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

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  1 /* ------------------------------------------------------------------------- */
  2 /*                                                                           */
  3 /* i2c.h - definitions for the i2c-bus interface                             */
  4 /*                                                                           */
  5 /* ------------------------------------------------------------------------- */
  6 /*   Copyright (C) 1995-2000 Simon G. Vogl
  7 
  8     This program is free software; you can redistribute it and/or modify
  9     it under the terms of the GNU General Public License as published by
 10     the Free Software Foundation; either version 2 of the License, or
 11     (at your option) any later version.
 12 
 13     This program is distributed in the hope that it will be useful,
 14     but WITHOUT ANY WARRANTY; without even the implied warranty of
 15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 16     GNU General Public License for more details.
 17 
 18     You should have received a copy of the GNU General Public License
 19     along with this program; if not, write to the Free Software
 20     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 21     MA 02110-1301 USA.                                                       */
 22 /* ------------------------------------------------------------------------- */
 23 
 24 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
 25    Frodo Looijaard <frodol@dds.nl> */
 26 #ifndef _LINUX_I2C_H
 27 #define _LINUX_I2C_H
 28 
 29 #include <linux/mod_devicetable.h>
 30 #include <linux/device.h>       /* for struct device */
 31 #include <linux/sched.h>        /* for completion */
 32 #include <linux/mutex.h>
 33 #include <linux/rtmutex.h>
 34 #include <linux/irqdomain.h>            /* for Host Notify IRQ */
 35 #include <linux/of.h>           /* for struct device_node */
 36 #include <linux/swab.h>         /* for swab16 */
 37 #include <uapi/linux/i2c.h>
 38 
 39 extern struct bus_type i2c_bus_type;
 40 extern struct device_type i2c_adapter_type;
 41 extern struct device_type i2c_client_type;
 42 
 43 /* --- General options ------------------------------------------------ */
 44 
 45 struct i2c_msg;
 46 struct i2c_algorithm;
 47 struct i2c_adapter;
 48 struct i2c_client;
 49 struct i2c_driver;
 50 struct i2c_device_identity;
 51 union i2c_smbus_data;
 52 struct i2c_board_info;
 53 enum i2c_slave_event;
 54 typedef int (*i2c_slave_cb_t)(struct i2c_client *, enum i2c_slave_event, u8 *);
 55 
 56 struct module;
 57 struct property_entry;
 58 
 59 #if IS_ENABLED(CONFIG_I2C)
 60 /*
 61  * The master routines are the ones normally used to transmit data to devices
 62  * on a bus (or read from them). Apart from two basic transfer functions to
 63  * transmit one message at a time, a more complex version can be used to
 64  * transmit an arbitrary number of messages without interruption.
 65  * @count must be be less than 64k since msg.len is u16.
 66  */
 67 extern int i2c_transfer_buffer_flags(const struct i2c_client *client,
 68                                      char *buf, int count, u16 flags);
 69 
 70 /**
 71  * i2c_master_recv - issue a single I2C message in master receive mode
 72  * @client: Handle to slave device
 73  * @buf: Where to store data read from slave
 74  * @count: How many bytes to read, must be less than 64k since msg.len is u16
 75  *
 76  * Returns negative errno, or else the number of bytes read.
 77  */
 78 static inline int i2c_master_recv(const struct i2c_client *client,
 79                                   char *buf, int count)
 80 {
 81         return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
 82 };
 83 
 84 /**
 85  * i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
 86  *                           using a DMA safe buffer
 87  * @client: Handle to slave device
 88  * @buf: Where to store data read from slave, must be safe to use with DMA
 89  * @count: How many bytes to read, must be less than 64k since msg.len is u16
 90  *
 91  * Returns negative errno, or else the number of bytes read.
 92  */
 93 static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
 94                                           char *buf, int count)
 95 {
 96         return i2c_transfer_buffer_flags(client, buf, count,
 97                                          I2C_M_RD | I2C_M_DMA_SAFE);
 98 };
 99 
100 /**
101  * i2c_master_send - issue a single I2C message in master transmit mode
102  * @client: Handle to slave device
103  * @buf: Data that will be written to the slave
104  * @count: How many bytes to write, must be less than 64k since msg.len is u16
105  *
106  * Returns negative errno, or else the number of bytes written.
