1  // SPDX-License-Identifier: GPL-2.0+
2  // Copyright IBM Corp 2019
3  /*
4   * The DPS310 is a barometric pressure and temperature sensor.
5   * Currently only reading a single temperature is supported by
6   * this driver.
7   *
8   * https://www.infineon.com/dgdl/?fileId=5546d462576f34750157750826c42242
9   *
10   * Temperature calculation:
11   *   c0 * 0.5 + c1 * T_raw / kT °C
12   *
13   * TODO:
14   *  - Optionally support the FIFO
15   */
16  
17  #include <linux/i2c.h>
18  #include <linux/limits.h>
19  #include <linux/math64.h>
20  #include <linux/module.h>
21  #include <linux/regmap.h>
22  
23  #include <linux/iio/iio.h>
24  #include <linux/iio/sysfs.h>
25  
26  #define DPS310_DEV_NAME		"dps310"
27  
28  #define DPS310_PRS_B0		0x00
29  #define DPS310_PRS_B1		0x01
30  #define DPS310_PRS_B2		0x02
31  #define DPS310_TMP_B0		0x03
32  #define DPS310_TMP_B1		0x04
33  #define DPS310_TMP_B2		0x05
34  #define DPS310_PRS_CFG		0x06
35  #define  DPS310_PRS_RATE_BITS	GENMASK(6, 4)
36  #define  DPS310_PRS_PRC_BITS	GENMASK(3, 0)
37  #define DPS310_TMP_CFG		0x07
38  #define  DPS310_TMP_RATE_BITS	GENMASK(6, 4)
39  #define  DPS310_TMP_PRC_BITS	GENMASK(3, 0)
40  #define  DPS310_TMP_EXT		BIT(7)
41  #define DPS310_MEAS_CFG		0x08
42  #define  DPS310_MEAS_CTRL_BITS	GENMASK(2, 0)
43  #define   DPS310_PRS_EN		BIT(0)
44  #define   DPS310_TEMP_EN	BIT(1)
45  #define   DPS310_BACKGROUND	BIT(2)
46  #define  DPS310_PRS_RDY		BIT(4)
47  #define  DPS310_TMP_RDY		BIT(5)
48  #define  DPS310_SENSOR_RDY	BIT(6)
49  #define  DPS310_COEF_RDY	BIT(7)
50  #define DPS310_CFG_REG		0x09
51  #define  DPS310_INT_HL		BIT(7)
52  #define  DPS310_TMP_SHIFT_EN	BIT(3)
53  #define  DPS310_PRS_SHIFT_EN	BIT(4)
54  #define  DPS310_FIFO_EN		BIT(5)
55  #define  DPS310_SPI_EN		BIT(6)
56  #define DPS310_RESET		0x0c
57  #define  DPS310_RESET_MAGIC	0x09
58  #define DPS310_COEF_BASE	0x10
59  
60  /* Make sure sleep time is <= 30ms for usleep_range */
61  #define DPS310_POLL_SLEEP_US(t)		min(30000, (t) / 8)
62  /* Silently handle error in rate value here */
63  #define DPS310_POLL_TIMEOUT_US(rc)	((rc) <= 0 ? 1000000 : 1000000 / (rc))
64  
65  #define DPS310_PRS_BASE		DPS310_PRS_B0
66  #define DPS310_TMP_BASE		DPS310_TMP_B0
67  
68  /*
69   * These values (defined in the spec) indicate how to scale the raw register
70   * values for each level of precision available.
