Commit | Line | Data |
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5bf1d290 | 1 | /* Copyright (c) 2010 Christoph Mair <christoph.mair@gmail.com> |
e939ca0a EA |
2 | * Copyright (c) 2012 Bosch Sensortec GmbH |
3 | * Copyright (c) 2012 Unixphere AB | |
4 | * | |
985087db EA |
5 | * This driver supports the bmp085 and bmp18x digital barometric pressure |
6 | * and temperature sensors from Bosch Sensortec. The datasheets | |
7 | * are available from their website: | |
e939ca0a | 8 | * http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-DS000-05.pdf |
985087db | 9 | * http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP180-DS000-07.pdf |
e939ca0a EA |
10 | * |
11 | * A pressure measurement is issued by reading from pressure0_input. | |
12 | * The return value ranges from 30000 to 110000 pascal with a resulution | |
13 | * of 1 pascal (0.01 millibar) which enables measurements from 9000m above | |
14 | * to 500m below sea level. | |
15 | * | |
16 | * The temperature can be read from temp0_input. Values range from | |
17 | * -400 to 850 representing the ambient temperature in degree celsius | |
18 | * multiplied by 10.The resolution is 0.1 celsius. | |
19 | * | |
20 | * Because ambient pressure is temperature dependent, a temperature | |
21 | * measurement will be executed automatically even if the user is reading | |
22 | * from pressure0_input. This happens if the last temperature measurement | |
23 | * has been executed more then one second ago. | |
24 | * | |
25 | * To decrease RMS noise from pressure measurements, the bmp085 can | |
26 | * autonomously calculate the average of up to eight samples. This is | |
27 | * set up by writing to the oversampling sysfs file. Accepted values | |
28 | * are 0, 1, 2 and 3. 2^x when x is the value written to this file | |
29 | * specifies the number of samples used to calculate the ambient pressure. | |
30 | * RMS noise is specified with six pascal (without averaging) and decreases | |
31 | * down to 3 pascal when using an oversampling setting of 3. | |
32 | * | |
33 | * This program is free software; you can redistribute it and/or modify | |
34 | * it under the terms of the GNU General Public License as published by | |
35 | * the Free Software Foundation; either version 2 of the License, or | |
36 | * (at your option) any later version. | |
37 | * | |
38 | * This program is distributed in the hope that it will be useful, | |
39 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
40 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
41 | * GNU General Public License for more details. | |
42 | * | |
43 | * You should have received a copy of the GNU General Public License | |
44 | * along with this program; if not, write to the Free Software | |
45 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
46 | */ | |
5bf1d290 CM |
47 | |
48 | #include <linux/module.h> | |
e939ca0a | 49 | #include <linux/device.h> |
5bf1d290 | 50 | #include <linux/slab.h> |
c5a86ab6 | 51 | #include <linux/of.h> |
985087db | 52 | #include "bmp085.h" |
c07f85c5 MB |
53 | #include <linux/interrupt.h> |
54 | #include <linux/completion.h> | |
55 | #include <linux/gpio.h> | |
5bf1d290 | 56 | |
5bf1d290 | 57 | #define BMP085_CHIP_ID 0x55 |
5bf1d290 CM |
