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@the-dreams.de>
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/mod_devicetable.h>
15  #include <linux/device.h>	/* for struct device */
16  #include <linux/sched.h>	/* for completion */
17  #include <linux/mutex.h>
18  #include <linux/rtmutex.h>
19  #include <linux/irqdomain.h>		/* for Host Notify IRQ */
20  #include <linux/of.h>		/* for struct device_node */
21  #include <linux/swab.h>		/* for swab16 */
22  #include <uapi/linux/i2c.h>
23  
24  extern struct bus_type i2c_bus_type;
25  extern struct device_type i2c_adapter_type;
26  extern struct device_type i2c_client_type;
27  
28  /* --- General options ------------------------------------------------	*/
29  
30  struct i2c_msg;
31  struct i2c_algorithm;
32  struct i2c_adapter;
33  struct i2c_client;
34  struct i2c_driver;
35  struct i2c_device_identity;
36  union i2c_smbus_data;
37  struct i2c_board_info;
38  enum i2c_slave_event;
39  typedef int (*i2c_slave_cb_t)(struct i2c_client *client,
40  			      enum i2c_slave_event event, u8 *val);
41  
42  struct module;
43  struct property_entry;
44  
45  #if IS_ENABLED(CONFIG_I2C)
46  /*
47   * The master routines are the ones normally used to transmit data to devices
48   * on a bus (or read from them). Apart from two basic transfer functions to
49   * transmit one message at a time, a more complex version can be used to
50   * transmit an arbitrary number of messages without interruption.
51   * @count must be be less than 64k since msg.len is u16.
52   */
53  extern int i2c_transfer_buffer_flags(const struct i2c_client *client,
54  				     char *buf, int count, u16 flags);
55  
56  /**
57   * i2c_master_recv - issue a single I2C message in master receive mode
58   * @client: Handle to slave device
59   * @buf: Where to store data read from slave
60   * @count: How many bytes to read, must be less than 64k since msg.len is u16
61   *
62   * Returns negative errno, or else the number of bytes read.
63   */
i2c_master_recv(const struct i2c_client * client,char * buf,int count)64  static inline int i2c_master_recv(const struct i2c_client *client,
65  				  char *buf, int count)
66  {
67  	return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
68  };
69  
70  /**
71   * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
72   *			     using a DMA safe buffer
73   * @client: Handle to slave device
74   * @buf: Where to store data read from slave, must be safe to use with DMA
75   * @count: How many bytes to read, must be less than 64k since msg.len is u16
76   *
77   * Returns negative errno, or else the number of bytes read.
78   */
i2c_master_recv_dmasafe(const struct i2c_client * client,char * buf,int count)79  static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
80  					  char *buf, int count)
81  {
82  	return i2c_transfer_buffer_flags(client, buf, count,
83  					 I2C_M_RD | I2C_M_DMA_SAFE);
84  };
85  
86  /**
87   * i2c_master_send - issue a single I2C message in master transmit mode
88   * @client: Handle to slave device
89   * @buf: Data that will be written to the slave
90   * @count: How many bytes to write, must be less than 64k since msg.len is u16
91   *
92   * Returns negative errno, or else the number of bytes written.
93   */
i2c_master_send(const struct i2c_client * client,const char * buf,int count)94  static inline int i2c_master_send(const struct i2c_client *client,
95  				  const char *buf, int count)
96  {
97  	return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
98  };
99  
100  /**
101   * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
102   *			     using a DMA safe buffer
103   * @client: Handle to slave device
104   * @buf: Data that will be written to the slave, must be safe to use with DMA
105   * @count: How many bytes to write, must be less than 64k since msg.len is u16
106   *
107   * Returns negative errno, or else the number of bytes written.
108   */
i2c_master_send_dmasafe(const struct i2c_client * client,const char * buf,int count)109  static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
110  					  const char *buf, int count)
111  {
112  	return i2c_transfer_buffer_flags(client, (char *)buf, count,
113  					 I2C_M_DMA_SAFE);
114  };
115  
116  /* Transfer num messages.
117   */
118  extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
119  			int num);
120  /* Unlocked flavor */
121  extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
122  			  int num);
123  
124  /* This is the very generalized SMBus access routine. You probably do not
125     want to use this, though; one of the functions below may be much easier,
126     and probably just as fast.
