1/*
2 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring
4 * Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/slab.h>
24#include <linux/jiffies.h>
25#include <linux/i2c.h>
26#include <linux/hwmon.h>
27#include <linux/hwmon-sysfs.h>
28#include <linux/err.h>
29#include <linux/of_device.h>
30#include <linux/of.h>
31#include <linux/regmap.h>
32#include "lm75.h"
33
34
35/*
36 * This driver handles the LM75 and compatible digital temperature sensors.
37 */
38
39enum lm75_type { /* keep sorted in alphabetical order */
40 adt75,
41 ds1775,
42 ds75,
43 ds7505,
44 g751,
45 lm75,
46 lm75a,
47 lm75b,
48 max6625,
49 max6626,
50 max31725,
51 mcp980x,
52 stds75,
53 stlm75,
54 tcn75,
55 tmp100,
56 tmp101,
57 tmp105,
58 tmp112,
59 tmp175,
60 tmp275,
61 tmp75,
62 tmp75c,
63};
64
65/* Addresses scanned */
66static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
67 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
68
69/* The LM75 registers */
70#define LM75_REG_TEMP 0x00
71#define LM75_REG_CONF 0x01
72#define LM75_REG_HYST 0x02
73#define LM75_REG_MAX 0x03
74
75/* Each client has this additional data */
76struct lm75_data {
77 struct i2c_client *client;
78 struct regmap *regmap;
79 u8 orig_conf;
80 u8 resolution; /* In bits, between 9 and 16 */
81 u8 resolution_limits;
82 unsigned int sample_time; /* In ms */
83};
84
85/*-----------------------------------------------------------------------*/
86
87static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
88{
89 return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
90}
91
92static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
93 u32 attr, int channel, long *val)
94{
95 struct lm75_data *data = dev_get_drvdata(dev);
96 unsigned int regval;
97 int err, reg;
98
99 switch (type) {
100 case hwmon_chip:
101 switch (attr) {
102 case hwmon_chip_update_interval:
103 *val = data->sample_time;
104 break;
105 default:
106 return -EINVAL;
107 }
108 break;
109 case hwmon_temp:
110 switch (attr) {
111 case hwmon_temp_input:
112 reg = LM75_REG_TEMP;
113 break;
114 case hwmon_temp_max:
115 reg = LM75_REG_MAX;
116 break;
117 case hwmon_temp_max_hyst:
118 reg = LM75_REG_HYST;
119 break;
120 default:
121 return -EINVAL;
122 }
123 err = regmap_read(data->regmap, reg, &regval);
124 if (err < 0)
125 return err;
126
127 *val = lm75_reg_to_mc(regval, data->resolution);
128 break;
129 default:
130 return -EINVAL;
131 }
132 return 0;
133}
134
135static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
136 u32 attr, int channel, long temp)
137{
138 struct lm75_data *data = dev_get_drvdata(dev);
139 u8 resolution;
140 int reg;
141
142 if (type != hwmon_temp)
143 return -EINVAL;
144
145 switch (attr) {
146 case hwmon_temp_max:
147 reg = LM75_REG_MAX;
148 break;
149 case hwmon_temp_max_hyst:
150 reg = LM75_REG_HYST;
151 break;
152 default:
153 return -EINVAL;
154 }
155
156 /*
157 * Resolution of limit registers is assumed to be the same as the
158 * temperature input register resolution unless given explicitly.
