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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 : : 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 : : int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
119 : : /* Unlocked flavor */
120 : : int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
121 : :
122 : : /* This is the very generalized SMBus access routine. You probably do not
123 : : want to use this, though; one of the functions below may be much easier,
124 : : and probably just as fast.
125 : : Note that we use i2c_adapter here, because you do not need a specific
126 : : smbus adapter to call this function. */
127 : : s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
128 : : unsigned short flags, char read_write, u8 command,
129 : : int protocol, union i2c_smbus_data *data);
130 : :
131 : : /* Unlocked flavor */
132 : : s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
133 : : unsigned short flags, char read_write, u8 command,
134 : : int protocol, union i2c_smbus_data *data);
135 : :
136 : : /* Now follow the 'nice' access routines. These also document the calling
137 : : conventions of i2c_smbus_xfer. */
138 : :
139 : : s32 i2c_smbus_read_byte(const struct i2c_client *client);
140 : : s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
141 : : s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command);
142 : : s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
143 : : u8 command, u8 value);
144 : : s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command);
145 : : s32 i2c_smbus_write_word_data(const struct i2c_client *client,
146 : : u8 command, u16 value);
147 : :
148 : : static inline s32
149 : : i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
150 : : {
151 : : s32 value = i2c_smbus_read_word_data(client, command);
152 : :
153 : : return (value < 0) ? value : swab16(value);
154 : : }
155 : :
156 : : static inline s32
157 : : i2c_smbus_write_word_swapped(const struct i2c_client *client,
158 : : u8 command, u16 value)
159 : : {
160 : : return i2c_smbus_write_word_data(client, command, swab16(value));
161 : : }
162 : :
163 : : /* Returns the number of read bytes */
164 : : s32 i2c_smbus_read_block_data(const struct i2c_client *client,
165 : : u8 command, u8 *values);
166 : : s32 i2c_smbus_write_block_data(const struct i2c_client *client,
167 : : u8 command, u8 length, const u8 *values);
168 : : /* Returns the number of read bytes */
169 : : s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
170 : : u8 command, u8 length, u8 *values);
171 : : s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
172 : : u8 command, u8 length, const u8 *values);
173 : : s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
174 : : u8 command, u8 length,
175 : : u8 *values);
176 : : int i2c_get_device_id(const struct i2c_client *client,
177 : : struct i2c_device_identity *id);
178 : : #endif /* I2C */
179 : :
180 : : /**
181 : : * struct i2c_device_identity - i2c client device identification
182 : : * @manufacturer_id: 0 - 4095, database maintained by NXP
183 : : * @part_id: 0 - 511, according to manufacturer
184 : : * @die_revision: 0 - 7, according to manufacturer
185 : : */
186 : : struct i2c_device_identity {
187 : : u16 manufacturer_id;
188 : : #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS 0
189 : : #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_1 1
190 : : #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_2 2
191 : : #define I2C_DEVICE_ID_NXP_SEMICONDUCTORS_3 3
192 : : #define I2C_DEVICE_ID_RAMTRON_INTERNATIONAL 4
193 : : #define I2C_DEVICE_ID_ANALOG_DEVICES 5
194 : : #define I2C_DEVICE_ID_STMICROELECTRONICS 6
195 : : #define I2C_DEVICE_ID_ON_SEMICONDUCTOR 7
196 : : #define I2C_DEVICE_ID_SPRINTEK_CORPORATION 8
197 : : #define I2C_DEVICE_ID_ESPROS_PHOTONICS_AG 9
198 : : #define I2C_DEVICE_ID_FUJITSU_SEMICONDUCTOR 10
199 : : #define I2C_DEVICE_ID_FLIR 11
200 : : #define I2C_DEVICE_ID_O2MICRO 12
201 : : #define I2C_DEVICE_ID_ATMEL 13
202 : : #define I2C_DEVICE_ID_NONE 0xffff
203 : : u16 part_id;
204 : : u8 die_revision;
205 : : };
206 : :
207 : : enum i2c_alert_protocol {
208 : : I2C_PROTOCOL_SMBUS_ALERT,
209 : : I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
210 : : };
211 : :
212 : : /**
213 : : * struct i2c_driver - represent an I2C device driver
214 : : * @class: What kind of i2c device we instantiate (for detect)
215 : : * @probe: Callback for device binding - soon to be deprecated
216 : : * @probe_new: New callback for device binding
217 : : * @remove: Callback for device unbinding
218 : : * @shutdown: Callback for device shutdown
219 : : * @alert: Alert callback, for example for the SMBus alert protocol
220 : : * @command: Callback for bus-wide signaling (optional)
221 : : * @driver: Device driver model driver
222 : : * @id_table: List of I2C devices supported by this driver
223 : : * @detect: Callback for device detection
224 : : * @address_list: The I2C addresses to probe (for detect)
225 : : * @clients: List of detected clients we created (for i2c-core use only)
226 : : * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
227 : : *
228 : : * The driver.owner field should be set to the module owner of this driver.
