xref: /linux/include/linux/i2c.h (revision adc4fb9c814b5d5cc6021022900fd5eb0b3c8165)
1  /* SPDX-License-Identifier: GPL-2.0-or-later */
2  /*
3   * i2c.h - definitions for the Linux i2c bus interface
4   * Copyright (C) 1995-2000 Simon G. Vogl
5   * Copyright (C) 2013-2019 Wolfram Sang <wsa@kernel.org>
6   *
7   * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
8   * Frodo Looijaard <frodol@dds.nl>
9   */
10  #ifndef _LINUX_I2C_H
11  #define _LINUX_I2C_H
12  
13  #include <linux/acpi.h>		/* for acpi_handle */
14  #include <linux/bits.h>
15  #include <linux/mod_devicetable.h>
16  #include <linux/device.h>	/* for struct device */
17  #include <linux/sched.h>	/* for completion */
18  #include <linux/mutex.h>
19  #include <linux/regulator/consumer.h>
20  #include <linux/rtmutex.h>
21  #include <linux/irqdomain.h>		/* for Host Notify IRQ */
22  #include <linux/of.h>		/* for struct device_node */
23  #include <linux/swab.h>		/* for swab16 */
24  #include <uapi/linux/i2c.h>
25  
26  extern const struct bus_type i2c_bus_type;
27  extern const struct device_type i2c_adapter_type;
28  extern const struct device_type i2c_client_type;
29  
30  /* --- General options ------------------------------------------------	*/
31  
32  struct i2c_msg;
33  struct i2c_adapter;
34  struct i2c_client;
35  struct i2c_driver;
36  struct i2c_device_identity;
37  union i2c_smbus_data;
38  struct i2c_board_info;
39  enum i2c_slave_event;
40  typedef int (*i2c_slave_cb_t)(struct i2c_client *client,
41  			      enum i2c_slave_event event, u8 *val);
42  
43  /* I2C Frequency Modes */
44  #define I2C_MAX_STANDARD_MODE_FREQ	100000
45  #define I2C_MAX_FAST_MODE_FREQ		400000
46  #define I2C_MAX_FAST_MODE_PLUS_FREQ	1000000
47  #define I2C_MAX_TURBO_MODE_FREQ		1400000
48  #define I2C_MAX_HIGH_SPEED_MODE_FREQ	3400000
49  #define I2C_MAX_ULTRA_FAST_MODE_FREQ	5000000
50  
51  struct module;
52  struct property_entry;
53  
54  #if IS_ENABLED(CONFIG_I2C)
55  /* Return the Frequency mode string based on the bus frequency */
56  const char *i2c_freq_mode_string(u32 bus_freq_hz);
57  
58  /*
59   * The master routines are the ones normally used to transmit data to devices
60   * on a bus (or read from them). Apart from two basic transfer functions to
61   * transmit one message at a time, a more complex version can be used to
62   * transmit an arbitrary number of messages without interruption.
63   * @count must be less than 64k since msg.len is u16.
64   */
65  int i2c_transfer_buffer_flags(const struct i2c_client *client,
66  			      char *buf, int count, u16 flags);
67  
68  /**
69   * i2c_master_recv - issue a single I2C message in master receive mode
70   * @client: Handle to slave device
71   * @buf: Where to store data read from slave
72   * @count: How many bytes to read, must be less than 64k since msg.len is u16
73   *
74   * Returns negative errno, or else the number of bytes read.
75   */
i2c_master_recv(const struct i2c_client * client,char * buf,int count)76  static inline int i2c_master_recv(const struct i2c_client *client,
77  				  char *buf, int count)
78  {
79  	return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
80  };
81  
82  /**
83   * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
84   *			     using a DMA safe buffer
85   * @client: Handle to slave device
86   * @buf: Where to store data read from slave, must be safe to use with DMA
87   * @count: How many bytes to read, must be less than 64k since msg.len is u16
88   *
89   * Returns negative errno, or else the number of bytes read.
90   */
i2c_master_recv_dmasafe(const struct i2c_client * client,char * buf,int count)91  static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
92  					  char *buf, int count)
93  {
94  	return i2c_transfer_buffer_flags(client, buf, count,
95  					 I2C_M_RD | I2C_M_DMA_SAFE);
96  };
97  
98  /**
99   * i2c_master_send - issue a single I2C message in master transmit mode
100   * @client: Handle to slave device
101   * @buf: Data that will be written to the slave
102   * @count: How many bytes to write, must be less than 64k since msg.len is u16
103   *
104   * Returns negative errno, or else the number of bytes written.
105   */
i2c_master_send(const struct i2c_client * client,const char * buf,int count)106  static inline int i2c_master_send(const struct i2c_client *client,
107  				  const char *buf, int count)
108  {
109  	return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
110  };
111  
112  /**
113   * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
114   *			     using a DMA safe buffer
115   * @client: Handle to slave device
116   * @buf: Data that will be written to the slave, must be safe to use with DMA
117   * @count: How many bytes to write, must be less than 64k since msg.len is u16
118   *
119   * Returns negative errno, or else the number of bytes written.
120   */
i2c_master_send_dmasafe(const struct i2c_client * client,const char * buf,int count)121  static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
122  					  const char *buf, int count)
123  {
124  	return i2c_transfer_buffer_flags(client, (char *)buf, count,
125  					 I2C_M_DMA_SAFE);
126  };
127  
128  /* Transfer num messages.
129   */
130  int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
131  /* Unlocked flavor */
132  int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
133  
134  /* This is the very generalized SMBus access routine. You probably do not
135     want to use this, though; one of the functions below may be much easier,
136     and probably just as fast.