71   */
72  static const int scale_factors[] = {
73  	 524288,
74  	1572864,
75  	3670016,
76  	7864320,
77  	 253952,
78  	 516096,
79  	1040384,
80  	2088960,
81  };
82  
83  struct dps310_data {
84  	struct i2c_client *client;
85  	struct regmap *regmap;
86  	struct mutex lock;	/* Lock for sequential HW access functions */
87  
88  	s32 c0, c1;
89  	s32 c00, c10, c20, c30, c01, c11, c21;
90  	s32 pressure_raw;
91  	s32 temp_raw;
92  	bool timeout_recovery_failed;
93  };
94  
95  static const struct iio_chan_spec dps310_channels[] = {
96  	{
97  		.type = IIO_TEMP,
98  		.info_mask_separate = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
99  			BIT(IIO_CHAN_INFO_SAMP_FREQ) |
100  			BIT(IIO_CHAN_INFO_PROCESSED),
101  	},
102  	{
103  		.type = IIO_PRESSURE,
104  		.info_mask_separate = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
105  			BIT(IIO_CHAN_INFO_SAMP_FREQ) |
106  			BIT(IIO_CHAN_INFO_PROCESSED),
107  	},
108  };
109  
110  /* To be called after checking the COEF_RDY bit in MEAS_CFG */
dps310_get_coefs(struct dps310_data * data)111  static int dps310_get_coefs(struct dps310_data *data)
112  {
113  	int rc;
114  	u8 coef[18];
115  	u32 c0, c1;
116  	u32 c00, c10, c20, c30, c01, c11, c21;
117  
118  	/* Read all sensor calibration coefficients from the COEF registers. */
119  	rc = regmap_bulk_read(data->regmap, DPS310_COEF_BASE, coef,
120  			      sizeof(coef));
121  	if (rc < 0)
122  		return rc;
123  
124  	/*
125  	 * Calculate temperature calibration coefficients c0 and c1. The
126  	 * numbers are 12-bit 2's complement numbers.
127  	 */
128  	c0 = (coef[0] << 4) | (coef[1] >> 4);
129  	data->c0 = sign_extend32(c0, 11);
130  
131  	c1 = ((coef[1] & GENMASK(3, 0)) << 8) | coef[2];
132  	data->c1 = sign_extend32(c1, 11);
133  
134  	/*
135  	 * Calculate pressure calibration coefficients. c00 and c10 are 20 bit
136  	 * 2's complement numbers, while the rest are 16 bit 2's complement
137  	 * numbers.
138  	 */
139  	c00 = (coef[3] << 12) | (coef[4] << 4) | (coef[5] >> 4);
140  	data->c00 = sign_extend32(c00, 19);
141  
142  	c10 = ((coef[5] & GENMASK(3, 0)) << 16) | (coef[6] << 8) | coef[7];
143  	data->c10 = sign_extend32(c10, 19);
144  
145  	c01 = (coef[8] << 8) | coef[9];
146  	data->c01 = sign_extend32(c01, 15);
147  
148  	c11 = (coef[10] << 8) | coef[11];
149  	data->c11 = sign_extend32(c11, 15);
150  
151  	c20 = (coef[12] << 8) | coef[13];
152  	data->c20 = sign_extend32(c20, 15);
153  
154  	c21 = (coef[14] << 8) | coef[15];
155  	data->c21 = sign_extend32(c21, 15);
156  
157  	c30 = (coef[16] << 8) | coef[17];
158  	data->c30 = sign_extend32(c30, 15);
159  
160  	return 0;
161  }
162  
163  /*
164   * Some versions of the chip will read temperatures in the ~60C range when
165   * it's actually ~20C. This is the manufacturer recommended workaround
166   * to correct the issue. The registers used below are undocumented.