229 : : * The driver.name field should be set to the name of this driver.
230 : : *
231 : : * For automatic device detection, both @detect and @address_list must
232 : : * be defined. @class should also be set, otherwise only devices forced
233 : : * with module parameters will be created. The detect function must
234 : : * fill at least the name field of the i2c_board_info structure it is
235 : : * handed upon successful detection, and possibly also the flags field.
236 : : *
237 : : * If @detect is missing, the driver will still work fine for enumerated
238 : : * devices. Detected devices simply won't be supported. This is expected
239 : : * for the many I2C/SMBus devices which can't be detected reliably, and
240 : : * the ones which can always be enumerated in practice.
241 : : *
242 : : * The i2c_client structure which is handed to the @detect callback is
243 : : * not a real i2c_client. It is initialized just enough so that you can
244 : : * call i2c_smbus_read_byte_data and friends on it. Don't do anything
245 : : * else with it. In particular, calling dev_dbg and friends on it is
246 : : * not allowed.
247 : : */
248 : : struct i2c_driver {
249 : : unsigned int class;
250 : :
251 : : /* Standard driver model interfaces */
252 : : int (*probe)(struct i2c_client *client, const struct i2c_device_id *id);
253 : : int (*remove)(struct i2c_client *client);
254 : :
255 : : /* New driver model interface to aid the seamless removal of the
256 : : * current probe()'s, more commonly unused than used second parameter.
257 : : */
258 : : int (*probe_new)(struct i2c_client *client);
259 : :
260 : : /* driver model interfaces that don't relate to enumeration */
261 : : void (*shutdown)(struct i2c_client *client);
262 : :
263 : : /* Alert callback, for example for the SMBus alert protocol.
264 : : * The format and meaning of the data value depends on the protocol.
265 : : * For the SMBus alert protocol, there is a single bit of data passed
266 : : * as the alert response's low bit ("event flag").
267 : : * For the SMBus Host Notify protocol, the data corresponds to the
268 : : * 16-bit payload data reported by the slave device acting as master.
269 : : */
270 : : void (*alert)(struct i2c_client *client, enum i2c_alert_protocol protocol,
271 : : unsigned int data);
272 : :
273 : : /* a ioctl like command that can be used to perform specific functions
274 : : * with the device.
275 : : */
276 : : int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
277 : :
278 : : struct device_driver driver;
279 : : const struct i2c_device_id *id_table;
280 : :
281 : : /* Device detection callback for automatic device creation */
282 : : int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
283 : : const unsigned short *address_list;
284 : : struct list_head clients;
285 : :
286 : : bool disable_i2c_core_irq_mapping;
287 : : };
288 : : #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
289 : :
290 : : /**
291 : : * struct i2c_client - represent an I2C slave device
292 : : * @flags: see I2C_CLIENT_* for possible flags
293 : : * @addr: Address used on the I2C bus connected to the parent adapter.
294 : : * @name: Indicates the type of the device, usually a chip name that's
295 : : * generic enough to hide second-sourcing and compatible revisions.
296 : : * @adapter: manages the bus segment hosting this I2C device
297 : : * @dev: Driver model device node for the slave.
298 : : * @init_irq: IRQ that was set at initialization
299 : : * @irq: indicates the IRQ generated by this device (if any)
300 : : * @detected: member of an i2c_driver.clients list or i2c-core's
301 : : * userspace_devices list
302 : : * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter
303 : : * calls it to pass on slave events to the slave driver.
304 : : *
305 : : * An i2c_client identifies a single device (i.e. chip) connected to an
306 : : * i2c bus. The behaviour exposed to Linux is defined by the driver
307 : : * managing the device.
