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/buffer.h>
22 #include <linux/iio/triggered_buffer.h>
23 #include <linux/iio/trigger_consumer.h>
24 #include "ms5611.h"
25 
26 static bool ms5611_prom_is_valid(u16 *prom, size_t len)
27 {
28 	int i, j;
29 	uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
30 
31 	prom[7] &= 0xFF00;
32 
33 	for (i = 0; i < len * 2; i++) {
34 		if (i % 2 == 1)
35 			crc ^= prom[i >> 1] & 0x00FF;
36 		else
37 			crc ^= prom[i >> 1] >> 8;
38 
39 		for (j = 0; j < 8; j++) {
40 			if (crc & 0x8000)
41 				crc = (crc << 1) ^ 0x3000;
42 			else
43 				crc <<= 1;
44 		}
45 	}
46 
47 	crc = (crc >> 12) & 0x000F;
48 
49 	return crc_orig != 0x0000 && crc == crc_orig;
50 }
51 
52 static int ms5611_read_prom(struct iio_dev *indio_dev)
53 {
54 	int ret, i;
55 	struct ms5611_state *st = iio_priv(indio_dev);
56 
57 	for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
58 		ret = st->read_prom_word(&indio_dev->dev,
59 					 i, &st->chip_info->prom[i]);
60 		if (ret < 0) {
61 			dev_err(&indio_dev->dev,
62 				"failed to read prom at %d\n", i);
63 			return ret;
64 		}
65 	}
66 
67 	if (!ms5611_prom_is_valid(st->chip_info->prom, MS5611_PROM_WORDS_NB)) {
68 		dev_err(&indio_dev->dev, "PROM integrity check failed\n");
69 		return -ENODEV;
70 	}
71 
72 	return 0;
73 }
74 
75 static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
76 					 s32 *temp, s32 *pressure)
77 {
78 	int ret;
79 	struct ms5611_state *st = iio_priv(indio_dev);
80 
81 	ret = st->read_adc_temp_and_pressure(&indio_dev->dev, temp, pressure);
82 	if (ret < 0) {
83 		dev_err(&indio_dev->dev,
84 			"failed to read temperature and pressure\n");
85 		return ret;
86 	}
87 
88 	return st->chip_info->temp_and_pressure_compensate(st->chip_info,
89 							   temp, pressure);
90 }
91 
92 static int ms5611_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
93 					       s32 *temp, s32 *pressure)
94 {
95 	s32 t = *temp, p = *pressure;
96 	s64 off, sens, dt;
97 
98 	dt = t - (chip_info->prom[5] << 8);
99 	off = ((s64)chip_info->prom[2] << 16) + ((chip_info->prom[4] * dt) >> 7);
100 	sens = ((s64)chip_info->prom[1] << 15) + ((chip_info->prom[3] * dt) >> 8);
101 
102 	t = 2000 + ((chip_info->prom[6] * dt) >> 23);
103 	if (t < 2000) {
104 		s64 off2, sens2, t2;
105 
106 		t2 = (dt * dt) >> 31;
107 		off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
108 		sens2 = off2 >> 1;
109 
110 		if (t < -1500) {
111 			s64 tmp = (t + 1500) * (t + 1500);
112 
113 			off2 += 7 * tmp;
114 			sens2 += (11 * tmp) >> 1;
115 		}
116 
117 		t -= t2;
118 		off -= off2;
119 		sens -= sens2;
120 	}
121 
122 	*temp = t;
123 	*pressure = (((p * sens) >> 21) - off) >> 15;
124 
125 	return 0;
126 }
127 
128 static int ms5607_temp_and_pressure_compensate(struct ms5611_chip_info *chip_info,
129 					       s32 *temp, s32 *pressure)
130 {
131 	s32 t = *temp, p = *pressure;
132 	s64 off, sens, dt;
133 
134 	dt = t - (chip_info->prom[5] << 8);