107  */
108 static inline int i2c_master_send(const struct i2c_client *client,
109                                   const char *buf, int count)
110 {
111         return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
112 };
113 
114 /**
115  * i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
116  *                           using a DMA safe buffer
117  * @client: Handle to slave device
118  * @buf: Data that will be written to the slave, must be safe to use with DMA
119  * @count: How many bytes to write, must be less than 64k since msg.len is u16
120  *
121  * Returns negative errno, or else the number of bytes written.
122  */
123 static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
124                                           const char *buf, int count)
125 {
126         return i2c_transfer_buffer_flags(client, (char *)buf, count,
127                                          I2C_M_DMA_SAFE);
128 };
129 
130 /* Transfer num messages.
131  */
132 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
133                         int num);
134 /* Unlocked flavor */
135 extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
136                           int num);
137 
138 /* This is the very generalized SMBus access routine. You probably do not
139    want to use this, though; one of the functions below may be much easier,
140    and probably just as fast.
141    Note that we use i2c_adapter here, because you do not need a specific
142    smbus adapter to call this function. */
143 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
144                    unsigned short flags, char read_write, u8 command,
145                    int protocol, union i2c_smbus_data *data);
146 
147 /* Unlocked flavor */
148 s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
149                      unsigned short flags, char read_write, u8 command,
150                      int protocol, union i2c_smbus_data *data);
151 
152 /* Now follow the 'nice' access routines. These also document the calling
153    conventions of i2c_smbus_xfer. */
154 
155 extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
156 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
157 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
158                                     u8 command);
159 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
160                                      u8 command, u8 value);
161 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
162                                     u8 command);
163 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
164                                      u8 command, u16 value);
165 
166 static inline s32
167 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
168 {
169         s32 value = i2c_smbus_read_word_data(client, command);
170 
171         return (value < 0) ? value : swab16(value);
172 }
173 
174 static inline s32
175 i2c_smbus_write_word_swapped(const struct i2c_client *client,
176                              u8 command, u16 value)
177 {
178         return i2c_smbus_write_word_data(client, command, swab16(value));
179 }
180 
181 /* Returns the number of read bytes */
182 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
183                                      u8 command, u8 *values);
184 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
185                                       u8 command, u8 length, const u8 *values);
186 /* Returns the number of read bytes */
187 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
188                                          u8 command, u8 length, u8 *values);
189 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
190                                           u8 command, u8 length,
191                                           const u8 *values);
192 extern s32
193 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
194                                           u8 command, u8 length, u8 *values);
195 int i2c_get_device_id(const struct i2c_client *client,
196                       struct i2c_device_identity *id);
197 #endif /* I2C */
198 
199 /**
200  * struct i2c_device_identity - i2c client device identification
201  * @manufacturer_id: 0 - 4095, database maintained by NXP
202  * @part_id: 0 - 511, according to manufacturer
203  * @die_revision: 0 - 7, according to manufacturer
204  */
205 struct i2c_device_identity {
206         u16 manufacturer_id;
207 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS                0
208 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1              1
209 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2              2
210 #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3              3
211 #define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL             4
212 #define I2C_DEVICE_ID_ANALOG_DEVICES                    5
213 #define I2C_DEVICE_ID_STMICROELECTRONICS                6
214 #define I2C_DEVICE_ID_ON_SEMICONDUCTOR                  7
215 #define I2C_DEVICE_ID_SPRINTEK_CORPORATION              8
216 #define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG               9
217 #define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR            10
218 #define I2C_DEVICE_ID_FLIR                             11
219 #define I2C_DEVICE_ID_O2MICRO                          12
220 #define I2C_DEVICE_ID_ATMEL                            13
221 #define I2C_DEVICE_ID_NONE                         0xffff
222         u16 part_id;
223         u8 die_revision;
224 };
225 
226 enum i2c_alert_protocol {
227         I2C_PROTOCOL_SMBUS_ALERT,
228         I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
229 };
230 
231 /**
232  * struct i2c_driver - represent an I2C device driver
233  * @class: What kind of i2c device we instantiate (for detect)
234  * @probe: Callback for device binding - soon to be deprecated
235  * @probe_new: New callback for device binding
236  * @remove: Callback for device unbinding
237  * @shutdown: Callback for device shutdown
238  * @alert: Alert callback, for example for the SMBus alert protocol
239  * @command: Callback for bus-wide signaling (optional)
240  * @driver: Device driver model driver
241  * @id_table: List of I2C devices supported by this driver
242  * @detect: Callback for device detection
243  * @address_list: The I2C addresses to probe (for detect)
244  * @clients: List of detected clients we created (for i2c-core use only)
245  * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
246  *
247  * The driver.owner field should be set to the module owner of this driver.