308 : : */
309 : : struct i2c_client {
310 : : unsigned short flags; /* div., see below */
311 : : #define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
312 : : #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
313 : : /* Must equal I2C_M_TEN below */
314 : : #define I2C_CLIENT_SLAVE 0x20 /* we are the slave */
315 : : #define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */
316 : : #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
317 : : #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
318 : : /* Must match I2C_M_STOP|IGNORE_NAK */
319 : :
320 : : unsigned short addr; /* chip address - NOTE: 7bit */
321 : : /* addresses are stored in the */
322 : : /* _LOWER_ 7 bits */
323 : : char name[I2C_NAME_SIZE];
324 : : struct i2c_adapter *adapter; /* the adapter we sit on */
325 : : struct device dev; /* the device structure */
326 : : int init_irq; /* irq set at initialization */
327 : : int irq; /* irq issued by device */
328 : : struct list_head detected;
329 : : #if IS_ENABLED(CONFIG_I2C_SLAVE)
330 : : i2c_slave_cb_t slave_cb; /* callback for slave mode */
331 : : #endif
332 : : };
333 : : #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
334 : :
335 : : struct i2c_client *i2c_verify_client(struct device *dev);
336 : : struct i2c_adapter *i2c_verify_adapter(struct device *dev);
337 : : const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
338 : : const struct i2c_client *client);
339 : :
340 : : static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
341 : : {
342 : : struct device * const dev = container_of(kobj, struct device, kobj);
343 : : return to_i2c_client(dev);
344 : : }
345 : :
346 : 0 : static inline void *i2c_get_clientdata(const struct i2c_client *dev)
347 : : {
348 : 0 : return dev_get_drvdata(&dev->dev);
349 : : }
350 : :
351 : 0 : static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
352 : : {
353 : 0 : dev_set_drvdata(&dev->dev, data);
354 : : }
355 : :
356 : : /* I2C slave support */
357 : :
358 : : #if IS_ENABLED(CONFIG_I2C_SLAVE)
359 : : enum i2c_slave_event {
360 : : I2C_SLAVE_READ_REQUESTED,
361 : : I2C_SLAVE_WRITE_REQUESTED,
362 : : I2C_SLAVE_READ_PROCESSED,
363 : : I2C_SLAVE_WRITE_RECEIVED,
364 : : I2C_SLAVE_STOP,
365 : : };
366 : :
367 : : int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
368 : : int i2c_slave_unregister(struct i2c_client *client);
369 : : bool i2c_detect_slave_mode(struct device *dev);
370 : :
371 : : static inline int i2c_slave_event(struct i2c_client *client,
372 : : enum i2c_slave_event event, u8 *val)
373 : : {
374 : : return client->slave_cb(client, event, val);
375 : : }
376 : : #else
377 : : static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
378 : : #endif
379 : :
380 : : /**
381 : : * struct i2c_board_info - template for device creation
382 : : * @type: chip type, to initialize i2c_client.name
383 : : * @flags: to initialize i2c_client.flags
384 : : * @addr: stored in i2c_client.addr
385 : : * @dev_name: Overrides the default <busnr>-<addr> dev_name if set
386 : : * @platform_data: stored in i2c_client.dev.platform_data
387 : : * @of_node: pointer to OpenFirmware device node
388 : : * @fwnode: device node supplied by the platform firmware
389 : : * @properties: additional device properties for the device
390 : : * @resources: resources associated with the device
391 : : * @num_resources: number of resources in the @resources array
392 : : * @irq: stored in i2c_client.irq
393 : : *
394 : : * I2C doesn't actually support hardware probing, although controllers and
395 : : * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
396 : : * a device at a given address. Drivers commonly need more information than
397 : : * that, such as chip type, configuration, associated IRQ, and so on.
398 : : *
399 : : * i2c_board_info is used to build tables of information listing I2C devices
400 : : * that are present. This information is used to grow the driver model tree.
401 : : * For mainboards this is done statically using i2c_register_board_info();
402 : : * bus numbers identify adapters that aren't yet available. For add-on boards,
403 : : * i2c_new_device() does this dynamically with the adapter already known.
404 : : */
405 : : struct i2c_board_info {
406 : : char type[I2C_NAME_SIZE];
407 : : unsigned short flags;
408 : : unsigned short addr;
409 : : const char *dev_name;
410 : : void *platform_data;
411 : : struct device_node *of_node;
412 : : struct fwnode_handle *fwnode;
413 : : const struct property_entry *properties;
414 : : const struct resource *resources;
415 : : unsigned int num_resources;
416 : : int irq;
417 : : };
418 : :
419 : : /**
420 : : * I2C_BOARD_INFO - macro used to list an i2c device and its address
421 : : * @dev_type: identifies the device type
422 : : * @dev_addr: the device's address on the bus.
423 : : *
424 : : * This macro initializes essential fields of a struct i2c_board_info,
425 : : * declaring what has been provided on a particular board. Optional
426 : : * fields (such as associated irq, or device-specific platform_data)
427 : : * are provided using conventional syntax.
428 : : */
429 : : #define I2C_BOARD_INFO(dev_type, dev_addr) \
430 : : .type = dev_type, .addr = (dev_addr)
431 : :
432 : :
433 : : #if IS_ENABLED(CONFIG_I2C)
434 : : /* Add-on boards should register/unregister their devices; e.g. a board
435 : : * with integrated I2C, a config eeprom, sensors, and a codec that's
436 : : * used in conjunction with the primary hardware.
