1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
4 * monitoring
5 * Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
6 */
7
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/jiffies.h>
12 #include <linux/i2c.h>
13 #include <linux/hwmon.h>
14 #include <linux/hwmon-sysfs.h>
15 #include <linux/err.h>
16 #include <linux/of_device.h>
17 #include <linux/of.h>
18 #include <linux/regmap.h>
19 #include <linux/util_macros.h>
20 #include <linux/regulator/consumer.h>
21 #include "lm75.h"
22
23 /*
24 * This driver handles the LM75 and compatible digital temperature sensors.
25 */
26
27 enum lm75_type { /* keep sorted in alphabetical order */
28 adt75,
29 ds1775,
30 ds75,
31 ds7505,
32 g751,
33 lm75,
34 lm75a,
35 lm75b,
36 max6625,
37 max6626,
38 max31725,
39 mcp980x,
40 pct2075,
41 stds75,
42 stlm75,
43 tcn75,
44 tmp100,
45 tmp101,
46 tmp105,
47 tmp112,
48 tmp175,
49 tmp275,
50 tmp75,
51 tmp75b,
52 tmp75c,
53 };
54
55 /**
56 * struct lm75_params - lm75 configuration parameters.
57 * @set_mask: Bits to set in configuration register when configuring
58 * the chip.
59 * @clr_mask: Bits to clear in configuration register when configuring
60 * the chip.
61 * @default_resolution: Default number of bits to represent the temperature
62 * value.
63 * @resolution_limits: Limit register resolution. Optional. Should be set if
64 * the resolution of limit registers does not match the
65 * resolution of the temperature register.
66 * @resolutions: List of resolutions associated with sample times.
67 * Optional. Should be set if num_sample_times is larger
68 * than 1, and if the resolution changes with sample times.
69 * If set, number of entries must match num_sample_times.
70 * @default_sample_time:Sample time to be set by default.
71 * @num_sample_times: Number of possible sample times to be set. Optional.
72 * Should be set if the number of sample times is larger
73 * than one.
74 * @sample_times: All the possible sample times to be set. Mandatory if
75 * num_sample_times is larger than 1. If set, number of
76 * entries must match num_sample_times.
77 */
78
79 struct lm75_params {
80 u8 set_mask;
81 u8 clr_mask;
82 u8 default_resolution;
83 u8 resolution_limits;
84 const u8 *resolutions;
85 unsigned int default_sample_time;
86 u8 num_sample_times;
87 const unsigned int *sample_times;
88 };
89
90 /* Addresses scanned */
91 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
92 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
93
94 /* The LM75 registers */
95 #define LM75_REG_TEMP 0x00
96 #define LM75_REG_CONF 0x01
97 #define LM75_REG_HYST 0x02
98 #define LM75_REG_MAX 0x03
99 #define PCT2075_REG_IDLE 0x04
100
101 /* Each client has this additional data */
102 struct lm75_data {
103 struct i2c_client *client;
104 struct regmap *regmap;
105 struct regulator *vs;
106 u8 orig_conf;
107 u8 current_conf;
108 u8 resolution; /* In bits, 9 to 16 */
109 unsigned int sample_time; /* In ms */
110 enum lm75_type kind;
111 const struct lm75_params *params;
112 };
113
114 /*-----------------------------------------------------------------------*/
115
116 static const u8 lm75_sample_set_masks[] = { 0 << 5, 1 << 5, 2 << 5, 3 << 5 };
117
118 #define LM75_SAMPLE_CLEAR_MASK (3 << 5)
119
120 /* The structure below stores the configuration values of the supported devices.