135 	off = ((s64)chip_info->prom[2] << 17) + ((chip_info->prom[4] * dt) >> 6);
136 	sens = ((s64)chip_info->prom[1] << 16) + ((chip_info->prom[3] * dt) >> 7);
137 
138 	t = 2000 + ((chip_info->prom[6] * dt) >> 23);
139 	if (t < 2000) {
140 		s64 off2, sens2, t2, tmp;
141 
142 		t2 = (dt * dt) >> 31;
143 		tmp = (t - 2000) * (t - 2000);
144 		off2 = (61 * tmp) >> 4;
145 		sens2 = tmp << 1;
146 
147 		if (t < -1500) {
148 			tmp = (t + 1500) * (t + 1500);
149 			off2 += 15 * tmp;
150 			sens2 += 8 * tmp;
151 		}
152 
153 		t -= t2;
154 		off -= off2;
155 		sens -= sens2;
156 	}
157 
158 	*temp = t;
159 	*pressure = (((p * sens) >> 21) - off) >> 15;
160 
161 	return 0;
162 }
163 
164 static int ms5611_reset(struct iio_dev *indio_dev)
165 {
166 	int ret;
167 	struct ms5611_state *st = iio_priv(indio_dev);
168 
169 	ret = st->reset(&indio_dev->dev);
170 	if (ret < 0) {
171 		dev_err(&indio_dev->dev, "failed to reset device\n");
172 		return ret;
173 	}
174 
175 	usleep_range(3000, 4000);
176 
177 	return 0;
178 }
179 
180 static irqreturn_t ms5611_trigger_handler(int irq, void *p)
181 {
182 	struct iio_poll_func *pf = p;
183 	struct iio_dev *indio_dev = pf->indio_dev;
184 	struct ms5611_state *st = iio_priv(indio_dev);
185 	s32 buf[4]; /* s32 (pressure) + s32 (temp) + 2 * s32 (timestamp) */
186 	int ret;
187 
188 	mutex_lock(&st->lock);
189 	ret = ms5611_read_temp_and_pressure(indio_dev, &buf[1], &buf[0]);
190 	mutex_unlock(&st->lock);
191 	if (ret < 0)
192 		goto err;
193 
194 	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
195 
196 err:
197 	iio_trigger_notify_done(indio_dev->trig);
198 
199 	return IRQ_HANDLED;
200 }
201 
202 static int ms5611_read_raw(struct iio_dev *indio_dev,
203 			   struct iio_chan_spec const *chan,
204 			   int *val, int *val2, long mask)
205 {
206 	int ret;
207 	s32 temp, pressure;
208 	struct ms5611_state *st = iio_priv(indio_dev);
209 
210 	switch (mask) {
211 	case IIO_CHAN_INFO_PROCESSED:
212 		mutex_lock(&st->lock);
213 		ret = ms5611_read_temp_and_pressure(indio_dev,
214 						    &temp, &pressure);
215 		mutex_unlock(&st->lock);
216 		if (ret < 0)
217 			return ret;
218 
219 		switch (chan->type) {
220 		case IIO_TEMP:
221 			*val = temp * 10;
222 			return IIO_VAL_INT;
223 		case IIO_PRESSURE:
224 			*val = pressure / 1000;
225 			*val2 = (pressure % 1000) * 1000;
226 			return IIO_VAL_INT_PLUS_MICRO;
227 		default:
228 			return -EINVAL;
229 		}
230 	case IIO_CHAN_INFO_SCALE:
231 		switch (chan->type) {
232 		case IIO_TEMP:
233 			*val = 10;
234 			return IIO_VAL_INT;
235 		case IIO_PRESSURE:
236 			*val = 0;
237 			*val2 = 1000;
238 			return IIO_VAL_INT_PLUS_MICRO;
239 		default:
240 			return -EINVAL;
241 		}
242 	}
243 
244 	return -EINVAL;
245 }
246 
247 static const unsigned long ms5611_scan_masks[] = {0x3, 0};
248 
249 static struct ms5611_chip_info chip_info_tbl[] = {
250 	[MS5611] = {
251 		.temp_and_pressure_compensate = ms5611_temp_and_pressure_compensate,
252 	},
253 	[MS5607] = {
