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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * STTS751 sensor driver
4 *
5 * Copyright (C) 2016-2017 Istituto Italiano di Tecnologia - RBCS - EDL
6 * Robotics, Brain and Cognitive Sciences department
7 * Electronic Design Laboratory
8 *
9 * Written by Andrea Merello <andrea.merello@gmail.com>
10 *
11 * Based on LM95241 driver and LM90 driver
12 */
13
14#include <linux/bitops.h>
15#include <linux/err.h>
16#include <linux/hwmon.h>
17#include <linux/hwmon-sysfs.h>
18#include <linux/i2c.h>
19#include <linux/init.h>
20#include <linux/interrupt.h>
21#include <linux/jiffies.h>
22#include <linux/module.h>
23#include <linux/mutex.h>
24#include <linux/property.h>
25#include <linux/slab.h>
26#include <linux/sysfs.h>
27#include <linux/util_macros.h>
28
29#define DEVNAME "stts751"
30
31static const unsigned short normal_i2c[] = {
32 0x48, 0x49, 0x38, 0x39, /* STTS751-0 */
33 0x4A, 0x4B, 0x3A, 0x3B, /* STTS751-1 */
34 I2C_CLIENT_END };
35
36#define STTS751_REG_TEMP_H 0x00
37#define STTS751_REG_STATUS 0x01
38#define STTS751_STATUS_TRIPT BIT(0)
39#define STTS751_STATUS_TRIPL BIT(5)
40#define STTS751_STATUS_TRIPH BIT(6)
41#define STTS751_REG_TEMP_L 0x02
42#define STTS751_REG_CONF 0x03
43#define STTS751_CONF_RES_MASK 0x0C
44#define STTS751_CONF_RES_SHIFT 2
45#define STTS751_CONF_EVENT_DIS BIT(7)
46#define STTS751_CONF_STOP BIT(6)
47#define STTS751_REG_RATE 0x04
48#define STTS751_REG_HLIM_H 0x05
49#define STTS751_REG_HLIM_L 0x06
50#define STTS751_REG_LLIM_H 0x07
51#define STTS751_REG_LLIM_L 0x08
52#define STTS751_REG_TLIM 0x20
53#define STTS751_REG_HYST 0x21
54#define STTS751_REG_SMBUS_TO 0x22
55
56#define STTS751_REG_PROD_ID 0xFD
57#define STTS751_REG_MAN_ID 0xFE
58#define STTS751_REG_REV_ID 0xFF
59
60#define STTS751_0_PROD_ID 0x00
61#define STTS751_1_PROD_ID 0x01
62#define ST_MAN_ID 0x53
63
64/*
65 * Possible update intervals are (in mS):
66 * 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62.5, 31.25
67 * However we are not going to complicate things too much and we stick to the
68 * approx value in mS.
69 */
70static const int stts751_intervals[] = {
71 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 63, 31
72};
73
74static const struct i2c_device_id stts751_id[] = {
75 { "stts751", 0 },
76 { }
77};
78
79static const struct of_device_id __maybe_unused stts751_of_match[] = {
80 { .compatible = "stts751" },
81 { },
82};
83MODULE_DEVICE_TABLE(of, stts751_of_match);
84
85struct stts751_priv {
86 struct device *dev;
87 struct i2c_client *client;
88 struct mutex access_lock;
89 u8 interval;
90 int res;
91 int event_max, event_min;
92 int therm;
93 int hyst;
94 bool smbus_timeout;
95 int temp;
96 unsigned long last_update, last_alert_update;
97 u8 config;
98 bool min_alert, max_alert, therm_trip;
99 bool data_valid, alert_valid;
100 bool notify_max, notify_min;
101};
102
103/*
104 * These functions converts temperature from HW format to integer format and
105 * vice-vers. They are (mostly) taken from lm90 driver. Unit is in mC.
106 */
107static int stts751_to_deg(s16 hw_val)
108{
109 return hw_val * 125 / 32;
110}
111
112static s32 stts751_to_hw(int val)
113{
114 return DIV_ROUND_CLOSEST(val, 125) * 32;
115}
116
117static int stts751_adjust_resolution(struct stts751_priv *priv)
118{
119 u8 res;
120
121 switch (priv->interval) {
122 case 9:
123 /* 10 bits */
124 res = 0;
125 break;
126 case 8:
127 /* 11 bits */
128 res = 1;
129 break;
130 default:
131 /* 12 bits */
132 res = 3;
133 break;
134 }
135
136 if (priv->res == res)
137 return 0;
138
139 priv->config &= ~STTS751_CONF_RES_MASK;
140 priv->config |= res << STTS751_CONF_RES_SHIFT;
141 dev_dbg(&priv->client->dev, "setting res %d. config %x",
142 res, priv->config);
143 priv->res = res;
144
145 return i2c_smbus_write_byte_data(priv->client,
146 STTS751_REG_CONF, priv->config);
147}
148
149static int stts751_update_temp(struct stts751_priv *priv)
150{
151 s32 integer1, integer2, frac;
152
153 /*
154 * There is a trick here, like in the lm90 driver. We have to read two
155 * registers to get the sensor temperature, but we have to beware a
156 * conversion could occur between the readings. We could use the
157 * one-shot conversion register, but we don't want to do this (disables
158 * hardware monitoring). So the solution used here is to read the high
159 * byte once, then the low byte, then the high byte again. If the new
160 * high byte matches the old one, then we have a valid reading. Else we
161 * have to read the low byte again, and now we believe we have a correct
162 * reading.