437 : : */
438 : : struct i2c_client *
439 : : i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
440 : :
441 : : struct i2c_client *
442 : : i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
443 : :
444 : : /* If you don't know the exact address of an I2C device, use this variant
445 : : * instead, which can probe for device presence in a list of possible
446 : : * addresses. The "probe" callback function is optional. If it is provided,
447 : : * it must return 1 on successful probe, 0 otherwise. If it is not provided,
448 : : * a default probing method is used.
449 : : */
450 : : struct i2c_client *
451 : : i2c_new_scanned_device(struct i2c_adapter *adap,
452 : : struct i2c_board_info *info,
453 : : unsigned short const *addr_list,
454 : : int (*probe)(struct i2c_adapter *adap, unsigned short addr));
455 : :
456 : : 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 *adap, unsigned short addr));
461 : :
462 : : /* Common custom probe functions */
463 : : int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr);
464 : :
465 : : struct i2c_client *
466 : : i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address);
467 : :
468 : : struct i2c_client *
469 : : devm_i2c_new_dummy_device(struct device *dev, struct i2c_adapter *adap, u16 address);
470 : :
471 : : struct i2c_client *
472 : : i2c_new_ancillary_device(struct i2c_client *client,
473 : : const char *name,
474 : : u16 default_addr);
475 : :
476 : : void i2c_unregister_device(struct i2c_client *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 : : 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 : : * @master_xfer_atomic: same as @master_xfer. Yet, only using atomic context
502 : : * so e.g. PMICs can be accessed very late before shutdown. Optional.
503 : : * @smbus_xfer: Issue smbus transactions to the given I2C adapter. If this
504 : : * is not present, then the bus layer will try and convert the SMBus calls
505 : : * into I2C transfers instead.
506 : : * @smbus_xfer_atomic: same as @smbus_xfer. Yet, only using atomic context
507 : : * so e.g. PMICs can be accessed very late before shutdown. Optional.
508 : : * @functionality: Return the flags that this algorithm/adapter pair supports
509 : : * from the ``I2C_FUNC_*`` flags.
510 : : * @reg_slave: Register given client to I2C slave mode of this adapter
511 : : * @unreg_slave: Unregister given client from I2C slave mode of this adapter
512 : : *
513 : : * The following structs are for those who like to implement new bus drivers:
514 : : * i2c_algorithm is the interface to a class of hardware solutions which can
515 : : * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
516 : : * to name two of the most common.
517 : : *
518 : : * The return codes from the ``master_xfer{_atomic}`` fields should indicate the
519 : : * type of error code that occurred during the transfer, as documented in the
520 : : * Kernel Documentation file Documentation/i2c/fault-codes.rst.
521 : : */
522 : : struct i2c_algorithm {
523 : : /*
524 : : * If an adapter algorithm can't do I2C-level access, set master_xfer
525 : : * to NULL. If an adapter algorithm can do SMBus access, set
526 : : * smbus_xfer. If set to NULL, the SMBus protocol is simulated
527 : : * using common I2C messages.
528 : : *
529 : : * master_xfer should return the number of messages successfully
530 : : * processed, or a negative value on error
531 : : */
532 : : int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
533 : : int num);
534 : : int (*master_xfer_atomic)(struct i2c_adapter *adap,
535 : : struct i2c_msg *msgs, int num);
536 : : int (*smbus_xfer)(struct i2c_adapter *adap, u16 addr,
537 : : unsigned short flags, char read_write,
538 : : u8 command, int size, union i2c_smbus_data *data);
539 : : int (*smbus_xfer_atomic)(struct i2c_adapter *adap, u16 addr,
540 : : unsigned short flags, char read_write,
541 : : u8 command, int size, union i2c_smbus_data *data);
542 : :
543 : : /* To determine what the adapter supports */
544 : : u32 (*functionality)(struct i2c_adapter *adap);
545 : :
546 : : #if IS_ENABLED(CONFIG_I2C_SLAVE)
547 : : int (*reg_slave)(struct i2c_client *client);
548 : : int (*unreg_slave)(struct i2c_client *client);
549 : : #endif
550 : : };
551 : :
552 : : /**
553 : : * struct i2c_lock_operations - represent I2C locking operations
554 : : * @lock_bus: Get exclusive access to an I2C bus segment
555 : : * @trylock_bus: Try to get exclusive access to an I2C bus segment
556 : : * @unlock_bus: Release exclusive access to an I2C bus segment
557 : : *
558 : : * The main operations are wrapped by i2c_lock_bus and i2c_unlock_bus.