127     Note that we use i2c_adapter here, because you do not need a specific
128     smbus adapter to call this function. */
129  s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
130  		   unsigned short flags, char read_write, u8 command,
131  		   int protocol, union i2c_smbus_data *data);
132  
133  /* Unlocked flavor */
134  s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
135  		     unsigned short flags, char read_write, u8 command,
136  		     int protocol, union i2c_smbus_data *data);
137  
138  /* Now follow the 'nice' access routines. These also document the calling
139     conventions of i2c_smbus_xfer. */
140  
141  extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
142  extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
143  extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
144  				    u8 command);
145  extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
146  				     u8 command, u8 value);
147  extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
148  				    u8 command);
149  extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
150  				     u8 command, u16 value);
151  
152  static inline s32
i2c_smbus_read_word_swapped(const struct i2c_client * client,u8 command)153  i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
154  {
155  	s32 value = i2c_smbus_read_word_data(client, command);
156  
157  	return (value < 0) ? value : swab16(value);
158  }
159  
160  static inline s32
i2c_smbus_write_word_swapped(const struct i2c_client * client,u8 command,u16 value)161  i2c_smbus_write_word_swapped(const struct i2c_client *client,
162  			     u8 command, u16 value)
163  {
164  	return i2c_smbus_write_word_data(client, command, swab16(value));
165  }
166  
167  /* Returns the number of read bytes */
168  extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
169  				     u8 command, u8 *values);
170  extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
171  				      u8 command, u8 length, const u8 *values);
172  /* Returns the number of read bytes */
173  extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
174  					 u8 command, u8 length, u8 *values);
175  extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
176  					  u8 command, u8 length,
177  					  const u8 *values);
178  extern s32
179  i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
180  					  u8 command, u8 length, u8 *values);
181  int i2c_get_device_id(const struct i2c_client *client,
182  		      struct i2c_device_identity *id);
183  #endif /* I2C */
184  
185  /**
186   * struct i2c_device_identity - i2c client device identification
187   * @manufacturer_id: 0 - 4095, database maintained by NXP
188   * @part_id: 0 - 511, according to manufacturer
189   * @die_revision: 0 - 7, according to manufacturer
190   */
191  struct i2c_device_identity {
192  	u16 manufacturer_id;
193  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS                0
194  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1              1
195  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2              2
196  #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3              3
197  #define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL             4
198  #define I2C_DEVICE_ID_ANALOG_DEVICES                    5
199  #define I2C_DEVICE_ID_STMICROELECTRONICS                6
200  #define I2C_DEVICE_ID_ON_SEMICONDUCTOR                  7
201  #define I2C_DEVICE_ID_SPRINTEK_CORPORATION              8
202  #define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG               9
203  #define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR            10
204  #define I2C_DEVICE_ID_FLIR                             11
205  #define I2C_DEVICE_ID_O2MICRO                          12
206  #define I2C_DEVICE_ID_ATMEL                            13
207  #define I2C_DEVICE_ID_NONE                         0xffff
208  	u16 part_id;
209  	u8 die_revision;
210  };
211  
212  enum i2c_alert_protocol {
213  	I2C_PROTOCOL_SMBUS_ALERT,
214  	I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
215  };
216  
217  /**
218   * struct i2c_driver - represent an I2C device driver
219   * @class: What kind of i2c device we instantiate (for detect)
220   * @probe: Callback for device binding - soon to be deprecated
221   * @probe_new: New callback for device binding
222   * @remove: Callback for device unbinding
223   * @shutdown: Callback for device shutdown
224   * @alert: Alert callback, for example for the SMBus alert protocol
225   * @command: Callback for bus-wide signaling (optional)
226   * @driver: Device driver model driver
227   * @id_table: List of I2C devices supported by this driver
228   * @detect: Callback for device detection
229   * @address_list: The I2C addresses to probe (for detect)
230   * @clients: List of detected clients we created (for i2c-core use only)
231   * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
232   *
233   * The driver.owner field should be set to the module owner of this driver.
234   * The driver.name field should be set to the name of this driver.
235   *
236   * For automatic device detection, both @detect and @address_list must
237   * be defined. @class should also be set, otherwise only devices forced
238   * with module parameters will be created. The detect function must
239   * fill at least the name field of the i2c_board_info structure it is
240   * handed upon successful detection, and possibly also the flags field.
241   *
242   * If @detect is missing, the driver will still work fine for enumerated
243   * devices. Detected devices simply won't be supported. This is expected
244   * for the many I2C/SMBus devices which can't be detected reliably, and
245   * the ones which can always be enumerated in practice.
246   *
247   * The i2c_client structure which is handed to the @detect callback is
248   * not a real i2c_client. It is initialized just enough so that you can
249   * call i2c_smbus_read_byte_data and friends on it. Don't do anything
250   * else with it. In particular, calling dev_dbg and friends on it is
251   * not allowed.
252   */
253  struct i2c_driver {
254  	unsigned int class;
255  
256  	/* Standard driver model interfaces */
257  	int (*probe)(struct i2c_client *client, const struct i2c_device_id *id);
258  	int (*remove)(struct i2c_client *client);
259  
260  	/* New driver model interface to aid the seamless removal of the
261  	 * current probe()'s, more commonly unused than used second parameter.
262  	 */
263  	int (*probe_new)(struct i2c_client *client);
264  
265  	/* driver model interfaces that don't relate to enumeration  */
266  	void (*shutdown)(struct i2c_client *client);
267  
268  	/* Alert callback, for example for the SMBus alert protocol.
