1 /*
2  * MS5611 pressure and temperature sensor driver
3  *
4  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * Data sheet:
11  *  http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
12  *  http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
13  *
14  */
15 
16 #include <linux/module.h>
17 #include <linux/iio/iio.h>
18 #include <linux/delay.h>
19 #include <linux/regulator/consumer.h>
20 
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/triggered_buffer.h>
24 #include <linux/iio/trigger_consumer.h>
25 #include "ms5611.h"
26 
27 #define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \
28 	{ .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate }
29 
30 static const struct ms5611_osr ms5611_avail_pressure_osr[] = {
31 	MS5611_INIT_OSR(0x40, 600,  256),
32 	MS5611_INIT_OSR(0x42, 1170, 512),
33 	MS5611_INIT_OSR(0x44, 2280, 1024),
34 	MS5611_INIT_OSR(0x46, 4540, 2048),
35 	MS5611_INIT_OSR(0x48, 9040, 4096)
36 };
37 
38 static const struct ms5611_osr ms5611_avail_temp_osr[] = {
39 	MS5611_INIT_OSR(0x50, 600,  256),
40 	MS5611_INIT_OSR(0x52, 1170, 512),
41 	MS5611_INIT_OSR(0x54, 2280, 1024),
42 	MS5611_INIT_OSR(0x56, 4540, 2048),
43 	MS5611_INIT_OSR(0x58, 9040, 4096)
44 };
45 
46 static const char ms5611_show_osr[] = "256 512 1024 2048 4096";
47 
48 static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr);
49 
50 static struct attribute *ms5611_attributes[] = {
51 	&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
52 	NULL,
53 };
54 
55 static const struct attribute_group ms5611_attribute_group = {
56 	.attrs = ms5611_attributes,
57 };
58 
59 static bool ms5611_prom_is_valid(u16 *prom, size_t len)
60 {
61 	int i, j;
62 	uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
63 
64 	prom[7] &= 0xFF00;
65 
66 	for (i = 0; i < len * 2; i++) {
67 		if (i % 2 == 1)
68 			crc ^= prom[i >> 1] & 0x00FF;
69 		else
70 			crc ^= prom[i >> 1] >> 8;
71 
72 		for (j = 0; j < 8; j++) {
73 			if (crc & 0x8000)
74 				crc = (crc << 1) ^ 0x3000;
75 			else
76 				crc <<= 1;
77 		}
78 	}
79 
80 	crc = (crc >> 12) & 0x000F;
81 
82 	return crc_orig != 0x0000 && crc == crc_orig;
83 }
84 
85 static int ms5611_read_prom(struct iio_dev *indio_dev)
86 {
87 	int ret, i;
88 	struct ms5611_state *st = iio_priv(indio_dev);
89 
90 	for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
91 		ret = st->read_prom_word(&indio_dev->dev,
92 					 i, &st->chip_info->prom[i]);
93 		if (ret < 0) {
94 			dev_err(&indio_dev->dev,
95 				"failed to read prom at %d\n", i);
96 			return ret;
97 		}
98 	}
99 
100 	if (!ms5611_prom_is_valid(st->chip_info->prom, MS5611_PROM_WORDS_NB)) {
101 		dev_err(&indio_dev->dev, "PROM integrity check failed\n");
102 		return -ENODEV;
103 	}
104 
105 	return 0;
106 }
107 
108 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
109 					 s32 *temp, s32 *pressure)
110 {
111 	int ret;
112 	struct ms5611_state *st = iio_priv(indio_dev);
113 
114 	ret = st->read_adc_temp_and_pressure(&indio_dev->dev, temp, pressure);
115 	if (ret < 0) {
116 		dev_err(&indio_dev->dev,
117 			"failed to read temperature and pressure\n");
118 		return ret;
119 	}
120 
121 	return st->chip_info->temp_and_pressure_compensate(st->chip_info,