163 */
164 integer1 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
165 if (integer1 < 0) {
166 dev_dbg(&priv->client->dev,
167 "I2C read failed (temp H). ret: %x\n", integer1);
168 return integer1;
169 }
170
171 frac = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_L);
172 if (frac < 0) {
173 dev_dbg(&priv->client->dev,
174 "I2C read failed (temp L). ret: %x\n", frac);
175 return frac;
176 }
177
178 integer2 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
179 if (integer2 < 0) {
180 dev_dbg(&priv->client->dev,
181 "I2C 2nd read failed (temp H). ret: %x\n", integer2);
182 return integer2;
183 }
184
185 if (integer1 != integer2) {
186 frac = i2c_smbus_read_byte_data(priv->client,
187 STTS751_REG_TEMP_L);
188 if (frac < 0) {
189 dev_dbg(&priv->client->dev,
190 "I2C 2nd read failed (temp L). ret: %x\n",
191 frac);
192 return frac;
193 }
194 }
195
196 priv->temp = stts751_to_deg((integer1 << 8) | frac);
197 return 0;
198}
199
200static int stts751_set_temp_reg16(struct stts751_priv *priv, int temp,
201 u8 hreg, u8 lreg)
202{
203 s32 hwval;
204 int ret;
205
206 hwval = stts751_to_hw(temp);
207
208 ret = i2c_smbus_write_byte_data(priv->client, hreg, hwval >> 8);
209 if (ret)
210 return ret;
211
212 return i2c_smbus_write_byte_data(priv->client, lreg, hwval & 0xff);
213}
214
215static int stts751_set_temp_reg8(struct stts751_priv *priv, int temp, u8 reg)
216{
217 s32 hwval;
218
219 hwval = stts751_to_hw(temp);
220 return i2c_smbus_write_byte_data(priv->client, reg, hwval >> 8);
221}
222
223static int stts751_read_reg16(struct stts751_priv *priv, int *temp,
224 u8 hreg, u8 lreg)
225{
226 int integer, frac;
227
228 integer = i2c_smbus_read_byte_data(priv->client, hreg);
229 if (integer < 0)
230 return integer;
231
232 frac = i2c_smbus_read_byte_data(priv->client, lreg);
233 if (frac < 0)
234 return frac;
235
236 *temp = stts751_to_deg((integer << 8) | frac);
237
238 return 0;
239}
240
241static int stts751_read_reg8(struct stts751_priv *priv, int *temp, u8 reg)
242{
243 int integer;
244
245 integer = i2c_smbus_read_byte_data(priv->client, reg);
246 if (integer < 0)
247 return integer;
248
249 *temp = stts751_to_deg(integer << 8);
250
251 return 0;
252}
253
254/*
255 * Update alert flags without waiting for cache to expire. We detects alerts
256 * immediately for the sake of the alert handler; we still need to deal with
257 * caching to workaround the fact that alarm flags int the status register,
258 * despite what the datasheet claims, gets always cleared on read.
259 */
260static int stts751_update_alert(struct stts751_priv *priv)
261{
262 int ret;
263 bool conv_done;
264 int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]);
265
266 /*
267 * Add another 10% because if we run faster than the HW conversion
268 * rate we will end up in reporting incorrectly alarms.
269 */
270 cache_time += cache_time / 10;
271
272 ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_STATUS);
273 if (ret < 0)
274 return ret;
275
276 dev_dbg(&priv->client->dev, "status reg %x\n", ret);
277 conv_done = ret & (STTS751_STATUS_TRIPH | STTS751_STATUS_TRIPL);
278 /*
279 * Reset the cache if the cache time expired, or if we are sure
280 * we have valid data from a device conversion, or if we know
281 * our cache has been never written.
282 *
283 * Note that when the cache has been never written the point is
284 * to correctly initialize the timestamp, rather than clearing
285 * the cache values.
286 *
287 * Note that updating the cache timestamp when we get an alarm flag
288 * is required, otherwise we could incorrectly report alarms to be zero.
289 */
290 if (time_after(jiffies, priv->last_alert_update + cache_time) ||
291 conv_done || !priv->alert_valid) {
292 priv->max_alert = false;
293 priv->min_alert = false;
294 priv->alert_valid = true;
295 priv->last_alert_update = jiffies;
296 dev_dbg(&priv->client->dev, "invalidating alert cache\n");
297 }
298
299 priv->max_alert |= !!(ret & STTS751_STATUS_TRIPH);
300 priv->min_alert |= !!(ret & STTS751_STATUS_TRIPL);
301 priv->therm_trip = !!(ret & STTS751_STATUS_TRIPT);
302
303 dev_dbg(&priv->client->dev, "max_alert: %d, min_alert: %d, therm_trip: %d\n",
304 priv->max_alert, priv->min_alert, priv->therm_trip);
305
306 return 0;
307}
308
309static void stts751_alert(struct i2c_client *client,
310 enum i2c_alert_protocol type, unsigned int data)
311{
312 int ret;
313 struct stts751_priv *priv = i2c_get_clientdata(client);
314
315 if (type != I2C_PROTOCOL_SMBUS_ALERT)
316 return;
317
318 dev_dbg(&client->dev, "alert!");
319
320 mutex_lock(&priv->access_lock);
321 ret = stts751_update_alert(priv);
322 if (ret < 0) {
323 /* default to worst case */
324 priv->max_alert = true;
325 priv->min_alert = true;
326
327 dev_warn(priv->dev,
328 "Alert received, but can't communicate to the device. Triggering all alarms!");
329 }
330
331 if (priv->max_alert) {
332 if (priv->notify_max)
333 dev_notice(priv->dev, "got alert for HIGH temperature");
334 priv->notify_max = false;
335
336 /* unblock alert poll */
337 sysfs_notify(&priv->dev->kobj, NULL, "temp1_max_alarm");
338 }
339
340 if (priv->min_alert) {
341 if (priv->notify_min)
342 dev_notice(priv->dev, "got alert for LOW temperature");
343 priv->notify_min = false;
344
345 /* unblock alert poll */
346 sysfs_notify(&priv->dev->kobj, NULL, "temp1_min_alarm");
347 }
348
349 if (priv->min_alert || priv->max_alert)
350 kobject_uevent(&priv->dev->kobj, KOBJ_CHANGE);
351
352 mutex_unlock(&priv->access_lock);
353}
354
355static int stts751_update(struct stts751_priv *priv)
356{
357 int ret;
358 int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]);
359
360 if (time_after(jiffies, priv->last_update + cache_time) ||
361 !priv->data_valid) {
362 ret = stts751_update_temp(priv);
363 if (ret)
364 return ret;
365
366 ret = stts751_update_alert(priv);
367 if (ret)
368 return ret;
369 priv->data_valid = true;
370 priv->last_update = jiffies;
371 }
372
373 return 0;
374}
375
376static ssize_t max_alarm_show(struct device *dev,
377 struct device_attribute *attr, char *buf)
378{
379 int ret;
380 struct stts751_priv *priv = dev_get_drvdata(dev);
381
382 mutex_lock(&priv->access_lock);
383 ret = stts751_update(priv);
384 if (!ret)
385 priv->notify_max = true;
386 mutex_unlock(&priv->access_lock);
387 if (ret < 0)
388 return ret;
389
390 return snprintf(buf, PAGE_SIZE, "%d\n", priv->max_alert);
391}
392
393static ssize_t min_alarm_show(struct device *dev,
394 struct device_attribute *attr, char *buf)
395{
396 int ret;
397 struct stts751_priv *priv = dev_get_drvdata(dev);
398
399 mutex_lock(&priv->access_lock);
400 ret = stts751_update(priv);
401 if (!ret)
402 priv->notify_min = true;
403 mutex_unlock(&priv->access_lock);
404 if (ret < 0)
405 return ret;
406
407 return snprintf(buf, PAGE_SIZE, "%d\n", priv->min_alert);
408}
409
410static ssize_t input_show(struct device *dev, struct device_attribute *attr,
411 char *buf)
412{
413 int ret;
414 struct stts751_priv *priv = dev_get_drvdata(dev);
415
416 mutex_lock(&priv->access_lock);
417 ret = stts751_update(priv);
418 mutex_unlock(&priv->access_lock);
419 if (ret < 0)
420 return ret;
421
422 return snprintf(buf, PAGE_SIZE, "%d\n", priv->temp);
423}
424
425static ssize_t therm_show(struct device *dev, struct device_attribute *attr,
426 char *buf)
427{
428 struct stts751_priv *priv = dev_get_drvdata(dev);
429
430 return snprintf(buf, PAGE_SIZE, "%d\n", priv->therm);
431}
432
433static ssize_t therm_store(struct device *dev, struct device_attribute *attr,
434 const char *buf, size_t count)
435{
436 int ret;
437 long temp;
438 struct stts751_priv *priv = dev_get_drvdata(dev);
439
440 if (kstrtol(buf, 10, &temp) < 0)
441 return -EINVAL;
442
443 /* HW works in range -64C to +127.937C */
444 temp = clamp_val(temp, -64000, 127937);
445 mutex_lock(&priv->access_lock);
446 ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_TLIM);
447 if (ret)
448 goto exit;
449
450 dev_dbg(&priv->client->dev, "setting therm %ld", temp);
451
452 /*
453 * hysteresis reg is relative to therm, so the HW does not need to be
454 * adjusted, we need to update our local copy only.
