aboutsummaryrefslogtreecommitdiff
path: root/src/drivers/batt_smbus/batt_smbus.cpp
blob: 604ce35c57bd9104053d7f18702f74091e92c674 (plain) (blame)
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
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
/****************************************************************************
 *
 *   Copyright (c) 2012-2015 PX4 Development Team. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/**
 * @file batt_smbus.cpp
 *
 * Driver for a battery monitor connected via SMBus (I2C).
 *
 * @author Randy Mackay <rmackay9@yahoo.com>
 */

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <sched.h>
#include <semaphore.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <ctype.h>

#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include <nuttx/clock.h>

#include <board_config.h>

#include <systemlib/perf_counter.h>
#include <systemlib/err.h>
#include <systemlib/systemlib.h>

#include <uORB/uORB.h>
#include <uORB/topics/subsystem_info.h>
#include <uORB/topics/battery_status.h>

#include <float.h>

#include <drivers/device/i2c.h>
#include <drivers/drv_hrt.h>
#include <drivers/drv_batt_smbus.h>
#include <drivers/device/ringbuffer.h>

#define BATT_SMBUS_ADDR_MIN			0x08	///< lowest possible address
#define BATT_SMBUS_ADDR_MAX			0x7F	///< highest possible address

#define BATT_SMBUS_I2C_BUS			PX4_I2C_BUS_EXPANSION
#define BATT_SMBUS_ADDR				0x0B	///< I2C address
#define BATT_SMBUS_TEMP				0x08	///< temperature register
#define BATT_SMBUS_VOLTAGE			0x09	///< voltage register
#define BATT_SMBUS_DESIGN_CAPACITY		0x18	///< design capacity register
#define BATT_SMBUS_DESIGN_VOLTAGE		0x19	///< design voltage register
#define BATT_SMBUS_SERIALNUM			0x1c	///< serial number register
#define BATT_SMBUS_MANUFACTURE_NAME		0x20	///< manufacturer name
#define BATT_SMBUS_MANUFACTURE_INFO		0x25	///< cell voltage register
#define BATT_SMBUS_CURRENT			0x2a	///< current register
#define BATT_SMBUS_MEASUREMENT_INTERVAL_MS	(1000000 / 10)	///< time in microseconds, measure at 10hz
#define BATT_SMBUS_TIMEOUT_MS		10000000	///< timeout looking for battery 10seconds after startup

#define BATT_SMBUS_PEC_POLYNOMIAL		0x07	///< Polynomial for calculating PEC

#ifndef CONFIG_SCHED_WORKQUEUE
# error This requires CONFIG_SCHED_WORKQUEUE.
#endif

class BATT_SMBUS : public device::I2C
{
public:
	BATT_SMBUS(int bus = PX4_I2C_BUS_EXPANSION, uint16_t batt_smbus_addr = BATT_SMBUS_ADDR);
	virtual ~BATT_SMBUS();

	/**
	 * Initialize device
	 *
	 * Calls probe() to check for device on bus.
	 *
	 * @return 0 on success, error code on failure
	 */
	virtual int		init();

	/**
	 * Test device
	 *
	 * @return 0 on success, error code on failure
	 */
	virtual int		test();

	/**
	 * Search all possible slave addresses for a smart battery
	 */
	int			search();

protected:
	/**
	 * Check if the device can be contacted
	 */
	virtual int		probe();

private:

	/**
	 * Start periodic reads from the battery
	 */
	void			start();

	/**
	 * Stop periodic reads from the battery
	 */
	void			stop();

	/**
	 * static function that is called by worker queue
	 */
	static void		cycle_trampoline(void *arg);

	/**
	 * perform a read from the battery
	 */
	void			cycle();

	/**
	 * Read a word from specified register
	 */
	int			read_reg(uint8_t reg, uint16_t &val);

	/**
	 * Read block from bus
	 * @return returns number of characters read if successful, zero if unsuccessful
	 */
	uint8_t			read_block(uint8_t reg, uint8_t *data, uint8_t max_len, bool append_zero);

	/**
	 * Calculate PEC for a read or write from the battery
	 * @param buff is the data that was read or will be written
	 */
	uint8_t			get_PEC(uint8_t cmd, bool reading, const uint8_t buff[], uint8_t len) const;

	// internal variables
	bool			_enabled;	///< true if we have successfully connected to battery
	work_s			_work;		///< work queue for scheduling reads
	RingBuffer		*_reports;	///< buffer of recorded voltages, currents
	struct battery_status_s _last_report;	///< last published report, used for test()
	orb_advert_t		_batt_topic;	///< uORB battery topic
	orb_id_t		_batt_orb_id;	///< uORB battery topic ID
	uint64_t		_start_time;	///< system time we first attempt to communicate with battery
};

namespace
{
BATT_SMBUS *g_batt_smbus;	///< device handle. For now, we only support one BATT_SMBUS device
}

void batt_smbus_usage();

extern "C" __EXPORT int batt_smbus_main(int argc, char *argv[]);