58 | #define BMP085_CALIBRATION_DATA_START 0xAA |
59 | #define BMP085_CALIBRATION_DATA_LENGTH 11 /* 16 bit values */ | |
60 | #define BMP085_CHIP_ID_REG 0xD0 | |
5bf1d290 CM |
61 | #define BMP085_CTRL_REG 0xF4 |
62 | #define BMP085_TEMP_MEASUREMENT 0x2E | |
63 | #define BMP085_PRESSURE_MEASUREMENT 0x34 | |
64 | #define BMP085_CONVERSION_REGISTER_MSB 0xF6 | |
65 | #define BMP085_CONVERSION_REGISTER_LSB 0xF7 | |
66 | #define BMP085_CONVERSION_REGISTER_XLSB 0xF8 | |
67 | #define BMP085_TEMP_CONVERSION_TIME 5 | |
68 | ||
5bf1d290 CM |
69 | struct bmp085_calibration_data { |
70 | s16 AC1, AC2, AC3; | |
71 | u16 AC4, AC5, AC6; | |
72 | s16 B1, B2; | |
73 | s16 MB, MC, MD; | |
74 | }; | |
75 | ||
5bf1d290 | 76 | struct bmp085_data { |
985087db EA |
77 | struct device *dev; |
78 | struct regmap *regmap; | |
e939ca0a EA |
79 | struct mutex lock; |
80 | struct bmp085_calibration_data calibration; | |
81 | u8 oversampling_setting; | |
82 | u32 raw_temperature; | |
83 | u32 raw_pressure; | |
84 | u32 temp_measurement_period; | |
b222258a | 85 | unsigned long last_temp_measurement; |
c5a86ab6 | 86 | u8 chip_id; |
e939ca0a | 87 | s32 b6; /* calculated temperature correction coefficient */ |
c07f85c5 MB |
88 | int irq; |
89 | struct completion done; | |
5bf1d290 CM |
90 | }; |
91 | ||
c07f85c5 MB |
92 | static irqreturn_t bmp085_eoc_isr(int irq, void *devid) |
93 | { | |
94 | struct bmp085_data *data = devid; | |
95 | ||
96 | complete(&data->done); | |
97 | ||
98 | return IRQ_HANDLED; | |
99 | } | |
100 | ||
985087db | 101 | static s32 bmp085_read_calibration_data(struct bmp085_data *data) |
5bf1d290 CM |
102 | { |
103 | u16 tmp[BMP085_CALIBRATION_DATA_LENGTH]; | |
5bf1d290 | 104 | struct bmp085_calibration_data *cali = &(data->calibration); |
985087db EA |
105 | s32 status = regmap_bulk_read(data->regmap, |
106 | BMP085_CALIBRATION_DATA_START, (u8 *)tmp, | |
107 | (BMP085_CALIBRATION_DATA_LENGTH << 1)); | |
5bf1d290 CM |
108 | if (status < 0) |
109 | return status; | |
110 | ||
5bf1d290 CM |
111 | cali->AC1 = be16_to_cpu(tmp[0]); |
112 | cali->AC2 = be16_to_cpu(tmp[1]); | |
113 | cali->AC3 = be16_to_cpu(tmp[2]); | |
114 | cali->AC4 = be16_to_cpu(tmp[3]); | |
115 | cali->AC5 = be16_to_cpu(tmp[4]); | |
116 | cali->AC6 = be16_to_cpu(tmp[5]); | |
117 | cali->B1 = be16_to_cpu(tmp[6]); | |
118 | cali->B2 = be16_to_cpu(tmp[7]); | |
119 | cali->MB = be16_to_cpu(tmp[8]); | |
120 | cali->MC = be16_to_cpu(tmp[9]); | |
121 | cali->MD = be16_to_cpu(tmp[10]); | |
122 | return 0; | |
123 | } | |
124 | ||
5bf1d290 CM |
125 | static s32 bmp085_update_raw_temperature(struct bmp085_data *data) |
126 | { | |
127 | u16 tmp; | |
128 | s32 status; | |
129 | ||
130 | mutex_lock(&data->lock); | |
c07f85c5 MB |
131 | |
132 | init_completion(&data->done); | |
133 | ||
985087db EA |
134 | status = regmap_write(data->regmap, BMP085_CTRL_REG, |
135 | BMP085_TEMP_MEASUREMENT); | |
e939ca0a | 136 | if (status < 0) { |
985087db | 137 | dev_err(data->dev, |
5bf1d290 CM |
138 | "Error while requesting temperature measurement.\n"); |
139 | goto exit; | |
140 | } | |
c07f85c5 MB |
141 | wait_for_completion_timeout(&data->done, 1 + msecs_to_jiffies( |
142 | BMP085_TEMP_CONVERSION_TIME)); | |
5bf1d290 | 143 | |
985087db EA |