167   */
dps310_temp_workaround(struct dps310_data * data)168  static int dps310_temp_workaround(struct dps310_data *data)
169  {
170  	int rc;
171  	int reg;
172  
173  	rc = regmap_read(data->regmap, 0x32, &reg);
174  	if (rc < 0)
175  		return rc;
176  
177  	/*
178  	 * If bit 1 is set then the device is okay, and the workaround does not
179  	 * need to be applied
180  	 */
181  	if (reg & BIT(1))
182  		return 0;
183  
184  	rc = regmap_write(data->regmap, 0x0e, 0xA5);
185  	if (rc)
186  		return rc;
187  
188  	rc = regmap_write(data->regmap, 0x0f, 0x96);
189  	if (rc)
190  		return rc;
191  
192  	rc = regmap_write(data->regmap, 0x62, 0x02);
193  	if (rc)
194  		return rc;
195  
196  	rc = regmap_write(data->regmap, 0x0e, 0x00);
197  	if (rc)
198  		return rc;
199  
200  	return regmap_write(data->regmap, 0x0f, 0x00);
201  }
202  
dps310_startup(struct dps310_data * data)203  static int dps310_startup(struct dps310_data *data)
204  {
205  	int rc;
206  	int ready;
207  
208  	/*
209  	 * Set up pressure sensor in single sample, one measurement per second
210  	 * mode
211  	 */
212  	rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0);
213  	if (rc)
214  		return rc;
215  
216  	/*
217  	 * Set up external (MEMS) temperature sensor in single sample, one
218  	 * measurement per second mode
219  	 */
220  	rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT);
221  	if (rc)
222  		return rc;
223  
224  	/* Temp and pressure shifts are disabled when PRC <= 8 */
225  	rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
226  			       DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0);
227  	if (rc)
228  		return rc;
229  
230  	/* MEAS_CFG doesn't update correctly unless first written with 0 */
231  	rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
232  			       DPS310_MEAS_CTRL_BITS, 0);
233  	if (rc)
234  		return rc;
235  
236  	/* Turn on temperature and pressure measurement in the background */
237  	rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
238  			       DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN |
239  			       DPS310_TEMP_EN | DPS310_BACKGROUND);
240  	if (rc)
241  		return rc;
242  
243  	/*
244  	 * Calibration coefficients required for reporting temperature.
245  	 * They are available 40ms after the device has started
246  	 */
247  	rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
248  				      ready & DPS310_COEF_RDY, 10000, 40000);
249  	if (rc)
250  		return rc;
251  
252  	rc = dps310_get_coefs(data);
253  	if (rc)
254  		return rc;
255  
256  	return dps310_temp_workaround(data);
257  }
258  
dps310_get_pres_precision(struct dps310_data * data,int * val)259  static int dps310_get_pres_precision(struct dps310_data *data, int *val)
260  {
261  	int reg_val, rc;
262  
263  	rc = regmap_read(data->regmap, DPS310_PRS_CFG, &reg_val);
264  	if (rc < 0)
265  		return rc;
266  
267  	*val = BIT(reg_val & GENMASK(2, 0));
268  
269  	return 0;
270  }
271  
dps310_get_temp_precision(struct dps310_data * data,int * val)272  static int dps310_get_temp_precision(struct dps310_data *data, int *val)
273  {
274  	int reg_val, rc;
275  
276  	rc = regmap_read(data->regmap, DPS310_TMP_CFG, &reg_val);
277  	if (rc < 0)
278  		return rc;
279  
280  	/*
281  	 * Scale factor is bottom 4 bits of the register, but 1111 is
282  	 * reserved so just grab bottom three
283  	 */
284  	*val = BIT(reg_val & GENMASK(2, 0));
285  
286  	return 0;
287  }
288  