137     Note that we use i2c_adapter here, because you do not need a specific
138     smbus adapter to call this function. */
139  s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
140  		   unsigned short flags, char read_write, u8 command,
141  		   int protocol, union i2c_smbus_data *data);
142  
143  /* Unlocked flavor */
144  s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
145  		     unsigned short flags, char read_write, u8 command,
146  		     int protocol, union i2c_smbus_data *data);
147  
148  /* Now follow the 'nice' access routines. These also document the calling
149     conventions of i2c_smbus_xfer. */
150  
151  u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count);
152  s32 i2c_smbus_read_byte(const struct i2c_client *client);
153  s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
154  s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command);
155  s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
156  			      u8 command, u8 value);
157  s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command);
158  s32 i2c_smbus_write_word_data(const struct i2c_client *client,
159  			      u8 command, u16 value);
160  
161  static inline s32
i2c_smbus_read_word_swapped(const struct i2c_client * client,u8 command)162  i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
163  {
164  	s32 value = i2c_smbus_read_word_data(client, command);
165  
166  	return (value < 0) ? value : swab16(value);
167  }
168  
169  static inline s32
i2c_smbus_write_word_swapped(const struct i2c_client * client,u8 command,u16 value)170  i2c_smbus_write_word_swapped(const struct i2c_client *client,
171  			     u8 command, u16 value)
172  {
173  	return i2c_smbus_write_word_data(client, command, swab16(value));
174  }
175  
176  /* Returns the number of read bytes */
177  s32 i2c_smbus_read_block_data(const struct i2c_client *client,
178  			      u8 command, u8 *values);
179  s32 i2c_smbus_write_block_data(const struct i2c_client *client,
180  			       u8 command, u8 length, const u8 *values);
181  /* Returns the number of read bytes */
182  s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
183  				  u8 command, u8 length, u8 *values);
184  s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
185  				   u8 command, u8 length, const u8 *values);
186  s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
187  					      u8 command, u8 length,
188  					      u8 *values);
189  int i2c_get_device_id(const struct i2c_client *client,
190  		      struct i2c_device_identity *id);
191  const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client);
192  #endif /* I2C */
193  
194  /**
195   * struct i2c_device_identity - i2c client device identification
196   * @manufacturer_id: 0 - 4095, database maintained by NXP
197   * @part_id: 0 - 511, according to manufacturer
198   * @die_revision: 0 - 7, according to manufacturer
199   */
200  struct i2c_device_identity {
201  	u16 manufacturer_id;
202  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS                0
203  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1              1
204  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2              2
205  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3              3
206  #define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL             4
207  #define I2C_DEVICE_ID_ANALOG_DEVICES                    5
208  #define I2C_DEVICE_ID_STMICROELECTRONICS                6
209  #define I2C_DEVICE_ID_ON_SEMICONDUCTOR                  7
210  #define I2C_DEVICE_ID_SPRINTEK_CORPORATION              8
211  #define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG               9
212  #define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR            10
213  #define I2C_DEVICE_ID_FLIR                             11
214  #define I2C_DEVICE_ID_O2MICRO                          12
215  #define I2C_DEVICE_ID_ATMEL                            13
216  #define I2C_DEVICE_ID_NONE                         0xffff
217  	u16 part_id;
218  	u8 die_revision;
219  };
220  
221  enum i2c_alert_protocol {
222  	I2C_PROTOCOL_SMBUS_ALERT,
223  	I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
224  };
225  
226  /**
227   * enum i2c_driver_flags - Flags for an I2C device driver
228   *
229   * @I2C_DRV_ACPI_WAIVE_D0_PROBE: Don't put the device in D0 state for probe
230   */
231  enum i2c_driver_flags {
232  	I2C_DRV_ACPI_WAIVE_D0_PROBE = BIT(0),
233  };
234  
235  /**
236   * struct i2c_driver - represent an I2C device driver
237   * @class: What kind of i2c device we instantiate (for detect)
238   * @probe: Callback for device binding
239   * @remove: Callback for device unbinding
240   * @shutdown: Callback for device shutdown
241   * @alert: Alert callback, for example for the SMBus alert protocol
242   * @command: Callback for bus-wide signaling (optional)
243   * @driver: Device driver model driver
244   * @id_table: List of I2C devices supported by this driver
245   * @detect: Callback for device detection
246   * @address_list: The I2C addresses to probe (for detect)
247   * @clients: List of detected clients we created (for i2c-core use only)
248   * @flags: A bitmask of flags defined in &enum i2c_driver_flags
249   *
250   * The driver.owner field should be set to the module owner of this driver.
251   * The driver.name field should be set to the name of this driver.
252   *
253   * For automatic device detection, both @detect and @address_list must
254   * be defined. @class should also be set, otherwise only devices forced
255   * with module parameters will be created. The detect function must
256   * fill at least the name field of the i2c_board_info structure it is
257   * handed upon successful detection, and possibly also the flags field.
258   *
259   * If @detect is missing, the driver will still work fine for enumerated
260   * devices. Detected devices simply won't be supported. This is expected
261   * for the many I2C/SMBus devices which can't be detected reliably, and
262   * the ones which can always be enumerated in practice.
263   *
264   * The i2c_client structure which is handed to the @detect callback is
265   * not a real i2c_client. It is initialized just enough so that you can
266   * call i2c_smbus_read_byte_data and friends on it. Don't do anything
267   * else with it. In particular, calling dev_dbg and friends on it is
268   * not allowed.
269   */
270  struct i2c_driver {
271  	unsigned int class;
272  
273  	/* Standard driver model interfaces */
274  	int (*probe)(struct i2c_client *client);
275  	void (*remove)(struct i2c_client *client);
276  
277  
278  	/* driver model interfaces that don't relate to enumeration  */
279  	void (*shutdown)(struct i2c_client *client);
280  
281  	/* Alert callback, for example for the SMBus alert protocol.