559 : : */
560 : : struct i2c_lock_operations {
561 : : void (*lock_bus)(struct i2c_adapter *adapter, unsigned int flags);
562 : : int (*trylock_bus)(struct i2c_adapter *adapter, unsigned int flags);
563 : : void (*unlock_bus)(struct i2c_adapter *adapter, unsigned int flags);
564 : : };
565 : :
566 : : /**
567 : : * struct i2c_timings - I2C timing information
568 : : * @bus_freq_hz: the bus frequency in Hz
569 : : * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
570 : : * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
571 : : * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
572 : : * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
573 : : * @sda_hold_ns: time IP core additionally needs to hold SDA in ns
574 : : * @digital_filter_width_ns: width in ns of spikes on i2c lines that the IP core
575 : : * digital filter can filter out
576 : : * @analog_filter_cutoff_freq_hz: threshold frequency for the low pass IP core
577 : : * analog filter
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 : : u32 digital_filter_width_ns;
587 : : u32 analog_filter_cutoff_freq_hz;
588 : : };
589 : :
590 : : /**
591 : : * struct i2c_bus_recovery_info - I2C bus recovery information
592 : : * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
593 : : * i2c_generic_scl_recovery().
594 : : * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
595 : : * recovery. Populated internally for generic GPIO recovery.
596 : : * @set_scl: This sets/clears the SCL line. Mandatory for generic SCL recovery.
597 : : * Populated internally for generic GPIO recovery.
598 : : * @get_sda: This gets current value of SDA line. This or set_sda() is mandatory
599 : : * for generic SCL recovery. Populated internally, if sda_gpio is a valid
600 : : * GPIO, for generic GPIO recovery.
601 : : * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for
602 : : * generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO,
603 : : * for generic GPIO recovery.
604 : : * @get_bus_free: Returns the bus free state as seen from the IP core in case it
605 : : * has a more complex internal logic than just reading SDA. Optional.
606 : : * @prepare_recovery: This will be called before starting recovery. Platform may
607 : : * configure padmux here for SDA/SCL line or something else they want.
608 : : * @unprepare_recovery: This will be called after completing recovery. Platform
609 : : * may configure padmux here for SDA/SCL line or something else they want.
610 : : * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery.
611 : : * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery.
612 : : */
613 : : struct i2c_bus_recovery_info {
614 : : int (*recover_bus)(struct i2c_adapter *adap);
615 : :
616 : : int (*get_scl)(struct i2c_adapter *adap);
617 : : void (*set_scl)(struct i2c_adapter *adap, int val);
618 : : int (*get_sda)(struct i2c_adapter *adap);
619 : : void (*set_sda)(struct i2c_adapter *adap, int val);
620 : : int (*get_bus_free)(struct i2c_adapter *adap);
621 : :
622 : : void (*prepare_recovery)(struct i2c_adapter *adap);
623 : : void (*unprepare_recovery)(struct i2c_adapter *adap);
624 : :
625 : : /* gpio recovery */
626 : : struct gpio_desc *scl_gpiod;
627 : : struct gpio_desc *sda_gpiod;
628 : : };
629 : :
630 : : int i2c_recover_bus(struct i2c_adapter *adap);
631 : :
632 : : /* Generic recovery routines */
633 : : int i2c_generic_scl_recovery(struct i2c_adapter *adap);
634 : :
635 : : /**
636 : : * struct i2c_adapter_quirks - describe flaws of an i2c adapter
637 : : * @flags: see I2C_AQ_* for possible flags and read below
638 : : * @max_num_msgs: maximum number of messages per transfer
639 : : * @max_write_len: maximum length of a write message
640 : : * @max_read_len: maximum length of a read message
641 : : * @max_comb_1st_msg_len: maximum length of the first msg in a combined message
642 : : * @max_comb_2nd_msg_len: maximum length of the second msg in a combined message
643 : : *
644 : : * Note about combined messages: Some I2C controllers can only send one message
645 : : * per transfer, plus something called combined message or write-then-read.
646 : : * This is (usually) a small write message followed by a read message and
647 : : * barely enough to access register based devices like EEPROMs. There is a flag
648 : : * to support this mode. It implies max_num_msg = 2 and does the length checks
649 : : * with max_comb_*_len because combined message mode usually has its own
650 : : * limitations. Because of HW implementations, some controllers can actually do
651 : : * write-then-anything or other variants. To support that, write-then-read has
652 : : * been broken out into smaller bits like write-first and read-second which can
653 : : * be combined as needed.
