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 
312 	if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
313 		return -EINVAL;
314 
315 	if (chan->type == IIO_TEMP)
316 		osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
317 				      ARRAY_SIZE(ms5611_avail_temp_osr));
318 	else if (chan->type == IIO_PRESSURE)
319 		osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
320 				      ARRAY_SIZE(ms5611_avail_pressure_osr));
321 	if (!osr)
322 		return -EINVAL;
323 
324 	mutex_lock(&st->lock);
325 
326 	if (iio_buffer_enabled(indio_dev)) {
327 		mutex_unlock(&st->lock);
328 		return -EBUSY;
329 	}
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 	return 0;
338 }
339 
340 static const unsigned long ms5611_scan_masks[] = {0x3, 0};
341 
342 static struct ms5611_chip_info chip_info_tbl[] = {
343 	[MS5611] = {
344 		.temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate,
345 	},
346 	[MS5607] = {
347 		.temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
348 	}
349 };
350 
351 static const struct iio_chan_spec ms5611_channels[] = {
352 	{
353 		.type = IIO_PRESSURE,
354 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
355 			BIT(IIO_CHAN_INFO_SCALE) |
356 			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
357 		.scan_index = 0,
358 		.scan_type = {
359 			.sign = 's',
360 			.realbits = 32,
361 			.storagebits = 32,
362 			.endianness = IIO_CPU,
363 		},
364 	},
365 	{
366 		.type = IIO_TEMP,
367 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
368 			BIT(IIO_CHAN_INFO_SCALE) |
369 			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
370 		.scan_index = 1,
371 		.scan_type = {
372 			.sign = 's',
373 			.realbits = 32,
374 			.storagebits = 32,
375 			.endianness = IIO_CPU,
376 		},
377 	},
378 	IIO_CHAN_SOFT_TIMESTAMP(2),
379 };
380 
381 static const struct iio_info ms5611_info = {
382 	.read_raw = &ms5611_read_raw,
383 	.write_raw = &ms5611_write_raw,
384 	.attrs = &ms5611_attribute_group,
385 	.driver_module = THIS_MODULE,
386 };
387 
388 static int ms5611_init(struct iio_dev *indio_dev)
389 {
390 	int ret;
391 	struct ms5611_state *st = iio_priv(indio_dev);
392 
393 	/* Enable attached regulator if any. */
394 	st->vdd = devm_regulator_get(indio_dev->dev.parent, "vdd");
395 	if (!IS_ERR(st->vdd)) {
396 		ret = regulator_enable(st->vdd);
397 		if (ret) {
398 			dev_err(indio_dev->dev.parent,
399 				"failed to enable Vdd supply: %d\n", ret);
400 			return ret;
401 		}
402 	} else {
403 		ret = PTR_ERR(st->vdd);
404 		if (ret != -ENODEV)
405 			return ret;
406 	}
407 
408 	ret = ms5611_reset(indio_dev);
409 	if (ret < 0)
410 		goto err_regulator_disable;
411 
412 	ret = ms5611_read_prom(indio_dev);
413 	if (ret < 0)
414 		goto err_regulator_disable;
415 
416 	return 0;
417 
418 err_regulator_disable:
419 	if (!IS_ERR_OR_NULL(st->vdd))
420 		regulator_disable(st->vdd);
421 	return ret;
422 }
423 
424 static void ms5611_fini(const struct iio_dev *indio_dev)
425 {
426 	const struct ms5611_state *st = iio_priv(indio_dev);
427 
428 	if (!IS_ERR_OR_NULL(st->vdd))
429 		regulator_disable(st->vdd);
430 }
431 
432 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
433 		 const char *name, int type)
434 {
435 	int ret;
436 	struct ms5611_state *st = iio_priv(indio_dev);
437 
438 	mutex_init(&st->lock);
439 	st->chip_info = &chip_info_tbl[type];
440 	st->temp_osr =
441 		&ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
442 	st->pressure_osr =
443 		&ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
444 					   - 1];
445 	indio_dev->dev.parent = dev;
446 	indio_dev->name = name;
447 	indio_dev->info = &ms5611_info;
448 	indio_dev->channels = ms5611_channels;
449 	indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
450 	indio_dev->modes = INDIO_DIRECT_MODE;
451 	indio_dev->available_scan_masks = ms5611_scan_masks;
452 
453 	ret = ms5611_init(indio_dev);
454 	if (ret < 0)
455 		return ret;
456 
457 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
458 					 ms5611_trigger_handler, NULL);
459 	if (ret < 0) {
460 		dev_err(dev, "iio triggered buffer setup failed\n");
461 		goto err_fini;
462 	}
463 
464 	ret = iio_device_register(indio_dev);
465 	if (ret < 0) {
466 		dev_err(dev, "unable to register iio device\n");
467 		goto err_buffer_cleanup;
468 	}
469 
470 	return 0;
471 
472 err_buffer_cleanup:
473 	iio_triggered_buffer_cleanup(indio_dev);
474 err_fini:
475 	ms5611_fini(indio_dev);
476 	return ret;
477 }
478 EXPORT_SYMBOL(ms5611_probe);
479 
480 int ms5611_remove(struct iio_dev *indio_dev)
481 {
482 	iio_device_unregister(indio_dev);
483 	iio_triggered_buffer_cleanup(indio_dev);
484 	ms5611_fini(indio_dev);
485 
486 	return 0;
487 }
488 EXPORT_SYMBOL(ms5611_remove);
489 
490 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
491 MODULE_DESCRIPTION("MS5611 core driver");
492 MODULE_LICENSE("GPL v2");
493