282  	 * The format and meaning of the data value depends on the protocol.
283  	 * For the SMBus alert protocol, there is a single bit of data passed
284  	 * as the alert response's low bit ("event flag").
285  	 * For the SMBus Host Notify protocol, the data corresponds to the
286  	 * 16-bit payload data reported by the slave device acting as master.
287  	 */
288  	void (*alert)(struct i2c_client *client, enum i2c_alert_protocol protocol,
289  		      unsigned int data);
290  
291  	/* a ioctl like command that can be used to perform specific functions
292  	 * with the device.
293  	 */
294  	int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
295  
296  	struct device_driver driver;
297  	const struct i2c_device_id *id_table;
298  
299  	/* Device detection callback for automatic device creation */
300  	int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
301  	const unsigned short *address_list;
302  	struct list_head clients;
303  
304  	u32 flags;
305  };
306  #define to_i2c_driver(d) container_of_const(d, struct i2c_driver, driver)
307  
308  /**
309   * struct i2c_client - represent an I2C slave device
310   * @flags: see I2C_CLIENT_* for possible flags
311   * @addr: Address used on the I2C bus connected to the parent adapter.
312   * @name: Indicates the type of the device, usually a chip name that's
313   *	generic enough to hide second-sourcing and compatible revisions.
314   * @adapter: manages the bus segment hosting this I2C device
315   * @dev: Driver model device node for the slave.
316   * @init_irq: IRQ that was set at initialization
317   * @irq: indicates the IRQ generated by this device (if any)
318   * @detected: member of an i2c_driver.clients list or i2c-core's
319   *	userspace_devices list
320   * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
321   *	calls it to pass on slave events to the slave driver.
322   * @devres_group_id: id of the devres group that will be created for resources
323   *	acquired when probing this device.
324   * @debugfs: pointer to the debugfs subdirectory which the I2C core created
325   *	for this client.
326   *
327   * An i2c_client identifies a single device (i.e. chip) connected to an
328   * i2c bus. The behaviour exposed to Linux is defined by the driver
329   * managing the device.
330   */
331  struct i2c_client {
332  	unsigned short flags;		/* div., see below		*/
333  #define I2C_CLIENT_PEC		0x04	/* Use Packet Error Checking */
334  #define I2C_CLIENT_TEN		0x10	/* we have a ten bit chip address */
335  					/* Must equal I2C_M_TEN below */
336  #define I2C_CLIENT_SLAVE	0x20	/* we are the slave */
337  #define I2C_CLIENT_HOST_NOTIFY	0x40	/* We want to use I2C host notify */
338  #define I2C_CLIENT_WAKE		0x80	/* for board_info; true iff can wake */
339  #define I2C_CLIENT_SCCB		0x9000	/* Use Omnivision SCCB protocol */
340  					/* Must match I2C_M_STOP|IGNORE_NAK */
341  
342  	unsigned short addr;		/* chip address - NOTE: 7bit	*/
343  					/* addresses are stored in the	*/
344  					/* _LOWER_ 7 bits		*/
345  	char name[I2C_NAME_SIZE];
346  	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
347  	struct device dev;		/* the device structure		*/
348  	int init_irq;			/* irq set at initialization	*/
349  	int irq;			/* irq issued by device		*/
350  	struct list_head detected;
351  #if IS_ENABLED(CONFIG_I2C_SLAVE)
352  	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
353  #endif
354  	void *devres_group_id;		/* ID of probe devres group	*/
355  	struct dentry *debugfs;		/* per-client debugfs dir	*/
356  };
357  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
358  
359  struct i2c_adapter *i2c_verify_adapter(struct device *dev);
360  const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
361  					 const struct i2c_client *client);
362  
363  const void *i2c_get_match_data(const struct i2c_client *client);
364  
kobj_to_i2c_client(struct kobject * kobj)365  static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
366  {
367  	struct device * const dev = kobj_to_dev(kobj);
368  	return to_i2c_client(dev);
369  }
370  
i2c_get_clientdata(const struct i2c_client * client)371  static inline void *i2c_get_clientdata(const struct i2c_client *client)
372  {
373  	return dev_get_drvdata(&client->dev);
374  }
375  
i2c_set_clientdata(struct i2c_client * client,void * data)376  static inline void i2c_set_clientdata(struct i2c_client *client, void *data)
377  {
378  	dev_set_drvdata(&client->dev, data);
379  }
380  
381  /* I2C slave support */
382  
383  enum i2c_slave_event {
384  	I2C_SLAVE_READ_REQUESTED,
385  	I2C_SLAVE_WRITE_REQUESTED,
386  	I2C_SLAVE_READ_PROCESSED,
387  	I2C_SLAVE_WRITE_RECEIVED,
388  	I2C_SLAVE_STOP,
389  };
390  
391  int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
392  int i2c_slave_unregister(struct i2c_client *client);
393  int i2c_slave_event(struct i2c_client *client,
394  		    enum i2c_slave_event event, u8 *val);
395  #if IS_ENABLED(CONFIG_I2C_SLAVE)
396  bool i2c_detect_slave_mode(struct device *dev);
397  #else
i2c_detect_slave_mode(struct device * dev)398  static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
399  #endif
400  
401  /**
402   * struct i2c_board_info - template for device creation
403   * @type: chip type, to initialize i2c_client.name
404   * @flags: to initialize i2c_client.flags
405   * @addr: stored in i2c_client.addr
406   * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
407   * @platform_data: stored in i2c_client.dev.platform_data
408   * @of_node: pointer to OpenFirmware device node
409   * @fwnode: device node supplied by the platform firmware
410   * @swnode: software node for the device
411   * @resources: resources associated with the device
412   * @num_resources: number of resources in the @resources array
413   * @irq: stored in i2c_client.irq
414   *
415   * I2C doesn't actually support hardware probing, although controllers and
416   * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
417   * a device at a given address.  Drivers commonly need more information than
418   * that, such as chip type, configuration, associated IRQ, and so on.