289  /* Called with lock held */
dps310_set_pres_precision(struct dps310_data * data,int val)290  static int dps310_set_pres_precision(struct dps310_data *data, int val)
291  {
292  	int rc;
293  	u8 shift_en;
294  
295  	if (val < 0 || val > 128)
296  		return -EINVAL;
297  
298  	shift_en = val >= 16 ? DPS310_PRS_SHIFT_EN : 0;
299  	rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
300  			       DPS310_PRS_SHIFT_EN, shift_en);
301  	if (rc)
302  		return rc;
303  
304  	return regmap_update_bits(data->regmap, DPS310_PRS_CFG,
305  				  DPS310_PRS_PRC_BITS, ilog2(val));
306  }
307  
308  /* Called with lock held */
dps310_set_temp_precision(struct dps310_data * data,int val)309  static int dps310_set_temp_precision(struct dps310_data *data, int val)
310  {
311  	int rc;
312  	u8 shift_en;
313  
314  	if (val < 0 || val > 128)
315  		return -EINVAL;
316  
317  	shift_en = val >= 16 ? DPS310_TMP_SHIFT_EN : 0;
318  	rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
319  			       DPS310_TMP_SHIFT_EN, shift_en);
320  	if (rc)
321  		return rc;
322  
323  	return regmap_update_bits(data->regmap, DPS310_TMP_CFG,
324  				  DPS310_TMP_PRC_BITS, ilog2(val));
325  }
326  
327  /* Called with lock held */
dps310_set_pres_samp_freq(struct dps310_data * data,int freq)328  static int dps310_set_pres_samp_freq(struct dps310_data *data, int freq)
329  {
330  	u8 val;
331  
332  	if (freq < 0 || freq > 128)
333  		return -EINVAL;
334  
335  	val = ilog2(freq) << 4;
336  
337  	return regmap_update_bits(data->regmap, DPS310_PRS_CFG,
338  				  DPS310_PRS_RATE_BITS, val);
339  }
340  
341  /* Called with lock held */
dps310_set_temp_samp_freq(struct dps310_data * data,int freq)342  static int dps310_set_temp_samp_freq(struct dps310_data *data, int freq)
343  {
344  	u8 val;
345  
346  	if (freq < 0 || freq > 128)
347  		return -EINVAL;
348  
349  	val = ilog2(freq) << 4;
350  
351  	return regmap_update_bits(data->regmap, DPS310_TMP_CFG,
352  				  DPS310_TMP_RATE_BITS, val);
353  }
354  
dps310_get_pres_samp_freq(struct dps310_data * data,int * val)355  static int dps310_get_pres_samp_freq(struct dps310_data *data, int *val)
356  {
357  	int reg_val, rc;
358  
359  	rc = regmap_read(data->regmap, DPS310_PRS_CFG, &reg_val);
360  	if (rc < 0)
361  		return rc;
362  
363  	*val = BIT((reg_val & DPS310_PRS_RATE_BITS) >> 4);
364  
365  	return 0;
366  }
367  
dps310_get_temp_samp_freq(struct dps310_data * data,int * val)368  static int dps310_get_temp_samp_freq(struct dps310_data *data, int *val)
369  {
370  	int reg_val, rc;
371  
372  	rc = regmap_read(data->regmap, DPS310_TMP_CFG, &reg_val);
373  	if (rc < 0)
374  		return rc;
375  
376  	*val = BIT((reg_val & DPS310_TMP_RATE_BITS) >> 4);
377  
378  	return 0;
379  }
380  
dps310_get_pres_k(struct dps310_data * data,int * val)381  static int dps310_get_pres_k(struct dps310_data *data, int *val)
382  {
383  	int reg_val, rc;
384  
385  	rc = regmap_read(data->regmap, DPS310_PRS_CFG, &reg_val);
386  	if (rc < 0)
387  		return rc;
388  
389  	*val = scale_factors[reg_val & GENMASK(2, 0)];
390  
391  	return 0;
392  }
393  
dps310_get_temp_k(struct dps310_data * data,int * val)394  static int dps310_get_temp_k(struct dps310_data *data, int *val)
395  {
396  	int reg_val, rc;
397  
398  	rc = regmap_read(data->regmap, DPS310_TMP_CFG, &reg_val);
399  	if (rc < 0)
400  		return rc;
401  
402  	*val = scale_factors[reg_val & GENMASK(2, 0)];
403  
404  	return 0;
405  }
406  