122 							   temp, pressure);
123 }
124 
125 static int ms5611_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
126 					       s32 *temp, s32 *pressure)
127 {
128 	s32 t = *temp, p = *pressure;
129 	s64 off, sens, dt;
130 
131 	dt = t - (chip_info->prom[5] << 8);
132 	off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7);
133 	sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8);
134 
135 	t = 2000 + ((chip_info->prom[6] * dt) >> 23);
136 	if (t < 2000) {
137 		s64 off2, sens2, t2;
138 
139 		t2 = (dt * dt) >> 31;
140 		off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
141 		sens2 = off2 >> 1;
142 
143 		if (t < -1500) {
144 			s64 tmp = (t + 1500) * (t + 1500);
145 
146 			off2 += 7 * tmp;
147 			sens2 += (11 * tmp) >> 1;
148 		}
149 
150 		t -= t2;
151 		off -= off2;
152 		sens -= sens2;
153 	}
154 
155 	*temp = t;
156 	*pressure = (((p * sens) >> 21) - off) >> 15;
157 
158 	return 0;
159 }
160 
161 static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
162 					       s32 *temp, s32 *pressure)
163 {
164 	s32 t = *temp, p = *pressure;
165 	s64 off, sens, dt;
166 
167 	dt = t - (chip_info->prom[5] << 8);
168 	off = ((s64)chip_info->prom[2] << 17) + ((chip_info->prom[4] * dt) >> 6);
169 	sens = ((s64)chip_info->prom[1] << 16) + ((chip_info->prom[3] * dt) >> 7);
170 
171 	t = 2000 + ((chip_info->prom[6] * dt) >> 23);
172 	if (t < 2000) {
173 		s64 off2, sens2, t2, tmp;
174 
175 		t2 = (dt * dt) >> 31;
176 		tmp = (t - 2000) * (t - 2000);
177 		off2 = (61 * tmp) >> 4;
178 		sens2 = tmp << 1;
179 
180 		if (t < -1500) {
181 			tmp = (t + 1500) * (t + 1500);
182 			off2 += 15 * tmp;
183 			sens2 += 8 * tmp;
184 		}
185 
186 		t -= t2;
187 		off -= off2;
188 		sens -= sens2;
189 	}
190 
191 	*temp = t;
192 	*pressure = (((p * sens) >> 21) - off) >> 15;
193 
194 	return 0;
195 }
196 
197 static int ms5611_reset(struct iio_dev *indio_dev)
198 {
199 	int ret;
200 	struct ms5611_state *st = iio_priv(indio_dev);
201 
202 	ret = st->reset(&indio_dev->dev);
203 	if (ret < 0) {
204 		dev_err(&indio_dev->dev, "failed to reset device\n");
205 		return ret;
206 	}
207 
208 	usleep_range(3000, 4000);
209 
210 	return 0;
211 }
212 
213 static irqreturn_t ms5611_trigger_handler(int irq, void *p)
214 {
215 	struct iio_poll_func *pf = p;
216 	struct iio_dev *indio_dev = pf->indio_dev;
217 	struct ms5611_state *st = iio_priv(indio_dev);
218 	s32 buf[4]; /* s32 (pressure) + s32 (temp) + 2 * s32 (timestamp) */
219 	int ret;
220 
221 	mutex_lock(&st->lock);
222 	ret = ms5611_read_temp_and_pressure(indio_dev, &buf[1], &buf[0]);
223 	mutex_unlock(&st->lock);
224 	if (ret < 0)
225 		goto err;
226 
227 	iio_push_to_buffers_with_timestamp(indio_dev, buf,
228 					   iio_get_time_ns(indio_dev));
229 
230 err:
231 	iio_trigger_notify_done(indio_dev->trig);
232 
233 	return IRQ_HANDLED;
234 }
235 
236 static int ms5611_read_raw(struct iio_dev *indio_dev,
237 			   struct iio_chan_spec const *chan,
238 			   int *val, int *val2, long mask)
239 {
240 	int ret;
241 	s32 temp, pressure;
242 	struct ms5611_state *st = iio_priv(indio_dev);
243 
244 	switch (mask) {
245 	case IIO_CHAN_INFO_PROCESSED:
246 		mutex_lock(&st->lock);
247 		ret = ms5611_read_temp_and_pressure(indio_dev,