269  	 * The format and meaning of the data value depends on the protocol.
270  	 * For the SMBus alert protocol, there is a single bit of data passed
271  	 * as the alert response's low bit ("event flag").
272  	 * For the SMBus Host Notify protocol, the data corresponds to the
273  	 * 16-bit payload data reported by the slave device acting as master.
274  	 */
275  	void (*alert)(struct i2c_client *client, enum i2c_alert_protocol protocol,
276  		      unsigned int data);
277  
278  	/* a ioctl like command that can be used to perform specific functions
279  	 * with the device.
280  	 */
281  	int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
282  
283  	struct device_driver driver;
284  	const struct i2c_device_id *id_table;
285  
286  	/* Device detection callback for automatic device creation */
287  	int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
288  	const unsigned short *address_list;
289  	struct list_head clients;
290  
291  	bool disable_i2c_core_irq_mapping;
292  };
293  #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
294  
295  /**
296   * struct i2c_client - represent an I2C slave device
297   * @flags: see I2C_CLIENT_* for possible flags
298   * @addr: Address used on the I2C bus connected to the parent adapter.
299   * @name: Indicates the type of the device, usually a chip name that's
300   *	generic enough to hide second-sourcing and compatible revisions.
301   * @adapter: manages the bus segment hosting this I2C device
302   * @dev: Driver model device node for the slave.
303   * @irq: indicates the IRQ generated by this device (if any)
304   * @detected: member of an i2c_driver.clients list or i2c-core's
305   *	userspace_devices list
306   * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
307   *	calls it to pass on slave events to the slave driver.
308   *
309   * An i2c_client identifies a single device (i.e. chip) connected to an
310   * i2c bus. The behaviour exposed to Linux is defined by the driver
311   * managing the device.
312   */
313  struct i2c_client {
314  	unsigned short flags;		/* div., see below		*/
315  #define I2C_CLIENT_PEC		0x04	/* Use Packet Error Checking */
316  #define I2C_CLIENT_TEN		0x10	/* we have a ten bit chip address */
317  					/* Must equal I2C_M_TEN below */
318  #define I2C_CLIENT_SLAVE	0x20	/* we are the slave */
319  #define I2C_CLIENT_HOST_NOTIFY	0x40	/* We want to use I2C host notify */
320  #define I2C_CLIENT_WAKE		0x80	/* for board_info; true iff can wake */
321  #define I2C_CLIENT_SCCB		0x9000	/* Use Omnivision SCCB protocol */
322  					/* Must match I2C_M_STOP|IGNORE_NAK */
323  
324  	unsigned short addr;		/* chip address - NOTE: 7bit	*/
325  					/* addresses are stored in the	*/
326  					/* _LOWER_ 7 bits		*/
327  	char name[I2C_NAME_SIZE];
328  	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
329  	struct device dev;		/* the device structure		*/
330  	int init_irq;			/* irq set at initialization	*/
331  	int irq;			/* irq issued by device		*/
332  	struct list_head detected;
333  #if IS_ENABLED(CONFIG_I2C_SLAVE)
334  	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
335  #endif
336  };
337  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
338  
339  extern struct i2c_client *i2c_verify_client(struct device *dev);
340  extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
341  extern const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
342  					const struct i2c_client *client);
343  
kobj_to_i2c_client(struct kobject * kobj)344  static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
345  {
346  	struct device * const dev = container_of(kobj, struct device, kobj);
347  	return to_i2c_client(dev);
348  }
349  
i2c_get_clientdata(const struct i2c_client * dev)350  static inline void *i2c_get_clientdata(const struct i2c_client *dev)
351  {
352  	return dev_get_drvdata(&dev->dev);
353  }
354  
i2c_set_clientdata(struct i2c_client * dev,void * data)355  static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
356  {
357  	dev_set_drvdata(&dev->dev, data);
358  }
359  
360  /* I2C slave support */
361  
362  #if IS_ENABLED(CONFIG_I2C_SLAVE)
363  enum i2c_slave_event {
364  	I2C_SLAVE_READ_REQUESTED,
365  	I2C_SLAVE_WRITE_REQUESTED,
366  	I2C_SLAVE_READ_PROCESSED,
367  	I2C_SLAVE_WRITE_RECEIVED,
368  	I2C_SLAVE_STOP,
369  };
370  
371  extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
372  extern int i2c_slave_unregister(struct i2c_client *client);
373  extern bool i2c_detect_slave_mode(struct device *dev);
374  
i2c_slave_event(struct i2c_client * client,enum i2c_slave_event event,u8 * val)375  static inline int i2c_slave_event(struct i2c_client *client,
376  				  enum i2c_slave_event event, u8 *val)
377  {
378  	return client->slave_cb(client, event, val);
379  }
380  #else
i2c_detect_slave_mode(struct device * dev)381  static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
382  #endif
383  
384  /**
385   * struct i2c_board_info - template for device creation
386   * @type: chip type, to initialize i2c_client.name
387   * @flags: to initialize i2c_client.flags
388   * @addr: stored in i2c_client.addr
389   * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
390   * @platform_data: stored in i2c_client.dev.platform_data
391   * @of_node: pointer to OpenFirmware device node
392   * @fwnode: device node supplied by the platform firmware
393   * @properties: additional device properties for the device
394   * @resources: resources associated with the device
395   * @num_resources: number of resources in the @resources array
396   * @irq: stored in i2c_client.irq
397   *
398   * I2C doesn't actually support hardware probing, although controllers and
399   * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
400   * a device at a given address.  Drivers commonly need more information than
401   * that, such as chip type, configuration, associated IRQ, and so on.