254 		.temp_and_pressure_compensate = ms5607_temp_and_pressure_compensate,
255 	}
256 };
257 
258 static const struct iio_chan_spec ms5611_channels[] = {
259 	{
260 		.type = IIO_PRESSURE,
261 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
262 			BIT(IIO_CHAN_INFO_SCALE),
263 		.scan_index = 0,
264 		.scan_type = {
265 			.sign = 's',
266 			.realbits = 32,
267 			.storagebits = 32,
268 			.endianness = IIO_CPU,
269 		},
270 	},
271 	{
272 		.type = IIO_TEMP,
273 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
274 			BIT(IIO_CHAN_INFO_SCALE),
275 		.scan_index = 1,
276 		.scan_type = {
277 			.sign = 's',
278 			.realbits = 32,
279 			.storagebits = 32,
280 			.endianness = IIO_CPU,
281 		},
282 	},
283 	IIO_CHAN_SOFT_TIMESTAMP(2),
284 };
285 
286 static const struct iio_info ms5611_info = {
287 	.read_raw = &ms5611_read_raw,
288 	.driver_module = THIS_MODULE,
289 };
290 
291 static int ms5611_init(struct iio_dev *indio_dev)
292 {
293 	int ret;
294 	struct regulator *vdd = devm_regulator_get(indio_dev->dev.parent,
295 	                                           "vdd");
296 
297 	/* Enable attached regulator if any. */
298 	if (!IS_ERR(vdd)) {
299 		ret = regulator_enable(vdd);
300 		if (ret) {
301 			dev_err(indio_dev->dev.parent,
302 			        "failed to enable Vdd supply: %d\n", ret);
303 			return ret;
304 		}
305 	}
306 
307 	ret = ms5611_reset(indio_dev);
308 	if (ret < 0)
309 		return ret;
310 
311 	return ms5611_read_prom(indio_dev);
312 }
313 
314 int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
315                  const char *name, int type)
316 {
317 	int ret;
318 	struct ms5611_state *st = iio_priv(indio_dev);
319 
320 	mutex_init(&st->lock);
321 	st->chip_info = &chip_info_tbl[type];
322 	indio_dev->dev.parent = dev;
323 	indio_dev->name = name;
324 	indio_dev->info = &ms5611_info;
325 	indio_dev->channels = ms5611_channels;
326 	indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
327 	indio_dev->modes = INDIO_DIRECT_MODE;
328 	indio_dev->available_scan_masks = ms5611_scan_masks;
329 
330 	ret = ms5611_init(indio_dev);
331 	if (ret < 0)
332 		return ret;
333 
334 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
335 					 ms5611_trigger_handler, NULL);
336 	if (ret < 0) {
337 		dev_err(dev, "iio triggered buffer setup failed\n");
338 		return ret;
339 	}
340 
341 	ret = iio_device_register(indio_dev);
342 	if (ret < 0) {
343 		dev_err(dev, "unable to register iio device\n");
344 		goto err_buffer_cleanup;
345 	}
346 
347 	return 0;
348 
349 err_buffer_cleanup:
350 	iio_triggered_buffer_cleanup(indio_dev);
351 
352 	return ret;
353 }
354 EXPORT_SYMBOL(ms5611_probe);
355 
356 int ms5611_remove(struct iio_dev *indio_dev)
357 {
358 	iio_device_unregister(indio_dev);
359 	iio_triggered_buffer_cleanup(indio_dev);
360 
361 	return 0;
362 }
363 EXPORT_SYMBOL(ms5611_remove);
364 
365 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
366 MODULE_DESCRIPTION("MS5611 core driver");
367 MODULE_LICENSE("GPL v2");
368