dps310_reset_wait(struct dps310_data * data)407  static int dps310_reset_wait(struct dps310_data *data)
408  {
409  	int rc;
410  
411  	rc = regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
412  	if (rc)
413  		return rc;
414  
415  	/* Wait for device chip access: 15ms in specification */
416  	usleep_range(15000, 55000);
417  	return 0;
418  }
419  
dps310_reset_reinit(struct dps310_data * data)420  static int dps310_reset_reinit(struct dps310_data *data)
421  {
422  	int rc;
423  
424  	rc = dps310_reset_wait(data);
425  	if (rc)
426  		return rc;
427  
428  	return dps310_startup(data);
429  }
430  
dps310_ready_status(struct dps310_data * data,int ready_bit,int timeout)431  static int dps310_ready_status(struct dps310_data *data, int ready_bit, int timeout)
432  {
433  	int sleep = DPS310_POLL_SLEEP_US(timeout);
434  	int ready;
435  
436  	return regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready, ready & ready_bit,
437  					sleep, timeout);
438  }
439  
dps310_ready(struct dps310_data * data,int ready_bit,int timeout)440  static int dps310_ready(struct dps310_data *data, int ready_bit, int timeout)
441  {
442  	int rc;
443  
444  	rc = dps310_ready_status(data, ready_bit, timeout);
445  	if (rc) {
446  		if (rc == -ETIMEDOUT && !data->timeout_recovery_failed) {
447  			/* Reset and reinitialize the chip. */
448  			if (dps310_reset_reinit(data)) {
449  				data->timeout_recovery_failed = true;
450  			} else {
451  				/* Try again to get sensor ready status. */
452  				if (dps310_ready_status(data, ready_bit, timeout))
453  					data->timeout_recovery_failed = true;
454  				else
455  					return 0;
456  			}
457  		}
458  
459  		return rc;
460  	}
461  
462  	data->timeout_recovery_failed = false;
463  	return 0;
464  }
465  
dps310_read_pres_raw(struct dps310_data * data)466  static int dps310_read_pres_raw(struct dps310_data *data)
467  {
468  	int rc;
469  	int rate;
470  	int timeout;
471  	s32 raw;
472  	u8 val[3];
473  
474  	if (mutex_lock_interruptible(&data->lock))
475  		return -EINTR;
476  
477  	rc = dps310_get_pres_samp_freq(data, &rate);
478  	if (rc)
479  		goto done;
480  
481  	timeout = DPS310_POLL_TIMEOUT_US(rate);
482  
483  	/* Poll for sensor readiness; base the timeout upon the sample rate. */
484  	rc = dps310_ready(data, DPS310_PRS_RDY, timeout);
485  	if (rc)
486  		goto done;
487  
488  	rc = regmap_bulk_read(data->regmap, DPS310_PRS_BASE, val, sizeof(val));
489  	if (rc < 0)
490  		goto done;
491  
492  	raw = (val[0] << 16) | (val[1] << 8) | val[2];
493  	data->pressure_raw = sign_extend32(raw, 23);
494  
495  done:
496  	mutex_unlock(&data->lock);
497  	return rc;
498  }
499  
500  /* Called with lock held */
dps310_read_temp_ready(struct dps310_data * data)501  static int dps310_read_temp_ready(struct dps310_data *data)
502  {
503  	int rc;
504  	u8 val[3];
505  	s32 raw;
506  
507  	rc = regmap_bulk_read(data->regmap, DPS310_TMP_BASE, val, sizeof(val));
508  	if (rc < 0)
509  		return rc;
510  
511  	raw = (val[0] << 16) | (val[1] << 8) | val[2];
512  	data->temp_raw = sign_extend32(raw, 23);
513  
514  	return 0;
515  }
516  
dps310_read_temp_raw(struct dps310_data * data)517  static int dps310_read_temp_raw(struct dps310_data *data)
518  {
519  	int rc;
520  	int rate;
521  	int timeout;
522  
523  	if (mutex_lock_interruptible(&data->lock))
524  		return -EINTR;
525  
526  	rc = dps310_get_temp_samp_freq(data, &rate);
527  	if (rc)
528  		goto done;