402   *
403   * i2c_board_info is used to build tables of information listing I2C devices
404   * that are present.  This information is used to grow the driver model tree.
405   * For mainboards this is done statically using i2c_register_board_info();
406   * bus numbers identify adapters that aren't yet available.  For add-on boards,
407   * i2c_new_device() does this dynamically with the adapter already known.
408   */
409  struct i2c_board_info {
410  	char		type[I2C_NAME_SIZE];
411  	unsigned short	flags;
412  	unsigned short	addr;
413  	const char	*dev_name;
414  	void		*platform_data;
415  	struct device_node *of_node;
416  	struct fwnode_handle *fwnode;
417  	const struct property_entry *properties;
418  	const struct resource *resources;
419  	unsigned int	num_resources;
420  	int		irq;
421  };
422  
423  /**
424   * I2C_BOARD_INFO - macro used to list an i2c device and its address
425   * @dev_type: identifies the device type
426   * @dev_addr: the device's address on the bus.
427   *
428   * This macro initializes essential fields of a struct i2c_board_info,
429   * declaring what has been provided on a particular board.  Optional
430   * fields (such as associated irq, or device-specific platform_data)
431   * are provided using conventional syntax.
432   */
433  #define I2C_BOARD_INFO(dev_type, dev_addr) \
434  	.type = dev_type, .addr = (dev_addr)
435  
436  
437  #if IS_ENABLED(CONFIG_I2C)
438  /* Add-on boards should register/unregister their devices; e.g. a board
439   * with integrated I2C, a config eeprom, sensors, and a codec that's
440   * used in conjunction with the primary hardware.
441   */
442  extern struct i2c_client *
443  i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
444  
445  extern struct i2c_client *
446  i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
447  
448  /* If you don't know the exact address of an I2C device, use this variant
449   * instead, which can probe for device presence in a list of possible
450   * addresses. The "probe" callback function is optional. If it is provided,
451   * it must return 1 on successful probe, 0 otherwise. If it is not provided,
452   * a default probing method is used.
453   */
454  extern struct i2c_client *
455  i2c_new_probed_device(struct i2c_adapter *adap,
456  		      struct i2c_board_info *info,
457  		      unsigned short const *addr_list,
458  		      int (*probe)(struct i2c_adapter *adap, unsigned short addr));
459  
460  /* Common custom probe functions */
461  extern int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr);
462  
463  /* For devices that use several addresses, use i2c_new_dummy() to make
464   * client handles for the extra addresses.
465   */
466  extern struct i2c_client *
467  i2c_new_dummy(struct i2c_adapter *adap, u16 address);
468  
469  extern struct i2c_client *
470  i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address);
471  
472  extern struct i2c_client *
473  devm_i2c_new_dummy_device(struct device *dev, struct i2c_adapter *adap, u16 address);
474  
475  extern struct i2c_client *
476  i2c_new_ancillary_device(struct i2c_client *client,
477  				const char *name,
478  				u16 default_addr);
479  
480  extern void i2c_unregister_device(struct i2c_client *client);
481  #endif /* I2C */
482  
483  /* Mainboard arch_initcall() code should register all its I2C devices.
484   * This is done at arch_initcall time, before declaring any i2c adapters.
485   * Modules for add-on boards must use other calls.
486   */
487  #ifdef CONFIG_I2C_BOARDINFO
488  extern int
489  i2c_register_board_info(int busnum, struct i2c_board_info const *info,
490  			unsigned n);
491  #else
492  static inline int
i2c_register_board_info(int busnum,struct i2c_board_info const * info,unsigned n)493  i2c_register_board_info(int busnum, struct i2c_board_info const *info,
494  			unsigned n)
495  {
496  	return 0;
497  }
498  #endif /* I2C_BOARDINFO */
499  
500  /**
501   * struct i2c_algorithm - represent I2C transfer method
502   * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
503   *   defined by the msgs array, with num messages available to transfer via
504   *   the adapter specified by adap.
