev);
252 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
253 extern const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
254 					const struct i2c_client *client);
255 
256 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
257 {
258 	struct device * const dev = container_of(kobj, struct device, kobj);
259 	return to_i2c_client(dev);
260 }
261 
262 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
263 {
264 	return dev_get_drvdata(&dev->dev);
265 }
266 
267 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
268 {
269 	dev_set_drvdata(&dev->dev, data);
270 }
271 
272 /* I2C slave support */
273 
274 #if IS_ENABLED(CONFIG_I2C_SLAVE)
275 enum i2c_slave_event {
276 	I2C_SLAVE_READ_REQUESTED,
277 	I2C_SLAVE_WRITE_REQUESTED,
278 	I2C_SLAVE_READ_PROCESSED,
279 	I2C_SLAVE_WRITE_RECEIVED,
280 	I2C_SLAVE_STOP,
281 };
282 
283 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
284 extern int i2c_slave_unregister(struct i2c_client *client);
285 
286 static inline int i2c_slave_event(struct i2c_client *client,
287 				  enum i2c_slave_event event, u8 *val)
288 {
289 	return client->slave_cb(client, event, val);
290 }
291 #endif
292 
293 /**
294  * struct i2c_board_info - template for device creation
295  * @type: chip type, to initialize i2c_client.name
296  * @flags: to initialize i2c_client.flags
297  * @addr: stored in i2c_client.addr
298  * @platform_data: stored in i2c_client.dev.platform_data
299  * @archdata: copied into i2c_client.dev.archdata
300  * @of_node: pointer to OpenFirmware device node
301  * @fwnode: device node supplied by the platform firmware
302  * @irq: stored in i2c_client.irq
303  *
304  * I2C doesn't actually support hardware probing, although controllers and
305  * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
306  * a device at a given address.  Drivers commonly need more information than
307  * that, such as chip type, configuration, associated IRQ, and so on.
308  *
309  * i2c_board_info is used to build tables of information listing I2C devices
310  * that are present.  This information is used to grow the driver model tree.
311  * For mainboards this is done statically using i2c_register_board_info();
312  * bus numbers identify adapters that aren't yet available.  For add-on boards,
313  * i2c_new_device() does this dynamically with the adapter already known.
314  */
315 struct i2c_board_info {
316 	char		type[I2C_NAME_SIZE];
317 	unsigned short	flags;
318 	unsigned short	addr;
319 	void		*platform_data;
320 	struct dev_archdata	*archdata;
321 	struct device_node *of_node;
322 	struct fwnode_handle *fwnode;
323 	int		irq;
324 };
325 
326 /**
327  * I2C_BOARD_INFO - macro used to list an i2c device and its address
328  * @dev_type: identifies the device type
329  * @dev_addr: the device's address on the bus.
330  *
331  * This macro initializes essential fields of a struct i2c_board_info,
332  * declaring what has been provided on a particular board.  Optional
333  * fields (such as associated irq, or device-specific platform_data)
334  * are provided using conventional syntax.
335  */
336 #define I2C_BOARD_INFO(dev_type, dev_addr) \
337 	.type = dev_type, .addr = (dev_addr)
338 
339 
340 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
341 /* Add-on boards should register/unregister their devices; e.g. a board
342  * with integrated I2C, a config eeprom, sensors, and a codec that's
343  * used in conjunction with the primary hardware.
344  */
345 extern struct i2c_client *
346 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
347 
348 /* If you don't know the exact address of an I2C device, use this variant
349  * instead, which can probe for device presence in a list of possible
350  * addresses. The "probe" callback function is optional. If it is provided,
351  * it must return 1 on successful probe, 0 otherwise. If it is not provided,
352  * a default probing method is used.