248  * The driver.name field should be set to the name of this driver.
249  *
250  * For automatic device detection, both @detect and @address_list must
251  * be defined. @class should also be set, otherwise only devices forced
252  * with module parameters will be created. The detect function must
253  * fill at least the name field of the i2c_board_info structure it is
254  * handed upon successful detection, and possibly also the flags field.
255  *
256  * If @detect is missing, the driver will still work fine for enumerated
257  * devices. Detected devices simply won't be supported. This is expected
258  * for the many I2C/SMBus devices which can't be detected reliably, and
259  * the ones which can always be enumerated in practice.
260  *
261  * The i2c_client structure which is handed to the @detect callback is
262  * not a real i2c_client. It is initialized just enough so that you can
263  * call i2c_smbus_read_byte_data and friends on it. Don't do anything
264  * else with it. In particular, calling dev_dbg and friends on it is
265  * not allowed.
266  */
267 struct i2c_driver {
268         unsigned int class;
269 
270         /* Standard driver model interfaces */
271         int (*probe)(struct i2c_client *, const struct i2c_device_id *);
272         int (*remove)(struct i2c_client *);
273 
274         /* New driver model interface to aid the seamless removal of the
275          * current probe()'s, more commonly unused than used second parameter.
276          */
277         int (*probe_new)(struct i2c_client *);
278 
279         /* driver model interfaces that don't relate to enumeration  */
280         void (*shutdown)(struct i2c_client *);
281 
282         /* Alert callback, for example for the SMBus alert protocol.
283          * The format and meaning of the data value depends on the protocol.
284          * For the SMBus alert protocol, there is a single bit of data passed
285          * as the alert response's low bit ("event flag").
286          * For the SMBus Host Notify protocol, the data corresponds to the
287          * 16-bit payload data reported by the slave device acting as master.
288          */
289         void (*alert)(struct i2c_client *, enum i2c_alert_protocol protocol,
290                       unsigned int data);
291 
292         /* a ioctl like command that can be used to perform specific functions
293          * with the device.
294          */
295         int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
296 
297         struct device_driver driver;
298         const struct i2c_device_id *id_table;
299 
300         /* Device detection callback for automatic device creation */
301         int (*detect)(struct i2c_client *, struct i2c_board_info *);
302         const unsigned short *address_list;
303         struct list_head clients;
304 
305         bool disable_i2c_core_irq_mapping;
306 };
307 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
308 
309 /**
310  * struct i2c_client - represent an I2C slave device
311  * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
312  *      I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
313  * @addr: Address used on the I2C bus connected to the parent adapter.
314  * @name: Indicates the type of the device, usually a chip name that's
315  *      generic enough to hide second-sourcing and compatible revisions.
316  * @adapter: manages the bus segment hosting this I2C device
317  * @dev: Driver model device node for the slave.
318  * @irq: indicates the IRQ generated by this device (if any)
319  * @detected: member of an i2c_driver.clients list or i2c-core's
320  *      userspace_devices list
321  * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
322  *      calls it to pass on slave events to the slave driver.
323  *
324  * An i2c_client identifies a single device (i.e. chip) connected to an
325  * i2c bus. The behaviour exposed to Linux is defined by the driver
326  * managing the device.