654 : : */
655 : :
656 : : struct i2c_adapter_quirks {
657 : : u64 flags;
658 : : int max_num_msgs;
659 : : u16 max_write_len;
660 : : u16 max_read_len;
661 : : u16 max_comb_1st_msg_len;
662 : : u16 max_comb_2nd_msg_len;
663 : : };
664 : :
665 : : /* enforce max_num_msgs = 2 and use max_comb_*_len for length checks */
666 : : #define I2C_AQ_COMB BIT(0)
667 : : /* first combined message must be write */
668 : : #define I2C_AQ_COMB_WRITE_FIRST BIT(1)
669 : : /* second combined message must be read */
670 : : #define I2C_AQ_COMB_READ_SECOND BIT(2)
671 : : /* both combined messages must have the same target address */
672 : : #define I2C_AQ_COMB_SAME_ADDR BIT(3)
673 : : /* convenience macro for typical write-then read case */
674 : : #define I2C_AQ_COMB_WRITE_THEN_READ (I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
675 : : I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
676 : : /* clock stretching is not supported */
677 : : #define I2C_AQ_NO_CLK_STRETCH BIT(4)
678 : : /* message cannot have length of 0 */
679 : : #define I2C_AQ_NO_ZERO_LEN_READ BIT(5)
680 : : #define I2C_AQ_NO_ZERO_LEN_WRITE BIT(6)
681 : : #define I2C_AQ_NO_ZERO_LEN (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
682 : :
683 : : /*
684 : : * i2c_adapter is the structure used to identify a physical i2c bus along
685 : : * with the access algorithms necessary to access it.
686 : : */
687 : : struct i2c_adapter {
688 : : struct module *owner;
689 : : unsigned int class; /* classes to allow probing for */
690 : : const struct i2c_algorithm *algo; /* the algorithm to access the bus */
691 : : void *algo_data;
692 : :
693 : : /* data fields that are valid for all devices */
694 : : const struct i2c_lock_operations *lock_ops;
695 : : struct rt_mutex bus_lock;
696 : : struct rt_mutex mux_lock;
697 : :
698 : : int timeout; /* in jiffies */
699 : : int retries;
700 : : struct device dev; /* the adapter device */
701 : : unsigned long locked_flags; /* owned by the I2C core */
702 : : #define I2C_ALF_IS_SUSPENDED 0
703 : : #define I2C_ALF_SUSPEND_REPORTED 1
704 : :
705 : : int nr;
706 : : char name[48];
707 : : struct completion dev_released;
708 : :
709 : : struct mutex userspace_clients_lock;
710 : : struct list_head userspace_clients;
711 : :
712 : : struct i2c_bus_recovery_info *bus_recovery_info;
713 : : const struct i2c_adapter_quirks *quirks;
714 : :
715 : : struct irq_domain *host_notify_domain;
716 : : };
717 : : #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
718 : :
719 : 0 : static inline void *i2c_get_adapdata(const struct i2c_adapter *adap)
720 : : {
721 [ # # ]: 0 : return dev_get_drvdata(&adap->dev);
722 : : }
723 : :
724 : 0 : static inline void i2c_set_adapdata(struct i2c_adapter *adap, void *data)
725 : : {
726 : 0 : dev_set_drvdata(&adap->dev, data);
727 : : }
728 : :
729 : : static inline struct i2c_adapter *
730 : 0 : i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
731 : : {
732 : : #if IS_ENABLED(CONFIG_I2C_MUX)
733 : : struct device *parent = adapter->dev.parent;
734 : :
735 : : if (parent != NULL && parent->type == &i2c_adapter_type)
736 : : return to_i2c_adapter(parent);
737 : : else
738 : : #endif
739 : 0 : return NULL;
740 : : }
741 : :
742 : : int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data));
743 : :
744 : : /* Adapter locking functions, exported for shared pin cases */
745 : : #define I2C_LOCK_ROOT_ADAPTER BIT(0)
746 : : #define I2C_LOCK_SEGMENT BIT(1)
747 : :
748 : : /**
749 : : * i2c_lock_bus - Get exclusive access to an I2C bus segment
750 : : * @adapter: Target I2C bus segment
751 : : * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
752 : : * locks only this branch in the adapter tree
753 : : */
754 : : static inline void
755 : 0 : i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
756 : : {
757 : 0 : adapter->lock_ops->lock_bus(adapter, flags);
758 : 0 : }
759 : :
760 : : /**
761 : : * i2c_trylock_bus - Try to get exclusive access to an I2C bus segment
762 : : * @adapter: Target I2C bus segment
763 : : * @flags: I2C_LOCK_ROOT_ADAPTER tries to locks the root i2c adapter,
764 : : * I2C_LOCK_SEGMENT tries to lock only this branch in the adapter tree
765 : : *
766 : : * Return: true if the I2C bus segment is locked, false otherwise
767 : : */
768 : : static inline int
769 : 0 : i2c_trylock_bus(struct i2c_adapter *adapter, unsigned int flags)
770 : : {
771 : 0 : return adapter->lock_ops->trylock_bus(adapter, flags);
772 : : }
773 : :
774 : : /**
775 : : * i2c_unlock_bus - Release exclusive access to an I2C bus segment
776 : : * @adapter: Target I2C bus segment
777 : : * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
778 : : * unlocks only this branch in the adapter tree
779 : : */
780 : : static inline void
781 : 0 : i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
782 : : {
783 : 0 : adapter->lock_ops->unlock_bus(adapter, flags);
784 : : }
785 : :
786 : : /**
787 : : * i2c_mark_adapter_suspended - Report suspended state of the adapter to the core
788 : : * @adap: Adapter to mark as suspended
789 : : *
790 : : * When using this helper to mark an adapter as suspended, the core will reject
791 : : * further transfers to this adapter. The usage of this helper is optional but
792 : : * recommended for devices having distinct handlers for system suspend and
793 : : * runtime suspend. More complex devices are free to implement custom solutions
794 : : * to reject transfers when suspended.