419   *
420   * i2c_board_info is used to build tables of information listing I2C devices
421   * that are present.  This information is used to grow the driver model tree.
422   * For mainboards this is done statically using i2c_register_board_info();
423   * bus numbers identify adapters that aren't yet available.  For add-on boards,
424   * i2c_new_client_device() does this dynamically with the adapter already known.
425   */
426  struct i2c_board_info {
427  	char		type[I2C_NAME_SIZE];
428  	unsigned short	flags;
429  	unsigned short	addr;
430  	const char	*dev_name;
431  	void		*platform_data;
432  	struct device_node *of_node;
433  	struct fwnode_handle *fwnode;
434  	const struct software_node *swnode;
435  	const struct resource *resources;
436  	unsigned int	num_resources;
437  	int		irq;
438  };
439  
440  /**
441   * I2C_BOARD_INFO - macro used to list an i2c device and its address
442   * @dev_type: identifies the device type
443   * @dev_addr: the device's address on the bus.
444   *
445   * This macro initializes essential fields of a struct i2c_board_info,
446   * declaring what has been provided on a particular board.  Optional
447   * fields (such as associated irq, or device-specific platform_data)
448   * are provided using conventional syntax.
449   */
450  #define I2C_BOARD_INFO(dev_type, dev_addr) \
451  	.type = dev_type, .addr = (dev_addr)
452  
453  
454  #if IS_ENABLED(CONFIG_I2C)
455  /*
456   * Add-on boards should register/unregister their devices; e.g. a board
457   * with integrated I2C, a config eeprom, sensors, and a codec that's
458   * used in conjunction with the primary hardware.
459   */
460  struct i2c_client *
461  i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
462  
463  /* If you don't know the exact address of an I2C device, use this variant
464   * instead, which can probe for device presence in a list of possible
465   * addresses. The "probe" callback function is optional. If it is provided,
466   * it must return 1 on successful probe, 0 otherwise. If it is not provided,
467   * a default probing method is used.
468   */
469  struct i2c_client *
470  i2c_new_scanned_device(struct i2c_adapter *adap,
471  		       struct i2c_board_info *info,
472  		       unsigned short const *addr_list,
473  		       int (*probe)(struct i2c_adapter *adap, unsigned short addr));
474  
475  /* Common custom probe functions */
476  int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr);
477  
478  struct i2c_client *
479  i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address);
480  
481  struct i2c_client *
482  devm_i2c_new_dummy_device(struct device *dev, struct i2c_adapter *adap, u16 address);
483  
484  struct i2c_client *
485  i2c_new_ancillary_device(struct i2c_client *client,
486  			 const char *name,
487  			 u16 default_addr);
488  
489  void i2c_unregister_device(struct i2c_client *client);
490  
491  struct i2c_client *i2c_verify_client(struct device *dev);
492  #else
i2c_verify_client(struct device * dev)493  static inline struct i2c_client *i2c_verify_client(struct device *dev)
494  {
495  	return NULL;
496  }
497  #endif /* I2C */
498  
499  /* Mainboard arch_initcall() code should register all its I2C devices.
500   * This is done at arch_initcall time, before declaring any i2c adapters.
501   * Modules for add-on boards must use other calls.
502   */
503  #ifdef CONFIG_I2C_BOARDINFO
504  int
505  i2c_register_board_info(int busnum, struct i2c_board_info const *info,
506  			unsigned n);
507  #else
508  static inline int
i2c_register_board_info(int busnum,struct i2c_board_info const * info,unsigned n)509  i2c_register_board_info(int busnum, struct i2c_board_info const *info,
510  			unsigned n)
511  {
512  	return 0;
513  }
514  #endif /* I2C_BOARDINFO */
515  
516  /**
517   * struct i2c_algorithm - represent I2C transfer methods
518   * @xfer: Transfer a given number of messages defined by the msgs array via
519   *   the specified adapter.
520   * @xfer_atomic: Same as @xfer. Yet, only using atomic context so e.g. PMICs
521   *   can be accessed very late before shutdown. Optional.
522   * @smbus_xfer: Issue SMBus transactions to the given I2C adapter. If this
523   *   is not present, then the bus layer will try and convert the SMBus calls
524   *   into I2C transfers instead.
525   * @smbus_xfer_atomic: Same as @smbus_xfer. Yet, only using atomic context
526   *   so e.g. PMICs can be accessed very late before shutdown. Optional.
527   * @functionality: Return the flags that this algorithm/adapter pair supports
528   *   from the ``I2C_FUNC_*`` flags.
529   * @reg_target: Register given client to local target mode of this adapter
530   * @unreg_target: Unregister given client from local target mode of this adapter
531   *
532   * @master_xfer: deprecated, use @xfer
533   * @master_xfer_atomic: deprecated, use @xfer_atomic
534   * @reg_slave: deprecated, use @reg_target
535   * @unreg_slave: deprecated, use @unreg_target
536   *
537   * i2c_algorithm is the interface to a class of hardware solutions which can
538   * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
539   * to name two of the most common.
540   *
541   * The return codes from the ``xfer{_atomic}`` fields should indicate the
542   * type of error code that occurred during the transfer, as documented in the
543   * Kernel Documentation file Documentation/i2c/fault-codes.rst. Otherwise, the
544   * number of messages executed should be returned.