455 */
456 priv->hyst = temp - (priv->therm - priv->hyst);
457 priv->therm = temp;
458
459exit:
460 mutex_unlock(&priv->access_lock);
461 if (ret)
462 return ret;
463
464 return count;
465}
466
467static ssize_t hyst_show(struct device *dev, struct device_attribute *attr,
468 char *buf)
469{
470 struct stts751_priv *priv = dev_get_drvdata(dev);
471
472 return snprintf(buf, PAGE_SIZE, "%d\n", priv->hyst);
473}
474
475static ssize_t hyst_store(struct device *dev, struct device_attribute *attr,
476 const char *buf, size_t count)
477{
478 int ret;
479 long temp;
480
481 struct stts751_priv *priv = dev_get_drvdata(dev);
482
483 if (kstrtol(buf, 10, &temp) < 0)
484 return -EINVAL;
485
486 mutex_lock(&priv->access_lock);
487 /* HW works in range -64C to +127.937C */
488 temp = clamp_val(temp, -64000, priv->therm);
489 priv->hyst = temp;
490 dev_dbg(&priv->client->dev, "setting hyst %ld", temp);
491 temp = priv->therm - temp;
492 ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_HYST);
493 mutex_unlock(&priv->access_lock);
494 if (ret)
495 return ret;
496
497 return count;
498}
499
500static ssize_t therm_trip_show(struct device *dev,
501 struct device_attribute *attr, char *buf)
502{
503 int ret;
504 struct stts751_priv *priv = dev_get_drvdata(dev);
505
506 mutex_lock(&priv->access_lock);
507 ret = stts751_update(priv);
508 mutex_unlock(&priv->access_lock);
509 if (ret < 0)
510 return ret;
511
512 return snprintf(buf, PAGE_SIZE, "%d\n", priv->therm_trip);
513}
514
515static ssize_t max_show(struct device *dev, struct device_attribute *attr,
516 char *buf)
517{
518 struct stts751_priv *priv = dev_get_drvdata(dev);
519
520 return snprintf(buf, PAGE_SIZE, "%d\n", priv->event_max);
521}
522
523static ssize_t max_store(struct device *dev, struct device_attribute *attr,
524 const char *buf, size_t count)
525{
526 int ret;
527 long temp;
528 struct stts751_priv *priv = dev_get_drvdata(dev);
529
530 if (kstrtol(buf, 10, &temp) < 0)
531 return -EINVAL;
532
533 mutex_lock(&priv->access_lock);
534 /* HW works in range -64C to +127.937C */
535 temp = clamp_val(temp, priv->event_min, 127937);
536 ret = stts751_set_temp_reg16(priv, temp,
537 STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
538 if (ret)
539 goto exit;
540
541 dev_dbg(&priv->client->dev, "setting event max %ld", temp);
542 priv->event_max = temp;
543 ret = count;
544exit:
545 mutex_unlock(&priv->access_lock);
546 return ret;
547}
548
549static ssize_t min_show(struct device *dev, struct device_attribute *attr,
550 char *buf)
551{
552 struct stts751_priv *priv = dev_get_drvdata(dev);
553
554 return snprintf(buf, PAGE_SIZE, "%d\n", priv->event_min);
555}
556
557static ssize_t min_store(struct device *dev, struct device_attribute *attr,
558 const char *buf, size_t count)
559{
560 int ret;
561 long temp;
562 struct stts751_priv *priv = dev_get_drvdata(dev);
563
564 if (kstrtol(buf, 10, &temp) < 0)
565 return -EINVAL;
566
567 mutex_lock(&priv->access_lock);
568 /* HW works in range -64C to +127.937C */
569 temp = clamp_val(temp, -64000, priv->event_max);
570 ret = stts751_set_temp_reg16(priv, temp,
571 STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
572 if (ret)
573 goto exit;
574
575 dev_dbg(&priv->client->dev, "setting event min %ld", temp);
576 priv->event_min = temp;
577 ret = count;
578exit:
579 mutex_unlock(&priv->access_lock);
580 return ret;
581}
582
583static ssize_t interval_show(struct device *dev,
584 struct device_attribute *attr, char *buf)
585{
586 struct stts751_priv *priv = dev_get_drvdata(dev);
587
588 return snprintf(buf, PAGE_SIZE, "%d\n",
589 stts751_intervals[priv->interval]);
590}
591
592static ssize_t interval_store(struct device *dev,
593 struct device_attribute *attr, const char *buf,
594 size_t count)
595{
596 unsigned long val;
597 int idx;
598 int ret = count;
599 struct stts751_priv *priv = dev_get_drvdata(dev);
600
601 if (kstrtoul(buf, 10, &val) < 0)
602 return -EINVAL;
603
604 idx = find_closest_descending(val, stts751_intervals,
605 ARRAY_SIZE(stts751_intervals));
606
607 dev_dbg(&priv->client->dev, "setting interval. req:%lu, idx: %d, val: %d",
608 val, idx, stts751_intervals[idx]);
609
610 mutex_lock(&priv->access_lock);
611 if (priv->interval == idx)
612 goto exit;
613
614 /*
615 * In early development stages I've become suspicious about the chip
616 * starting to misbehave if I ever set, even briefly, an invalid
617 * configuration. While I'm not sure this is really needed, be
618 * conservative and set rate/resolution in such an order that avoids
619 * passing through an invalid configuration.