BATT_SMBUS::BATT_SMBUS(int bus, uint16_t batt_smbus_addr) :
	I2C("batt_smbus", BATT_SMBUS_DEVICE_PATH, bus, batt_smbus_addr, 400000),
	_enabled(false),
	_work{},
	_reports(nullptr),
	_batt_topic(-1),
	_batt_orb_id(nullptr),
	_start_time(0)
{
	// work_cancel in the dtor will explode if we don't do this...
	memset(&_work, 0, sizeof(_work));

	// capture startup time
	_start_time = hrt_absolute_time();
}

BATT_SMBUS::~BATT_SMBUS()
{
	// make sure we are truly inactive
	stop();

	if (_reports != nullptr) {
		delete _reports;
	}
}

int
BATT_SMBUS::init()
{
	int ret = ENOTTY;

	// attempt to initialise I2C bus
	ret = I2C::init();

	if (ret != OK) {
		errx(1, "failed to init I2C");
		return ret;

	} else {
		// allocate basic report buffers
		_reports = new RingBuffer(2, sizeof(struct battery_status_s));

		if (_reports == nullptr) {
			ret = ENOTTY;

		} else {
			// start work queue
			start();
		}
	}

	// init orb id
	_batt_orb_id = ORB_ID(battery_status);

	return ret;
}

int
BATT_SMBUS::test()
{
	int sub = orb_subscribe(ORB_ID(battery_status));
	bool updated = false;
	struct battery_status_s status;
	uint64_t start_time = hrt_absolute_time();

	// loop for 5 seconds
	while ((hrt_absolute_time() - start_time) < 5000000) {

		// display new info that has arrived from the orb
		orb_check(sub, &updated);

		if (updated) {
			if (orb_copy(ORB_ID(battery_status), sub, &status) == OK) {
				warnx("V=%4.2f C=%4.2f", status.voltage_v, status.current_a);
			}
		}

		// sleep for 0.05 seconds
		usleep(50000);
	}

	return OK;
}

int
BATT_SMBUS::search()
{
	bool found_slave = false;
	uint16_t tmp;

	// search through all valid SMBus addresses
	for (uint8_t i = BATT_SMBUS_ADDR_MIN; i <= BATT_SMBUS_ADDR_MAX; i++) {
		set_address(i);

		if (read_reg(BATT_SMBUS_VOLTAGE, tmp) == OK) {
			warnx("battery found at 0x%x", (int)i);
			found_slave = true;
		}

		// short sleep
		usleep(1);
	}

	// display completion message
	if (found_slave) {
		warnx("Done.");

	} else {
		warnx("No smart batteries found.");
	}

	return OK;
}

int
BATT_SMBUS::probe()
{
	// always return OK to ensure device starts
	return OK;
}

void
BATT_SMBUS::start()
{
	// reset the report ring and state machine
	_reports->flush();

	// schedule a cycle to start things
	work_queue(HPWORK, &_work, (worker_t)&BATT_SMBUS::cycle_trampoline, this, 1);
}

void
BATT_SMBUS::stop()
{
	work_cancel(HPWORK, &_work);
}

void
BATT_SMBUS::cycle_trampoline(void *arg)
{
	BATT_SMBUS *dev = (BATT_SMBUS *)arg;

	dev->cycle();
}

void
BATT_SMBUS::cycle()
{
	// get current time
	uint64_t now = hrt_absolute_time();

	// exit without rescheduling if we have failed to find a battery after 10 seconds
	if (!_enabled && (now - _start_time > BATT_SMBUS_TIMEOUT_MS)) {
		warnx("did not find smart battery");
		return;
	}

	// read data from sensor
	struct battery_status_s new_report;

	// set time of reading
	new_report.timestamp = now;

	// read voltage
	uint16_t tmp;

	if (read_reg(BATT_SMBUS_VOLTAGE, tmp) == OK) {
		// initialise new_report
		memset(&new_report, 0, sizeof(new_report));

		// convert millivolts to volts
		new_report.voltage_v = ((float)tmp) / 1000.0f;

		// read current
		usleep(1);
		uint8_t buff[4];

		if (read_block(BATT_SMBUS_CURRENT, buff, 4, false) == 4) {
			new_report.current_a = -(float)((int32_t)((uint32_t)buff[3] << 24 | (uint32_t)buff[2] << 16 | (uint32_t)buff[1] << 8 | (uint32_t)buff[0])) / 1000.0f;
		}

		// publish to orb
		if (_batt_topic != -1) {
			orb_publish(_batt_orb_id, _batt_topic, &new_report);

		} else {
			_batt_topic = orb_advertise(_batt_orb_id, &new_report);

			if (_batt_topic < 0) {
				errx(1, "ADVERT FAIL");
			}
		}

		// copy report for test()
		_last_report = new_report;

		// post a report to the ring
		_reports->force(&new_report);

		// notify anyone waiting for data
		poll_notify(POLLIN);

		// record we are working
		_enabled = true;
	}

	// schedule a fresh cycle call when the measurement is done
	work_queue(HPWORK, &_work, (worker_t)&BATT_SMBUS::cycle_trampoline, this,
		   USEC2TICK(BATT_SMBUS_MEASUREMENT_INTERVAL_MS));
}

int
BATT_SMBUS::read_reg(uint8_t reg, uint16_t &val)
{
	uint8_t buff[3];	// 2 bytes of data + PEC