327  */
328 struct i2c_client {
329         unsigned short flags;           /* div., see below              */
330         unsigned short addr;            /* chip address - NOTE: 7bit    */
331                                         /* addresses are stored in the  */
332                                         /* _LOWER_ 7 bits               */
333         char name[I2C_NAME_SIZE];
334         struct i2c_adapter *adapter;    /* the adapter we sit on        */
335         struct device dev;              /* the device structure         */
336         int irq;                        /* irq issued by device         */
337         struct list_head detected;
338 #if IS_ENABLED(CONFIG_I2C_SLAVE)
339         i2c_slave_cb_t slave_cb;        /* callback for slave mode      */
340 #endif
341 };
342 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
343 
344 extern struct i2c_client *i2c_verify_client(struct device *dev);
345 extern struct i2c_adapter *i2c_verify_adapter(struct device *dev);
346 extern const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
347                                         const struct i2c_client *client);
348 
349 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
350 {
351         struct device * const dev = container_of(kobj, struct device, kobj);
352         return to_i2c_client(dev);
353 }
354 
355 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
356 {
357         return dev_get_drvdata(&dev->dev);
358 }
359 
360 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
361 {
362         dev_set_drvdata(&dev->dev, data);
363 }
364 
365 /* I2C slave support */
366 
367 #if IS_ENABLED(CONFIG_I2C_SLAVE)
368 enum i2c_slave_event {
369         I2C_SLAVE_READ_REQUESTED,
370         I2C_SLAVE_WRITE_REQUESTED,
371         I2C_SLAVE_READ_PROCESSED,
372         I2C_SLAVE_WRITE_RECEIVED,
373         I2C_SLAVE_STOP,
374 };
375 
376 extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
377 extern int i2c_slave_unregister(struct i2c_client *client);
378 extern bool i2c_detect_slave_mode(struct device *dev);
379 
380 static inline int i2c_slave_event(struct i2c_client *client,
381                                   enum i2c_slave_event event, u8 *val)
382 {
383         return client->slave_cb(client, event, val);
384 }
385 #else
386 static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
387 #endif
388 
389 /**
390  * struct i2c_board_info - template for device creation
391  * @type: chip type, to initialize i2c_client.name
392  * @flags: to initialize i2c_client.flags
393  * @addr: stored in i2c_client.addr
394  * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
395  * @platform_data: stored in i2c_client.dev.platform_data
396  * @of_node: pointer to OpenFirmware device node
397  * @fwnode: device node supplied by the platform firmware
398  * @properties: additional device properties for the device
399  * @resources: resources associated with the device
400  * @num_resources: number of resources in the @resources array
401  * @irq: stored in i2c_client.irq
402  *
403  * I2C doesn't actually support hardware probing, although controllers and
404  * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
405  * a device at a given address.  Drivers commonly need more information than
406  * that, such as chip type, configuration, associated IRQ, and so on.
407  *
408  * i2c_board_info is used to build tables of information listing I2C devices
409  * that are present.  This information is used to grow the driver model tree.
410  * For mainboards this is done statically using i2c_register_board_info();
411  * bus numbers identify adapters that aren't yet available.  For add-on boards,
412  * i2c_new_device() does this dynamically with the adapter already known.
413  */
414 struct i2c_board_info {
415         char            type[I2C_NAME_SIZE];
416         unsigned short  flags;
417         unsigned short  addr;
418         const char      *dev_name;
419         void            *platform_data;
420         struct device_node *of_node;
421         struct fwnode_handle *fwnode;
422         const struct property_entry *properties;
423         const struct resource *resources;
424         unsigned int    num_resources;
425         int             irq;
426 };
427 
428 /**
429  * I2C_BOARD_INFO - macro used to list an i2c device and its address
430  * @dev_type: identifies the device type
431  * @dev_addr: the device's address on the bus.
432  *
433  * This macro initializes essential fields of a struct i2c_board_info,
434  * declaring what has been provided on a particular board.  Optional
435  * fields (such as associated irq, or device-specific platform_data)
436  * are provided using conventional syntax.
437  */
438 #define I2C_BOARD_INFO(dev_type, dev_addr) \
439         .type = dev_type, .addr = (dev_addr)
440 
441 
442 #if IS_ENABLED(CONFIG_I2C)
443 /* Add-on boards should register/unregister their devices; e.g. a board
444  * with integrated I2C, a config eeprom, sensors, and a codec that's
445  * used in conjunction with the primary hardware.
446  */
447 extern struct i2c_client *
448 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
449 
450 /* If you don't know the exact address of an I2C device, use this variant
451  * instead, which can probe for device presence in a list of possible
452  * addresses. The "probe" callback function is optional. If it is provided,
453  * it must return 1 on successful probe, 0 otherwise. If it is not provided,
454  * a default probing method is used.