121 * In case of being supported multiple configurations, the default one must
122 * always be the first element of the array
123 */
124 static const struct lm75_params device_params[] = {
125 [adt75] = {
126 .clr_mask = 1 << 5, /* not one-shot mode */
127 .default_resolution = 12,
128 .default_sample_time = MSEC_PER_SEC / 10,
129 },
130 [ds1775] = {
131 .clr_mask = 3 << 5,
132 .set_mask = 2 << 5, /* 11-bit mode */
133 .default_resolution = 11,
134 .default_sample_time = 500,
135 .num_sample_times = 4,
136 .sample_times = (unsigned int []){ 125, 250, 500, 1000 },
137 .resolutions = (u8 []) {9, 10, 11, 12 },
138 },
139 [ds75] = {
140 .clr_mask = 3 << 5,
141 .set_mask = 2 << 5, /* 11-bit mode */
142 .default_resolution = 11,
143 .default_sample_time = 600,
144 .num_sample_times = 4,
145 .sample_times = (unsigned int []){ 150, 300, 600, 1200 },
146 .resolutions = (u8 []) {9, 10, 11, 12 },
147 },
148 [stds75] = {
149 .clr_mask = 3 << 5,
150 .set_mask = 2 << 5, /* 11-bit mode */
151 .default_resolution = 11,
152 .default_sample_time = 600,
153 .num_sample_times = 4,
154 .sample_times = (unsigned int []){ 150, 300, 600, 1200 },
155 .resolutions = (u8 []) {9, 10, 11, 12 },
156 },
157 [stlm75] = {
158 .default_resolution = 9,
159 .default_sample_time = MSEC_PER_SEC / 6,
160 },
161 [ds7505] = {
162 .set_mask = 3 << 5, /* 12-bit mode*/
163 .default_resolution = 12,
164 .default_sample_time = 200,
165 .num_sample_times = 4,
166 .sample_times = (unsigned int []){ 25, 50, 100, 200 },
167 .resolutions = (u8 []) {9, 10, 11, 12 },
168 },
169 [g751] = {
170 .default_resolution = 9,
171 .default_sample_time = MSEC_PER_SEC / 10,
172 },
173 [lm75] = {
174 .default_resolution = 9,
175 .default_sample_time = MSEC_PER_SEC / 10,
176 },
177 [lm75a] = {
178 .default_resolution = 9,
179 .default_sample_time = MSEC_PER_SEC / 10,
180 },
181 [lm75b] = {
182 .default_resolution = 11,
183 .default_sample_time = MSEC_PER_SEC / 10,
184 },
185 [max6625] = {
186 .default_resolution = 9,
187 .default_sample_time = MSEC_PER_SEC / 7,
188 },
189 [max6626] = {
190 .default_resolution = 12,
191 .default_sample_time = MSEC_PER_SEC / 7,
192 .resolution_limits = 9,
193 },
194 [max31725] = {
195 .default_resolution = 16,
196 .default_sample_time = MSEC_PER_SEC / 20,
197 },
198 [tcn75] = {
199 .default_resolution = 9,
200 .default_sample_time = MSEC_PER_SEC / 18,
201 },
202 [pct2075] = {
203 .default_resolution = 11,
204 .default_sample_time = MSEC_PER_SEC / 10,
205 .num_sample_times = 31,
206 .sample_times = (unsigned int []){ 100, 200, 300, 400, 500, 600,
207 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700,
208 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700,
209 2800, 2900, 3000, 3100 },
210 },
211 [mcp980x] = {
212 .set_mask = 3 << 5, /* 12-bit mode */
213 .clr_mask = 1 << 7, /* not one-shot mode */
214 .default_resolution = 12,
215 .resolution_limits = 9,
216 .default_sample_time = 240,
217 .num_sample_times = 4,
218 .sample_times = (unsigned int []){ 30, 60, 120, 240 },
219 .resolutions = (u8 []) {9, 10, 11, 12 },
220 },
221 [tmp100] = {
222 .set_mask = 3 << 5, /* 12-bit mode */
223 .clr_mask = 1 << 7, /* not one-shot mode */
224 .default_resolution = 12,
225 .default_sample_time = 320,
226 .num_sample_times = 4,
227 .sample_times = (unsigned int []){ 40, 80, 160, 320 },
228 .resolutions = (u8 []) {9, 10, 11, 12 },
229 },
230 [tmp101] = {
231 .set_mask = 3 << 5, /* 12-bit mode */
232 .clr_mask = 1 << 7, /* not one-shot mode */
233 .default_resolution = 12,
234 .default_sample_time = 320,
235 .num_sample_times = 4,
236 .sample_times = (unsigned int []){ 40, 80, 160, 320 },
237 .resolutions = (u8 []) {9, 10, 11, 12 },
238 },
239 [tmp105] = {
240 .set_mask = 3 << 5, /* 12-bit mode */
241 .clr_mask = 1 << 7, /* not one-shot mode*/
242 .default_resolution = 12,
243 .default_sample_time = 220,
244 .num_sample_times = 4,
245 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