505   * @master_xfer_atomic: same as @master_xfer. Yet, only using atomic context
506   *   so e.g. PMICs can be accessed very late before shutdown. Optional.
507   * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
508   *   is not present, then the bus layer will try and convert the SMBus calls
509   *   into I2C transfers instead.
510   * @smbus_xfer_atomic: same as @smbus_xfer. Yet, only using atomic context
511   *   so e.g. PMICs can be accessed very late before shutdown. Optional.
512   * @functionality: Return the flags that this algorithm/adapter pair supports
513   *   from the I2C_FUNC_* flags.
514   * @reg_slave: Register given client to I2C slave mode of this adapter
515   * @unreg_slave: Unregister given client from I2C slave mode of this adapter
516   *
517   * The following structs are for those who like to implement new bus drivers:
518   * i2c_algorithm is the interface to a class of hardware solutions which can
519   * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
520   * to name two of the most common.
521   *
522   * The return codes from the @master_xfer{_atomic} fields should indicate the
523   * type of error code that occurred during the transfer, as documented in the
524   * Kernel Documentation file Documentation/i2c/fault-codes.rst.
525   */
526  struct i2c_algorithm {
527  	/*
528  	 * If an adapter algorithm can't do I2C-level access, set master_xfer
529  	 * to NULL. If an adapter algorithm can do SMBus access, set
530  	 * smbus_xfer. If set to NULL, the SMBus protocol is simulated
531  	 * using common I2C messages.
532  	 *
533  	 * master_xfer should return the number of messages successfully
534  	 * processed, or a negative value on error
535  	 */
536  	int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
537  			   int num);
538  	int (*master_xfer_atomic)(struct i2c_adapter *adap,
539  				   struct i2c_msg *msgs, int num);
540  	int (*smbus_xfer)(struct i2c_adapter *adap, u16 addr,
541  			  unsigned short flags, char read_write,
542  			  u8 command, int size, union i2c_smbus_data *data);
543  	int (*smbus_xfer_atomic)(struct i2c_adapter *adap, u16 addr,
544  				 unsigned short flags, char read_write,
545  				 u8 command, int size, union i2c_smbus_data *data);
546  
547  	/* To determine what the adapter supports */
548  	u32 (*functionality)(struct i2c_adapter *adap);
549  
550  #if IS_ENABLED(CONFIG_I2C_SLAVE)
551  	int (*reg_slave)(struct i2c_client *client);
552  	int (*unreg_slave)(struct i2c_client *client);
553  #endif
554  };
555  
556  /**
557   * struct i2c_lock_operations - represent I2C locking operations
558   * @lock_bus: Get exclusive access to an I2C bus segment
559   * @trylock_bus: Try to get exclusive access to an I2C bus segment
560   * @unlock_bus: Release exclusive access to an I2C bus segment
561   *
562   * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
563   */
564  struct i2c_lock_operations {
565  	void (*lock_bus)(struct i2c_adapter *adapter, unsigned int flags);
566  	int (*trylock_bus)(struct i2c_adapter *adapter, unsigned int flags);
567  	void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags);
568  };
569  
570  /**
571   * struct i2c_timings - I2C timing information
572   * @bus_freq_hz: the bus frequency in Hz
573   * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
574   * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
575   * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
576   * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
577   * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
578   */
579  struct i2c_timings {
580  	u32 bus_freq_hz;
581  	u32 scl_rise_ns;
582  	u32 scl_fall_ns;
583  	u32 scl_int_delay_ns;
584  	u32 sda_fall_ns;
585  	u32 sda_hold_ns;
586  };
587  
588  /**
589   * struct i2c_bus_recovery_info - I2C bus recovery information
590   * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
591   *	i2c_generic_scl_recovery().
592   * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
593   *      recovery. Populated internally for generic GPIO recovery.
594   * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
595   *      Populated internally for generic GPIO recovery.
596   * @get_sda: This gets current value of SDA line. This or set_sda() is mandatory
597   *	for generic SCL recovery. Populated internally, if sda_gpio is a valid
598   *	GPIO, for generic GPIO recovery.
599   * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for
600   *	generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO,
601   *	for generic GPIO recovery.
602   * @get_bus_free: Returns the bus free state as seen from the IP core in case it
603   *	has a more complex internal logic than just reading SDA. Optional.
604   * @prepare_recovery: This will be called before starting recovery. Platform may
605   *	configure padmux here for SDA/SCL line or something else they want.
606   * @unprepare_recovery: This will be called after completing recovery. Platform
607   *	may configure padmux here for SDA/SCL line or something else they want.