455  */
456 extern struct i2c_client *
457 i2c_new_probed_device(struct i2c_adapter *adap,
458                       struct i2c_board_info *info,
459                       unsigned short const *addr_list,
460                       int (*probe)(struct i2c_adapter *, unsigned short addr));
461 
462 /* Common custom probe functions */
463 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
464 
465 /* For devices that use several addresses, use i2c_new_dummy() to make
466  * client handles for the extra addresses.
467  */
468 extern struct i2c_client *
469 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
470 
471 extern struct i2c_client *
472 i2c_new_secondary_device(struct i2c_client *client,
473                                 const char *name,
474                                 u16 default_addr);
475 
476 extern void i2c_unregister_device(struct i2c_client *);
477 #endif /* I2C */
478 
479 /* Mainboard arch_initcall() code should register all its I2C devices.
480  * This is done at arch_initcall time, before declaring any i2c adapters.
481  * Modules for add-on boards must use other calls.
482  */
483 #ifdef CONFIG_I2C_BOARDINFO
484 extern int
485 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
486                         unsigned n);
487 #else
488 static inline int
489 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
490                         unsigned n)
491 {
492         return 0;
493 }
494 #endif /* I2C_BOARDINFO */
495 
496 /**
497  * struct i2c_algorithm - represent I2C transfer method
498  * @master_xfer: Issue a set of i2c transactions to the given I2C adapter
499  *   defined by the msgs array, with num messages available to transfer via
500  *   the adapter specified by adap.
501  * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
502  *   is not present, then the bus layer will try and convert the SMBus calls
503  *   into I2C transfers instead.
504  * @functionality: Return the flags that this algorithm/adapter pair supports
505  *   from the I2C_FUNC_* flags.
506  * @reg_slave: Register given client to I2C slave mode of this adapter
507  * @unreg_slave: Unregister given client from I2C slave mode of this adapter
508  *
509  * The following structs are for those who like to implement new bus drivers:
510  * i2c_algorithm is the interface to a class of hardware solutions which can
511  * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
512  * to name two of the most common.
513  *
514  * The return codes from the @master_xfer field should indicate the type of
515  * error code that occurred during the transfer, as documented in the kernel
516  * Documentation file Documentation/i2c/fault-codes.
517  */
518 struct i2c_algorithm {
519         /* If an adapter algorithm can't do I2C-level access, set master_xfer
520            to NULL. If an adapter algorithm can do SMBus access, set
521            smbus_xfer. If set to NULL, the SMBus protocol is simulated
522            using common I2C messages */
523         /* master_xfer should return the number of messages successfully
524            processed, or a negative value on error */
525         int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
526                            int num);
527         int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
528                            unsigned short flags, char read_write,
529                            u8 command, int size, union i2c_smbus_data *data);
530 
531         /* To determine what the adapter supports */
532         u32 (*functionality) (struct i2c_adapter *);
533 
534 #if IS_ENABLED(CONFIG_I2C_SLAVE)
535         int (*reg_slave)(struct i2c_client *client);
536         int (*unreg_slave)(struct i2c_client *client);
537 #endif
538 };
539 
540 /**
541  * struct i2c_lock_operations - represent I2C locking operations
542  * @lock_bus: Get exclusive access to an I2C bus segment
543  * @trylock_bus: Try to get exclusive access to an I2C bus segment
544  * @unlock_bus: Release exclusive access to an I2C bus segment
545  *
546  * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
547  */
548 struct i2c_lock_operations {
549         void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
550         int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
551         void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
552 };
553 
554 /**
555  * struct i2c_timings - I2C timing information
556  * @bus_freq_hz: the bus frequency in Hz
557  * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
558  * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
559  * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
560  * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
561  * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
562  */
563 struct i2c_timings {
564         u32 bus_freq_hz;
565         u32 scl_rise_ns;
566         u32 scl_fall_ns;
567         u32 scl_int_delay_ns;
568         u32 sda_fall_ns;
569         u32 sda_hold_ns;
570 };
571 
572 /**
573  * struct i2c_bus_recovery_info - I2C bus recovery information
574  * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
575  *      i2c_generic_scl_recovery().