246 .resolutions = (u8 []) {9, 10, 11, 12 },
247 },
248 [tmp112] = {
249 .set_mask = 3 << 5, /* 8 samples / second */
250 .clr_mask = 1 << 7, /* no one-shot mode*/
251 .default_resolution = 12,
252 .default_sample_time = 125,
253 .num_sample_times = 4,
254 .sample_times = (unsigned int []){ 125, 250, 1000, 4000 },
255 },
256 [tmp175] = {
257 .set_mask = 3 << 5, /* 12-bit mode */
258 .clr_mask = 1 << 7, /* not one-shot mode*/
259 .default_resolution = 12,
260 .default_sample_time = 220,
261 .num_sample_times = 4,
262 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
263 .resolutions = (u8 []) {9, 10, 11, 12 },
264 },
265 [tmp275] = {
266 .set_mask = 3 << 5, /* 12-bit mode */
267 .clr_mask = 1 << 7, /* not one-shot mode*/
268 .default_resolution = 12,
269 .default_sample_time = 220,
270 .num_sample_times = 4,
271 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
272 .resolutions = (u8 []) {9, 10, 11, 12 },
273 },
274 [tmp75] = {
275 .set_mask = 3 << 5, /* 12-bit mode */
276 .clr_mask = 1 << 7, /* not one-shot mode*/
277 .default_resolution = 12,
278 .default_sample_time = 220,
279 .num_sample_times = 4,
280 .sample_times = (unsigned int []){ 28, 55, 110, 220 },
281 .resolutions = (u8 []) {9, 10, 11, 12 },
282 },
283 [tmp75b] = { /* not one-shot mode, Conversion rate 37Hz */
284 .clr_mask = 1 << 7 | 3 << 5,
285 .default_resolution = 12,
286 .default_sample_time = MSEC_PER_SEC / 37,
287 .sample_times = (unsigned int []){ MSEC_PER_SEC / 37,
288 MSEC_PER_SEC / 18,
289 MSEC_PER_SEC / 9, MSEC_PER_SEC / 4 },
290 .num_sample_times = 4,
291 },
292 [tmp75c] = {
293 .clr_mask = 1 << 5, /*not one-shot mode*/
294 .default_resolution = 12,
295 .default_sample_time = MSEC_PER_SEC / 12,
296 }
297 };
298
lm75_reg_to_mc(s16 temp,u8 resolution)299 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
300 {
301 return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
302 }
303
lm75_write_config(struct lm75_data * data,u8 set_mask,u8 clr_mask)304 static int lm75_write_config(struct lm75_data *data, u8 set_mask,
305 u8 clr_mask)
306 {
307 u8 value;
308
309 clr_mask |= LM75_SHUTDOWN;
310 value = data->current_conf & ~clr_mask;
311 value |= set_mask;
312
313 if (data->current_conf != value) {
314 s32 err;
315
316 err = i2c_smbus_write_byte_data(data->client, LM75_REG_CONF,
317 value);
318 if (err)
319 return err;
320 data->current_conf = value;
321 }
322 return 0;
323 }
324
lm75_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)325 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
326 u32 attr, int channel, long *val)
327 {
328 struct lm75_data *data = dev_get_drvdata(dev);
329 unsigned int regval;
330 int err, reg;
331
332 switch (type) {
333 case hwmon_chip:
334 switch (attr) {
335 case hwmon_chip_update_interval:
336 *val = data->sample_time;
337 break;
338 default:
339 return -EINVAL;
340 }
341 break;
342 case hwmon_temp:
343 switch (attr) {
344 case hwmon_temp_input:
345 reg = LM75_REG_TEMP;
346 break;
347 case hwmon_temp_max:
348 reg = LM75_REG_MAX;
349 break;
350 case hwmon_temp_max_hyst:
351 reg = LM75_REG_HYST;
352 break;
353 default:
354 return -EINVAL;
355 }
356 err = regmap_read(data->regmap, reg, ®val);
357 if (err < 0)
358 return err;
359
360 *val = lm75_reg_to_mc(regval, data->resolution);
361 break;
362 default:
363 return -EINVAL;
364 }
365 return 0;
366 }
367
lm75_write_temp(struct device * dev,u32 attr,long temp)368 static int lm75_write_temp(struct device *dev, u32 attr, long temp)
369 {
370 struct lm75_data *data = dev_get_drvdata(dev);
371 u8 resolution;
372 int reg;
373
374 switch (attr) {
375 case hwmon_temp_max:
376 reg = LM75_REG_MAX;
377 break;
378 case hwmon_temp_max_hyst:
379 reg = LM75_REG_HYST;
380 break;
381 default:
382 return -EINVAL;
383 }
384
385 /*
386 * Resolution of limit registers is assumed to be the same as the
387 * temperature input register resolution unless given explicitly.