608   * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
609   * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
610   */
611  struct i2c_bus_recovery_info {
612  	int (*recover_bus)(struct i2c_adapter *adap);
613  
614  	int (*get_scl)(struct i2c_adapter *adap);
615  	void (*set_scl)(struct i2c_adapter *adap, int val);
616  	int (*get_sda)(struct i2c_adapter *adap);
617  	void (*set_sda)(struct i2c_adapter *adap, int val);
618  	int (*get_bus_free)(struct i2c_adapter *adap);
619  
620  	void (*prepare_recovery)(struct i2c_adapter *adap);
621  	void (*unprepare_recovery)(struct i2c_adapter *adap);
622  
623  	/* gpio recovery */
624  	struct gpio_desc *scl_gpiod;
625  	struct gpio_desc *sda_gpiod;
626  };
627  
628  int i2c_recover_bus(struct i2c_adapter *adap);
629  
630  /* Generic recovery routines */
631  int i2c_generic_scl_recovery(struct i2c_adapter *adap);
632  
633  /**
634   * struct i2c_adapter_quirks - describe flaws of an i2c adapter
635   * @flags: see I2C_AQ_* for possible flags and read below
636   * @max_num_msgs: maximum number of messages per transfer
637   * @max_write_len: maximum length of a write message
638   * @max_read_len: maximum length of a read message
639   * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
640   * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
641   *
642   * Note about combined messages: Some I2C controllers can only send one message
643   * per transfer, plus something called combined message or write-then-read.
644   * This is (usually) a small write message followed by a read message and
645   * barely enough to access register based devices like EEPROMs. There is a flag
646   * to support this mode. It implies max_num_msg = 2 and does the length checks
647   * with max_comb_*_len because combined message mode usually has its own
648   * limitations. Because of HW implementations, some controllers can actually do
649   * write-then-anything or other variants. To support that, write-then-read has
650   * been broken out into smaller bits like write-first and read-second which can
651   * be combined as needed.
652   */
653  
654  struct i2c_adapter_quirks {
655  	u64 flags;
656  	int max_num_msgs;
657  	u16 max_write_len;
658  	u16 max_read_len;
659  	u16 max_comb_1st_msg_len;
660  	u16 max_comb_2nd_msg_len;
661  };
662  
663  /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
664  #define I2C_AQ_COMB			BIT(0)
665  /* first combined message must be write */
666  #define I2C_AQ_COMB_WRITE_FIRST		BIT(1)
667  /* second combined message must be read */
668  #define I2C_AQ_COMB_READ_SECOND		BIT(2)
669  /* both combined messages must have the same target address */
670  #define I2C_AQ_COMB_SAME_ADDR		BIT(3)
671  /* convenience macro for typical write-then read case */
672  #define I2C_AQ_COMB_WRITE_THEN_READ	(I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
673  					 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
674  /* clock stretching is not supported */
675  #define I2C_AQ_NO_CLK_STRETCH		BIT(4)
676  /* message cannot have length of 0 */
677  #define I2C_AQ_NO_ZERO_LEN_READ		BIT(5)
678  #define I2C_AQ_NO_ZERO_LEN_WRITE	BIT(6)
679  #define I2C_AQ_NO_ZERO_LEN		(I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
680  
681  /*
682   * i2c_adapter is the structure used to identify a physical i2c bus along
683   * with the access algorithms necessary to access it.
684   */
685  struct i2c_adapter {
686  	struct module *owner;
687  	unsigned int class;		  /* classes to allow probing for */
688  	const struct i2c_algorithm *algo; /* the algorithm to access the bus */
689  	void *algo_data;
690  
691  	/* data fields that are valid for all devices	*/
692  	const struct i2c_lock_operations *lock_ops;
693  	struct rt_mutex bus_lock;
694  	struct rt_mutex mux_lock;
695  
696  	int timeout;			/* in jiffies */
697  	int retries;
698  	struct device dev;		/* the adapter device */
699  	unsigned long locked_flags;	/* owned by the I2C core */
700  #define I2C_ALF_IS_SUSPENDED		0
701  #define I2C_ALF_SUSPEND_REPORTED	1
702  
703  	int nr;
704  	char name[48];
705  	struct completion dev_released;
706  
707  	struct mutex userspace_clients_lock;
708  	struct list_head userspace_clients;
709  
710  	struct i2c_bus_recovery_info *bus_recovery_info;
711  	const struct i2c_adapter_quirks *quirks;
712  
713  	struct irq_domain *host_notify_domain;
714  };
715  #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
716  
i2c_get_adapdata(const struct i2c_adapter * adap)717  static inline void *i2c_get_adapdata(const struct i2c_adapter *adap)
