1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * MS5611 pressure and temperature sensor driver
4 *
5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
6 *
7 * Data sheet:
8 * http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
9 * http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
10 *
11 */
12
13 #include <linux/module.h>
14 #include <linux/iio/iio.h>
15 #include <linux/delay.h>
16 #include <linux/regulator/consumer.h>
17
18 #include <linux/iio/sysfs.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/triggered_buffer.h>
21 #include <linux/iio/trigger_consumer.h>
22 #include "ms5611.h"
23
24 #define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \
25 { .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate }
26
27 static const struct ms5611_osr ms5611_avail_pressure_osr[] = {
28 MS5611_INIT_OSR(0x40, 600, 256),
29 MS5611_INIT_OSR(0x42, 1170, 512),
30 MS5611_INIT_OSR(0x44, 2280, 1024),
31 MS5611_INIT_OSR(0x46, 4540, 2048),
32 MS5611_INIT_OSR(0x48, 9040, 4096)
33 };
34
35 static const struct ms5611_osr ms5611_avail_temp_osr[] = {
36 MS5611_INIT_OSR(0x50, 600, 256),
37 MS5611_INIT_OSR(0x52, 1170, 512),
38 MS5611_INIT_OSR(0x54, 2280, 1024),
39 MS5611_INIT_OSR(0x56, 4540, 2048),
40 MS5611_INIT_OSR(0x58, 9040, 4096)
41 };
42
43 static const char ms5611_show_osr[] = "256 512 1024 2048 4096";
44
45 static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr);
46
47 static struct attribute *ms5611_attributes[] = {
48 &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
49 NULL,
50 };
51
52 static const struct attribute_group ms5611_attribute_group = {
53 .attrs = ms5611_attributes,
54 };
55
ms5611_prom_is_valid(u16 * prom,size_t len)56 static bool ms5611_prom_is_valid(u16 *prom, size_t len)
57 {
58 int i, j;
59 uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
60
61 prom[7] &= 0xFF00;
62
63 for (i = 0; i < len * 2; i++) {
64 if (i % 2 == 1)
65 crc ^= prom[i >> 1] & 0x00FF;
66 else
67 crc ^= prom[i >> 1] >> 8;
68
69 for (j = 0; j < 8; j++) {
70 if (crc & 0x8000)
71 crc = (crc << 1) ^ 0x3000;
72 else
73 crc <<= 1;
74 }
75 }
76
77 crc = (crc >> 12) & 0x000F;
78
79 return crc == crc_orig;
80 }
81
ms5611_read_prom(struct iio_dev * indio_dev)82 static int ms5611_read_prom(struct iio_dev *indio_dev)
83 {
84 int ret, i;
85 struct ms5611_state *st = iio_priv(indio_dev);
86
87 for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
88 ret = st->read_prom_word(st, i, &st->prom[i]);
89 if (ret < 0) {
90 dev_err(&indio_dev->dev,
91 "failed to read prom at %d\n", i);
92 return ret;
93 }
94 }
95
96 if (!ms5611_prom_is_valid(st->prom, MS5611_PROM_WORDS_NB)) {
97 dev_err(&indio_dev->dev, "PROM integrity check failed\n");
98 return -ENODEV;
99 }
100
101 return 0;
102 }
103
ms5611_read_temp_and_pressure(struct iio_dev * indio_dev,s32 * temp,s32 * pressure)104 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
105 s32 *temp, s32 *pressure)
106 {
107 int ret;
108 struct ms5611_state *st = iio_priv(indio_dev);
109
110 ret = st->read_adc_temp_and_pressure(st, temp, pressure);
111 if (ret < 0) {
112 dev_err(&indio_dev->dev,
113 "failed to read temperature and pressure\n");
114 return ret;
115 }
116
117 return st->compensate_temp_and_pressure(st, temp, pressure);
118 }
119
ms5611_temp_and_pressure_compensate(struct ms5611_state * st,s32 * temp,s32 * pressure)120 static int ms5611_temp_and_pressure_compensate(struct ms5611_state *st,
121 s32 *temp, s32 *pressure)
122 {
123 s32 t = *temp, p = *pressure;
124 s64 off, sens, dt;
125
126 dt = t - (st->prom[5] << 8);
127 off = ((s64)st->prom[2] << 16) + ((st->prom[4] * dt) >> 7);
128 sens = ((s64)st->prom[1] << 15) + ((st->prom[3] * dt) >> 8);
129
130 t = 2000 + ((st->prom[6] * dt) >> 23);
131 if (t < 2000) {
132 s64 off2, sens2, t2;
133
134 t2 = (dt * dt) >> 31;
135 off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
136 sens2 = off2 >> 1;
137
138 if (t < -1500) {
139 s64 tmp = (t + 1500) * (t + 1500);
140
141 off2 += 7 * tmp;
142 sens2 += (11 * tmp) >> 1;
143 }
144
145 t -= t2;
146 off -= off2;
147 sens -= sens2;
148 }
149
150 *temp = t;
151 *pressure = (((p * sens) >> 21) - off) >> 15;
152
153 return 0;
154 }
155
ms5607_temp_and_pressure_compensate(struct ms5611_state * st,s32 * temp,s32 * pressure)156 static int ms5607_temp_and_pressure_compensate(struct ms5611_state *st,
157 s32 *temp, s32 *pressure)
158 {
159 s32 t = *temp, p = *pressure;
160 s64 off, sens, dt;
161
162 dt = t - (st->prom[5] << 8);
163 off = ((s64)st->prom[2] << 17) + ((st->prom[4] * dt) >> 6);
164 sens = ((s64)st->prom[1] << 16) + ((st->prom[3] * dt) >> 7);
165
166 t = 2000 + ((st->prom[6] * dt) >> 23);
167 if (t < 2000) {
168 s64 off2, sens2, t2, tmp;
169
170 t2 = (dt * dt) >> 31;