388 */
389 if (data->params->resolution_limits)
390 resolution = data->params->resolution_limits;
391 else
392 resolution = data->resolution;
393
394 temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
395 temp = DIV_ROUND_CLOSEST(temp << (resolution - 8),
396 1000) << (16 - resolution);
397
398 return regmap_write(data->regmap, reg, (u16)temp);
399 }
400
lm75_update_interval(struct device * dev,long val)401 static int lm75_update_interval(struct device *dev, long val)
402 {
403 struct lm75_data *data = dev_get_drvdata(dev);
404 unsigned int reg;
405 u8 index;
406 s32 err;
407
408 index = find_closest(val, data->params->sample_times,
409 (int)data->params->num_sample_times);
410
411 switch (data->kind) {
412 default:
413 err = lm75_write_config(data, lm75_sample_set_masks[index],
414 LM75_SAMPLE_CLEAR_MASK);
415 if (err)
416 return err;
417
418 data->sample_time = data->params->sample_times[index];
419 if (data->params->resolutions)
420 data->resolution = data->params->resolutions[index];
421 break;
422 case tmp112:
423 err = regmap_read(data->regmap, LM75_REG_CONF, ®);
424 if (err < 0)
425 return err;
426 reg &= ~0x00c0;
427 reg |= (3 - index) << 6;
428 err = regmap_write(data->regmap, LM75_REG_CONF, reg);
429 if (err < 0)
430 return err;
431 data->sample_time = data->params->sample_times[index];
432 break;
433 case pct2075:
434 err = i2c_smbus_write_byte_data(data->client, PCT2075_REG_IDLE,
435 index + 1);
436 if (err)
437 return err;
438 data->sample_time = data->params->sample_times[index];
439 break;
440 }
441 return 0;
442 }
443
lm75_write_chip(struct device * dev,u32 attr,long val)444 static int lm75_write_chip(struct device *dev, u32 attr, long val)
445 {
446 switch (attr) {
447 case hwmon_chip_update_interval:
448 return lm75_update_interval(dev, val);
449 default:
450 return -EINVAL;
451 }
452 return 0;
453 }
454
lm75_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)455 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
456 u32 attr, int channel, long val)
457 {
458 switch (type) {
459 case hwmon_chip:
460 return lm75_write_chip(dev, attr, val);
461 case hwmon_temp:
462 return lm75_write_temp(dev, attr, val);
463 default:
464 return -EINVAL;
465 }
466 return 0;
467 }
468
lm75_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)469 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
470 u32 attr, int channel)
471 {
472 const struct lm75_data *config_data = data;
473
474 switch (type) {
475 case hwmon_chip:
476 switch (attr) {
477 case hwmon_chip_update_interval:
478 if (config_data->params->num_sample_times > 1)
479 return 0644;
480 return 0444;
481 }
482 break;
483 case hwmon_temp:
484 switch (attr) {
485 case hwmon_temp_input:
486 return 0444;
487 case hwmon_temp_max:
488 case hwmon_temp_max_hyst:
489 return 0644;
490 }
491 break;
492 default:
493 break;
494 }
495 return 0;
496 }
497
498 static const struct hwmon_channel_info *lm75_info[] = {
499 HWMON_CHANNEL_INFO(chip,
500 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
501 HWMON_CHANNEL_INFO(temp,
502 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
503 NULL
504 };
505
506 static const struct hwmon_ops lm75_hwmon_ops = {
507 .is_visible = lm75_is_visible,
508 .read = lm75_read,
509 .write = lm75_write,
510 };
511
512 static const struct hwmon_chip_info lm75_chip_info = {
513 .ops = &lm75_hwmon_ops,
514 .info = lm75_info,
515 };
516
lm75_is_writeable_reg(struct device * dev,unsigned int reg)517 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
518 {
519 return reg != LM75_REG_TEMP;
520 }
521
lm75_is_volatile_reg(struct device * dev,unsigned int reg)522 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