144 | status = regmap_bulk_read(data->regmap, BMP085_CONVERSION_REGISTER_MSB, |
145 | &tmp, sizeof(tmp)); | |
146 | if (status < 0) { | |
147 | dev_err(data->dev, | |
5bf1d290 | 148 | "Error while reading temperature measurement result\n"); |
5bf1d290 CM |
149 | goto exit; |
150 | } | |
151 | data->raw_temperature = be16_to_cpu(tmp); | |
152 | data->last_temp_measurement = jiffies; | |
153 | status = 0; /* everything ok, return 0 */ | |
154 | ||
155 | exit: | |
156 | mutex_unlock(&data->lock); | |
157 | return status; | |
158 | } | |
159 | ||
160 | static s32 bmp085_update_raw_pressure(struct bmp085_data *data) | |
161 | { | |
162 | u32 tmp = 0; | |
163 | s32 status; | |
164 | ||
165 | mutex_lock(&data->lock); | |
c07f85c5 MB |
166 | |
167 | init_completion(&data->done); | |
168 | ||
985087db | 169 | status = regmap_write(data->regmap, BMP085_CTRL_REG, |
e939ca0a EA |
170 | BMP085_PRESSURE_MEASUREMENT + |
171 | (data->oversampling_setting << 6)); | |
172 | if (status < 0) { | |
985087db | 173 | dev_err(data->dev, |
5bf1d290 CM |
174 | "Error while requesting pressure measurement.\n"); |
175 | goto exit; | |
176 | } | |
177 | ||
178 | /* wait for the end of conversion */ | |
c07f85c5 MB |
179 | wait_for_completion_timeout(&data->done, 1 + msecs_to_jiffies( |
180 | 2+(3 << data->oversampling_setting))); | |
5bf1d290 | 181 | /* copy data into a u32 (4 bytes), but skip the first byte. */ |
985087db EA |
182 | status = regmap_bulk_read(data->regmap, BMP085_CONVERSION_REGISTER_MSB, |
183 | ((u8 *)&tmp)+1, 3); | |
184 | if (status < 0) { | |
185 | dev_err(data->dev, | |
5bf1d290 | 186 | "Error while reading pressure measurement results\n"); |
5bf1d290 CM |
187 | goto exit; |
188 | } | |
189 | data->raw_pressure = be32_to_cpu((tmp)); | |
190 | data->raw_pressure >>= (8-data->oversampling_setting); | |
191 | status = 0; /* everything ok, return 0 */ | |
192 | ||
193 | exit: | |
194 | mutex_unlock(&data->lock); | |
195 | return status; | |
196 | } | |
197 | ||
5bf1d290 CM |
198 | /* |
199 | * This function starts the temperature measurement and returns the value | |
200 | * in tenth of a degree celsius. | |
201 | */ | |
202 | static s32 bmp085_get_temperature(struct bmp085_data *data, int *temperature) | |
203 | { | |
204 | struct bmp085_calibration_data *cali = &data->calibration; | |
205 | long x1, x2; | |
206 | int status; | |
207 | ||
208 | status = bmp085_update_raw_temperature(data); | |
e939ca0a | 209 | if (status < 0) |
5bf1d290 CM |
210 | goto exit; |
211 | ||
212 | x1 = ((data->raw_temperature - cali->AC6) * cali->AC5) >> 15; | |
213 | x2 = (cali->MC << 11) / (x1 + cali->MD); | |
214 | data->b6 = x1 + x2 - 4000; | |
215 | /* if NULL just update b6. Used for pressure only measurements */ | |
216 | if (temperature != NULL) | |
217 | *temperature = (x1+x2+8) >> 4; | |
218 | ||
219 | exit: | |
f80ea668 | 220 | return status; |
5bf1d290 CM |
221 | } |
222 | ||
223 | /* | |
224 | * This function starts the pressure measurement and returns the value | |
225 | * in millibar. Since the pressure depends on the ambient temperature, | |
e939ca0a EA |
226 | * a temperature measurement is executed according to the given temperature |
227 | * measurement period (default is 1 sec boundary). This period could vary | |