353  */
354 extern struct i2c_client *
355 i2c_new_probed_device(struct i2c_adapter *adap,
356 		      struct i2c_board_info *info,
357 		      unsigned short const *addr_list,
358 		      int (*probe)(struct i2c_adapter *, unsigned short addr));
359 
360 /* Common custom probe functions */
361 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
362 
363 /* For devices that use several addresses, use i2c_new_dummy() to make
364  * client handles for the extra addresses.
365  */
366 extern struct i2c_client *
367 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
368 
369 extern struct i2c_client *
370 i2c_new_secondary_device(struct i2c_client *client,
371 				const char *name,
372 				u16 default_addr);
373 
374 extern void i2c_unregister_device(struct i2c_client *);
375 #endif /* I2C */
376 
377 /* Mainboard arch_initcall() code should register all its I2C devices.
378  * This is done at arch_initcall time, before declaring any i2c adapters.
379  * Modules for add-on boards must use other calls.
380  */
381 #ifdef CONFIG_I2C_BOARDINFO
382 extern int
383 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
384 			unsigned n);
385 #else
386 static inline int
387 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
388 			unsigned n)
389 {
390 	return 0;
391 }
392 #endif /* I2C_BOARDINFO */
393 
394 /**
395  * struct i2c_algorithm - represent I2C transfer method
396  * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
397  *   defined by the msgs array, with num messages available to transfer via
398  *   the adapter specified by adap.
399  * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
400  *   is not present, then the bus layer will try and convert the SMBus calls
401  *   into I2C transfers instead.
402  * @functionality: Return the flags that this algorithm/adapter pair supports
403  *   from the I2C_FUNC_* flags.
404  * @reg_slave: Register given client to I2C slave mode of this adapter
405  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
406  *
407  * The following structs are for those who like to implement new bus drivers:
408  * i2c_algorithm is the interface to a class of hardware solutions which can
409  * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
410  * to name two of the most common.
411  *
412  * The return codes from the @master_xfer field should indicate the type of
413  * error code that occurred during the transfer, as documented in the kernel
414  * Documentation file Documentation/i2c/fault-codes.
415  */
416 struct i2c_algorithm {
417 	/* If an adapter algorithm can't do I2C-level access, set master_xfer
418 	   to NULL. If an adapter algorithm can do SMBus access, set
419 	   smbus_xfer. If set to NULL, the SMBus protocol is simulated
420 	   using common I2C messages */
421 	/* master_xfer should return the number of messages successfully
422 	   processed, or a negative value on error */
423 	int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
424 			   int num);
425 	int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
426 			   unsigned short flags, char read_write,
427 			   u8 command, int size, union i2c_smbus_data *data);
428 
429 	/* To determine what the adapter supports */
430 	u32 (*functionality) (struct i2c_adapter *);
431 
432 #if IS_ENABLED(CONFIG_I2C_SLAVE)
433 	int (*reg_slave)(struct i2c_client *client);
434 	int (*unreg_slave)(struct i2c_client *client);
435 #endif
436 };
437 
438 /**
439  * struct i2c_lock_operations - represent I2C locking operations
440  * @lock_bus: Get exclusive access to an I2C bus segment
441  * @trylock_bus: Try to get exclusive access to an I2C bus segment
442  * @unlock_bus: Release exclusive access to an I2C bus segment
443  *
444  * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
445  */
446 struct i2c_lock_operations {
447 	void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
448 	int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
449 	void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
450 };
451 
452 /**
453  * struct i2c_timings - I2C timing information
454  * @bus_freq_hz: the bus frequency in Hz
455  * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
456  * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
457  * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
458  * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
459  */
460 struct i2c_timings {
461 	u32 bus_freq_hz;
462 	u32 scl_rise_ns;
463 	u32 scl_fall_ns;
464 	u32 scl_int_delay_ns;
465 	u32 sda_fall_ns;
466 };
467 
468 /**
469  * struct i2c_bus_recovery_info - I2C bus recovery information
470  * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
471  *	i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
472  * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
473  *      recovery. Used internally for generic GPIO recovery.
474  * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used
475  *      internally for generic GPIO recovery.