529  
530  	timeout = DPS310_POLL_TIMEOUT_US(rate);
531  
532  	/* Poll for sensor readiness; base the timeout upon the sample rate. */
533  	rc = dps310_ready(data, DPS310_TMP_RDY, timeout);
534  	if (rc)
535  		goto done;
536  
537  	rc = dps310_read_temp_ready(data);
538  
539  done:
540  	mutex_unlock(&data->lock);
541  	return rc;
542  }
543  
dps310_is_writeable_reg(struct device * dev,unsigned int reg)544  static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg)
545  {
546  	switch (reg) {
547  	case DPS310_PRS_CFG:
548  	case DPS310_TMP_CFG:
549  	case DPS310_MEAS_CFG:
550  	case DPS310_CFG_REG:
551  	case DPS310_RESET:
552  	/* No documentation available on the registers below */
553  	case 0x0e:
554  	case 0x0f:
555  	case 0x62:
556  		return true;
557  	default:
558  		return false;
559  	}
560  }
561  
dps310_is_volatile_reg(struct device * dev,unsigned int reg)562  static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg)
563  {
564  	switch (reg) {
565  	case DPS310_PRS_B0:
566  	case DPS310_PRS_B1:
567  	case DPS310_PRS_B2:
568  	case DPS310_TMP_B0:
569  	case DPS310_TMP_B1:
570  	case DPS310_TMP_B2:
571  	case DPS310_MEAS_CFG:
572  	case 0x32:	/* No documentation available on this register */
573  		return true;
574  	default:
575  		return false;
576  	}
577  }
578  
dps310_write_raw(struct iio_dev * iio,struct iio_chan_spec const * chan,int val,int val2,long mask)579  static int dps310_write_raw(struct iio_dev *iio,
580  			    struct iio_chan_spec const *chan, int val,
581  			    int val2, long mask)
582  {
583  	int rc;
584  	struct dps310_data *data = iio_priv(iio);
585  
586  	if (mutex_lock_interruptible(&data->lock))
587  		return -EINTR;
588  
589  	switch (mask) {
590  	case IIO_CHAN_INFO_SAMP_FREQ:
591  		switch (chan->type) {
592  		case IIO_PRESSURE:
593  			rc = dps310_set_pres_samp_freq(data, val);
594  			break;
595  
596  		case IIO_TEMP:
597  			rc = dps310_set_temp_samp_freq(data, val);
598  			break;
599  
600  		default:
601  			rc = -EINVAL;
602  			break;
603  		}
604  		break;
605  
606  	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
607  		switch (chan->type) {
608  		case IIO_PRESSURE:
609  			rc = dps310_set_pres_precision(data, val);
610  			break;
611  
612  		case IIO_TEMP:
613  			rc = dps310_set_temp_precision(data, val);
614  			break;
615  
616  		default:
617  			rc = -EINVAL;
618  			break;
619  		}
620  		break;
621  
622  	default:
623  		rc = -EINVAL;
624  		break;
625  	}
626  
627  	mutex_unlock(&data->lock);
628  	return rc;
629  }
630  
dps310_calculate_pressure(struct dps310_data * data,int * val)631  static int dps310_calculate_pressure(struct dps310_data *data, int *val)
632  {
633  	int i;
634  	int rc;
635  	int t_ready;
636  	int kpi;
637  	int kti;
638  	s64 rem = 0ULL;
639  	s64 pressure = 0ULL;
640  	s64 p;
641  	s64 t;
642  	s64 denoms[7];
643  	s64 nums[7];
644  	s64 rems[7];
645  	s64 kp;
646  	s64 kt;
647  
648  	rc = dps310_get_pres_k(data, &kpi);
649  	if (rc)
650  		return rc;
651  
652  	rc = dps310_get_temp_k(data, &kti);
653  	if (rc)
654  		return rc;
655  
656  	kp = (s64)kpi;
657  	kt = (s64)kti;
658  
659  	/* Refresh temp if it's ready, otherwise just use the latest value */
660  	if (mutex_trylock(&data->lock)) {
661  		rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &t_ready);
662  		if (rc >= 0 && t_ready & DPS310_TMP_RDY)
663  			dps310_read_temp_ready(data);
664  
665  		mutex_unlock(&data->lock);