228 | * and needs to be adjusted according to the sensor environment, i.e. if big | |
229 | * temperature variations then the temperature needs to be read out often. | |
5bf1d290 CM |
230 | */ |
231 | static s32 bmp085_get_pressure(struct bmp085_data *data, int *pressure) | |
232 | { | |
233 | struct bmp085_calibration_data *cali = &data->calibration; | |
234 | s32 x1, x2, x3, b3; | |
235 | u32 b4, b7; | |
236 | s32 p; | |
237 | int status; | |
238 | ||
239 | /* alt least every second force an update of the ambient temperature */ | |
e939ca0a EA |
240 | if ((data->last_temp_measurement == 0) || |
241 | time_is_before_jiffies(data->last_temp_measurement + 1*HZ)) { | |
5bf1d290 | 242 | status = bmp085_get_temperature(data, NULL); |
e939ca0a EA |
243 | if (status < 0) |
244 | return status; | |
5bf1d290 CM |
245 | } |
246 | ||
247 | status = bmp085_update_raw_pressure(data); | |
e939ca0a EA |
248 | if (status < 0) |
249 | return status; | |
5bf1d290 CM |
250 | |
251 | x1 = (data->b6 * data->b6) >> 12; | |
252 | x1 *= cali->B2; | |
253 | x1 >>= 11; | |
254 | ||
255 | x2 = cali->AC2 * data->b6; | |
256 | x2 >>= 11; | |
257 | ||
258 | x3 = x1 + x2; | |
259 | ||
260 | b3 = (((((s32)cali->AC1) * 4 + x3) << data->oversampling_setting) + 2); | |
261 | b3 >>= 2; | |
262 | ||
263 | x1 = (cali->AC3 * data->b6) >> 13; | |
264 | x2 = (cali->B1 * ((data->b6 * data->b6) >> 12)) >> 16; | |
265 | x3 = (x1 + x2 + 2) >> 2; | |
266 | b4 = (cali->AC4 * (u32)(x3 + 32768)) >> 15; | |
267 | ||
268 | b7 = ((u32)data->raw_pressure - b3) * | |
269 | (50000 >> data->oversampling_setting); | |
270 | p = ((b7 < 0x80000000) ? ((b7 << 1) / b4) : ((b7 / b4) * 2)); | |
271 | ||
272 | x1 = p >> 8; | |
273 | x1 *= x1; | |
274 | x1 = (x1 * 3038) >> 16; | |
275 | x2 = (-7357 * p) >> 16; | |
276 | p += (x1 + x2 + 3791) >> 4; | |
277 | ||
278 | *pressure = p; | |
279 | ||
e939ca0a | 280 | return 0; |
5bf1d290 CM |
281 | } |
282 | ||
283 | /* | |
284 | * This function sets the chip-internal oversampling. Valid values are 0..3. | |
285 | * The chip will use 2^oversampling samples for internal averaging. | |
286 | * This influences the measurement time and the accuracy; larger values | |
e939ca0a | 287 | * increase both. The datasheet gives an overview on how measurement time, |
5bf1d290 CM |
288 | * accuracy and noise correlate. |
289 | */ | |
290 | static void bmp085_set_oversampling(struct bmp085_data *data, | |
291 | unsigned char oversampling) | |
292 | { | |
293 | if (oversampling > 3) | |
294 | oversampling = 3; | |
295 | data->oversampling_setting = oversampling; | |
296 | } | |
297 | ||
298 | /* | |
299 | * Returns the currently selected oversampling. Range: 0..3 | |
300 | */ | |
301 | static unsigned char bmp085_get_oversampling(struct bmp085_data *data) | |
302 | { | |
303 | return data->oversampling_setting; | |
304 | } | |
305 | ||
306 | /* sysfs callbacks */ | |
307 | static ssize_t set_oversampling(struct device *dev, | |
308 | struct device_attribute *attr, | |
309 | const char *buf, size_t count) | |
310 | { | |
985087db | 311 | struct bmp085_data *data = dev_get_drvdata(dev); |
5bf1d290 | 312 | unsigned long oversampling; |
e939ca0a EA |
313 | int err = kstrtoul(buf, 10, &oversampling); |
314 | ||