718  {
719  	return dev_get_drvdata(&adap->dev);
720  }
721  
i2c_set_adapdata(struct i2c_adapter * adap,void * data)722  static inline void i2c_set_adapdata(struct i2c_adapter *adap, void *data)
723  {
724  	dev_set_drvdata(&adap->dev, data);
725  }
726  
727  static inline struct i2c_adapter *
i2c_parent_is_i2c_adapter(const struct i2c_adapter * adapter)728  i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
729  {
730  #if IS_ENABLED(CONFIG_I2C_MUX)
731  	struct device *parent = adapter->dev.parent;
732  
733  	if (parent != NULL && parent->type == &i2c_adapter_type)
734  		return to_i2c_adapter(parent);
735  	else
736  #endif
737  		return NULL;
738  }
739  
740  int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data));
741  
742  /* Adapter locking functions, exported for shared pin cases */
743  #define I2C_LOCK_ROOT_ADAPTER BIT(0)
744  #define I2C_LOCK_SEGMENT      BIT(1)
745  
746  /**
747   * i2c_lock_bus - Get exclusive access to an I2C bus segment
748   * @adapter: Target I2C bus segment
749   * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
750   *	locks only this branch in the adapter tree
751   */
752  static inline void
i2c_lock_bus(struct i2c_adapter * adapter,unsigned int flags)753  i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
754  {
755  	adapter->lock_ops->lock_bus(adapter, flags);
756  }
757  
758  /**
759   * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
760   * @adapter: Target I2C bus segment
761   * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
762   *	I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
763   *
764   * Return: true if the I2C bus segment is locked, false otherwise
765   */
766  static inline int
i2c_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)767  i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
768  {
769  	return adapter->lock_ops->trylock_bus(adapter, flags);
770  }
771  
772  /**
773   * i2c_unlock_bus - Release exclusive access to an I2C bus segment
774   * @adapter: Target I2C bus segment
775   * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
776   *	unlocks only this branch in the adapter tree
777   */
778  static inline void
i2c_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)779  i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
780  {
781  	adapter->lock_ops->unlock_bus(adapter, flags);
782  }
783  
784  /**
785   * i2c_mark_adapter_suspended - Report suspended state of the adapter to the core
786   * @adap: Adapter to mark as suspended
787   *
788   * When using this helper to mark an adapter as suspended, the core will reject
789   * further transfers to this adapter. The usage of this helper is optional but
790   * recommended for devices having distinct handlers for system suspend and
791   * runtime suspend. More complex devices are free to implement custom solutions
792   * to reject transfers when suspended.
793   */
i2c_mark_adapter_suspended(struct i2c_adapter * adap)794  static inline void i2c_mark_adapter_suspended(struct i2c_adapter *adap)
795  {
796  	i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
797  	set_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
798  	i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
799  }
800  
801  /**
802   * i2c_mark_adapter_resumed - Report resumed state of the adapter to the core
803   * @adap: Adapter to mark as resumed
804   *
805   * When using this helper to mark an adapter as resumed, the core will allow
806   * further transfers to this adapter. See also further notes to
807   * @i2c_mark_adapter_suspended().
808   */
i2c_mark_adapter_resumed(struct i2c_adapter * adap)809  static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap)
810  {
811  	i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
812  	clear_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
813  	i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
814  }
815  
816  /* i2c adapter classes (bitmask) */
817  #define I2C_CLASS_HWMON		(1<<0)	/* lm_sensors, ... */
818  #define I2C_CLASS_DDC		(1<<3)	/* DDC bus on graphics adapters */
819  #define I2C_CLASS_SPD		(1<<7)	/* Memory modules */
820  /* Warn users that the adapter doesn't support classes anymore */
821  #define I2C_CLASS_DEPRECATED	(1<<8)
822  
823  /* Internal numbers to terminate lists */
824  #define I2C_CLIENT_END		0xfffeU
825  
826  /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
827  #define I2C_ADDRS(addr, addrs...) \
828  	((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
829  
830  
831  /* ----- functions exported by i2c.o */
832  
833  /* administration...