545   */
546  struct i2c_algorithm {
547  	/*
548  	 * If an adapter algorithm can't do I2C-level access, set xfer
549  	 * to NULL. If an adapter algorithm can do SMBus access, set
550  	 * smbus_xfer. If set to NULL, the SMBus protocol is simulated
551  	 * using common I2C messages.
552  	 */
553  	union {
554  		int (*xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
555  			    int num);
556  		int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
557  				   int num);
558  	};
559  	union {
560  		int (*xfer_atomic)(struct i2c_adapter *adap,
561  				   struct i2c_msg *msgs, int num);
562  		int (*master_xfer_atomic)(struct i2c_adapter *adap,
563  					   struct i2c_msg *msgs, int num);
564  	};
565  	int (*smbus_xfer)(struct i2c_adapter *adap, u16 addr,
566  			  unsigned short flags, char read_write,
567  			  u8 command, int size, union i2c_smbus_data *data);
568  	int (*smbus_xfer_atomic)(struct i2c_adapter *adap, u16 addr,
569  				 unsigned short flags, char read_write,
570  				 u8 command, int size, union i2c_smbus_data *data);
571  
572  	/* To determine what the adapter supports */
573  	u32 (*functionality)(struct i2c_adapter *adap);
574  
575  #if IS_ENABLED(CONFIG_I2C_SLAVE)
576  	union {
577  		int (*reg_target)(struct i2c_client *client);
578  		int (*reg_slave)(struct i2c_client *client);
579  	};
580  	union {
581  		int (*unreg_target)(struct i2c_client *client);
582  		int (*unreg_slave)(struct i2c_client *client);
583  	};
584  #endif
585  };
586  
587  /**
588   * struct i2c_lock_operations - represent I2C locking operations
589   * @lock_bus: Get exclusive access to an I2C bus segment
590   * @trylock_bus: Try to get exclusive access to an I2C bus segment
591   * @unlock_bus: Release exclusive access to an I2C bus segment
592   *
593   * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
594   */
595  struct i2c_lock_operations {
596  	void (*lock_bus)(struct i2c_adapter *adapter, unsigned int flags);
597  	int (*trylock_bus)(struct i2c_adapter *adapter, unsigned int flags);
598  	void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags);
599  };
600  
601  /**
602   * struct i2c_timings - I2C timing information
603   * @bus_freq_hz: the bus frequency in Hz
604   * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
605   * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
606   * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
607   * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
608   * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
609   * @digital_filter_width_ns: width in ns of spikes on i2c lines that the IP core
610   *	digital filter can filter out
611   * @analog_filter_cutoff_freq_hz: threshold frequency for the low pass IP core
612   *	analog filter
613   */
614  struct i2c_timings {
615  	u32 bus_freq_hz;
616  	u32 scl_rise_ns;
617  	u32 scl_fall_ns;
618  	u32 scl_int_delay_ns;
619  	u32 sda_fall_ns;
620  	u32 sda_hold_ns;
621  	u32 digital_filter_width_ns;
622  	u32 analog_filter_cutoff_freq_hz;
623  };
624  
625  /**
626   * struct i2c_bus_recovery_info - I2C bus recovery information
627   * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
628   *	i2c_generic_scl_recovery().
629   * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
630   *      recovery. Populated internally for generic GPIO recovery.
631   * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
632   *      Populated internally for generic GPIO recovery.
633   * @get_sda: This gets current value of SDA line. This or set_sda() is mandatory
634   *	for generic SCL recovery. Populated internally, if sda_gpio is a valid
635   *	GPIO, for generic GPIO recovery.
636   * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for
637   *	generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO,
638   *	for generic GPIO recovery.
639   * @get_bus_free: Returns the bus free state as seen from the IP core in case it
640   *	has a more complex internal logic than just reading SDA. Optional.
641   * @prepare_recovery: This will be called before starting recovery. Platform may
642   *	configure padmux here for SDA/SCL line or something else they want.
643   * @unprepare_recovery: This will be called after completing recovery. Platform
644   *	may configure padmux here for SDA/SCL line or something else they want.
645   * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
646   * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
647   * @pinctrl: pinctrl used by GPIO recovery to change the state of the I2C pins.
648   *      Optional.
649   * @pins_default: default pinctrl state of SCL/SDA lines, when they are assigned
650   *      to the I2C bus. Optional. Populated internally for GPIO recovery, if
651   *      state with the name PINCTRL_STATE_DEFAULT is found and pinctrl is valid.
652   * @pins_gpio: recovery pinctrl state of SCL/SDA lines, when they are used as
653   *      GPIOs. Optional. Populated internally for GPIO recovery, if this state
654   *      is called "gpio" or "recovery" and pinctrl is valid.
655   */
656  struct i2c_bus_recovery_info {
657  	int (*recover_bus)(struct i2c_adapter *adap);
658  
659  	int (*get_scl)(struct i2c_adapter *adap);
660  	void (*set_scl)(struct i2c_adapter *adap, int val);
661  	int (*get_sda)(struct i2c_adapter *adap);
662  	void (*set_sda)(struct i2c_adapter *adap, int val);
663  	int (*get_bus_free)(struct i2c_adapter *adap);
664  
665  	void (*prepare_recovery)(struct i2c_adapter *adap);
666  	void (*unprepare_recovery)(struct i2c_adapter *adap);
667  
668  	/* gpio recovery */
669  	struct gpio_desc *scl_gpiod;
670  	struct gpio_desc *sda_gpiod;
671  	struct pinctrl *pinctrl;
672  	struct pinctrl_state *pins_default;
673  	struct pinctrl_state *pins_gpio;
674  };
675  
676  int i2c_recover_bus(struct i2c_adapter *adap);
677  
678  /* Generic recovery routines */
679  int i2c_generic_scl_recovery(struct i2c_adapter *adap);
680  
681  /**
682   * struct i2c_adapter_quirks - describe flaws of an i2c adapter
683   * @flags: see I2C_AQ_* for possible flags and read below
684   * @max_num_msgs: maximum number of messages per transfer
685   * @max_write_len: maximum length of a write message
686   * @max_read_len: maximum length of a read message
687   * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
688   * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
689   *
690   * Note about combined messages: Some I2C controllers can only send one message
691   * per transfer, plus something called combined message or write-then-read.