248 						    &temp, &pressure);
249 		mutex_unlock(&st->lock);
250 		if (ret < 0)
251 			return ret;
252 
253 		switch (chan->type) {
254 		case IIO_TEMP:
255 			*val = temp * 10;
256 			return IIO_VAL_INT;
257 		case IIO_PRESSURE:
258 			*val = pressure / 1000;
259 			*val2 = (pressure % 1000) * 1000;
260 			return IIO_VAL_INT_PLUS_MICRO;
261 		default:
262 			return -EINVAL;
263 		}
264 	case IIO_CHAN_INFO_SCALE:
265 		switch (chan->type) {
266 		case IIO_TEMP:
267 			*val = 10;
268 			return IIO_VAL_INT;
269 		case IIO_PRESSURE:
270 			*val = 0;
271 			*val2 = 1000;
272 			return IIO_VAL_INT_PLUS_MICRO;
273 		default:
274 			return -EINVAL;
275 		}
276 	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
277 		if (chan->type != IIO_TEMP && chan->type != IIO_PRESSURE)
278 			break;
279 		mutex_lock(&st->lock);
280 		if (chan->type == IIO_TEMP)
281 			*val = (int)st->temp_osr->rate;
282 		else
283 			*val = (int)st->pressure_osr->rate;
284 		mutex_unlock(&st->lock);
285 		return IIO_VAL_INT;
286 	}
287 
288 	return -EINVAL;
289 }
290 
291 static const struct ms5611_osr *ms5611_find_osr(int rate,
292 						const struct ms5611_osr *osr,
293 						size_t count)
294 {
295 	unsigned int r;
296 
297 	for (r = 0; r < count; r++)
298 		if ((unsigned short)rate == osr[r].rate)
299 			break;
300 	if (r >= count)
301 		return NULL;
302 	return &osr[r];
303 }
304 
305 static int ms5611_write_raw(struct iio_dev *indio_dev,
306 			    struct iio_chan_spec const *chan,
307 			    int val, int val2, long mask)
308 {
309 	struct ms5611_state *st = iio_priv(indio_dev);
310 	const struct ms5611_osr *osr = NULL;
311 	int ret;
312 
313 	if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
314 		return -EINVAL;
315 
316 	if (chan->type == IIO_TEMP)
317 		osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
318 				      ARRAY_SIZE(ms5611_avail_temp_osr));
319 	else if (chan->type == IIO_PRESSURE)
320 		osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
321 				      ARRAY_SIZE(ms5611_avail_pressure_osr));
322 	if (!osr)
323 		return -EINVAL;
324 
325 	ret = iio_device_claim_direct_mode(indio_dev);
326 	if (ret)
327 		return ret;
328 
329 	mutex_lock(&st->lock);
330 
331 	if (chan->type == IIO_TEMP)
332 		st->temp_osr = osr;
333 	else
334 		st->pressure_osr = osr;
335 
336 	mutex_unlock(&st->lock);
337 	iio_device_release_direct_mode(indio_dev);
338 
339 	return 0;
340 }
341 
342 static const unsigned long ms5611_scan_masks[] = {0x3, 0};
343 
344 static struct ms5611_chip_info chip_info_tbl[] = {
345 	[MS5611] = {
346 		.temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate,
347 	},
348 	[MS5607] = {
349 		.temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
350 	}
351 };
352 
353 static const struct iio_chan_spec ms5611_channels[] = {
354 	{
355 		.type = IIO_PRESSURE,
356 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
357 			BIT(IIO_CHAN_INFO_SCALE) |
358 			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
359 		.scan_index = 0,
360 		.scan_type = {
361 			.sign = 's',
362 			.realbits = 32,
363 			.storagebits = 32,
364 			.endianness = IIO_CPU,
365 		},
366 	},
367 	{
368 		.type = IIO_TEMP,