576  * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
577  *      recovery. Populated internally for generic GPIO recovery.
578  * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
579  *      Populated internally for generic GPIO recovery.
580  * @get_sda: This gets current value of SDA line. This or set_sda() is mandatory
581  *      for generic SCL recovery. Populated internally, if sda_gpio is a valid
582  *      GPIO, for generic GPIO recovery.
583  * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for
584  *      generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO,
585  *      for generic GPIO recovery.
586  * @get_bus_free: Returns the bus free state as seen from the IP core in case it
587  *      has a more complex internal logic than just reading SDA. Optional.
588  * @prepare_recovery: This will be called before starting recovery. Platform may
589  *      configure padmux here for SDA/SCL line or something else they want.
590  * @unprepare_recovery: This will be called after completing recovery. Platform
591  *      may configure padmux here for SDA/SCL line or something else they want.
592  * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
593  * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
594  */
595 struct i2c_bus_recovery_info {
596         int (*recover_bus)(struct i2c_adapter *adap);
597 
598         int (*get_scl)(struct i2c_adapter *adap);
599         void (*set_scl)(struct i2c_adapter *adap, int val);
600         int (*get_sda)(struct i2c_adapter *adap);
601         void (*set_sda)(struct i2c_adapter *adap, int val);
602         int (*get_bus_free)(struct i2c_adapter *adap);
603 
604         void (*prepare_recovery)(struct i2c_adapter *adap);
605         void (*unprepare_recovery)(struct i2c_adapter *adap);
606 
607         /* gpio recovery */
608         struct gpio_desc *scl_gpiod;
609         struct gpio_desc *sda_gpiod;
610 };
611 
612 int i2c_recover_bus(struct i2c_adapter *adap);
613 
614 /* Generic recovery routines */
615 int i2c_generic_scl_recovery(struct i2c_adapter *adap);
616 
617 /**
618  * struct i2c_adapter_quirks - describe flaws of an i2c adapter
619  * @flags: see I2C_AQ_* for possible flags and read below
620  * @max_num_msgs: maximum number of messages per transfer
621  * @max_write_len: maximum length of a write message
622  * @max_read_len: maximum length of a read message
623  * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
624  * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
625  *
626  * Note about combined messages: Some I2C controllers can only send one message
627  * per transfer, plus something called combined message or write-then-read.
628  * This is (usually) a small write message followed by a read message and
629  * barely enough to access register based devices like EEPROMs. There is a flag
630  * to support this mode. It implies max_num_msg = 2 and does the length checks
631  * with max_comb_*_len because combined message mode usually has its own
632  * limitations. Because of HW implementations, some controllers can actually do
633  * write-then-anything or other variants. To support that, write-then-read has
634  * been broken out into smaller bits like write-first and read-second which can
635  * be combined as needed.
636  */
637 
638 struct i2c_adapter_quirks {
639         u64 flags;
640         int max_num_msgs;
641         u16 max_write_len;
642         u16 max_read_len;
643         u16 max_comb_1st_msg_len;
644         u16 max_comb_2nd_msg_len;
645 };
646 
647 /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
648 #define I2C_AQ_COMB                     BIT(0)
649 /* first combined message must be write */
650 #define I2C_AQ_COMB_WRITE_FIRST         BIT(1)
651 /* second combined message must be read */
652 #define I2C_AQ_COMB_READ_SECOND         BIT(2)
653 /* both combined messages must have the same target address */
654 #define I2C_AQ_COMB_SAME_ADDR           BIT(3)
655 /* convenience macro for typical write-then read case */
656 #define I2C_AQ_COMB_WRITE_THEN_READ     (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
657                                          I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
658 /* clock stretching is not supported */
659 #define I2C_AQ_NO_CLK_STRETCH           BIT(4)
660 /* message cannot have length of 0 */
661 #define I2C_AQ_NO_ZERO_LEN_READ         BIT(5)
662 #define I2C_AQ_NO_ZERO_LEN_WRITE        BIT(6)
663 #define I2C_AQ_NO_ZERO_LEN              (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
664 
665 /*
666  * i2c_adapter is the structure used to identify a physical i2c bus along
667  * with the access algorithms necessary to access it.