692   * This is (usually) a small write message followed by a read message and
693   * barely enough to access register based devices like EEPROMs. There is a flag
694   * to support this mode. It implies max_num_msg = 2 and does the length checks
695   * with max_comb_*_len because combined message mode usually has its own
696   * limitations. Because of HW implementations, some controllers can actually do
697   * write-then-anything or other variants. To support that, write-then-read has
698   * been broken out into smaller bits like write-first and read-second which can
699   * be combined as needed.
700   */
701  
702  struct i2c_adapter_quirks {
703  	u64 flags;
704  	int max_num_msgs;
705  	u16 max_write_len;
706  	u16 max_read_len;
707  	u16 max_comb_1st_msg_len;
708  	u16 max_comb_2nd_msg_len;
709  };
710  
711  /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
712  #define I2C_AQ_COMB			BIT(0)
713  /* first combined message must be write */
714  #define I2C_AQ_COMB_WRITE_FIRST		BIT(1)
715  /* second combined message must be read */
716  #define I2C_AQ_COMB_READ_SECOND		BIT(2)
717  /* both combined messages must have the same target address */
718  #define I2C_AQ_COMB_SAME_ADDR		BIT(3)
719  /* convenience macro for typical write-then read case */
720  #define I2C_AQ_COMB_WRITE_THEN_READ	(I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
721  					 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
722  /* clock stretching is not supported */
723  #define I2C_AQ_NO_CLK_STRETCH		BIT(4)
724  /* message cannot have length of 0 */
725  #define I2C_AQ_NO_ZERO_LEN_READ		BIT(5)
726  #define I2C_AQ_NO_ZERO_LEN_WRITE	BIT(6)
727  #define I2C_AQ_NO_ZERO_LEN		(I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
728  /* adapter cannot do repeated START */
729  #define I2C_AQ_NO_REP_START		BIT(7)
730  
731  /*
732   * i2c_adapter is the structure used to identify a physical i2c bus along
733   * with the access algorithms necessary to access it.
734   */
735  struct i2c_adapter {
736  	struct module *owner;
737  	unsigned int class;		  /* classes to allow probing for */
738  	const struct i2c_algorithm *algo; /* the algorithm to access the bus */
739  	void *algo_data;
740  
741  	/* data fields that are valid for all devices	*/
742  	const struct i2c_lock_operations *lock_ops;
743  	struct rt_mutex bus_lock;
744  	struct rt_mutex mux_lock;
745  
746  	int timeout;			/* in jiffies */
747  	int retries;
748  	struct device dev;		/* the adapter device */
749  	unsigned long locked_flags;	/* owned by the I2C core */
750  #define I2C_ALF_IS_SUSPENDED		0
751  #define I2C_ALF_SUSPEND_REPORTED	1
752  
753  	int nr;
754  	char name[48];
755  	struct completion dev_released;
756  
757  	struct mutex userspace_clients_lock;
758  	struct list_head userspace_clients;
759  
760  	struct i2c_bus_recovery_info *bus_recovery_info;
761  	const struct i2c_adapter_quirks *quirks;
762  
763  	struct irq_domain *host_notify_domain;
764  	struct regulator *bus_regulator;
765  
766  	struct dentry *debugfs;
767  
768  	/* 7bit address space */
769  	DECLARE_BITMAP(addrs_in_instantiation, 1 << 7);
770  };
771  #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
772  
i2c_get_adapdata(const struct i2c_adapter * adap)773  static inline void *i2c_get_adapdata(const struct i2c_adapter *adap)
774  {
775  	return dev_get_drvdata(&adap->dev);
776  }
777  
i2c_set_adapdata(struct i2c_adapter * adap,void * data)778  static inline void i2c_set_adapdata(struct i2c_adapter *adap, void *data)
779  {
780  	dev_set_drvdata(&adap->dev, data);
781  }
782  
783  static inline struct i2c_adapter *
i2c_parent_is_i2c_adapter(const struct i2c_adapter * adapter)784  i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
785  {
786  #if IS_ENABLED(CONFIG_I2C_MUX)
787  	struct device *parent = adapter->dev.parent;
788  
789  	if (parent != NULL && parent->type == &i2c_adapter_type)
790  		return to_i2c_adapter(parent);
791  	else
792  #endif
793  		return NULL;
794  }
795  
796  int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data));
797  
798  /* Adapter locking functions, exported for shared pin cases */
799  #define I2C_LOCK_ROOT_ADAPTER BIT(0)
800  #define I2C_LOCK_SEGMENT      BIT(1)
801  
802  /**
803   * i2c_lock_bus - Get exclusive access to an I2C bus segment
804   * @adapter: Target I2C bus segment
805   * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
806   *	locks only this branch in the adapter tree
807   */
808  static inline void
i2c_lock_bus(struct i2c_adapter * adapter,unsigned int flags)809  i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
810  {
811  	adapter->lock_ops->lock_bus(adapter, flags);
812  }
813  
814  /**
815   * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
816   * @adapter: Target I2C bus segment
817   * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
818   *	I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
819   *
820   * Return: true if the I2C bus segment is locked, false otherwise
821   */
822  static inline int
i2c_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)823  i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
824  {
825  	return adapter->lock_ops->trylock_bus(adapter, flags);
826  }
827  
828  /**
829   * i2c_unlock_bus - Release exclusive access to an I2C bus segment
830   * @adapter: Target I2C bus segment
831   * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
832   *	unlocks only this branch in the adapter tree
833   */
834  static inline void
i2c_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)835  i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
836  {
837  	adapter->lock_ops->unlock_bus(adapter, flags);
838  }
839  
840  /**
841   * i2c_mark_adapter_suspended - Report suspended state of the adapter to the core
842   * @adap: Adapter to mark as suspended
843   *
844   * When using this helper to mark an adapter as suspended, the core will reject
845   * further transfers to this adapter. The usage of this helper is optional but
846   * recommended for devices having distinct handlers for system suspend and
847   * runtime suspend. More complex devices are free to implement custom solutions
848   * to reject transfers when suspended.