666  	}
667  
668  	p = (s64)data->pressure_raw;
669  	t = (s64)data->temp_raw;
670  
671  	/* Section 4.9.1 of the DPS310 spec; algebra'd to avoid underflow */
672  	nums[0] = (s64)data->c00;
673  	denoms[0] = 1LL;
674  	nums[1] = p * (s64)data->c10;
675  	denoms[1] = kp;
676  	nums[2] = p * p * (s64)data->c20;
677  	denoms[2] = kp * kp;
678  	nums[3] = p * p * p * (s64)data->c30;
679  	denoms[3] = kp * kp * kp;
680  	nums[4] = t * (s64)data->c01;
681  	denoms[4] = kt;
682  	nums[5] = t * p * (s64)data->c11;
683  	denoms[5] = kp * kt;
684  	nums[6] = t * p * p * (s64)data->c21;
685  	denoms[6] = kp * kp * kt;
686  
687  	/* Kernel lacks a div64_s64_rem function; denoms are all positive */
688  	for (i = 0; i < 7; ++i) {
689  		u64 irem;
690  
691  		if (nums[i] < 0LL) {
692  			pressure -= div64_u64_rem(-nums[i], denoms[i], &irem);
693  			rems[i] = -irem;
694  		} else {
695  			pressure += div64_u64_rem(nums[i], denoms[i], &irem);
696  			rems[i] = (s64)irem;
697  		}
698  	}
699  
700  	/* Increase precision and calculate the remainder sum */
701  	for (i = 0; i < 7; ++i)
702  		rem += div64_s64((s64)rems[i] * 1000000000LL, denoms[i]);
703  
704  	pressure += div_s64(rem, 1000000000LL);
705  	if (pressure < 0LL)
706  		return -ERANGE;
707  
708  	*val = (int)min_t(s64, pressure, INT_MAX);
709  
710  	return 0;
711  }
712  
dps310_read_pressure(struct dps310_data * data,int * val,int * val2,long mask)713  static int dps310_read_pressure(struct dps310_data *data, int *val, int *val2,
714  				long mask)
715  {
716  	int rc;
717  
718  	switch (mask) {
719  	case IIO_CHAN_INFO_SAMP_FREQ:
720  		rc = dps310_get_pres_samp_freq(data, val);
721  		if (rc)
722  			return rc;
723  
724  		return IIO_VAL_INT;
725  
726  	case IIO_CHAN_INFO_PROCESSED:
727  		rc = dps310_read_pres_raw(data);
728  		if (rc)
729  			return rc;
730  
731  		rc = dps310_calculate_pressure(data, val);
732  		if (rc)
733  			return rc;
734  
735  		*val2 = 1000; /* Convert Pa to KPa per IIO ABI */
736  		return IIO_VAL_FRACTIONAL;
737  
738  	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
739  		rc = dps310_get_pres_precision(data, val);
740  		if (rc)
741  			return rc;
742  		return IIO_VAL_INT;
743  
744  	default:
745  		return -EINVAL;
746  	}
747  }
748  
dps310_calculate_temp(struct dps310_data * data,int * val)749  static int dps310_calculate_temp(struct dps310_data *data, int *val)
750  {
751  	s64 c0;
752  	s64 t;
753  	int kt, rc;
754  
755  	rc = dps310_get_temp_k(data, &kt);
756  	if (rc)
757  		return rc;
758  
759  	/* Obtain inverse-scaled offset */
760  	c0 = div_s64((s64)kt * (s64)data->c0, 2);
761  
762  	/* Add the offset to the unscaled temperature */
763  	t = c0 + ((s64)data->temp_raw * (s64)data->c1);
764  
765  	/* Convert to milliCelsius and scale the temperature */
766  	*val = (int)div_s64(t * 1000LL, kt);
767  
768  	return 0;
769  }
770  
dps310_read_temp(struct dps310_data * data,int * val,int * val2,long mask)771  static int dps310_read_temp(struct dps310_data *data, int *val, int *val2,
772  			    long mask)
773  {
774  	int rc;
775  
776  	switch (mask) {
777  	case IIO_CHAN_INFO_SAMP_FREQ:
778  		rc = dps310_get_temp_samp_freq(data, val);
779  		if (rc)
780  			return rc;
781  
782  		return IIO_VAL_INT;
783  
784  	case IIO_CHAN_INFO_PROCESSED:
785  		rc = dps310_read_temp_raw(data);
786  		if (rc)
787  			return rc;
788  
789  		rc = dps310_calculate_temp(data, val);
790  		if (rc)