834   */
835  #if IS_ENABLED(CONFIG_I2C)
836  extern int i2c_add_adapter(struct i2c_adapter *adap);
837  extern void i2c_del_adapter(struct i2c_adapter *adap);
838  extern int i2c_add_numbered_adapter(struct i2c_adapter *adap);
839  
840  extern int i2c_register_driver(struct module *owner, struct i2c_driver *driver);
841  extern void i2c_del_driver(struct i2c_driver *driver);
842  
843  /* use a define to avoid include chaining to get THIS_MODULE */
844  #define i2c_add_driver(driver) \
845  	i2c_register_driver(THIS_MODULE, driver)
846  
847  extern struct i2c_client *i2c_use_client(struct i2c_client *client);
848  extern void i2c_release_client(struct i2c_client *client);
849  
850  /* call the i2c_client->command() of all attached clients with
851   * the given arguments */
852  extern void i2c_clients_command(struct i2c_adapter *adap,
853  				unsigned int cmd, void *arg);
854  
855  extern struct i2c_adapter *i2c_get_adapter(int nr);
856  extern void i2c_put_adapter(struct i2c_adapter *adap);
857  extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
858  
859  void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
860  
861  /* Return the functionality mask */
i2c_get_functionality(struct i2c_adapter * adap)862  static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
863  {
864  	return adap->algo->functionality(adap);
865  }
866  
867  /* Return 1 if adapter supports everything we need, 0 if not. */
i2c_check_functionality(struct i2c_adapter * adap,u32 func)868  static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
869  {
870  	return (func & i2c_get_functionality(adap)) == func;
871  }
872  
873  /**
874   * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
875   * @adap: i2c adapter
876   * @quirks: quirk flags
877   *
878   * Return: true if the adapter has all the specified quirk flags, false if not
879   */
i2c_check_quirks(struct i2c_adapter * adap,u64 quirks)880  static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
881  {
882  	if (!adap->quirks)
883  		return false;
884  	return (adap->quirks->flags & quirks) == quirks;
885  }
886  
887  /* Return the adapter number for a specific adapter */
i2c_adapter_id(struct i2c_adapter * adap)888  static inline int i2c_adapter_id(struct i2c_adapter *adap)
889  {
890  	return adap->nr;
891  }
892  
i2c_8bit_addr_from_msg(const struct i2c_msg * msg)893  static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
894  {
895  	return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
896  }
897  
898  u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
899  void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
900  
901  int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
902  /**
903   * module_i2c_driver() - Helper macro for registering a modular I2C driver
904   * @__i2c_driver: i2c_driver struct
905   *
906   * Helper macro for I2C drivers which do not do anything special in module
907   * init/exit. This eliminates a lot of boilerplate. Each module may only
908   * use this macro once, and calling it replaces module_init() and module_exit()
909   */
910  #define module_i2c_driver(__i2c_driver) \
911  	module_driver(__i2c_driver, i2c_add_driver, \
912  			i2c_del_driver)
913  
914  /**
915   * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
916   * @__i2c_driver: i2c_driver struct
917   *
918   * Helper macro for I2C drivers which do not do anything special in their
919   * init. This eliminates a lot of boilerplate. Each driver may only
920   * use this macro once, and calling it replaces device_initcall().
921   */
922  #define builtin_i2c_driver(__i2c_driver) \
923  	builtin_driver(__i2c_driver, i2c_add_driver)
924  
925  #endif /* I2C */
926  
927  #if IS_ENABLED(CONFIG_OF)
928  /* must call put_device() when done with returned i2c_client device */
929  extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
930  
931  /* must call put_device() when done with returned i2c_adapter device */
932  extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
933  
934  /* must call i2c_put_adapter() when done with returned i2c_adapter device */
935  struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
936  
937  extern const struct of_device_id
938  *i2c_of_match_device(const struct of_device_id *matches,
939  		     struct i2c_client *client);
940  
941  int of_i2c_get_board_info(struct device *dev, struct device_node *node,
942  			  struct i2c_board_info *info);
943  
944  #else
945  
of_find_i2c_device_by_node(struct device_node * node)946  static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
947  {
948  	return NULL;
949  }
950  
of_find_i2c_adapter_by_node(struct device_node * node)951  static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
952  {
953  	return NULL;
954  }
955  
of_get_i2c_adapter_by_node(struct device_node * node)956  static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
957  {
958  	return NULL;
959  }
960  
961  static inline const struct of_device_id
i2c_of_match_device(const struct of_device_id * matches,struct i2c_client * client)962  *i2c_of_match_device(const struct of_device_id *matches,
963  		     struct i2c_client *client)
964  {
965  	return NULL;
966  }
967  
of_i2c_get_board_info(struct device * dev,struct device_node * node,struct i2c_board_info * info)968  static inline int of_i2c_get_board_info(struct device *dev,
969  					struct device_node *node,
970  					struct i2c_board_info *info)
971  {
972  	return -ENOTSUPP;
973  }
974  
975  #endif /* CONFIG_OF */
976  
977  struct acpi_resource;
978  struct acpi_resource_i2c_serialbus;
979  
980  #if IS_ENABLED(CONFIG_ACPI)
981  bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
982  			       struct acpi_resource_i2c_serialbus **i2c);
983  u32 i2c_acpi_find_bus_speed(struct device *dev);
984  struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
985  				       struct i2c_board_info *info);
986  struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
987  #else
i2c_acpi_get_i2c_resource(struct acpi_resource * ares,struct acpi_resource_i2c_serialbus ** i2c)988  static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
989  					     struct acpi_resource_i2c_serialbus **i2c)
990  {
991  	return false;
992  }
i2c_acpi_find_bus_speed(struct device * dev)993  static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
994  {
995  	return 0;
996  }
i2c_acpi_new_device(struct device * dev,int index,struct i2c_board_info * info)997  static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
998  					int index, struct i2c_board_info *info)
999  {
1000  	return NULL;
1001  }
i2c_acpi_find_adapter_by_handle(acpi_handle handle)1002  static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
1003  {
1004  	return NULL;
1005  }
1006  #endif /* CONFIG_ACPI */
1007  
1008  #endif /* _LINUX_I2C_H */
1009