620 */
621
622 /* speed up: lower the resolution, then modify convrate */
623 if (priv->interval < idx) {
624 dev_dbg(&priv->client->dev, "lower resolution, then modify convrate");
625 priv->interval = idx;
626 ret = stts751_adjust_resolution(priv);
627 if (ret)
628 goto exit;
629 }
630
631 ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_RATE, idx);
632 if (ret)
633 goto exit;
634 /* slow down: modify convrate, then raise resolution */
635 if (priv->interval != idx) {
636 dev_dbg(&priv->client->dev, "modify convrate, then raise resolution");
637 priv->interval = idx;
638 ret = stts751_adjust_resolution(priv);
639 if (ret)
640 goto exit;
641 }
642 ret = count;
643exit:
644 mutex_unlock(&priv->access_lock);
645
646 return ret;
647}
648
649static int stts751_detect(struct i2c_client *new_client,
650 struct i2c_board_info *info)
651{
652 struct i2c_adapter *adapter = new_client->adapter;
653 const char *name;
654 int tmp;
655
656 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
657 return -ENODEV;
658
659 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_MAN_ID);
660 if (tmp != ST_MAN_ID)
661 return -ENODEV;
662
663 /* lower temperaure registers always have bits 0-3 set to zero */
664 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_TEMP_L);
665 if (tmp & 0xf)
666 return -ENODEV;
667
668 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_HLIM_L);
669 if (tmp & 0xf)
670 return -ENODEV;
671
672 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_LLIM_L);
673 if (tmp & 0xf)
674 return -ENODEV;
675
676 /* smbus timeout register always have bits 0-7 set to zero */
677 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_SMBUS_TO);
678 if (tmp & 0x7f)
679 return -ENODEV;
680
681 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_PROD_ID);
682
683 switch (tmp) {
684 case STTS751_0_PROD_ID:
685 name = "STTS751-0";
686 break;
687 case STTS751_1_PROD_ID:
688 name = "STTS751-1";
689 break;
690 default:
691 return -ENODEV;
692 }
693 dev_dbg(&new_client->dev, "Chip %s detected", name);
694
695 strlcpy(info->type, stts751_id[0].name, I2C_NAME_SIZE);
696 return 0;
697}
698
699static int stts751_read_chip_config(struct stts751_priv *priv)
700{
701 int ret;
702 int tmp;
703
704 ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_CONF);
705 if (ret < 0)
706 return ret;
707 priv->config = ret;
708 priv->res = (ret & STTS751_CONF_RES_MASK) >> STTS751_CONF_RES_SHIFT;
709
710 ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_RATE);
711 if (ret < 0)
712 return ret;
713 if (ret >= ARRAY_SIZE(stts751_intervals)) {
714 dev_err(priv->dev, "Unrecognized conversion rate 0x%x\n", ret);
715 return -ENODEV;
716 }
717 priv->interval = ret;
718
719 ret = stts751_read_reg16(priv, &priv->event_max,
720 STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
721 if (ret)
722 return ret;
723
724 ret = stts751_read_reg16(priv, &priv->event_min,
725 STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
726 if (ret)
727 return ret;
728
729 ret = stts751_read_reg8(priv, &priv->therm, STTS751_REG_TLIM);
730 if (ret)
731 return ret;
732
733 ret = stts751_read_reg8(priv, &tmp, STTS751_REG_HYST);
734 if (ret)
735 return ret;
736 priv->hyst = priv->therm - tmp;
737
738 return 0;
739}
740
741static SENSOR_DEVICE_ATTR_RO(temp1_input, input, 0);
742static SENSOR_DEVICE_ATTR_RW(temp1_min, min, 0);
743static SENSOR_DEVICE_ATTR_RW(temp1_max, max, 0);
744static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, min_alarm, 0);
745static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, max_alarm, 0);
746static SENSOR_DEVICE_ATTR_RW(temp1_crit, therm, 0);
747static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, hyst, 0);
748static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, therm_trip, 0);
749static SENSOR_DEVICE_ATTR_RW(update_interval, interval, 0);
750
751static struct attribute *stts751_attrs[] = {
752 &sensor_dev_attr_temp1_input.dev_attr.attr,
753 &sensor_dev_attr_temp1_min.dev_attr.attr,
754 &sensor_dev_attr_temp1_max.dev_attr.attr,
755 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
756 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
757 &sensor_dev_attr_temp1_crit.dev_attr.attr,
758 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
759 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
760 &sensor_dev_attr_update_interval.dev_attr.attr,
761 NULL
762};
763ATTRIBUTE_GROUPS(stts751);
764
765static int stts751_probe(struct i2c_client *client,
766 const struct i2c_device_id *id)
767{
768 struct stts751_priv *priv;
769 int ret;
770 bool smbus_nto;
771 int rev_id;
772
773 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
774 if (!priv)
775 return -ENOMEM;
776
777 priv->client = client;
778 priv->notify_max = true;
779 priv->notify_min = true;
780 i2c_set_clientdata(client, priv);
781 mutex_init(&priv->access_lock);
782
783 if (device_property_present(&client->dev,
784 "smbus-timeout-disable")) {
785 smbus_nto = device_property_read_bool(&client->dev,
786 "smbus-timeout-disable");
787
788 ret = i2c_smbus_write_byte_data(client, STTS751_REG_SMBUS_TO,
789 smbus_nto ? 0 : 0x80);
790 if (ret)
791 return ret;
792 }
793
794 rev_id = i2c_smbus_read_byte_data(client, STTS751_REG_REV_ID);
795 if (rev_id < 0)
796 return -ENODEV;
797 if (rev_id != 0x1) {
798 dev_dbg(&client->dev, "Chip revision 0x%x is untested\n",
799 rev_id);
800 }
801
802 ret = stts751_read_chip_config(priv);
803 if (ret)
804 return ret;
805
806 priv->config &= ~(STTS751_CONF_STOP | STTS751_CONF_EVENT_DIS);
807 ret = i2c_smbus_write_byte_data(client, STTS751_REG_CONF, priv->config);
808 if (ret)
809 return ret;
810
811 priv->dev = devm_hwmon_device_register_with_groups(&client->dev,
812 client->name, priv,
813 stts751_groups);
814 return PTR_ERR_OR_ZERO(priv->dev);
815}
816
817MODULE_DEVICE_TABLE(i2c, stts751_id);
818
819static struct i2c_driver stts751_driver = {
820 .class = I2C_CLASS_HWMON,
821 .driver = {
822 .name = DEVNAME,
823 .of_match_table = of_match_ptr(stts751_of_match),
824 },
825 .probe = stts751_probe,
826 .id_table = stts751_id,
827 .detect = stts751_detect,
828 .alert = stts751_alert,
829 .address_list = normal_i2c,
830};
831
832module_i2c_driver(stts751_driver);
833
834MODULE_AUTHOR("Andrea Merello <andrea.merello@gmail.com>");
835MODULE_DESCRIPTION("STTS751 sensor driver");
836MODULE_LICENSE("GPL");
1/*
2 * STTS751 sensor driver
3 *
4 * Copyright (C) 2016-2017 Istituto Italiano di Tecnologia - RBCS - EDL
5 * Robotics, Brain and Cognitive Sciences department
6 * Electronic Design Laboratory
7 *
8 * Written by Andrea Merello <andrea.merello@gmail.com>
9 *
10 * Based on LM95241 driver and LM90 driver
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 */