476  * @get_sda: This gets current value of SDA line. Optional for generic SCL
477  *      recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO
478  *      recovery.
479  * @prepare_recovery: This will be called before starting recovery. Platform may
480  *	configure padmux here for SDA/SCL line or something else they want.
481  * @unprepare_recovery: This will be called after completing recovery. Platform
482  *	may configure padmux here for SDA/SCL line or something else they want.
483  * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery.
484  * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery.
485  */
486 struct i2c_bus_recovery_info {
487 	int (*recover_bus)(struct i2c_adapter *);
488 
489 	int (*get_scl)(struct i2c_adapter *);
490 	void (*set_scl)(struct i2c_adapter *, int val);
491 	int (*get_sda)(struct i2c_adapter *);
492 
493 	void (*prepare_recovery)(struct i2c_adapter *);
494 	void (*unprepare_recovery)(struct i2c_adapter *);
495 
496 	/* gpio recovery */
497 	int scl_gpio;
498 	int sda_gpio;
499 };
500 
501 int i2c_recover_bus(struct i2c_adapter *adap);
502 
503 /* Generic recovery routines */
504 int i2c_generic_gpio_recovery(struct i2c_adapter *adap);
505 int i2c_generic_scl_recovery(struct i2c_adapter *adap);
506 
507 /**
508  * struct i2c_adapter_quirks - describe flaws of an i2c adapter
509  * @flags: see I2C_AQ_* for possible flags and read below
510  * @max_num_msgs: maximum number of messages per transfer
511  * @max_write_len: maximum length of a write message
512  * @max_read_len: maximum length of a read message
513  * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
514  * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
515  *
516  * Note about combined messages: Some I2C controllers can only send one message
517  * per transfer, plus something called combined message or write-then-read.
518  * This is (usually) a small write message followed by a read message and
519  * barely enough to access register based devices like EEPROMs. There is a flag
520  * to support this mode. It implies max_num_msg = 2 and does the length checks
521  * with max_comb_*_len because combined message mode usually has its own
522  * limitations. Because of HW implementations, some controllers can actually do
523  * write-then-anything or other variants. To support that, write-then-read has
524  * been broken out into smaller bits like write-first and read-second which can
525  * be combined as needed.
526  */
527 
528 struct i2c_adapter_quirks {
529 	u64 flags;
530 	int max_num_msgs;
531 	u16 max_write_len;
532 	u16 max_read_len;
533 	u16 max_comb_1st_msg_len;
534 	u16 max_comb_2nd_msg_len;
535 };
536 
537 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
538 #define I2C_AQ_COMB			BIT(0)
539 /* first combined message must be write */
540 #define I2C_AQ_COMB_WRITE_FIRST		BIT(1)
541 /* second combined message must be read */
542 #define I2C_AQ_COMB_READ_SECOND		BIT(2)
543 /* both combined messages must have the same target address */
544 #define I2C_AQ_COMB_SAME_ADDR		BIT(3)
545 /* convenience macro for typical write-then read case */
546 #define I2C_AQ_COMB_WRITE_THEN_READ	(I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
547 					 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
548 /* clock stretching is not supported */
549 #define I2C_AQ_NO_CLK_STRETCH		BIT(4)
550 
551 /*
552  * i2c_adapter is the structure used to identify a physical i2c bus along
553  * with the access algorithms necessary to access it.