791  			return rc;
792  
793  		return IIO_VAL_INT;
794  
795  	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
796  		rc = dps310_get_temp_precision(data, val);
797  		if (rc)
798  			return rc;
799  
800  		return IIO_VAL_INT;
801  
802  	default:
803  		return -EINVAL;
804  	}
805  }
806  
dps310_read_raw(struct iio_dev * iio,struct iio_chan_spec const * chan,int * val,int * val2,long mask)807  static int dps310_read_raw(struct iio_dev *iio,
808  			   struct iio_chan_spec const *chan,
809  			   int *val, int *val2, long mask)
810  {
811  	struct dps310_data *data = iio_priv(iio);
812  
813  	switch (chan->type) {
814  	case IIO_PRESSURE:
815  		return dps310_read_pressure(data, val, val2, mask);
816  
817  	case IIO_TEMP:
818  		return dps310_read_temp(data, val, val2, mask);
819  
820  	default:
821  		return -EINVAL;
822  	}
823  }
824  
dps310_reset(void * action_data)825  static void dps310_reset(void *action_data)
826  {
827  	struct dps310_data *data = action_data;
828  
829  	dps310_reset_wait(data);
830  }
831  
832  static const struct regmap_config dps310_regmap_config = {
833  	.reg_bits = 8,
834  	.val_bits = 8,
835  	.writeable_reg = dps310_is_writeable_reg,
836  	.volatile_reg = dps310_is_volatile_reg,
837  	.cache_type = REGCACHE_RBTREE,
838  	.max_register = 0x62, /* No documentation available on this register */
839  };
840  
841  static const struct iio_info dps310_info = {
842  	.read_raw = dps310_read_raw,
843  	.write_raw = dps310_write_raw,
844  };
845  
dps310_probe(struct i2c_client * client)846  static int dps310_probe(struct i2c_client *client)
847  {
848  	const struct i2c_device_id *id = i2c_client_get_device_id(client);
849  	struct dps310_data *data;
850  	struct iio_dev *iio;
851  	int rc;
852  
853  	iio = devm_iio_device_alloc(&client->dev,  sizeof(*data));
854  	if (!iio)
855  		return -ENOMEM;
856  
857  	data = iio_priv(iio);
858  	data->client = client;
859  	mutex_init(&data->lock);
860  
861  	iio->name = id->name;
862  	iio->channels = dps310_channels;
863  	iio->num_channels = ARRAY_SIZE(dps310_channels);
864  	iio->info = &dps310_info;
865  	iio->modes = INDIO_DIRECT_MODE;
866  
867  	data->regmap = devm_regmap_init_i2c(client, &dps310_regmap_config);
868  	if (IS_ERR(data->regmap))
869  		return PTR_ERR(data->regmap);
870  
871  	/* Register to run the device reset when the device is removed */
872  	rc = devm_add_action_or_reset(&client->dev, dps310_reset, data);
873  	if (rc)
874  		return rc;
875  
876  	rc = dps310_startup(data);
877  	if (rc)
878  		return rc;
879  
880  	rc = devm_iio_device_register(&client->dev, iio);
881  	if (rc)
882  		return rc;
883  
884  	i2c_set_clientdata(client, iio);
885  
886  	return 0;
887  }
888  
889  static const struct i2c_device_id dps310_id[] = {
890  	{ DPS310_DEV_NAME },
891  	{}
892  };
893  MODULE_DEVICE_TABLE(i2c, dps310_id);
894  
895  static const struct acpi_device_id dps310_acpi_match[] = {
896  	{ "IFX3100" },
897  	{}
898  };
899  MODULE_DEVICE_TABLE(acpi, dps310_acpi_match);
900  
901  static struct i2c_driver dps310_driver = {
902  	.driver = {
903  		.name = DPS310_DEV_NAME,
904  		.acpi_match_table = dps310_acpi_match,
905  	},
906  	.probe = dps310_probe,
907  	.id_table = dps310_id,
908  };
909  module_i2c_driver(dps310_driver);
910  
911  MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
912  MODULE_DESCRIPTION("Infineon DPS310 pressure and temperature sensor");
913  MODULE_LICENSE("GPL v2");
914