159 */
160 if (data->resolution_limits)
161 resolution = data->resolution_limits;
162 else
163 resolution = data->resolution;
164
165 temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
166 temp = DIV_ROUND_CLOSEST(temp << (resolution - 8),
167 1000) << (16 - resolution);
168
169 return regmap_write(data->regmap, reg, temp);
170}
171
172static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
173 u32 attr, int channel)
174{
175 switch (type) {
176 case hwmon_chip:
177 switch (attr) {
178 case hwmon_chip_update_interval:
179 return 0444;
180 }
181 break;
182 case hwmon_temp:
183 switch (attr) {
184 case hwmon_temp_input:
185 return 0444;
186 case hwmon_temp_max:
187 case hwmon_temp_max_hyst:
188 return 0644;
189 }
190 break;
191 default:
192 break;
193 }
194 return 0;
195}
196
197/*-----------------------------------------------------------------------*/
198
199/* device probe and removal */
200
201/* chip configuration */
202
203static const u32 lm75_chip_config[] = {
204 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
205 0
206};
207
208static const struct hwmon_channel_info lm75_chip = {
209 .type = hwmon_chip,
210 .config = lm75_chip_config,
211};
212
213static const u32 lm75_temp_config[] = {
214 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
215 0
216};
217
218static const struct hwmon_channel_info lm75_temp = {
219 .type = hwmon_temp,
220 .config = lm75_temp_config,
221};
222
223static const struct hwmon_channel_info *lm75_info[] = {
224 &lm75_chip,
225 &lm75_temp,
226 NULL
227};
228
229static const struct hwmon_ops lm75_hwmon_ops = {
230 .is_visible = lm75_is_visible,
231 .read = lm75_read,
232 .write = lm75_write,
233};
234
235static const struct hwmon_chip_info lm75_chip_info = {
236 .ops = &lm75_hwmon_ops,
237 .info = lm75_info,
238};
239
240static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
241{
242 return reg != LM75_REG_TEMP;
243}
244
245static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
246{
247 return reg == LM75_REG_TEMP;
248}
249
250static const struct regmap_config lm75_regmap_config = {
251 .reg_bits = 8,
252 .val_bits = 16,
253 .max_register = LM75_REG_MAX,
254 .writeable_reg = lm75_is_writeable_reg,
255 .volatile_reg = lm75_is_volatile_reg,
256 .val_format_endian = REGMAP_ENDIAN_BIG,
257 .cache_type = REGCACHE_RBTREE,
258 .use_single_read = true,
259 .use_single_write = true,
260};
261
262static void lm75_remove(void *data)
263{
264 struct lm75_data *lm75 = data;
265 struct i2c_client *client = lm75->client;
266
267 i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
268}
269
270static int
271lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
272{
273 struct device *dev = &client->dev;
274 struct device *hwmon_dev;
275 struct lm75_data *data;
276 int status, err;
277 u8 set_mask, clr_mask;
278 int new;
279 enum lm75_type kind;
280
281 if (client->dev.of_node)
282 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
283 else
284 kind = id->driver_data;
285
286 if (!i2c_check_functionality(client->adapter,
287 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
288 return -EIO;
289
290 data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
291 if (!data)
292 return -ENOMEM;
293
294 data->client = client;
295
296 data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
297 if (IS_ERR(data->regmap))
298 return PTR_ERR(data->regmap);
299
300 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
301 * Then tweak to be more precise when appropriate.
302 */
303 set_mask = 0;
304 clr_mask = LM75_SHUTDOWN; /* continuous conversions */
305
306 switch (kind) {
307 case adt75:
308 clr_mask |= 1 << 5; /* not one-shot mode */
309 data->resolution = 12;
310 data->sample_time = MSEC_PER_SEC / 8;
311 break;
312 case ds1775:
313 case ds75:
314 case stds75:
315 clr_mask |= 3 << 5;
316 set_mask |= 2 << 5; /* 11-bit mode */
317 data->resolution = 11;
318 data->sample_time = MSEC_PER_SEC;
319 break;
320 case stlm75:
321 data->resolution = 9;
322 data->sample_time = MSEC_PER_SEC / 5;
323 break;
324 case ds7505:
325 set_mask |= 3 << 5; /* 12-bit mode */
326 data->resolution = 12;
327 data->sample_time = MSEC_PER_SEC / 4;
328 break;
329 case g751:
330 case lm75:
331 case lm75a:
332 data->resolution = 9;
333 data->sample_time = MSEC_PER_SEC / 2;
334 break;
335 case lm75b:
336 data->resolution = 11;
337 data->sample_time = MSEC_PER_SEC / 4;
338 break;
339 case max6625:
340 data->resolution = 9;
341 data->sample_time = MSEC_PER_SEC / 4;
342 break;
343 case max6626:
344 data->resolution = 12;
345 data->resolution_limits = 9;
346 data->sample_time = MSEC_PER_SEC / 4;
347 break;
348 case max31725:
349 data->resolution = 16;
350 data->sample_time = MSEC_PER_SEC / 8;
351 break;
352 case tcn75:
353 data->resolution = 9;
354 data->sample_time = MSEC_PER_SEC / 8;
355 break;
356 case mcp980x:
357 data->resolution_limits = 9;