523 {
524 return reg == LM75_REG_TEMP || reg == LM75_REG_CONF;
525 }
526
527 static const struct regmap_config lm75_regmap_config = {
528 .reg_bits = 8,
529 .val_bits = 16,
530 .max_register = PCT2075_REG_IDLE,
531 .writeable_reg = lm75_is_writeable_reg,
532 .volatile_reg = lm75_is_volatile_reg,
533 .val_format_endian = REGMAP_ENDIAN_BIG,
534 .cache_type = REGCACHE_RBTREE,
535 .use_single_read = true,
536 .use_single_write = true,
537 };
538
lm75_disable_regulator(void * data)539 static void lm75_disable_regulator(void *data)
540 {
541 struct lm75_data *lm75 = data;
542
543 regulator_disable(lm75->vs);
544 }
545
lm75_remove(void * data)546 static void lm75_remove(void *data)
547 {
548 struct lm75_data *lm75 = data;
549 struct i2c_client *client = lm75->client;
550
551 i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
552 }
553
554 static const struct i2c_device_id lm75_ids[];
555
lm75_probe(struct i2c_client * client)556 static int lm75_probe(struct i2c_client *client)
557 {
558 struct device *dev = &client->dev;
559 struct device *hwmon_dev;
560 struct lm75_data *data;
561 int status, err;
562 enum lm75_type kind;
563
564 if (client->dev.of_node)
565 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
566 else
567 kind = i2c_match_id(lm75_ids, client)->driver_data;
568
569 if (!i2c_check_functionality(client->adapter,
570 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
571 return -EIO;
572
573 data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
574 if (!data)
575 return -ENOMEM;
576
577 data->client = client;
578 data->kind = kind;
579
580 data->vs = devm_regulator_get(dev, "vs");
581 if (IS_ERR(data->vs))
582 return PTR_ERR(data->vs);
583
584 data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
585 if (IS_ERR(data->regmap))
586 return PTR_ERR(data->regmap);
587
588 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
589 * Then tweak to be more precise when appropriate.
590 */
591
592 data->params = &device_params[data->kind];
593
594 /* Save default sample time and resolution*/
595 data->sample_time = data->params->default_sample_time;
596 data->resolution = data->params->default_resolution;
597
598 /* Enable the power */
599 err = regulator_enable(data->vs);
600 if (err) {
601 dev_err(dev, "failed to enable regulator: %d\n", err);
602 return err;
603 }
604
605 err = devm_add_action_or_reset(dev, lm75_disable_regulator, data);
606 if (err)
607 return err;
608
609 /* Cache original configuration */
610 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
611 if (status < 0) {
612 dev_dbg(dev, "Can't read config? %d\n", status);
613 return status;
614 }
615 data->orig_conf = status;
616 data->current_conf = status;
617
618 err = lm75_write_config(data, data->params->set_mask,
619 data->params->clr_mask);
620 if (err)
621 return err;
622
623 err = devm_add_action_or_reset(dev, lm75_remove, data);
624 if (err)
625 return err;
626
627 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
628 data, &lm75_chip_info,
629 NULL);
630 if (IS_ERR(hwmon_dev))
631 return PTR_ERR(hwmon_dev);
632
633 dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
634
635 return 0;
636 }
637
638 static const struct i2c_device_id lm75_ids[] = {
639 { "adt75", adt75, },
640 { "ds1775", ds1775, },
641 { "ds75", ds75, },
642 { "ds7505", ds7505, },
643 { "g751", g751, },
644 { "lm75", lm75, },
645 { "lm75a", lm75a, },
646 { "lm75b", lm75b, },
647 { "max6625", max6625, },
648 { "max6626", max6626, },
649 { "max31725", max31725, },
650 { "max31726", max31725, },
651 { "mcp980x", mcp980x, },
652 { "pct2075", pct2075, },