22
23#include <linux/bitops.h>
24#include <linux/err.h>
25#include <linux/hwmon.h>
26#include <linux/hwmon-sysfs.h>
27#include <linux/i2c.h>
28#include <linux/init.h>
29#include <linux/interrupt.h>
30#include <linux/jiffies.h>
31#include <linux/module.h>
32#include <linux/mutex.h>
33#include <linux/property.h>
34#include <linux/slab.h>
35#include <linux/sysfs.h>
36#include <linux/util_macros.h>
37
38#define DEVNAME "stts751"
39
40static const unsigned short normal_i2c[] = {
41 0x48, 0x49, 0x38, 0x39, /* STTS751-0 */
42 0x4A, 0x4B, 0x3A, 0x3B, /* STTS751-1 */
43 I2C_CLIENT_END };
44
45#define STTS751_REG_TEMP_H 0x00
46#define STTS751_REG_STATUS 0x01
47#define STTS751_STATUS_TRIPT BIT(0)
48#define STTS751_STATUS_TRIPL BIT(5)
49#define STTS751_STATUS_TRIPH BIT(6)
50#define STTS751_REG_TEMP_L 0x02
51#define STTS751_REG_CONF 0x03
52#define STTS751_CONF_RES_MASK 0x0C
53#define STTS751_CONF_RES_SHIFT 2
54#define STTS751_CONF_EVENT_DIS BIT(7)
55#define STTS751_CONF_STOP BIT(6)
56#define STTS751_REG_RATE 0x04
57#define STTS751_REG_HLIM_H 0x05
58#define STTS751_REG_HLIM_L 0x06
59#define STTS751_REG_LLIM_H 0x07
60#define STTS751_REG_LLIM_L 0x08
61#define STTS751_REG_TLIM 0x20
62#define STTS751_REG_HYST 0x21
63#define STTS751_REG_SMBUS_TO 0x22
64
65#define STTS751_REG_PROD_ID 0xFD
66#define STTS751_REG_MAN_ID 0xFE
67#define STTS751_REG_REV_ID 0xFF
68
69#define STTS751_0_PROD_ID 0x00
70#define STTS751_1_PROD_ID 0x01
71#define ST_MAN_ID 0x53
72
73/*
74 * Possible update intervals are (in mS):
75 * 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62.5, 31.25
76 * However we are not going to complicate things too much and we stick to the
77 * approx value in mS.
78 */
79static const int stts751_intervals[] = {
80 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 63, 31
81};
82
83static const struct i2c_device_id stts751_id[] = {
84 { "stts751", 0 },
85 { }
86};
87
88static const struct of_device_id stts751_of_match[] = {
89 { .compatible = "stts751" },
90 { },
91};
92MODULE_DEVICE_TABLE(of, stts751_of_match);
93
94struct stts751_priv {
95 struct device *dev;
96 struct i2c_client *client;
97 struct mutex access_lock;
98 u8 interval;
99 int res;
100 int event_max, event_min;
101 int therm;
102 int hyst;
103 bool smbus_timeout;
104 int temp;
105 unsigned long last_update, last_alert_update;
106 u8 config;
107 bool min_alert, max_alert, therm_trip;
108 bool data_valid, alert_valid;
109 bool notify_max, notify_min;
110};
111
112/*
113 * These functions converts temperature from HW format to integer format and
114 * vice-vers. They are (mostly) taken from lm90 driver. Unit is in mC.
115 */
116static int stts751_to_deg(s16 hw_val)
117{
118 return hw_val * 125 / 32;
119}
120
121static s32 stts751_to_hw(int val)
122{
123 return DIV_ROUND_CLOSEST(val, 125) * 32;
124}
125
126static int stts751_adjust_resolution(struct stts751_priv *priv)
127{
128 u8 res;
129
130 switch (priv->interval) {
131 case 9:
132 /* 10 bits */
133 res = 0;
134 break;
135 case 8:
136 /* 11 bits */
137 res = 1;
138 break;
139 default:
140 /* 12 bits */
141 res = 3;
142 break;
143 }
144
145 if (priv->res == res)
146 return 0;
147
148 priv->config &= ~STTS751_CONF_RES_MASK;
149 priv->config |= res << STTS751_CONF_RES_SHIFT;
150 dev_dbg(&priv->client->dev, "setting res %d. config %x",
151 res, priv->config);
152 priv->res = res;
153
154 return i2c_smbus_write_byte_data(priv->client,
155 STTS751_REG_CONF, priv->config);
156}
157
158static int stts751_update_temp(struct stts751_priv *priv)
159{
160 s32 integer1, integer2, frac;
161
162 /*
163 * There is a trick here, like in the lm90 driver. We have to read two
164 * registers to get the sensor temperature, but we have to beware a
165 * conversion could occur between the readings. We could use the
166 * one-shot conversion register, but we don't want to do this (disables
167 * hardware monitoring). So the solution used here is to read the high
168 * byte once, then the low byte, then the high byte again. If the new
169 * high byte matches the old one, then we have a valid reading. Else we
170 * have to read the low byte again, and now we believe we have a correct
171 * reading.
172 */
173 integer1 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
174 if (integer1 < 0) {
175 dev_dbg(&priv->client->dev,
176 "I2C read failed (temp H). ret: %x\n", integer1);
177 return integer1;
178 }
179
180 frac = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_L);
181 if (frac < 0) {
182 dev_dbg(&priv->client->dev,
183 "I2C read failed (temp L). ret: %x\n", frac);
184 return frac;
185 }
186
187 integer2 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
188 if (integer2 < 0) {
189 dev_dbg(&priv->client->dev,
190 "I2C 2nd read failed (temp H). ret: %x\n", integer2);
191 return integer2;
192 }
193
194 if (integer1 != integer2) {
195 frac = i2c_smbus_read_byte_data(priv->client,
196 STTS751_REG_TEMP_L);
197 if (frac < 0) {
198 dev_dbg(&priv->client->dev,
199 "I2C 2nd read failed (temp L). ret: %x\n",
200 frac);
201 return frac;
202 }
203 }
204
205 priv->temp = stts751_to_deg((integer1 << 8) | frac);
206 return 0;
207}
208
209static int stts751_set_temp_reg16(struct stts751_priv *priv, int temp,
210 u8 hreg, u8 lreg)
211{
212 s32 hwval;
213 int ret;
214
215 hwval = stts751_to_hw(temp);
216
217 ret = i2c_smbus_write_byte_data(priv->client, hreg, hwval >> 8);
218 if (ret)
219 return ret;
220
221 return i2c_smbus_write_byte_data(priv->client, lreg, hwval & 0xff);
222}
223
224static int stts751_set_temp_reg8(struct stts751_priv *priv, int temp, u8 reg)
225{
226 s32 hwval;
227
228 hwval = stts751_to_hw(temp);
229 return i2c_smbus_write_byte_data(priv->client, reg, hwval >> 8);
230}
231
232static int stts751_read_reg16(struct stts751_priv *priv, int *temp,
233 u8 hreg, u8 lreg)
234{
235 int integer, frac;
236
237 integer = i2c_smbus_read_byte_data(priv->client, hreg);
238 if (integer < 0)
239 return integer;
240
241 frac = i2c_smbus_read_byte_data(priv->client, lreg);
242 if (frac < 0)
243 return frac;
244
245 *temp = stts751_to_deg((integer << 8) | frac);
246
247 return 0;
248}
249
250static int stts751_read_reg8(struct stts751_priv *priv, int *temp, u8 reg)
251{
252 int integer;
253
254 integer = i2c_smbus_read_byte_data(priv->client, reg);
255 if (integer < 0)
256 return integer;
257
258 *temp = stts751_to_deg(integer << 8);
259
260 return 0;
261}
262
263/*
264 * Update alert flags without waiting for cache to expire. We detects alerts
265 * immediately for the sake of the alert handler; we still need to deal with
266 * caching to workaround the fact that alarm flags int the status register,
267 * despite what the datasheet claims, gets always cleared on read.