358 /* fall through */
359 case tmp100:
360 case tmp101:
361 set_mask |= 3 << 5; /* 12-bit mode */
362 data->resolution = 12;
363 data->sample_time = MSEC_PER_SEC;
364 clr_mask |= 1 << 7; /* not one-shot mode */
365 break;
366 case tmp112:
367 set_mask |= 3 << 5; /* 12-bit mode */
368 clr_mask |= 1 << 7; /* not one-shot mode */
369 data->resolution = 12;
370 data->sample_time = MSEC_PER_SEC / 4;
371 break;
372 case tmp105:
373 case tmp175:
374 case tmp275:
375 case tmp75:
376 set_mask |= 3 << 5; /* 12-bit mode */
377 clr_mask |= 1 << 7; /* not one-shot mode */
378 data->resolution = 12;
379 data->sample_time = MSEC_PER_SEC / 2;
380 break;
381 case tmp75c:
382 clr_mask |= 1 << 5; /* not one-shot mode */
383 data->resolution = 12;
384 data->sample_time = MSEC_PER_SEC / 4;
385 break;
386 }
387
388 /* configure as specified */
389 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
390 if (status < 0) {
391 dev_dbg(dev, "Can't read config? %d\n", status);
392 return status;
393 }
394 data->orig_conf = status;
395 new = status & ~clr_mask;
396 new |= set_mask;
397 if (status != new)
398 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
399
400 err = devm_add_action_or_reset(dev, lm75_remove, data);
401 if (err)
402 return err;
403
404 dev_dbg(dev, "Config %02x\n", new);
405
406 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
407 data, &lm75_chip_info,
408 NULL);
409 if (IS_ERR(hwmon_dev))
410 return PTR_ERR(hwmon_dev);
411
412 dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
413
414 return 0;
415}
416
417static const struct i2c_device_id lm75_ids[] = {
418 { "adt75", adt75, },
419 { "ds1775", ds1775, },
420 { "ds75", ds75, },
421 { "ds7505", ds7505, },
422 { "g751", g751, },
423 { "lm75", lm75, },
424 { "lm75a", lm75a, },
425 { "lm75b", lm75b, },
426 { "max6625", max6625, },
427 { "max6626", max6626, },
428 { "max31725", max31725, },
429 { "max31726", max31725, },
430 { "mcp980x", mcp980x, },
431 { "stds75", stds75, },
432 { "stlm75", stlm75, },
433 { "tcn75", tcn75, },
434 { "tmp100", tmp100, },
435 { "tmp101", tmp101, },
436 { "tmp105", tmp105, },
437 { "tmp112", tmp112, },
438 { "tmp175", tmp175, },
439 { "tmp275", tmp275, },
440 { "tmp75", tmp75, },
441 { "tmp75c", tmp75c, },
442 { /* LIST END */ }
443};
444MODULE_DEVICE_TABLE(i2c, lm75_ids);
445
446static const struct of_device_id lm75_of_match[] = {
447 {
448 .compatible = "adi,adt75",
449 .data = (void *)adt75
450 },
451 {
452 .compatible = "dallas,ds1775",
453 .data = (void *)ds1775
454 },
455 {
456 .compatible = "dallas,ds75",
457 .data = (void *)ds75
458 },
459 {
460 .compatible = "dallas,ds7505",
461 .data = (void *)ds7505
462 },
463 {
464 .compatible = "gmt,g751",
465 .data = (void *)g751
466 },
467 {
468 .compatible = "national,lm75",
469 .data = (void *)lm75
470 },
471 {
472 .compatible = "national,lm75a",
473 .data = (void *)lm75a
474 },
475 {
476 .compatible = "national,lm75b",
477 .data = (void *)lm75b
478 },
479 {
480 .compatible = "maxim,max6625",
481 .data = (void *)max6625
482 },
483 {
484 .compatible = "maxim,max6626",
485 .data = (void *)max6626
486 },
487 {
488 .compatible = "maxim,max31725",
489 .data = (void *)max31725
490 },
491 {
492 .compatible = "maxim,max31726",
493 .data = (void *)max31725
494 },
495 {
496 .compatible = "maxim,mcp980x",
497 .data = (void *)mcp980x
498 },
499 {
500 .compatible = "st,stds75",
501 .data = (void *)stds75
502 },
503 {
504 .compatible = "st,stlm75",
505 .data = (void *)stlm75
506 },
507 {
508 .compatible = "microchip,tcn75",
509 .data = (void *)tcn75
510 },
511 {
512 .compatible = "ti,tmp100",
513 .data = (void *)tmp100
514 },
515 {
516 .compatible = "ti,tmp101",
517 .data = (void *)tmp101
518 },
519 {
520 .compatible = "ti,tmp105",
521 .data = (void *)tmp105
522 },
523 {
524 .compatible = "ti,tmp112",
525 .data = (void *)tmp112
526 },
527 {
528 .compatible = "ti,tmp175",
529 .data = (void *)tmp175
530 },
531 {
532 .compatible = "ti,tmp275",
533 .data = (void *)tmp275
534 },
535 {
536 .compatible = "ti,tmp75",
537 .data = (void *)tmp75
538 },
539 {
540 .compatible = "ti,tmp75c",
541 .data = (void *)tmp75c
542 },
543 { },
544};
545MODULE_DEVICE_TABLE(of, lm75_of_match);
546
547#define LM75A_ID 0xA1
548
549/* Return 0 if detection is successful, -ENODEV otherwise */
550static int lm75_detect(struct i2c_client *new_client,
551 struct i2c_board_info *info)
552{
553 struct i2c_adapter *adapter = new_client->adapter;
554 int i;
555 int conf, hyst, os;
556 bool is_lm75a = 0;
557
558 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
559 I2C_FUNC_SMBUS_WORD_DATA))
560 return -ENODEV;
561
562 /*
563 * Now, we do the remaining detection. There is no identification-
564 * dedicated register so we have to rely on several tricks:
565 * unused bits, registers cycling over 8-address boundaries,
566 * addresses 0x04-0x07 returning the last read value.