795 : : */
796 : : static inline void i2c_mark_adapter_suspended(struct i2c_adapter *adap)
797 : : {
798 : : i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
799 : : set_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
800 : : i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
801 : : }
802 : :
803 : : /**
804 : : * i2c_mark_adapter_resumed - Report resumed state of the adapter to the core
805 : : * @adap: Adapter to mark as resumed
806 : : *
807 : : * When using this helper to mark an adapter as resumed, the core will allow
808 : : * further transfers to this adapter. See also further notes to
809 : : * @i2c_mark_adapter_suspended().
810 : : */
811 : : static inline void i2c_mark_adapter_resumed(struct i2c_adapter *adap)
812 : : {
813 : : i2c_lock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
814 : : clear_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags);
815 : : i2c_unlock_bus(adap, I2C_LOCK_ROOT_ADAPTER);
816 : : }
817 : :
818 : : /* i2c adapter classes (bitmask) */
819 : : #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */
820 : : #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */
821 : : #define I2C_CLASS_SPD (1<<7) /* Memory modules */
822 : : /* Warn users that the adapter doesn't support classes anymore */
823 : : #define I2C_CLASS_DEPRECATED (1<<8)
824 : :
825 : : /* Internal numbers to terminate lists */
826 : : #define I2C_CLIENT_END 0xfffeU
827 : :
828 : : /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
829 : : #define I2C_ADDRS(addr, addrs...) \
830 : : ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
831 : :
832 : :
833 : : /* ----- functions exported by i2c.o */
834 : :
835 : : /* administration...
836 : : */
837 : : #if IS_ENABLED(CONFIG_I2C)
838 : : int i2c_add_adapter(struct i2c_adapter *adap);
839 : : void i2c_del_adapter(struct i2c_adapter *adap);
840 : : int i2c_add_numbered_adapter(struct i2c_adapter *adap);
841 : :
842 : : int i2c_register_driver(struct module *owner, struct i2c_driver *driver);
843 : : void i2c_del_driver(struct i2c_driver *driver);
844 : :
845 : : /* use a define to avoid include chaining to get THIS_MODULE */
846 : : #define i2c_add_driver(driver) \
847 : : i2c_register_driver(THIS_MODULE, driver)
848 : :
849 : : static inline bool i2c_client_has_driver(struct i2c_client *client)
850 : : {
851 : : return !IS_ERR_OR_NULL(client) && client->dev.driver;
852 : : }
853 : :
854 : : /* call the i2c_client->command() of all attached clients with
855 : : * the given arguments */
856 : : void i2c_clients_command(struct i2c_adapter *adap,
857 : : unsigned int cmd, void *arg);
858 : :
859 : : struct i2c_adapter *i2c_get_adapter(int nr);
860 : : void i2c_put_adapter(struct i2c_adapter *adap);
861 : : unsigned int i2c_adapter_depth(struct i2c_adapter *adapter);
862 : :
863 : : void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
864 : :
865 : : /* Return the functionality mask */
866 : 0 : static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
867 : : {
868 : 0 : return adap->algo->functionality(adap);
869 : : }
870 : :
871 : : /* Return 1 if adapter supports everything we need, 0 if not. */
872 : 0 : static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
873 : : {
874 [ # # # # : 0 : return (func & i2c_get_functionality(adap)) == func;
# # # # #
# ]
875 : : }
876 : :
877 : : /**
878 : : * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
879 : : * @adap: i2c adapter
880 : : * @quirks: quirk flags
881 : : *
882 : : * Return: true if the adapter has all the specified quirk flags, false if not
883 : : */
884 : : static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
885 : : {
886 : : if (!adap->quirks)
887 : : return false;
888 : : return (adap->quirks->flags & quirks) == quirks;
889 : : }
890 : :
891 : : /* Return the adapter number for a specific adapter */
892 : 0 : static inline int i2c_adapter_id(struct i2c_adapter *adap)
893 : : {
894 [ # # ]: 0 : return adap->nr;
895 : : }
896 : :
897 : 0 : static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
898 : : {
