Boot Linux faster!

Check our new training course

Boot Linux faster!

Check our new training course
and Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
/**
 * @file
 *
 * @brief Public APIs for the I2C drivers.
 */

/*
 * Copyright (c) 2015 Intel Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef __DRIVERS_I2C_H
#define __DRIVERS_I2C_H

/**
 * @brief I2C Interface
 * @defgroup i2c_interface I2C Interface
 * @ingroup io_interfaces
 * @{
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <device.h>

/*
 * The following #defines are used to configure the I2C controller.
 */

/** I2C Standard Speed */
#define I2C_SPEED_STANDARD		(0x1)

/** I2C Fast Speed */
#define I2C_SPEED_FAST			(0x2)

/** I2C Fast Plus Speed */
#define I2C_SPEED_FAST_PLUS		(0x3)

/** I2C High Speed */
#define I2C_SPEED_HIGH			(0x4)

/** I2C Ultra Fast Speed */
#define I2C_SPEED_ULTRA			(0x5)

/** For internal use. */
#define I2C_SPEED_MASK			(0x7 << 1)	/* 3 bits */

/** Use 10-bit addressing. */
#define I2C_ADDR_10_BITS		(1 << 0)

/** Controller to act as Master. */
#define I2C_MODE_MASTER			(1 << 4)

/** Controller to act as Slave. */
#define I2C_MODE_SLAVE_READ		(1 << 5)


/*
 * I2C_MSG_* are I2C Message flags.
 */

/** Write message to I2C bus. */
#define I2C_MSG_WRITE			(0 << 0)

/** Read message from I2C bus. */
#define I2C_MSG_READ			(1 << 0)

/** For internal use. */
#define I2C_MSG_RW_MASK			(1 << 0)

/** Send STOP after this message. */
#define I2C_MSG_STOP			(1 << 1)

/** RESTART I2C transaction for this message. */
#define I2C_MSG_RESTART			(1 << 2)

/**
 * @brief One I2C Message.
 *
 * This defines one I2C message to transact on the I2C bus.
 */
struct i2c_msg {
	/** Data buffer in bytes */
	uint8_t		*buf;

	/** Length of buffer in bytes */
	uint32_t	len;

	/** Flags for this message */
	uint8_t		flags;

	uint8_t		stride[3];
};

union dev_config {
	uint32_t raw;
	struct {
		uint32_t        use_10_bit_addr : 1;
		uint32_t        speed : 3;
		uint32_t        is_master_device : 1;
		uint32_t        is_slave_read : 1;
		uint32_t        reserved : 26;
	} bits;
};

/**
 * @cond INTERNAL_HIDDEN
 *
 * These are for internal use only, so skip these in
 * public documentation.
 */
typedef int (*i2c_api_configure_t)(struct device *dev,
				   uint32_t dev_config);
typedef int (*i2c_api_full_io_t)(struct device *dev,
				 struct i2c_msg *msgs,
				 uint8_t num_msgs,
				 uint16_t addr);
typedef int (*i2c_api_suspend_t)(struct device *dev);
typedef int (*i2c_api_resume_t)(struct device *dev);

struct i2c_driver_api {
	i2c_api_configure_t configure;
	i2c_api_full_io_t transfer;
	i2c_api_suspend_t suspend;
	i2c_api_resume_t resume;
};
/**
 * @endcond
 */

/**
 * @brief Configure operation of a host controller.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_config Bit-packed 32-bit value to the device runtime configuration
 * for the I2C controller.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_configure(struct device *dev, uint32_t dev_config)
{
	struct i2c_driver_api *api;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->configure(dev, dev_config);
}

/**
 * @brief Write a set amount of data to an I2C device.
 *
 * This routine writes a set amount of data synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param buf Memory pool from which the data is transferred.
 * @param len Size of the memory pool available for reading.
 * @param addr Address to the target I2C device for writing.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_write(struct device *dev, uint8_t *buf,
			    uint32_t len, uint16_t addr)
{
	struct i2c_driver_api *api;
	struct i2c_msg msg;

	msg.buf = buf;
	msg.len = len;
	msg.flags = I2C_MSG_WRITE | I2C_MSG_STOP;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->transfer(dev, &msg, 1, addr);
}

/**
 * @brief Read a set amount of data from an I2C device.
 *
 * This routine reads a set amount of data synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param buf Memory pool that stores the retrieved data.
 * @param len Size of the memory pool available for writing.
 * @param addr Address of the I2C device being read.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_read(struct device *dev, uint8_t *buf,
			   uint32_t len, uint16_t addr)
{
	struct i2c_driver_api *api;
	struct i2c_msg msg;

	msg.buf = buf;
	msg.len = len;
	msg.flags = I2C_MSG_READ | I2C_MSG_STOP;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->transfer(dev, &msg, 1, addr);
}