	// read from register
	int ret = transfer(&reg, 1, buff, 3);

	if (ret == OK) {
		// check PEC
		uint8_t pec = get_PEC(reg, true, buff, 2);

		if (pec == buff[2]) {
			val = (uint16_t)buff[1] << 8 | (uint16_t)buff[0];

		} else {
			ret = ENOTTY;
		}
	}

	// return success or failure
	return ret;
}

uint8_t
BATT_SMBUS::read_block(uint8_t reg, uint8_t *data, uint8_t max_len, bool append_zero)
{
	uint8_t buff[max_len + 2];  // buffer to hold results

	usleep(1);

	// read bytes including PEC
	int ret = transfer(&reg, 1, buff, max_len + 2);

	// return zero on failure
	if (ret != OK) {
		return 0;
	}

	// get length
	uint8_t bufflen = buff[0];

	// sanity check length returned by smbus
	if (bufflen == 0 || bufflen > max_len) {
		return 0;
	}

	// check PEC
	uint8_t pec = get_PEC(reg, true, buff, bufflen + 1);

	if (pec != buff[bufflen + 1]) {
		// debug
		warnx("CurrPEC:%x vs MyPec:%x", (int)buff[bufflen + 1], (int)pec);
		return 0;

	}

	// copy data
	memcpy(data, &buff[1], bufflen);

	// optionally add zero to end
	if (append_zero) {
		data[bufflen] = '\0';
	}

	// return success
	return bufflen;
}

uint8_t
BATT_SMBUS::get_PEC(uint8_t cmd, bool reading, const uint8_t buff[], uint8_t len) const
{
	// exit immediately if no data
	if (len <= 0) {
		return 0;
	}

	// prepare temp buffer for calcing crc
	uint8_t tmp_buff[len + 3];
	tmp_buff[0] = (uint8_t)get_address() << 1;
	tmp_buff[1] = cmd;
	tmp_buff[2] = tmp_buff[0] | (uint8_t)reading;
	memcpy(&tmp_buff[3], buff, len);

	// initialise crc to zero
	uint8_t crc = 0;
	uint8_t shift_reg = 0;
	bool do_invert;

	// for each byte in the stream
	for (uint8_t i = 0; i < sizeof(tmp_buff); i++) {
		// load next data byte into the shift register
		shift_reg = tmp_buff[i];

		// for each bit in the current byte
		for (uint8_t j = 0; j < 8; j++) {
			do_invert = (crc ^ shift_reg) & 0x80;
			crc <<= 1;
			shift_reg <<= 1;

			if (do_invert) {
				crc ^= BATT_SMBUS_PEC_POLYNOMIAL;
			}
		}
	}

	// return result
	return crc;
}

///////////////////////// shell functions ///////////////////////

void
batt_smbus_usage()
{
	warnx("missing command: try 'start', 'test', 'stop', 'search'");
	warnx("options:");
	warnx("    -b i2cbus (%d)", BATT_SMBUS_I2C_BUS);
	warnx("    -a addr (0x%x)", BATT_SMBUS_ADDR);
}

int
batt_smbus_main(int argc, char *argv[])
{
	int i2cdevice = BATT_SMBUS_I2C_BUS;
	int batt_smbusadr = BATT_SMBUS_ADDR; // 7bit address

	int ch;

	// jump over start/off/etc and look at options first
	while ((ch = getopt(argc, argv, "a:b:")) != EOF) {
		switch (ch) {
		case 'a':
			batt_smbusadr = strtol(optarg, NULL, 0);
			break;

		case 'b':
			i2cdevice = strtol(optarg, NULL, 0);
			break;

		default:
			batt_smbus_usage();
			exit(0);
		}
	}

	if (optind >= argc) {
		batt_smbus_usage();
		exit(1);
	}

	const char *verb = argv[optind];

	if (!strcmp(verb, "start")) {
		if (g_batt_smbus != nullptr) {
			errx(1, "already started");

		} else {
			// create new global object
			g_batt_smbus = new BATT_SMBUS(i2cdevice, batt_smbusadr);

			if (g_batt_smbus == nullptr) {
				errx(1, "new failed");
			}

			if (OK != g_batt_smbus->init()) {
				delete g_batt_smbus;
				g_batt_smbus = nullptr;
				errx(1, "init failed");
			}
		}

		exit(0);
	}

	// need the driver past this point
	if (g_batt_smbus == nullptr) {
		warnx("not started");
		batt_smbus_usage();
		exit(1);
	}

	if (!strcmp(verb, "test")) {
		g_batt_smbus->test();
		exit(0);
	}

	if (!strcmp(verb, "stop")) {
		delete g_batt_smbus;
		g_batt_smbus = nullptr;
		exit(0);
	}

	if (!strcmp(verb, "search")) {
		g_batt_smbus->search();
		exit(0);
	}

	batt_smbus_usage();
	exit(0);
}