171 tmp = (t - 2000) * (t - 2000);
172 off2 = (61 * tmp) >> 4;
173 sens2 = tmp << 1;
174
175 if (t < -1500) {
176 tmp = (t + 1500) * (t + 1500);
177 off2 += 15 * tmp;
178 sens2 += 8 * tmp;
179 }
180
181 t -= t2;
182 off -= off2;
183 sens -= sens2;
184 }
185
186 *temp = t;
187 *pressure = (((p * sens) >> 21) - off) >> 15;
188
189 return 0;
190 }
191
ms5611_reset(struct iio_dev * indio_dev)192 static int ms5611_reset(struct iio_dev *indio_dev)
193 {
194 int ret;
195 struct ms5611_state *st = iio_priv(indio_dev);
196
197 ret = st->reset(st);
198 if (ret < 0) {
199 dev_err(&indio_dev->dev, "failed to reset device\n");
200 return ret;
201 }
202
203 usleep_range(3000, 4000);
204
205 return 0;
206 }
207
ms5611_trigger_handler(int irq,void * p)208 static irqreturn_t ms5611_trigger_handler(int irq, void *p)
209 {
210 struct iio_poll_func *pf = p;
211 struct iio_dev *indio_dev = pf->indio_dev;
212 struct ms5611_state *st = iio_priv(indio_dev);
213 /* Ensure buffer elements are naturally aligned */
214 struct {
215 s32 channels[2];
216 s64 ts __aligned(8);
217 } scan;
218 int ret;
219
220 mutex_lock(&st->lock);
221 ret = ms5611_read_temp_and_pressure(indio_dev, &scan.channels[1],
222 &scan.channels[0]);
223 mutex_unlock(&st->lock);
224 if (ret < 0)
225 goto err;
226
227 iio_push_to_buffers_with_timestamp(indio_dev, &scan,
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
ms5611_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)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
ms5611_find_osr(int rate,const struct ms5611_osr * osr,size_t count)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
ms5611_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)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 const struct iio_chan_spec ms5611_channels[] = {
345 {
346 .type = IIO_PRESSURE,
347 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
348 BIT(IIO_CHAN_INFO_SCALE) |
349 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
350 .scan_index = 0,
351 .scan_type = {
352 .sign = 's',
353 .realbits = 32,
354 .storagebits = 32,
355 .endianness = IIO_CPU,
356 },
357 },
358 {
359 .type = IIO_TEMP,
360 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
361 BIT(IIO_CHAN_INFO_SCALE) |
362 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
363 .scan_index = 1,
364 .scan_type = {
365 .sign = 's',
366 .realbits = 32,
367 .storagebits = 32,
368 .endianness = IIO_CPU,
369 },
370 },
371 IIO_CHAN_SOFT_TIMESTAMP(2),
372 };
373
374 static const struct iio_info ms5611_info = {
375 .read_raw = &ms5611_read_raw,
376 .write_raw = &ms5611_write_raw,
377 .attrs = &ms5611_attribute_group,
378 };
379
ms5611_init(struct iio_dev * indio_dev)380 static int ms5611_init(struct iio_dev *indio_dev)
381 {
382 int ret;
383
384 /* Enable attached regulator if any. */
385 ret = devm_regulator_get_enable(indio_dev->dev.parent, "vdd");
386 if (ret)
387 return ret;
388
389 ret = ms5611_reset(indio_dev);
390 if (ret < 0)
391 return ret;
392
393 ret = ms5611_read_prom(indio_dev);
394 if (ret < 0)
395 return ret;
396
397 return 0;
398 }
399
ms5611_probe(struct iio_dev * indio_dev,struct device * dev,const char * name,int type)400 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
401 const char *name, int type)
402 {
403 int ret;
404 struct ms5611_state *st = iio_priv(indio_dev);
405
406 mutex_init(&st->lock);
407
408 switch (type) {
409 case MS5611:
410 st->compensate_temp_and_pressure =
411 ms5611_temp_and_pressure_compensate;
412 break;
413 case MS5607:
414 st->compensate_temp_and_pressure =
415 ms5607_temp_and_pressure_compensate;
416 break;
417 default:
418 return -EINVAL;
419 }
420
421 st->temp_osr =
422 &ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
423 st->pressure_osr =
424 &ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
425 - 1];
426 indio_dev->name = name;
427 indio_dev->info = &ms5611_info;
428 indio_dev->channels = ms5611_channels;
429 indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
430 indio_dev->modes = INDIO_DIRECT_MODE;
431 indio_dev->available_scan_masks = ms5611_scan_masks;
432
433 ret = ms5611_init(indio_dev);
434 if (ret < 0)
435 return ret;
436
437 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
438 ms5611_trigger_handler, NULL);
439 if (ret < 0) {
440 dev_err(dev, "iio triggered buffer setup failed\n");
441 return ret;
442 }
443
444 ret = devm_iio_device_register(dev, indio_dev);
445 if (ret < 0) {
446 dev_err(dev, "unable to register iio device\n");
447 return ret;
448 }
449
450 return 0;
451 }
452 EXPORT_SYMBOL_NS(ms5611_probe, IIO_MS5611);
453
454 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
455 MODULE_DESCRIPTION("MS5611 core driver");
456 MODULE_LICENSE("GPL v2");
457