668  */
669 struct i2c_adapter {
670         struct module *owner;
671         unsigned int class;               /* classes to allow probing for */
672         const struct i2c_algorithm *algo; /* the algorithm to access the bus */
673         void *algo_data;
674 
675         /* data fields that are valid for all devices   */
676         const struct i2c_lock_operations *lock_ops;
677         struct rt_mutex bus_lock;
678         struct rt_mutex mux_lock;
679 
680         int timeout;                    /* in jiffies */
681         int retries;
682         struct device dev;              /* the adapter device */
683 
684         int nr;
685         char name[48];
686         struct completion dev_released;
687 
688         struct mutex userspace_clients_lock;
689         struct list_head userspace_clients;
690 
691         struct i2c_bus_recovery_info *bus_recovery_info;
692         const struct i2c_adapter_quirks *quirks;
693 
694         struct irq_domain *host_notify_domain;
695 };
696 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
697 
698 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
699 {
700         return dev_get_drvdata(&dev->dev);
701 }
702 
703 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
704 {
705         dev_set_drvdata(&dev->dev, data);
706 }
707 
708 static inline struct i2c_adapter *
709 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
710 {
711 #if IS_ENABLED(CONFIG_I2C_MUX)
712         struct device *parent = adapter->dev.parent;
713 
714         if (parent != NULL && parent->type == &i2c_adapter_type)
715                 return to_i2c_adapter(parent);
716         else
717 #endif
718                 return NULL;
719 }
720 
721 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
722 
723 /* Adapter locking functions, exported for shared pin cases */
724 #define I2C_LOCK_ROOT_ADAPTER BIT(0)
725 #define I2C_LOCK_SEGMENT      BIT(1)
726 
727 /**
728  * i2c_lock_bus - Get exclusive access to an I2C bus segment
729  * @adapter: Target I2C bus segment
730  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
731  *      locks only this branch in the adapter tree
732  */
733 static inline void
734 i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
735 {
736         adapter->lock_ops->lock_bus(adapter, flags);
737 }
738 
739 /**
740  * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
741  * @adapter: Target I2C bus segment
742  * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
743  *      I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
744  *
745  * Return: true if the I2C bus segment is locked, false otherwise
746  */
747 static inline int
748 i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
749 {
750         return adapter->lock_ops->trylock_bus(adapter, flags);
751 }
752 
753 /**
754  * i2c_unlock_bus - Release exclusive access to an I2C bus segment
755  * @adapter: Target I2C bus segment
756  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
757  *      unlocks only this branch in the adapter tree
758  */
759 static inline void
760 i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
761 {
762         adapter->lock_ops->unlock_bus(adapter, flags);
763 }
764 
765 /*flags for the client struct: */
766 #define I2C_CLIENT_PEC          0x04    /* Use Packet Error Checking */
767 #define I2C_CLIENT_TEN          0x10    /* we have a ten bit chip address */
768                                         /* Must equal I2C_M_TEN below */
769 #define I2C_CLIENT_SLAVE        0x20    /* we are the slave */
770 #define I2C_CLIENT_HOST_NOTIFY  0x40    /* We want to use I2C host notify */
771 #define I2C_CLIENT_WAKE         0x80    /* for board_info; true iff can wake */
772 #define I2C_CLIENT_SCCB         0x9000  /* Use Omnivision SCCB protocol */
773                                         /* Must match I2C_M_STOP|IGNORE_NAK */
774 
775 /* i2c adapter classes (bitmask) */
776 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
777 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
778 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
779 /* Warn users that the adapter doesn't support classes anymore */
780 #define I2C_CLASS_DEPRECATED    (1<<8)
781 
782 /* Internal numbers to terminate lists */
783 #define I2C_CLIENT_END          0xfffeU
784 
785 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
786 #define I2C_ADDRS(addr, addrs...) \
787         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
788 
789 
790 /* ----- functions exported by i2c.o */
791 
792 /* administration...