554  */
555 struct i2c_adapter {
556 	struct module *owner;
557 	unsigned int class;		  /* classes to allow probing for */
558 	const struct i2c_algorithm *algo; /* the algorithm to access the bus */
559 	void *algo_data;
560 
561 	/* data fields that are valid for all devices	*/
562 	const struct i2c_lock_operations *lock_ops;
563 	struct rt_mutex bus_lock;
564 	struct rt_mutex mux_lock;
565 
566 	int timeout;			/* in jiffies */
567 	int retries;
568 	struct device dev;		/* the adapter device */
569 
570 	int nr;
571 	char name[48];
572 	struct completion dev_released;
573 
574 	struct mutex userspace_clients_lock;
575 	struct list_head userspace_clients;
576 
577 	struct i2c_bus_recovery_info *bus_recovery_info;
578 	const struct i2c_adapter_quirks *quirks;
579 
580 	struct irq_domain *host_notify_domain;
581 };
582 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
583 
584 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
585 {
586 	return dev_get_drvdata(&dev->dev);
587 }
588 
589 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
590 {
591 	dev_set_drvdata(&dev->dev, data);
592 }
593 
594 static inline struct i2c_adapter *
595 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
596 {
597 #if IS_ENABLED(CONFIG_I2C_MUX)
598 	struct device *parent = adapter->dev.parent;
599 
600 	if (parent != NULL && parent->type == &i2c_adapter_type)
601 		return to_i2c_adapter(parent);
602 	else
603 #endif
604 		return NULL;
605 }
606 
607 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
608 
609 /* Adapter locking functions, exported for shared pin cases */
610 #define I2C_LOCK_ROOT_ADAPTER BIT(0)
611 #define I2C_LOCK_SEGMENT      BIT(1)
612 
613 /**
614  * i2c_lock_bus - Get exclusive access to an I2C bus segment
615  * @adapter: Target I2C bus segment
616  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
617  *	locks only this branch in the adapter tree
618  */
619 static inline void
620 i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
621 {
622 	adapter->lock_ops->lock_bus(adapter, flags);
623 }
624 
625 /**
626  * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
627  * @adapter: Target I2C bus segment
628  * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
629  *	I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
630  *
631  * Return: true if the I2C bus segment is locked, false otherwise
632  */
633 static inline int
634 i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
635 {
636 	return adapter->lock_ops->trylock_bus(adapter, flags);
637 }
638 
639 /**
640  * i2c_unlock_bus - Release exclusive access to an I2C bus segment
641  * @adapter: Target I2C bus segment
642  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
643  *	unlocks only this branch in the adapter tree
644  */
645 static inline void
646 i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
647 {
648 	adapter->lock_ops->unlock_bus(adapter, flags);
649 }
650 
651 static inline void
652 i2c_lock_adapter(struct i2c_adapter *adapter)
653 {
654 	i2c_lock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
655 }
656 
657 static inline void
658 i2c_unlock_adapter(struct i2c_adapter *adapter)
659 {
660 	i2c_unlock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
661 }
662 
663 /*flags for the client struct: */
664 #define I2C_CLIENT_PEC		0x04	/* Use Packet Error Checking */
665 #define I2C_CLIENT_TEN		0x10	/* we have a ten bit chip address */
666 					/* Must equal I2C_M_TEN below */
667 #define I2C_CLIENT_SLAVE	0x20	/* we are the slave */
668 #define I2C_CLIENT_WAKE		0x80	/* for board_info; true iff can wake */
669 #define I2C_CLIENT_SCCB		0x9000	/* Use Omnivision SCCB protocol */
670 					/* Must match I2C_M_STOP|IGNORE_NAK */
671 
672 /* i2c adapter classes (bitmask) */
673 #define I2C_CLASS_HWMON		(1<<0)	/* lm_sensors, ... */
674 #define I2C_CLASS_DDC		(1<<3)	/* DDC bus on graphics adapters */
675 #define I2C_CLASS_SPD		(1<<7)	/* Memory modules */
676 #define I2C_CLASS_DEPRECATED	(1<<8)	/* Warn users that adapter will stop using classes */
677 
678 /* Internal numbers to terminate lists */
679 #define I2C_CLIENT_END		0xfffeU
680 
681 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
682 #define I2C_ADDRS(addr, addrs...) \
683 	((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
684 
685 
686 /* ----- functions exported by i2c.o */
687 
688 /* administration...