/**
 * @brief Perform data transfer to another I2C device.
 *
 * This routine provides a generic interface to perform data transfer
 * to another I2C device synchronously. Use i2c_read()/i2c_write()
 * for simple read or write.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param msgs Array of messages to transfer.
 * @param num_msgs Number of messages to transfer.
 * @param addr Address of the I2C target device.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_transfer(struct device *dev,
			       struct i2c_msg *msgs, uint8_t num_msgs,
			       uint16_t addr)
{
	struct i2c_driver_api *api;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->transfer(dev, msgs, num_msgs, addr);
}

/**
 * @brief Read multiple bytes from an internal address of an I2C device.
 *
 * This routine reads multiple bytes from an internal address of an
 * I2C device synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_addr Address of the I2C device for reading.
 * @param start_addr Internal address from which the data is being read.
 * @param buf Memory pool that stores the retrieved data.
 * @param num_bytes Number of bytes being read.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_burst_read(struct device *dev, uint16_t dev_addr,
				 uint8_t start_addr, uint8_t *buf,
				 uint8_t num_bytes)
{
	struct i2c_driver_api *api;
	struct i2c_msg msg[2];

	msg[0].buf = &start_addr;
	msg[0].len = 1;
	msg[0].flags = I2C_MSG_WRITE | I2C_MSG_RESTART;

	msg[1].buf = buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_READ | I2C_MSG_STOP;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->transfer(dev, msg, 2, dev_addr);
}

/**
 * @brief Write multiple bytes to an internal address of an I2C device.
 *
 * This routine writes multiple bytes to an internal address of an
 * I2C device synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_addr Address of the I2C device for writing.
 * @param start_addr Internal address to which the data is being written.
 * @param buf Memory pool from which the data is transferred.
 * @param num_bytes Number of bytes being written.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_burst_write(struct device *dev, uint16_t dev_addr,
				  uint8_t start_addr, uint8_t *buf,
				  uint8_t num_bytes)
{
	struct i2c_driver_api *api;
	struct i2c_msg msg[2];

	msg[0].buf = &start_addr;
	msg[0].len = 1;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_WRITE | I2C_MSG_STOP;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->transfer(dev, msg, 2, dev_addr);
}

/**
 * @brief Read internal register of an I2C device.
 *
 * This routine reads the value of an 8-bit internal register of an I2C
 * device synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_addr Address of the I2C device for reading.
 * @param reg_addr Address of the internal register being read.
 * @param value Memory pool that stores the retrieved register value.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_reg_read_byte(struct device *dev, uint16_t dev_addr,
				    uint8_t reg_addr, uint8_t *value)
{
	return i2c_burst_read(dev, dev_addr, reg_addr, value, 1);
}

/**
 * @brief Write internal register of an I2C device.
 *
 * This routine writes a value to an 8-bit internal register of an I2C
 * device synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_addr Address of the I2C device for writing.
 * @param reg_addr Address of the internal register being written.
 * @param value Value to be written to internal register.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_reg_write_byte(struct device *dev, uint16_t dev_addr,
				     uint8_t reg_addr, uint8_t value)
{
	uint8_t tx_buf[2] = {reg_addr, value};

	return i2c_write(dev, tx_buf, 2, dev_addr);
}

/**
 * @brief Update internal register of an I2C device.
 *
 * This routine updates the value of a set of bits from an 8-bit internal
 * register of an I2C device synchronously.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_addr Address of the I2C device for updating.
 * @param reg_addr Address of the internal register being updated.
 * @param mask Bitmask for updating internal register.
 * @param value Value for updating internal register.
 *
 * @retval 0 If successful.
 * @retval Negative errno code if failure.
 */
static inline int i2c_reg_update_byte(struct device *dev, uint8_t dev_addr,
				      uint8_t reg_addr, uint8_t mask,
				      uint8_t value)
{
	uint8_t old_value, new_value;
	int rc;

	rc = i2c_reg_read_byte(dev, dev_addr, reg_addr, &old_value);
	if (rc != 0) {
		return rc;
	}

	new_value = (old_value & ~mask) | (value & mask);
	if (new_value == old_value) {
		return 0;
	}

	return i2c_reg_write_byte(dev, dev_addr, reg_addr, new_value);
}

/**
 * @brief Suspend an I2C driver.
 * @param dev Pointer to the device structure for the driver instance.
 *
 * @retval 0 If successful.
 */
static inline int i2c_suspend(struct device *dev)
{
	struct i2c_driver_api *api;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->suspend(dev);
}

/**
 * @brief Resume an I2C driver.
 * @param dev Pointer to the device structure for the driver instance.
 *
 * @retval 0 If successful.
 */
static inline int i2c_resume(struct device *dev)
{
	struct i2c_driver_api *api;

	api = (struct i2c_driver_api *)dev->driver_api;
	return api->resume(dev);
}

#ifdef __cplusplus
}
#endif

/**
 * @}
 */


#endif /* __DRIVERS_I2C_H */