268 */
269static int stts751_update_alert(struct stts751_priv *priv)
270{
271 int ret;
272 bool conv_done;
273 int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]);
274
275 /*
276 * Add another 10% because if we run faster than the HW conversion
277 * rate we will end up in reporting incorrectly alarms.
278 */
279 cache_time += cache_time / 10;
280
281 ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_STATUS);
282 if (ret < 0)
283 return ret;
284
285 dev_dbg(&priv->client->dev, "status reg %x\n", ret);
286 conv_done = ret & (STTS751_STATUS_TRIPH | STTS751_STATUS_TRIPL);
287 /*
288 * Reset the cache if the cache time expired, or if we are sure
289 * we have valid data from a device conversion, or if we know
290 * our cache has been never written.
291 *
292 * Note that when the cache has been never written the point is
293 * to correctly initialize the timestamp, rather than clearing
294 * the cache values.
295 *
296 * Note that updating the cache timestamp when we get an alarm flag
297 * is required, otherwise we could incorrectly report alarms to be zero.
298 */
299 if (time_after(jiffies, priv->last_alert_update + cache_time) ||
300 conv_done || !priv->alert_valid) {
301 priv->max_alert = false;
302 priv->min_alert = false;
303 priv->alert_valid = true;
304 priv->last_alert_update = jiffies;
305 dev_dbg(&priv->client->dev, "invalidating alert cache\n");
306 }
307
308 priv->max_alert |= !!(ret & STTS751_STATUS_TRIPH);
309 priv->min_alert |= !!(ret & STTS751_STATUS_TRIPL);
310 priv->therm_trip = !!(ret & STTS751_STATUS_TRIPT);
311
312 dev_dbg(&priv->client->dev, "max_alert: %d, min_alert: %d, therm_trip: %d\n",
313 priv->max_alert, priv->min_alert, priv->therm_trip);
314
315 return 0;
316}
317
318static void stts751_alert(struct i2c_client *client,
319 enum i2c_alert_protocol type, unsigned int data)
320{
321 int ret;
322 struct stts751_priv *priv = i2c_get_clientdata(client);
323
324 if (type != I2C_PROTOCOL_SMBUS_ALERT)
325 return;
326
327 dev_dbg(&client->dev, "alert!");
328
329 mutex_lock(&priv->access_lock);
330 ret = stts751_update_alert(priv);
331 if (ret < 0) {
332 /* default to worst case */
333 priv->max_alert = true;
334 priv->min_alert = true;
335
336 dev_warn(priv->dev,
337 "Alert received, but can't communicate to the device. Triggering all alarms!");
338 }
339
340 if (priv->max_alert) {
341 if (priv->notify_max)
342 dev_notice(priv->dev, "got alert for HIGH temperature");
343 priv->notify_max = false;
344
345 /* unblock alert poll */
346 sysfs_notify(&priv->dev->kobj, NULL, "temp1_max_alarm");
347 }
348
349 if (priv->min_alert) {
350 if (priv->notify_min)
351 dev_notice(priv->dev, "got alert for LOW temperature");
352 priv->notify_min = false;
353
354 /* unblock alert poll */
355 sysfs_notify(&priv->dev->kobj, NULL, "temp1_min_alarm");
356 }
357
358 if (priv->min_alert || priv->max_alert)
359 kobject_uevent(&priv->dev->kobj, KOBJ_CHANGE);
360
361 mutex_unlock(&priv->access_lock);
362}
363
364static int stts751_update(struct stts751_priv *priv)
365{
366 int ret;
367 int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]);
368
369 if (time_after(jiffies, priv->last_update + cache_time) ||
370 !priv->data_valid) {
371 ret = stts751_update_temp(priv);
372 if (ret)
373 return ret;
374
375 ret = stts751_update_alert(priv);
376 if (ret)
377 return ret;
378 priv->data_valid = true;
379 priv->last_update = jiffies;
380 }
381
382 return 0;
383}
384
385static ssize_t show_max_alarm(struct device *dev, struct device_attribute *attr,
386 char *buf)
387{
388 int ret;
389 struct stts751_priv *priv = dev_get_drvdata(dev);
390
391 mutex_lock(&priv->access_lock);
392 ret = stts751_update(priv);
393 if (!ret)
394 priv->notify_max = true;
395 mutex_unlock(&priv->access_lock);
396 if (ret < 0)
397 return ret;
398
399 return snprintf(buf, PAGE_SIZE, "%d\n", priv->max_alert);
400}
401
402static ssize_t show_min_alarm(struct device *dev, struct device_attribute *attr,
403 char *buf)
404{
405 int ret;
406 struct stts751_priv *priv = dev_get_drvdata(dev);
407
408 mutex_lock(&priv->access_lock);
409 ret = stts751_update(priv);
410 if (!ret)
411 priv->notify_min = true;
412 mutex_unlock(&priv->access_lock);
413 if (ret < 0)
414 return ret;
415
416 return snprintf(buf, PAGE_SIZE, "%d\n", priv->min_alert);
417}
418
419static ssize_t show_input(struct device *dev, struct device_attribute *attr,
420 char *buf)
421{
422 int ret;
423 struct stts751_priv *priv = dev_get_drvdata(dev);
424
425 mutex_lock(&priv->access_lock);
426 ret = stts751_update(priv);
427 mutex_unlock(&priv->access_lock);
428 if (ret < 0)
429 return ret;
430
431 return snprintf(buf, PAGE_SIZE, "%d\n", priv->temp);
432}
433
434static ssize_t show_therm(struct device *dev, struct device_attribute *attr,
435 char *buf)
436{
437 struct stts751_priv *priv = dev_get_drvdata(dev);
438
439 return snprintf(buf, PAGE_SIZE, "%d\n", priv->therm);
440}
441
442static ssize_t set_therm(struct device *dev, struct device_attribute *attr,
443 const char *buf, size_t count)
444{
445 int ret;
446 long temp;
447 struct stts751_priv *priv = dev_get_drvdata(dev);
448
449 if (kstrtol(buf, 10, &temp) < 0)
450 return -EINVAL;
451
452 /* HW works in range -64C to +127.937C */
453 temp = clamp_val(temp, -64000, 127937);
454 mutex_lock(&priv->access_lock);
455 ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_TLIM);
456 if (ret)
457 goto exit;
458
459 dev_dbg(&priv->client->dev, "setting therm %ld", temp);
460
461 /*
462 * hysteresis reg is relative to therm, so the HW does not need to be
463 * adjusted, we need to update our local copy only.