899 [ # # ]: 0 : return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
900 : : }
901 : :
902 : : u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold);
903 : : void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred);
904 : :
905 : : int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
906 : : /**
907 : : * module_i2c_driver() - Helper macro for registering a modular I2C driver
908 : : * @__i2c_driver: i2c_driver struct
909 : : *
910 : : * Helper macro for I2C drivers which do not do anything special in module
911 : : * init/exit. This eliminates a lot of boilerplate. Each module may only
912 : : * use this macro once, and calling it replaces module_init() and module_exit()
913 : : */
914 : : #define module_i2c_driver(__i2c_driver) \
915 : : module_driver(__i2c_driver, i2c_add_driver, \
916 : : i2c_del_driver)
917 : :
918 : : /**
919 : : * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
920 : : * @__i2c_driver: i2c_driver struct
921 : : *
922 : : * Helper macro for I2C drivers which do not do anything special in their
923 : : * init. This eliminates a lot of boilerplate. Each driver may only
924 : : * use this macro once, and calling it replaces device_initcall().
925 : : */
926 : : #define builtin_i2c_driver(__i2c_driver) \
927 : : builtin_driver(__i2c_driver, i2c_add_driver)
928 : :
929 : : #endif /* I2C */
930 : :
931 : : #if IS_ENABLED(CONFIG_OF)
932 : : /* must call put_device() when done with returned i2c_client device */
933 : : struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
934 : :
935 : : /* must call put_device() when done with returned i2c_adapter device */
936 : : struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
937 : :
938 : : /* must call i2c_put_adapter() when done with returned i2c_adapter device */
939 : : struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
940 : :
941 : : const struct of_device_id
942 : : *i2c_of_match_device(const struct of_device_id *matches,
943 : : struct i2c_client *client);
944 : :
945 : : int of_i2c_get_board_info(struct device *dev, struct device_node *node,
946 : : struct i2c_board_info *info);
947 : :
948 : : #else
949 : :
950 : : static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
951 : : {
952 : : return NULL;
953 : : }
954 : :
955 : : static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
956 : : {
957 : : return NULL;
958 : : }
959 : :
960 : : static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
961 : : {
962 : : return NULL;
963 : : }
964 : :
965 : : static inline const struct of_device_id
966 : 0 : *i2c_of_match_device(const struct of_device_id *matches,
967 : : struct i2c_client *client)
968 : : {
969 : 0 : return NULL;
970 : : }
971 : :
972 : : static inline int of_i2c_get_board_info(struct device *dev,
973 : : struct device_node *node,
974 : : struct i2c_board_info *info)
975 : : {
976 : : return -ENOTSUPP;
977 : : }
978 : :
979 : : #endif /* CONFIG_OF */
980 : :
981 : : struct acpi_resource;
982 : : struct acpi_resource_i2c_serialbus;
983 : :
984 : : #if IS_ENABLED(CONFIG_ACPI)
985 : : bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
986 : : struct acpi_resource_i2c_serialbus **i2c);
987 : : u32 i2c_acpi_find_bus_speed(struct device *dev);
988 : : struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
989 : : struct i2c_board_info *info);
990 : : struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
991 : : #else
992 : : static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
993 : : struct acpi_resource_i2c_serialbus **i2c)
994 : : {
995 : : return false;
996 : : }
997 : : static inline u32 i2c_acpi_find_bus_speed(struct device *dev)
998 : : {
999 : : return 0;
1000 : : }
1001 : : static inline struct i2c_client *i2c_acpi_new_device(struct device *dev,
1002 : : int index, struct i2c_board_info *info)
1003 : : {
1004 : : return NULL;
1005 : : }
1006 : : static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
1007 : : {
1008 : : return NULL;
1009 : : }
1010 : : #endif /* CONFIG_ACPI */
1011 : :
1012 : : #endif /* _LINUX_I2C_H */
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