849   */
i2c_mark_adapter_suspended(struct i2c_adapter * adap)850  static inline void i2c_mark_adapter_suspended(struct i2c_adapter *adap)
851  {
852  	i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
853  	set_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
854  	i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
855  }
856  
857  /**
858   * i2c_mark_adapter_resumed - Report resumed state of the adapter to the core
859   * @adap: Adapter to mark as resumed
860   *
861   * When using this helper to mark an adapter as resumed, the core will allow
862   * further transfers to this adapter. See also further notes to
863   * @i2c_mark_adapter_suspended().
864   */
i2c_mark_adapter_resumed(struct i2c_adapter * adap)865  static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap)
866  {
867  	i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
868  	clear_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
869  	i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
870  }
871  
872  /* i2c adapter classes (bitmask) */
873  #define I2C_CLASS_HWMON		(1<<0)	/* lm_sensors, ... */
874  /* Warn users that the adapter doesn't support classes anymore */
875  #define I2C_CLASS_DEPRECATED	(1<<8)
876  
877  /* Internal numbers to terminate lists */
878  #define I2C_CLIENT_END		0xfffeU
879  
880  /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
881  #define I2C_ADDRS(addr, addrs...) \
882  	((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
883  
884  
885  /* ----- functions exported by i2c.o */
886  
887  /* administration...
888   */
889  #if IS_ENABLED(CONFIG_I2C)
890  int i2c_add_adapter(struct i2c_adapter *adap);
891  int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter);
892  void i2c_del_adapter(struct i2c_adapter *adap);
893  int i2c_add_numbered_adapter(struct i2c_adapter *adap);
894  
895  int i2c_register_driver(struct module *owner, struct i2c_driver *driver);
896  void i2c_del_driver(struct i2c_driver *driver);
897  
898  /* use a define to avoid include chaining to get THIS_MODULE */
899  #define i2c_add_driver(driver) \
900  	i2c_register_driver(THIS_MODULE, driver)
901  
i2c_client_has_driver(struct i2c_client * client)902  static inline bool i2c_client_has_driver(struct i2c_client *client)
903  {
904  	return !IS_ERR_OR_NULL(client) && client->dev.driver;
905  }
906  
907  /* call the i2c_client->command() of all attached clients with
908   * the given arguments */
909  void i2c_clients_command(struct i2c_adapter *adap,
910  			 unsigned int cmd, void *arg);
911  
912  struct i2c_adapter *i2c_get_adapter(int nr);
913  void i2c_put_adapter(struct i2c_adapter *adap);
914  unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
915  
916  void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
917  
918  /* Return the functionality mask */
i2c_get_functionality(struct i2c_adapter * adap)919  static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
920  {
921  	return adap->algo->functionality(adap);
922  }
923  
924  /* Return 1 if adapter supports everything we need, 0 if not. */
i2c_check_functionality(struct i2c_adapter * adap,u32 func)925  static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
926  {
927  	return (func & i2c_get_functionality(adap)) == func;
928  }
929  
930  /**
931   * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
932   * @adap: i2c adapter
933   * @quirks: quirk flags
934   *
935   * Return: true if the adapter has all the specified quirk flags, false if not
936   */
i2c_check_quirks(struct i2c_adapter * adap,u64 quirks)937  static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
938  {
939  	if (!adap->quirks)
940  		return false;
941  	return (adap->quirks->flags & quirks) == quirks;
942  }
943  
944  /* Return the adapter number for a specific adapter */
i2c_adapter_id(struct i2c_adapter * adap)945  static inline int i2c_adapter_id(struct i2c_adapter *adap)
946  {
947  	return adap->nr;
948  }
949  
i2c_8bit_addr_from_msg(const struct i2c_msg * msg)950  static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
951  {
952  	return (msg->addr << 1) | (msg->flags & I2C_M_RD);
953  }
954  
955  u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
956  void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
957  
958  int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
959  /**
960   * module_i2c_driver() - Helper macro for registering a modular I2C driver
961   * @__i2c_driver: i2c_driver struct
962   *
963   * Helper macro for I2C drivers which do not do anything special in module
964   * init/exit. This eliminates a lot of boilerplate. Each module may only
965   * use this macro once, and calling it replaces module_init() and module_exit()
966   */
967  #define module_i2c_driver(__i2c_driver) \
968  	module_driver(__i2c_driver, i2c_add_driver, \
969  			i2c_del_driver)
970  
971  /**
972   * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
973   * @__i2c_driver: i2c_driver struct
974   *
975   * Helper macro for I2C drivers which do not do anything special in their
976   * init. This eliminates a lot of boilerplate. Each driver may only
977   * use this macro once, and calling it replaces device_initcall().