315 | if (err == 0) { | |
316 | mutex_lock(&data->lock); | |
5bf1d290 | 317 | bmp085_set_oversampling(data, oversampling); |
e939ca0a | 318 | mutex_unlock(&data->lock); |
5bf1d290 CM |
319 | return count; |
320 | } | |
e939ca0a EA |
321 | |
322 | return err; | |
5bf1d290 CM |
323 | } |
324 | ||
325 | static ssize_t show_oversampling(struct device *dev, | |
326 | struct device_attribute *attr, char *buf) | |
327 | { | |
985087db | 328 | struct bmp085_data *data = dev_get_drvdata(dev); |
e939ca0a | 329 | |
5bf1d290 CM |
330 | return sprintf(buf, "%u\n", bmp085_get_oversampling(data)); |
331 | } | |
332 | static DEVICE_ATTR(oversampling, S_IWUSR | S_IRUGO, | |
333 | show_oversampling, set_oversampling); | |
334 | ||
335 | ||
336 | static ssize_t show_temperature(struct device *dev, | |
337 | struct device_attribute *attr, char *buf) | |
338 | { | |
339 | int temperature; | |
340 | int status; | |
985087db | 341 | struct bmp085_data *data = dev_get_drvdata(dev); |
5bf1d290 CM |
342 | |
343 | status = bmp085_get_temperature(data, &temperature); | |
e939ca0a | 344 | if (status < 0) |
5bf1d290 CM |
345 | return status; |
346 | else | |
347 | return sprintf(buf, "%d\n", temperature); | |
348 | } | |
349 | static DEVICE_ATTR(temp0_input, S_IRUGO, show_temperature, NULL); | |
350 | ||
351 | ||
352 | static ssize_t show_pressure(struct device *dev, | |
353 | struct device_attribute *attr, char *buf) | |
354 | { | |
355 | int pressure; | |
356 | int status; | |
985087db | 357 | struct bmp085_data *data = dev_get_drvdata(dev); |
5bf1d290 CM |
358 | |
359 | status = bmp085_get_pressure(data, &pressure); | |
e939ca0a | 360 | if (status < 0) |
5bf1d290 CM |
361 | return status; |
362 | else | |
363 | return sprintf(buf, "%d\n", pressure); | |
364 | } | |
365 | static DEVICE_ATTR(pressure0_input, S_IRUGO, show_pressure, NULL); | |
366 | ||
367 | ||
368 | static struct attribute *bmp085_attributes[] = { | |
369 | &dev_attr_temp0_input.attr, | |
370 | &dev_attr_pressure0_input.attr, | |
371 | &dev_attr_oversampling.attr, | |
372 | NULL | |
373 | }; | |
374 | ||
375 | static const struct attribute_group bmp085_attr_group = { | |
376 | .attrs = bmp085_attributes, | |
377 | }; | |
378 | ||
985087db | 379 | int bmp085_detect(struct device *dev) |
5bf1d290 | 380 | { |
985087db EA |
381 | struct bmp085_data *data = dev_get_drvdata(dev); |
382 | unsigned int id; | |
383 | int ret; | |
384 | ||
385 | ret = regmap_read(data->regmap, BMP085_CHIP_ID_REG, &id); | |
386 | if (ret < 0) | |
387 | return ret; | |
5bf1d290 | 388 | |
985087db | 389 | if (id != data->chip_id) |
5bf1d290 CM |
390 | return -ENODEV; |
391 | ||
392 | return 0; | |
393 | } | |
985087db | 394 | EXPORT_SYMBOL_GPL(bmp085_detect); |
5bf1d290 | 395 | |
d396034a | 396 | static void bmp085_get_of_properties(struct bmp085_data *data) |
c5a86ab6 EA |
397 | { |
398 | #ifdef CONFIG_OF | |
985087db | 399 | struct device_node *np = data->dev->of_node; |
c5a86ab6 EA |
400 | u32 prop; |
401 | ||
402 | if (!np) | |
403 | return; | |
404 | ||
405 | if (!of_property_read_u32(np, "chip-id", &prop)) | |
406 | data->chip_id = prop & 0xff; | |
407 | ||
408 | if (!of_property_read_u32(np, "temp-measurement-period", &prop)) | |
409 | data->temp_measurement_period = (prop/100)*HZ; | |
