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TOMOYO Linux Cross Reference
Linux/include/linux/i2c.h

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  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  */
 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  */
 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  */
 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  */
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
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
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 
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 
350 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
351 {
352         return dev_get_drvdata(&dev->dev);
353 }
354 
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 
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
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_secondary_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
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.
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 
717 static inline void *i2c_get_adapdata(const struct i2c_adapter *adap)
718 {
719         return dev_get_drvdata(&adap->dev);
720 }
721 
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 *
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
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
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
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  */
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  */
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 */
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. */
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  */
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 */
888 static inline int i2c_adapter_id(struct i2c_adapter *adap)
889 {
890         return adap->nr;
891 }
892 
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 
946 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
947 {
948         return NULL;
949 }
950 
951 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
952 {
953         return NULL;
954 }
955 
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
962 *i2c_of_match_device(const struct of_device_id *matches,
963                      struct i2c_client *client)
964 {
965         return NULL;
966 }
967 
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
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 }
993 static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
994 {
995         return 0;
996 }
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 }
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 

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