464 */
465 priv->hyst = temp - (priv->therm - priv->hyst);
466 priv->therm = temp;
467
468exit:
469 mutex_unlock(&priv->access_lock);
470 if (ret)
471 return ret;
472
473 return count;
474}
475
476static ssize_t show_hyst(struct device *dev, struct device_attribute *attr,
477 char *buf)
478{
479 struct stts751_priv *priv = dev_get_drvdata(dev);
480
481 return snprintf(buf, PAGE_SIZE, "%d\n", priv->hyst);
482}
483
484static ssize_t set_hyst(struct device *dev, struct device_attribute *attr,
485 const char *buf, size_t count)
486{
487 int ret;
488 long temp;
489
490 struct stts751_priv *priv = dev_get_drvdata(dev);
491
492 if (kstrtol(buf, 10, &temp) < 0)
493 return -EINVAL;
494
495 mutex_lock(&priv->access_lock);
496 /* HW works in range -64C to +127.937C */
497 temp = clamp_val(temp, -64000, priv->therm);
498 priv->hyst = temp;
499 dev_dbg(&priv->client->dev, "setting hyst %ld", temp);
500 temp = priv->therm - temp;
501 ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_HYST);
502 mutex_unlock(&priv->access_lock);
503 if (ret)
504 return ret;
505
506 return count;
507}
508
509static ssize_t show_therm_trip(struct device *dev,
510 struct device_attribute *attr, char *buf)
511{
512 int ret;
513 struct stts751_priv *priv = dev_get_drvdata(dev);
514
515 mutex_lock(&priv->access_lock);
516 ret = stts751_update(priv);
517 mutex_unlock(&priv->access_lock);
518 if (ret < 0)
519 return ret;
520
521 return snprintf(buf, PAGE_SIZE, "%d\n", priv->therm_trip);
522}
523
524static ssize_t show_max(struct device *dev, struct device_attribute *attr,
525 char *buf)
526{
527 struct stts751_priv *priv = dev_get_drvdata(dev);
528
529 return snprintf(buf, PAGE_SIZE, "%d\n", priv->event_max);
530}
531
532static ssize_t set_max(struct device *dev, struct device_attribute *attr,
533 const char *buf, size_t count)
534{
535 int ret;
536 long temp;
537 struct stts751_priv *priv = dev_get_drvdata(dev);
538
539 if (kstrtol(buf, 10, &temp) < 0)
540 return -EINVAL;
541
542 mutex_lock(&priv->access_lock);
543 /* HW works in range -64C to +127.937C */
544 temp = clamp_val(temp, priv->event_min, 127937);
545 ret = stts751_set_temp_reg16(priv, temp,
546 STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
547 if (ret)
548 goto exit;
549
550 dev_dbg(&priv->client->dev, "setting event max %ld", temp);
551 priv->event_max = temp;
552 ret = count;
553exit:
554 mutex_unlock(&priv->access_lock);
555 return ret;
556}
557
558static ssize_t show_min(struct device *dev, struct device_attribute *attr,
559 char *buf)
560{
561 struct stts751_priv *priv = dev_get_drvdata(dev);
562
563 return snprintf(buf, PAGE_SIZE, "%d\n", priv->event_min);
564}
565
566static ssize_t set_min(struct device *dev, struct device_attribute *attr,
567 const char *buf, size_t count)
568{
569 int ret;
570 long temp;
571 struct stts751_priv *priv = dev_get_drvdata(dev);
572
573 if (kstrtol(buf, 10, &temp) < 0)
574 return -EINVAL;
575
576 mutex_lock(&priv->access_lock);
577 /* HW works in range -64C to +127.937C */
578 temp = clamp_val(temp, -64000, priv->event_max);
579 ret = stts751_set_temp_reg16(priv, temp,
580 STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
581 if (ret)
582 goto exit;
583
584 dev_dbg(&priv->client->dev, "setting event min %ld", temp);
585 priv->event_min = temp;
586 ret = count;
587exit:
588 mutex_unlock(&priv->access_lock);
589 return ret;
590}
591
592static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
593 char *buf)
594{
595 struct stts751_priv *priv = dev_get_drvdata(dev);
596
597 return snprintf(buf, PAGE_SIZE, "%d\n",
598 stts751_intervals[priv->interval]);
599}
600
601static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
602 const char *buf, size_t count)
603{
604 unsigned long val;
605 int idx;
606 int ret = count;
607 struct stts751_priv *priv = dev_get_drvdata(dev);
608
609 if (kstrtoul(buf, 10, &val) < 0)
610 return -EINVAL;
611
612 idx = find_closest_descending(val, stts751_intervals,
613 ARRAY_SIZE(stts751_intervals));
614
615 dev_dbg(&priv->client->dev, "setting interval. req:%lu, idx: %d, val: %d",
616 val, idx, stts751_intervals[idx]);
617
618 mutex_lock(&priv->access_lock);
619 if (priv->interval == idx)
620 goto exit;
621
622 /*
623 * In early development stages I've become suspicious about the chip
624 * starting to misbehave if I ever set, even briefly, an invalid
625 * configuration. While I'm not sure this is really needed, be
626 * conservative and set rate/resolution in such an order that avoids
627 * passing through an invalid configuration.