793  */
794 #if IS_ENABLED(CONFIG_I2C)
795 extern int i2c_add_adapter(struct i2c_adapter *);
796 extern void i2c_del_adapter(struct i2c_adapter *);
797 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
798 
799 extern int i2c_register_driver(struct module *, struct i2c_driver *);
800 extern void i2c_del_driver(struct i2c_driver *);
801 
802 /* use a define to avoid include chaining to get THIS_MODULE */
803 #define i2c_add_driver(driver) \
804         i2c_register_driver(THIS_MODULE, driver)
805 
806 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
807 extern void i2c_release_client(struct i2c_client *client);
808 
809 /* call the i2c_client->command() of all attached clients with
810  * the given arguments */
811 extern void i2c_clients_command(struct i2c_adapter *adap,
812                                 unsigned int cmd, void *arg);
813 
814 extern struct i2c_adapter *i2c_get_adapter(int nr);
815 extern void i2c_put_adapter(struct i2c_adapter *adap);
816 extern unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
817 
818 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
819 
820 /* Return the functionality mask */
821 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
822 {
823         return adap->algo->functionality(adap);
824 }
825 
826 /* Return 1 if adapter supports everything we need, 0 if not. */
827 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
828 {
829         return (func & i2c_get_functionality(adap)) == func;
830 }
831 
832 /**
833  * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
834  * @adap: i2c adapter
835  * @quirks: quirk flags
836  *
837  * Return: true if the adapter has all the specified quirk flags, false if not
838  */
839 static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
840 {
841         if (!adap->quirks)
842                 return false;
843         return (adap->quirks->flags & quirks) == quirks;
844 }
845 
846 /* Return the adapter number for a specific adapter */
847 static inline int i2c_adapter_id(struct i2c_adapter *adap)
848 {
849         return adap->nr;
850 }
851 
852 static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
853 {
854         return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
855 }
856 
857 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
858 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
859 
860 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
861 /**
862  * module_i2c_driver() - Helper macro for registering a modular I2C driver
863  * @__i2c_driver: i2c_driver struct
864  *
865  * Helper macro for I2C drivers which do not do anything special in module
866  * init/exit. This eliminates a lot of boilerplate. Each module may only
867  * use this macro once, and calling it replaces module_init() and module_exit()
868  */
869 #define module_i2c_driver(__i2c_driver) \
870         module_driver(__i2c_driver, i2c_add_driver, \
871                         i2c_del_driver)
872 
873 /**
874  * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
875  * @__i2c_driver: i2c_driver struct
876  *
877  * Helper macro for I2C drivers which do not do anything special in their
878  * init. This eliminates a lot of boilerplate. Each driver may only
879  * use this macro once, and calling it replaces device_initcall().
880  */
881 #define builtin_i2c_driver(__i2c_driver) \
882         builtin_driver(__i2c_driver, i2c_add_driver)
883 
884 #endif /* I2C */
885 
886 #if IS_ENABLED(CONFIG_OF)
887 /* must call put_device() when done with returned i2c_client device */
888 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
889 
890 /* must call put_device() when done with returned i2c_adapter device */
891 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
892 
893 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
894 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
895 
896 extern const struct of_device_id
897 *i2c_of_match_device(const struct of_device_id *matches,
898                      struct i2c_client *client);
899 
900 int of_i2c_get_board_info(struct device *dev, struct device_node *node,
901                           struct i2c_board_info *info);
902 
903 #else
904 
905 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
906 {
907         return NULL;
908 }
909 
910 static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
911 {
912         return NULL;
913 }
914 
915 static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
916 {
917         return NULL;
918 }
919 
920 static inline const struct of_device_id
921 *i2c_of_match_device(const struct of_device_id *matches,
922                      struct i2c_client *client)
923 {
924         return NULL;
925 }
926 
927 static inline int of_i2c_get_board_info(struct device *dev,
928                                         struct device_node *node,
929                                         struct i2c_board_info *info)
930 {
931         return -ENOTSUPP;
932 }
933 
934 #endif /* CONFIG_OF */
935 
936 #if IS_ENABLED(CONFIG_ACPI)
937 u32 i2c_acpi_find_bus_speed(struct device *dev);
938 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
939                                        struct i2c_board_info *info);
940 #else
941 static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
942 {
943         return 0;
944 }
945 static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
946                                         int index, struct i2c_board_info *info)
947 {
948         return NULL;
949 }
950 #endif /* CONFIG_ACPI */
951 
952 #endif /* _LINUX_I2C_H */
953 

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