2 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
4 * Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
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.
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.
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.
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>
31 #include <linux/regmap.h>
36 * This driver handles the LM75 and compatible digital temperature sensors.
39 enum lm75_type { /* keep sorted in alphabetical order */
64 /* Addresses scanned */
65 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
66 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
68 /* The LM75 registers */
69 #define LM75_REG_TEMP 0x00
70 #define LM75_REG_CONF 0x01
71 #define LM75_REG_HYST 0x02
72 #define LM75_REG_MAX 0x03
74 /* Each client has this additional data */
76 struct i2c_client *client;
77 struct regmap *regmap;
79 u8 resolution; /* In bits, between 9 and 16 */
81 unsigned int sample_time; /* In ms */
84 /*-----------------------------------------------------------------------*/
86 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
88 return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
91 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
92 u32 attr, int channel, long *val)
94 struct lm75_data *data = dev_get_drvdata(dev);
101 case hwmon_chip_update_interval:
102 *val = data->sample_time;
110 case hwmon_temp_input:
116 case hwmon_temp_max_hyst:
122 err = regmap_read(data->regmap, reg, ®val);
126 *val = lm75_reg_to_mc(regval, data->resolution);
134 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
135 u32 attr, int channel, long temp)
137 struct lm75_data *data = dev_get_drvdata(dev);
141 if (type != hwmon_temp)
148 case hwmon_temp_max_hyst:
156 * Resolution of limit registers is assumed to be the same as the
157 * temperature input register resolution unless given explicitly.
159 if (data->resolution_limits)
160 resolution = data->resolution_limits;
162 resolution = data->resolution;
164 temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
165 temp = DIV_ROUND_CLOSEST(temp << (resolution - 8),
166 1000) << (16 - resolution);
168 return regmap_write(data->regmap, reg, temp);
171 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
172 u32 attr, int channel)
177 case hwmon_chip_update_interval:
183 case hwmon_temp_input:
186 case hwmon_temp_max_hyst:
187 return S_IRUGO | S_IWUSR;
196 /*-----------------------------------------------------------------------*/
198 /* device probe and removal */
200 /* chip configuration */
202 static const u32 lm75_chip_config[] = {
203 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
207 static const struct hwmon_channel_info lm75_chip = {
209 .config = lm75_chip_config,
212 static const u32 lm75_temp_config[] = {
213 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
217 static const struct hwmon_channel_info lm75_temp = {
219 .config = lm75_temp_config,
222 static const struct hwmon_channel_info *lm75_info[] = {
228 static const struct hwmon_ops lm75_hwmon_ops = {
229 .is_visible = lm75_is_visible,
234 static const struct hwmon_chip_info lm75_chip_info = {
235 .ops = &lm75_hwmon_ops,
239 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
241 return reg != LM75_REG_TEMP;
244 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
246 return reg == LM75_REG_TEMP;
249 static const struct regmap_config lm75_regmap_config = {
252 .max_register = LM75_REG_MAX,
253 .writeable_reg = lm75_is_writeable_reg,
254 .volatile_reg = lm75_is_volatile_reg,
255 .val_format_endian = REGMAP_ENDIAN_BIG,
256 .cache_type = REGCACHE_RBTREE,
257 .use_single_read = true,
258 .use_single_write = true,
261 static void lm75_remove(void *data)
263 struct lm75_data *lm75 = data;
264 struct i2c_client *client = lm75->client;
266 i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
270 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
272 struct device *dev = &client->dev;
273 struct device *hwmon_dev;
274 struct lm75_data *data;
276 u8 set_mask, clr_mask;
280 if (client->dev.of_node)
281 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
283 kind = id->driver_data;
285 if (!i2c_check_functionality(client->adapter,
286 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
289 data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
293 data->client = client;
295 data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
296 if (IS_ERR(data->regmap))
297 return PTR_ERR(data->regmap);
299 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
300 * Then tweak to be more precise when appropriate.