653 { "stds75", stds75, },
654 { "stlm75", stlm75, },
655 { "tcn75", tcn75, },
656 { "tmp100", tmp100, },
657 { "tmp101", tmp101, },
658 { "tmp105", tmp105, },
659 { "tmp112", tmp112, },
660 { "tmp175", tmp175, },
661 { "tmp275", tmp275, },
662 { "tmp75", tmp75, },
663 { "tmp75b", tmp75b, },
664 { "tmp75c", tmp75c, },
665 { /* LIST END */ }
666 };
667 MODULE_DEVICE_TABLE(i2c, lm75_ids);
668
669 static const struct of_device_id __maybe_unused lm75_of_match[] = {
670 {
671 .compatible = "adi,adt75",
672 .data = (void *)adt75
673 },
674 {
675 .compatible = "dallas,ds1775",
676 .data = (void *)ds1775
677 },
678 {
679 .compatible = "dallas,ds75",
680 .data = (void *)ds75
681 },
682 {
683 .compatible = "dallas,ds7505",
684 .data = (void *)ds7505
685 },
686 {
687 .compatible = "gmt,g751",
688 .data = (void *)g751
689 },
690 {
691 .compatible = "national,lm75",
692 .data = (void *)lm75
693 },
694 {
695 .compatible = "national,lm75a",
696 .data = (void *)lm75a
697 },
698 {
699 .compatible = "national,lm75b",
700 .data = (void *)lm75b
701 },
702 {
703 .compatible = "maxim,max6625",
704 .data = (void *)max6625
705 },
706 {
707 .compatible = "maxim,max6626",
708 .data = (void *)max6626
709 },
710 {
711 .compatible = "maxim,max31725",
712 .data = (void *)max31725
713 },
714 {
715 .compatible = "maxim,max31726",
716 .data = (void *)max31725
717 },
718 {
719 .compatible = "maxim,mcp980x",
720 .data = (void *)mcp980x
721 },
722 {
723 .compatible = "nxp,pct2075",
724 .data = (void *)pct2075
725 },
726 {
727 .compatible = "st,stds75",
728 .data = (void *)stds75
729 },
730 {
731 .compatible = "st,stlm75",
732 .data = (void *)stlm75
733 },
734 {
735 .compatible = "microchip,tcn75",
736 .data = (void *)tcn75
737 },
738 {
739 .compatible = "ti,tmp100",
740 .data = (void *)tmp100
741 },
742 {
743 .compatible = "ti,tmp101",
744 .data = (void *)tmp101
745 },
746 {
747 .compatible = "ti,tmp105",
748 .data = (void *)tmp105
749 },
750 {
751 .compatible = "ti,tmp112",
752 .data = (void *)tmp112
753 },
754 {
755 .compatible = "ti,tmp175",
756 .data = (void *)tmp175
757 },
758 {
759 .compatible = "ti,tmp275",
760 .data = (void *)tmp275
761 },
762 {
763 .compatible = "ti,tmp75",
764 .data = (void *)tmp75
765 },
766 {
767 .compatible = "ti,tmp75b",
768 .data = (void *)tmp75b
769 },
770 {
771 .compatible = "ti,tmp75c",
772 .data = (void *)tmp75c
773 },
774 { },
775 };
776 MODULE_DEVICE_TABLE(of, lm75_of_match);
777
778 #define LM75A_ID 0xA1
779
780 /* Return 0 if detection is successful, -ENODEV otherwise */
lm75_detect(struct i2c_client * new_client,struct i2c_board_info * info)781 static int lm75_detect(struct i2c_client *new_client,
782 struct i2c_board_info *info)
783 {
784 struct i2c_adapter *adapter = new_client->adapter;
785 int i;
786 int conf, hyst, os;
787 bool is_lm75a = 0;
788
789 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
790 I2C_FUNC_SMBUS_WORD_DATA))
791 return -ENODEV;
792
793 /*
794 * Now, we do the remaining detection. There is no identification-
795 * dedicated register so we have to rely on several tricks:
796 * unused bits, registers cycling over 8-address boundaries,
797 * addresses 0x04-0x07 returning the last read value.
798 * The cycling+unused addresses combination is not tested,
799 * since it would significantly slow the detection down and would
800 * hardly add any value.
801 *
802 * The National Semiconductor LM75A is different than earlier
803 * LM75s. It has an ID byte of 0xaX (where X is the chip
804 * revision, with 1 being the only revision in existence) in
805 * register 7, and unused registers return 0xff rather than the
806 * last read value.