689  */
690 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
691 extern int i2c_add_adapter(struct i2c_adapter *);
692 extern void i2c_del_adapter(struct i2c_adapter *);
693 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
694 
695 extern int i2c_register_driver(struct module *, struct i2c_driver *);
696 extern void i2c_del_driver(struct i2c_driver *);
697 
698 /* use a define to avoid include chaining to get THIS_MODULE */
699 #define i2c_add_driver(driver) \
700 	i2c_register_driver(THIS_MODULE, driver)
701 
702 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
703 extern void i2c_release_client(struct i2c_client *client);
704 
705 /* call the i2c_client->command() of all attached clients with
706  * the given arguments */
707 extern void i2c_clients_command(struct i2c_adapter *adap,
708 				unsigned int cmd, void *arg);
709 
710 extern struct i2c_adapter *i2c_get_adapter(int nr);
711 extern void i2c_put_adapter(struct i2c_adapter *adap);
712 extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
713 
714 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
715 
716 /* Return the functionality mask */
717 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
718 {
719 	return adap->algo->functionality(adap);
720 }
721 
722 /* Return 1 if adapter supports everything we need, 0 if not. */
723 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
724 {
725 	return (func & i2c_get_functionality(adap)) == func;
726 }
727 
728 /**
729  * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
730  * @adap: i2c adapter
731  * @quirks: quirk flags
732  *
733  * Return: true if the adapter has all the specified quirk flags, false if not
734  */
735 static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
736 {
737 	if (!adap->quirks)
738 		return false;
739 	return (adap->quirks->flags & quirks) == quirks;
740 }
741 
742 /* Return the adapter number for a specific adapter */
743 static inline int i2c_adapter_id(struct i2c_adapter *adap)
744 {
745 	return adap->nr;
746 }
747 
748 static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
749 {
750 	return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
751 }
752 
753 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
754 /**
755  * module_i2c_driver() - Helper macro for registering a modular I2C driver
756  * @__i2c_driver: i2c_driver struct
757  *
758  * Helper macro for I2C drivers which do not do anything special in module
759  * init/exit. This eliminates a lot of boilerplate. Each module may only
760  * use this macro once, and calling it replaces module_init() and module_exit()
761  */
762 #define module_i2c_driver(__i2c_driver) \
763 	module_driver(__i2c_driver, i2c_add_driver, \
764 			i2c_del_driver)
765 
766 /**
767  * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
768  * @__i2c_driver: i2c_driver struct
769  *
770  * Helper macro for I2C drivers which do not do anything special in their
771  * init. This eliminates a lot of boilerplate. Each driver may only
772  * use this macro once, and calling it replaces device_initcall().
773  */
774 #define builtin_i2c_driver(__i2c_driver) \
775 	builtin_driver(__i2c_driver, i2c_add_driver)
776 
777 #endif /* I2C */
778 
779 #if IS_ENABLED(CONFIG_OF)
780 /* must call put_device() when done with returned i2c_client device */
781 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
782 
783 /* must call put_device() when done with returned i2c_adapter device */
784 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
785 
786 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
787 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
788 
789 extern const struct of_device_id
790 *i2c_of_match_device(const struct of_device_id *matches,
791 		     struct i2c_client *client);
792 
793 #else
794 
795 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
796 {
797 	return NULL;
798 }
799 
800 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
801 {
802 	return NULL;
803 }
804 
805 static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
806 {
807 	return NULL;
808 }
809 
810 static inline const struct of_device_id
811 *i2c_of_match_device(const struct of_device_id *matches,
812 		     struct i2c_client *client)
813 {
814 	return NULL;
815 }
816 
817 #endif /* CONFIG_OF */
818 
819 #if IS_ENABLED(CONFIG_ACPI)
820 u32 i2c_acpi_find_bus_speed(struct device *dev);
821 #else
822 static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
823 {
824 	return 0;
825 }
826 #endif /* CONFIG_ACPI */
827 
828 #endif /* _LINUX_I2C_H */
829