978   */
979  #define builtin_i2c_driver(__i2c_driver) \
980  	builtin_driver(__i2c_driver, i2c_add_driver)
981  
982  /* must call put_device() when done with returned i2c_client device */
983  struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode);
984  
985  /* must call put_device() when done with returned i2c_adapter device */
986  struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode);
987  
988  /* must call i2c_put_adapter() when done with returned i2c_adapter device */
989  struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode);
990  
991  #else /* I2C */
992  
993  static inline struct i2c_client *
i2c_find_device_by_fwnode(struct fwnode_handle * fwnode)994  i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
995  {
996  	return NULL;
997  }
998  
999  static inline struct i2c_adapter *
i2c_find_adapter_by_fwnode(struct fwnode_handle * fwnode)1000  i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1001  {
1002  	return NULL;
1003  }
1004  
1005  static inline struct i2c_adapter *
i2c_get_adapter_by_fwnode(struct fwnode_handle * fwnode)1006  i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1007  {
1008  	return NULL;
1009  }
1010  
1011  #endif /* !I2C */
1012  
1013  #if IS_ENABLED(CONFIG_OF)
1014  /* must call put_device() when done with returned i2c_client device */
of_find_i2c_device_by_node(struct device_node * node)1015  static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1016  {
1017  	return i2c_find_device_by_fwnode(of_fwnode_handle(node));
1018  }
1019  
1020  /* must call put_device() when done with returned i2c_adapter device */
of_find_i2c_adapter_by_node(struct device_node * node)1021  static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1022  {
1023  	return i2c_find_adapter_by_fwnode(of_fwnode_handle(node));
1024  }
1025  
1026  /* must call i2c_put_adapter() when done with returned i2c_adapter device */
of_get_i2c_adapter_by_node(struct device_node * node)1027  static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
1028  {
1029  	return i2c_get_adapter_by_fwnode(of_fwnode_handle(node));
1030  }
1031  
1032  const struct of_device_id
1033  *i2c_of_match_device(const struct of_device_id *matches,
1034  		     struct i2c_client *client);
1035  
1036  int of_i2c_get_board_info(struct device *dev, struct device_node *node,
1037  			  struct i2c_board_info *info);
1038  
1039  #else
1040  
of_find_i2c_device_by_node(struct device_node * node)1041  static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1042  {
1043  	return NULL;
1044  }
1045  
of_find_i2c_adapter_by_node(struct device_node * node)1046  static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1047  {
1048  	return NULL;
1049  }
1050  
of_get_i2c_adapter_by_node(struct device_node * node)1051  static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
1052  {
1053  	return NULL;
1054  }
1055  
1056  static inline const struct of_device_id
i2c_of_match_device(const struct of_device_id * matches,struct i2c_client * client)1057  *i2c_of_match_device(const struct of_device_id *matches,
1058  		     struct i2c_client *client)
1059  {
1060  	return NULL;
1061  }
1062  
of_i2c_get_board_info(struct device * dev,struct device_node * node,struct i2c_board_info * info)1063  static inline int of_i2c_get_board_info(struct device *dev,
1064  					struct device_node *node,
1065  					struct i2c_board_info *info)
1066  {
1067  	return -ENOTSUPP;
1068  }
1069  
1070  #endif /* CONFIG_OF */
1071  
1072  struct acpi_resource;
1073  struct acpi_resource_i2c_serialbus;
1074  
1075  #if IS_REACHABLE(CONFIG_ACPI) && IS_REACHABLE(CONFIG_I2C)
1076  bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
1077  			       struct acpi_resource_i2c_serialbus **i2c);
1078  int i2c_acpi_client_count(struct acpi_device *adev);
1079  u32 i2c_acpi_find_bus_speed(struct device *dev);
1080  struct i2c_client *i2c_acpi_new_device_by_fwnode(struct fwnode_handle *fwnode,
1081  						 int index,
1082  						 struct i2c_board_info *info);
1083  struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
1084  bool i2c_acpi_waive_d0_probe(struct device *dev);
1085  #else
i2c_acpi_get_i2c_resource(struct acpi_resource * ares,struct acpi_resource_i2c_serialbus ** i2c)1086  static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
1087  					     struct acpi_resource_i2c_serialbus **i2c)
1088  {
1089  	return false;
1090  }
i2c_acpi_client_count(struct acpi_device * adev)1091  static inline int i2c_acpi_client_count(struct acpi_device *adev)
1092  {
1093  	return 0;
1094  }
i2c_acpi_find_bus_speed(struct device * dev)1095  static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
1096  {
1097  	return 0;
1098  }
i2c_acpi_new_device_by_fwnode(struct fwnode_handle * fwnode,int index,struct i2c_board_info * info)1099  static inline struct i2c_client *i2c_acpi_new_device_by_fwnode(
1100  					struct fwnode_handle *fwnode, int index,
1101  					struct i2c_board_info *info)
1102  {
1103  	return ERR_PTR(-ENODEV);
1104  }
i2c_acpi_find_adapter_by_handle(acpi_handle handle)1105  static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
1106  {
1107  	return NULL;
1108  }
i2c_acpi_waive_d0_probe(struct device * dev)1109  static inline bool i2c_acpi_waive_d0_probe(struct device *dev)
1110  {
1111  	return false;
1112  }
1113  #endif /* CONFIG_ACPI */
1114  
i2c_acpi_new_device(struct device * dev,int index,struct i2c_board_info * info)1115  static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
1116  						     int index,
1117  						     struct i2c_board_info *info)
1118  {
1119  	return i2c_acpi_new_device_by_fwnode(dev_fwnode(dev), index, info);
1120  }
1121  
1122  #endif /* _LINUX_I2C_H */
1123