807 *
808 * Note that this function only detects the original National
809 * Semiconductor LM75 and the LM75A. Clones from other vendors
810 * aren't detected, on purpose, because they are typically never
811 * found on PC hardware. They are found on embedded designs where
812 * they can be instantiated explicitly so detection is not needed.
813 * The absence of identification registers on all these clones
814 * would make their exhaustive detection very difficult and weak,
815 * and odds are that the driver would bind to unsupported devices.
816 */
817
818 /* Unused bits */
819 conf = i2c_smbus_read_byte_data(new_client, 1);
820 if (conf & 0xe0)
821 return -ENODEV;
822
823 /* First check for LM75A */
824 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
825 /*
826 * LM75A returns 0xff on unused registers so
827 * just to be sure we check for that too.
828 */
829 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
830 || i2c_smbus_read_byte_data(new_client, 5) != 0xff
831 || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
832 return -ENODEV;
833 is_lm75a = 1;
834 hyst = i2c_smbus_read_byte_data(new_client, 2);
835 os = i2c_smbus_read_byte_data(new_client, 3);
836 } else { /* Traditional style LM75 detection */
837 /* Unused addresses */
838 hyst = i2c_smbus_read_byte_data(new_client, 2);
839 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
840 || i2c_smbus_read_byte_data(new_client, 5) != hyst
841 || i2c_smbus_read_byte_data(new_client, 6) != hyst
842 || i2c_smbus_read_byte_data(new_client, 7) != hyst)
843 return -ENODEV;
844 os = i2c_smbus_read_byte_data(new_client, 3);
845 if (i2c_smbus_read_byte_data(new_client, 4) != os
846 || i2c_smbus_read_byte_data(new_client, 5) != os
847 || i2c_smbus_read_byte_data(new_client, 6) != os
848 || i2c_smbus_read_byte_data(new_client, 7) != os)
849 return -ENODEV;
850 }
851 /*
852 * It is very unlikely that this is a LM75 if both
853 * hysteresis and temperature limit registers are 0.
854 */
855 if (hyst == 0 && os == 0)
856 return -ENODEV;
857
858 /* Addresses cycling */
859 for (i = 8; i <= 248; i += 40) {
860 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
861 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
862 || i2c_smbus_read_byte_data(new_client, i + 3) != os)
863 return -ENODEV;
864 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
865 != LM75A_ID)
866 return -ENODEV;
867 }
868
869 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
870
871 return 0;
872 }
873
874 #ifdef CONFIG_PM
lm75_suspend(struct device * dev)875 static int lm75_suspend(struct device *dev)
876 {
877 int status;
878 struct i2c_client *client = to_i2c_client(dev);
879
880 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
881 if (status < 0) {
882 dev_dbg(&client->dev, "Can't read config? %d\n", status);
883 return status;
884 }
885 status = status | LM75_SHUTDOWN;
886 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
887 return 0;
888 }
889
lm75_resume(struct device * dev)890 static int lm75_resume(struct device *dev)
891 {
892 int status;
893 struct i2c_client *client = to_i2c_client(dev);
894
895 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
896 if (status < 0) {
897 dev_dbg(&client->dev, "Can't read config? %d\n", status);
898 return status;
899 }
900 status = status & ~LM75_SHUTDOWN;
901 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
902 return 0;
903 }
904
905 static const struct dev_pm_ops lm75_dev_pm_ops = {
906 .suspend = lm75_suspend,
907 .resume = lm75_resume,
908 };
909 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
910 #else
911 #define LM75_DEV_PM_OPS NULL
912 #endif /* CONFIG_PM */
913
914 static struct i2c_driver lm75_driver = {
915 .class = I2C_CLASS_HWMON,
916 .driver = {
917 .name = "lm75",
918 .of_match_table = of_match_ptr(lm75_of_match),
919 .pm = LM75_DEV_PM_OPS,
920 },
921 .probe_new = lm75_probe,
922 .id_table = lm75_ids,
923 .detect = lm75_detect,
924 .address_list = normal_i2c,
925 };
926
927 module_i2c_driver(lm75_driver);
928
929 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
930 MODULE_DESCRIPTION("LM75 driver");
931 MODULE_LICENSE("GPL");
932