369 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
370 			BIT(IIO_CHAN_INFO_SCALE) |
371 			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
372 		.scan_index = 1,
373 		.scan_type = {
374 			.sign = 's',
375 			.realbits = 32,
376 			.storagebits = 32,
377 			.endianness = IIO_CPU,
378 		},
379 	},
380 	IIO_CHAN_SOFT_TIMESTAMP(2),
381 };
382 
383 static const struct iio_info ms5611_info = {
384 	.read_raw = &ms5611_read_raw,
385 	.write_raw = &ms5611_write_raw,
386 	.attrs = &ms5611_attribute_group,
387 };
388 
389 static int ms5611_init(struct iio_dev *indio_dev)
390 {
391 	int ret;
392 	struct ms5611_state *st = iio_priv(indio_dev);
393 
394 	/* Enable attached regulator if any. */
395 	st->vdd = devm_regulator_get(indio_dev->dev.parent, "vdd");
396 	if (IS_ERR(st->vdd))
397 		return PTR_ERR(st->vdd);
398 
399 	ret = regulator_enable(st->vdd);
400 	if (ret) {
401 		dev_err(indio_dev->dev.parent,
402 			"failed to enable Vdd supply: %d\n", ret);
403 		return ret;
404 	}
405 
406 	ret = ms5611_reset(indio_dev);
407 	if (ret < 0)
408 		goto err_regulator_disable;
409 
410 	ret = ms5611_read_prom(indio_dev);
411 	if (ret < 0)
412 		goto err_regulator_disable;
413 
414 	return 0;
415 
416 err_regulator_disable:
417 	regulator_disable(st->vdd);
418 	return ret;
419 }
420 
421 static void ms5611_fini(const struct iio_dev *indio_dev)
422 {
423 	const struct ms5611_state *st = iio_priv(indio_dev);
424 
425 	regulator_disable(st->vdd);
426 }
427 
428 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
429 		 const char *name, int type)
430 {
431 	int ret;
432 	struct ms5611_state *st = iio_priv(indio_dev);
433 
434 	mutex_init(&st->lock);
435 	st->chip_info = &chip_info_tbl[type];
436 	st->temp_osr =
437 		&ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
438 	st->pressure_osr =
439 		&ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
440 					   - 1];
441 	indio_dev->dev.parent = dev;
442 	indio_dev->name = name;
443 	indio_dev->info = &ms5611_info;
444 	indio_dev->channels = ms5611_channels;
445 	indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
446 	indio_dev->modes = INDIO_DIRECT_MODE;
447 	indio_dev->available_scan_masks = ms5611_scan_masks;
448 
449 	ret = ms5611_init(indio_dev);
450 	if (ret < 0)
451 		return ret;
452 
453 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
454 					 ms5611_trigger_handler, NULL);
455 	if (ret < 0) {
456 		dev_err(dev, "iio triggered buffer setup failed\n");
457 		goto err_fini;
458 	}
459 
460 	ret = iio_device_register(indio_dev);
461 	if (ret < 0) {
462 		dev_err(dev, "unable to register iio device\n");
463 		goto err_buffer_cleanup;
464 	}
465 
466 	return 0;
467 
468 err_buffer_cleanup:
469 	iio_triggered_buffer_cleanup(indio_dev);
470 err_fini:
471 	ms5611_fini(indio_dev);
472 	return ret;
473 }
474 EXPORT_SYMBOL(ms5611_probe);
475 
476 int ms5611_remove(struct iio_dev *indio_dev)
477 {
478 	iio_device_unregister(indio_dev);
479 	iio_triggered_buffer_cleanup(indio_dev);
480 	ms5611_fini(indio_dev);
481 
482 	return 0;
483 }
484 EXPORT_SYMBOL(ms5611_remove);
485 
486 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
487 MODULE_DESCRIPTION("MS5611 core driver");
488 MODULE_LICENSE("GPL v2");
489