628 */
629
630 /* speed up: lower the resolution, then modify convrate */
631 if (priv->interval < idx) {
632 dev_dbg(&priv->client->dev, "lower resolution, then modify convrate");
633 priv->interval = idx;
634 ret = stts751_adjust_resolution(priv);
635 if (ret)
636 goto exit;
637 }
638
639 ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_RATE, idx);
640 if (ret)
641 goto exit;
642 /* slow down: modify convrate, then raise resolution */
643 if (priv->interval != idx) {
644 dev_dbg(&priv->client->dev, "modify convrate, then raise resolution");
645 priv->interval = idx;
646 ret = stts751_adjust_resolution(priv);
647 if (ret)
648 goto exit;
649 }
650 ret = count;
651exit:
652 mutex_unlock(&priv->access_lock);
653
654 return ret;
655}
656
657static int stts751_detect(struct i2c_client *new_client,
658 struct i2c_board_info *info)
659{
660 struct i2c_adapter *adapter = new_client->adapter;
661 const char *name;
662 int tmp;
663
664 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
665 return -ENODEV;
666
667 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_MAN_ID);
668 if (tmp != ST_MAN_ID)
669 return -ENODEV;
670
671 /* lower temperaure registers always have bits 0-3 set to zero */
672 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_TEMP_L);
673 if (tmp & 0xf)
674 return -ENODEV;
675
676 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_HLIM_L);
677 if (tmp & 0xf)
678 return -ENODEV;
679
680 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_LLIM_L);
681 if (tmp & 0xf)
682 return -ENODEV;
683
684 /* smbus timeout register always have bits 0-7 set to zero */
685 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_SMBUS_TO);
686 if (tmp & 0x7f)
687 return -ENODEV;
688
689 tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_PROD_ID);
690
691 switch (tmp) {
692 case STTS751_0_PROD_ID:
693 name = "STTS751-0";
694 break;
695 case STTS751_1_PROD_ID:
696 name = "STTS751-1";
697 break;
698 default:
699 return -ENODEV;
700 }
701 dev_dbg(&new_client->dev, "Chip %s detected", name);
702
703 strlcpy(info->type, stts751_id[0].name, I2C_NAME_SIZE);
704 return 0;
705}
706
707static int stts751_read_chip_config(struct stts751_priv *priv)
708{
709 int ret;
710 int tmp;
711
712 ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_CONF);
713 if (ret < 0)
714 return ret;
715 priv->config = ret;
716 priv->res = (ret & STTS751_CONF_RES_MASK) >> STTS751_CONF_RES_SHIFT;
717
718 ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_RATE);
719 if (ret < 0)
720 return ret;
721 if (ret >= ARRAY_SIZE(stts751_intervals)) {
722 dev_err(priv->dev, "Unrecognized conversion rate 0x%x\n", ret);
723 return -ENODEV;
724 }
725 priv->interval = ret;
726
727 ret = stts751_read_reg16(priv, &priv->event_max,
728 STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
729 if (ret)
730 return ret;
731
732 ret = stts751_read_reg16(priv, &priv->event_min,
733 STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
734 if (ret)
735 return ret;
736
737 ret = stts751_read_reg8(priv, &priv->therm, STTS751_REG_TLIM);
738 if (ret)
739 return ret;
740
741 ret = stts751_read_reg8(priv, &tmp, STTS751_REG_HYST);
742 if (ret)
743 return ret;
744 priv->hyst = priv->therm - tmp;
745
746 return 0;
747}
748
749static SENSOR_DEVICE_ATTR(temp1_input, 0444, show_input, NULL, 0);
750static SENSOR_DEVICE_ATTR(temp1_min, 0644, show_min, set_min, 0);
751static SENSOR_DEVICE_ATTR(temp1_max, 0644, show_max, set_max, 0);
752static SENSOR_DEVICE_ATTR(temp1_min_alarm, 0444, show_min_alarm, NULL, 0);
753static SENSOR_DEVICE_ATTR(temp1_max_alarm, 0444, show_max_alarm, NULL, 0);
754static SENSOR_DEVICE_ATTR(temp1_crit, 0644, show_therm, set_therm, 0);
755static SENSOR_DEVICE_ATTR(temp1_crit_hyst, 0644, show_hyst, set_hyst, 0);
756static SENSOR_DEVICE_ATTR(temp1_crit_alarm, 0444, show_therm_trip, NULL, 0);
757static SENSOR_DEVICE_ATTR(update_interval, 0644,
758 show_interval, set_interval, 0);
759
760static struct attribute *stts751_attrs[] = {
761 &sensor_dev_attr_temp1_input.dev_attr.attr,
762 &sensor_dev_attr_temp1_min.dev_attr.attr,
763 &sensor_dev_attr_temp1_max.dev_attr.attr,
764 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
765 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
766 &sensor_dev_attr_temp1_crit.dev_attr.attr,
767 &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
768 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
769 &sensor_dev_attr_update_interval.dev_attr.attr,
770 NULL
771};
772ATTRIBUTE_GROUPS(stts751);
773
774static int stts751_probe(struct i2c_client *client,
775 const struct i2c_device_id *id)
776{
777 struct stts751_priv *priv;
778 int ret;
779 bool smbus_nto;
780 int rev_id;
781
782 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
783 if (!priv)
784 return -ENOMEM;
785
786 priv->client = client;
787 priv->notify_max = true;
788 priv->notify_min = true;
789 i2c_set_clientdata(client, priv);
790 mutex_init(&priv->access_lock);
791
792 if (device_property_present(&client->dev,
793 "smbus-timeout-disable")) {
794 smbus_nto = device_property_read_bool(&client->dev,
795 "smbus-timeout-disable");
796
797 ret = i2c_smbus_write_byte_data(client, STTS751_REG_SMBUS_TO,
798 smbus_nto ? 0 : 0x80);
799 if (ret)
800 return ret;
801 }
802
803 rev_id = i2c_smbus_read_byte_data(client, STTS751_REG_REV_ID);
804 if (rev_id < 0)
805 return -ENODEV;
806 if (rev_id != 0x1) {
807 dev_dbg(&client->dev, "Chip revision 0x%x is untested\n",
808 rev_id);
809 }
810
811 ret = stts751_read_chip_config(priv);
812 if (ret)
813 return ret;
814
815 priv->config &= ~(STTS751_CONF_STOP | STTS751_CONF_EVENT_DIS);
816 ret = i2c_smbus_write_byte_data(client, STTS751_REG_CONF, priv->config);
817 if (ret)
818 return ret;
819
820 priv->dev = devm_hwmon_device_register_with_groups(&client->dev,
821 client->name, priv,
822 stts751_groups);
823 return PTR_ERR_OR_ZERO(priv->dev);
824}
825
826MODULE_DEVICE_TABLE(i2c, stts751_id);
827
828static struct i2c_driver stts751_driver = {
829 .class = I2C_CLASS_HWMON,
830 .driver = {
831 .name = DEVNAME,
832 .of_match_table = of_match_ptr(stts751_of_match),
833 },
834 .probe = stts751_probe,
835 .id_table = stts751_id,
836 .detect = stts751_detect,
837 .alert = stts751_alert,
838 .address_list = normal_i2c,
839};
840
841module_i2c_driver(stts751_driver);
842
843MODULE_AUTHOR("Andrea Merello <andrea.merello@gmail.com>");
844MODULE_DESCRIPTION("STTS751 sensor driver");
845MODULE_LICENSE("GPL");