567 * The cycling+unused addresses combination is not tested,
568 * since it would significantly slow the detection down and would
569 * hardly add any value.
570 *
571 * The National Semiconductor LM75A is different than earlier
572 * LM75s. It has an ID byte of 0xaX (where X is the chip
573 * revision, with 1 being the only revision in existence) in
574 * register 7, and unused registers return 0xff rather than the
575 * last read value.
576 *
577 * Note that this function only detects the original National
578 * Semiconductor LM75 and the LM75A. Clones from other vendors
579 * aren't detected, on purpose, because they are typically never
580 * found on PC hardware. They are found on embedded designs where
581 * they can be instantiated explicitly so detection is not needed.
582 * The absence of identification registers on all these clones
583 * would make their exhaustive detection very difficult and weak,
584 * and odds are that the driver would bind to unsupported devices.
585 */
586
587 /* Unused bits */
588 conf = i2c_smbus_read_byte_data(new_client, 1);
589 if (conf & 0xe0)
590 return -ENODEV;
591
592 /* First check for LM75A */
593 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
594 /* LM75A returns 0xff on unused registers so
595 just to be sure we check for that too. */
596 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
597 || i2c_smbus_read_byte_data(new_client, 5) != 0xff
598 || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
599 return -ENODEV;
600 is_lm75a = 1;
601 hyst = i2c_smbus_read_byte_data(new_client, 2);
602 os = i2c_smbus_read_byte_data(new_client, 3);
603 } else { /* Traditional style LM75 detection */
604 /* Unused addresses */
605 hyst = i2c_smbus_read_byte_data(new_client, 2);
606 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
607 || i2c_smbus_read_byte_data(new_client, 5) != hyst
608 || i2c_smbus_read_byte_data(new_client, 6) != hyst
609 || i2c_smbus_read_byte_data(new_client, 7) != hyst)
610 return -ENODEV;
611 os = i2c_smbus_read_byte_data(new_client, 3);
612 if (i2c_smbus_read_byte_data(new_client, 4) != os
613 || i2c_smbus_read_byte_data(new_client, 5) != os
614 || i2c_smbus_read_byte_data(new_client, 6) != os
615 || i2c_smbus_read_byte_data(new_client, 7) != os)
616 return -ENODEV;
617 }
618 /*
619 * It is very unlikely that this is a LM75 if both
620 * hysteresis and temperature limit registers are 0.
621 */
622 if (hyst == 0 && os == 0)
623 return -ENODEV;
624
625 /* Addresses cycling */
626 for (i = 8; i <= 248; i += 40) {
627 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
628 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
629 || i2c_smbus_read_byte_data(new_client, i + 3) != os)
630 return -ENODEV;
631 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
632 != LM75A_ID)
633 return -ENODEV;
634 }
635
636 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
637
638 return 0;
639}
640
641#ifdef CONFIG_PM
642static int lm75_suspend(struct device *dev)
643{
644 int status;
645 struct i2c_client *client = to_i2c_client(dev);
646 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
647 if (status < 0) {
648 dev_dbg(&client->dev, "Can't read config? %d\n", status);
649 return status;
650 }
651 status = status | LM75_SHUTDOWN;
652 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
653 return 0;
654}
655
656static int lm75_resume(struct device *dev)
657{
658 int status;
659 struct i2c_client *client = to_i2c_client(dev);
660 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
661 if (status < 0) {
662 dev_dbg(&client->dev, "Can't read config? %d\n", status);
663 return status;
664 }
665 status = status & ~LM75_SHUTDOWN;
666 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
667 return 0;
668}
669
670static const struct dev_pm_ops lm75_dev_pm_ops = {
671 .suspend = lm75_suspend,
672 .resume = lm75_resume,
673};
674#define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
675#else
676#define LM75_DEV_PM_OPS NULL
677#endif /* CONFIG_PM */
678
679static struct i2c_driver lm75_driver = {
680 .class = I2C_CLASS_HWMON,
681 .driver = {
682 .name = "lm75",
683 .of_match_table = of_match_ptr(lm75_of_match),
684 .pm = LM75_DEV_PM_OPS,
685 },
686 .probe = lm75_probe,
687 .id_table = lm75_ids,
688 .detect = lm75_detect,
689 .address_list = normal_i2c,
690};
691
692module_i2c_driver(lm75_driver);
693
694MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
695MODULE_DESCRIPTION("LM75 driver");
696MODULE_LICENSE("GPL");
697