410 | ||
411 | if (!of_property_read_u32(np, "default-oversampling", &prop)) | |
412 | data->oversampling_setting = prop & 0xff; | |
413 | #endif | |
414 | } | |
415 | ||
985087db | 416 | static int bmp085_init_client(struct bmp085_data *data) |
5bf1d290 | 417 | { |
985087db | 418 | int status = bmp085_read_calibration_data(data); |
e939ca0a EA |
419 | |
420 | if (status < 0) | |
421 | return status; | |
422 | ||
c5a86ab6 | 423 | /* default settings */ |
c5a86ab6 | 424 | data->chip_id = BMP085_CHIP_ID; |
5bf1d290 | 425 | data->last_temp_measurement = 0; |
e939ca0a | 426 | data->temp_measurement_period = 1*HZ; |
5bf1d290 | 427 | data->oversampling_setting = 3; |
c5a86ab6 | 428 | |
985087db | 429 | bmp085_get_of_properties(data); |
c5a86ab6 | 430 | |
5bf1d290 | 431 | mutex_init(&data->lock); |
e939ca0a EA |
432 | |
433 | return 0; | |
5bf1d290 CM |
434 | } |
435 | ||
985087db EA |
436 | struct regmap_config bmp085_regmap_config = { |
437 | .reg_bits = 8, | |
438 | .val_bits = 8 | |
439 | }; | |
440 | EXPORT_SYMBOL_GPL(bmp085_regmap_config); | |
441 | ||
c07f85c5 | 442 | int bmp085_probe(struct device *dev, struct regmap *regmap, int irq) |
5bf1d290 CM |
443 | { |
444 | struct bmp085_data *data; | |
445 | int err = 0; | |
446 | ||
447 | data = kzalloc(sizeof(struct bmp085_data), GFP_KERNEL); | |
448 | if (!data) { | |
449 | err = -ENOMEM; | |
450 | goto exit; | |
451 | } | |
452 | ||
985087db EA |
453 | dev_set_drvdata(dev, data); |
454 | data->dev = dev; | |
455 | data->regmap = regmap; | |
c07f85c5 MB |
456 | data->irq = irq; |
457 | ||
458 | if (data->irq > 0) { | |
459 | err = devm_request_irq(dev, data->irq, bmp085_eoc_isr, | |
460 | IRQF_TRIGGER_RISING, "bmp085", | |
461 | data); | |
462 | if (err < 0) | |
463 | goto exit_free; | |
464 | } | |
5bf1d290 CM |
465 | |
466 | /* Initialize the BMP085 chip */ | |
985087db | 467 | err = bmp085_init_client(data); |
e939ca0a | 468 | if (err < 0) |
5bf1d290 CM |
469 | goto exit_free; |
470 | ||
985087db EA |
471 | err = bmp085_detect(dev); |
472 | if (err < 0) { | |
473 | dev_err(dev, "%s: chip_id failed!\n", BMP085_NAME); | |
474 | goto exit_free; | |
475 | } | |
476 | ||
5bf1d290 | 477 | /* Register sysfs hooks */ |
985087db | 478 | err = sysfs_create_group(&dev->kobj, &bmp085_attr_group); |
5bf1d290 CM |
479 | if (err) |
480 | goto exit_free; | |
481 | ||
985087db | 482 | dev_info(dev, "Successfully initialized %s!\n", BMP085_NAME); |
e939ca0a EA |
483 | |
484 | return 0; | |
5bf1d290 CM |
485 | |
486 | exit_free: | |
487 | kfree(data); | |
488 | exit: | |
489 | return err; | |
490 | } | |
985087db | 491 | EXPORT_SYMBOL_GPL(bmp085_probe); |
5bf1d290 | 492 | |
985087db | 493 | int bmp085_remove(struct device *dev) |
5bf1d290 | 494 | { |
985087db | 495 | struct bmp085_data *data = dev_get_drvdata(dev); |
e939ca0a | 496 | |
985087db | 497 | sysfs_remove_group(&data->dev->kobj, &bmp085_attr_group); |
e939ca0a EA |
498 | kfree(data); |
499 | ||
5bf1d290 CM |
500 | return 0; |
501 | } | |
985087db | 502 | EXPORT_SYMBOL_GPL(bmp085_remove); |
5bf1d290 | 503 | |
e939ca0a | 504 | MODULE_AUTHOR("Christoph Mair <christoph.mair@gmail.com>"); |
5bf1d290 CM |
505 | MODULE_DESCRIPTION("BMP085 driver"); |
506 | MODULE_LICENSE("GPL"); |