303 clr_mask = LM75_SHUTDOWN; /* continuous conversions */
307 clr_mask |= 1 << 5; /* not one-shot mode */
308 data->resolution = 12;
309 data->sample_time = MSEC_PER_SEC / 8;
315 set_mask |= 2 << 5; /* 11-bit mode */
316 data->resolution = 11;
317 data->sample_time = MSEC_PER_SEC;
320 set_mask |= 3 << 5; /* 12-bit mode */
321 data->resolution = 12;
322 data->sample_time = MSEC_PER_SEC / 4;
327 data->resolution = 9;
328 data->sample_time = MSEC_PER_SEC / 2;
331 data->resolution = 11;
332 data->sample_time = MSEC_PER_SEC / 4;
335 data->resolution = 9;
336 data->sample_time = MSEC_PER_SEC / 4;
339 data->resolution = 12;
340 data->resolution_limits = 9;
341 data->sample_time = MSEC_PER_SEC / 4;
344 data->resolution = 16;
345 data->sample_time = MSEC_PER_SEC / 8;
348 data->resolution = 9;
349 data->sample_time = MSEC_PER_SEC / 8;
352 data->resolution_limits = 9;
356 set_mask |= 3 << 5; /* 12-bit mode */
357 data->resolution = 12;
358 data->sample_time = MSEC_PER_SEC;
359 clr_mask |= 1 << 7; /* not one-shot mode */
362 set_mask |= 3 << 5; /* 12-bit mode */
363 clr_mask |= 1 << 7; /* not one-shot mode */
364 data->resolution = 12;
365 data->sample_time = MSEC_PER_SEC / 4;
371 set_mask |= 3 << 5; /* 12-bit mode */
372 clr_mask |= 1 << 7; /* not one-shot mode */
373 data->resolution = 12;
374 data->sample_time = MSEC_PER_SEC / 2;
377 clr_mask |= 1 << 5; /* not one-shot mode */
378 data->resolution = 12;
379 data->sample_time = MSEC_PER_SEC / 4;
383 /* configure as specified */
384 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
386 dev_dbg(dev, "Can't read config? %d\n", status);
389 data->orig_conf = status;
390 new = status & ~clr_mask;
393 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
395 err = devm_add_action_or_reset(dev, lm75_remove, data);
399 dev_dbg(dev, "Config %02x\n", new);
401 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
402 data, &lm75_chip_info,
404 if (IS_ERR(hwmon_dev))
405 return PTR_ERR(hwmon_dev);
407 dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
412 static const struct i2c_device_id lm75_ids[] = {
414 { "ds1775", ds1775, },
416 { "ds7505", ds7505, },
421 { "max6625", max6625, },
422 { "max6626", max6626, },
423 { "max31725", max31725, },
424 { "max31726", max31725, },
425 { "mcp980x", mcp980x, },
426 { "stds75", stds75, },
428 { "tmp100", tmp100, },
429 { "tmp101", tmp101, },
430 { "tmp105", tmp105, },
431 { "tmp112", tmp112, },
432 { "tmp175", tmp175, },
433 { "tmp275", tmp275, },
435 { "tmp75c", tmp75c, },
438 MODULE_DEVICE_TABLE(i2c, lm75_ids);
440 static const struct of_device_id lm75_of_match[] = {
442 .compatible = "adi,adt75",
443 .data = (void *)adt75
446 .compatible = "dallas,ds1775",
447 .data = (void *)ds1775
450 .compatible = "dallas,ds75",
454 .compatible = "dallas,ds7505",
455 .data = (void *)ds7505
458 .compatible = "gmt,g751",
462 .compatible = "national,lm75",
466 .compatible = "national,lm75a",
467 .data = (void *)lm75a
470 .compatible = "national,lm75b",
471 .data = (void *)lm75b
474 .compatible = "maxim,max6625",
475 .data = (void *)max6625
478 .compatible = "maxim,max6626",
479 .data = (void *)max6626
482 .compatible = "maxim,max31725",
483 .data = (void *)max31725
486 .compatible = "maxim,max31726",
487 .data = (void *)max31725
490 .compatible = "maxim,mcp980x",
491 .data = (void *)mcp980x
494 .compatible = "st,stds75",
495 .data = (void *)stds75
498 .compatible = "microchip,tcn75",
499 .data = (void *)tcn75
502 .compatible = "ti,tmp100",
503 .data = (void *)tmp100
506 .compatible = "ti,tmp101",
507 .data = (void *)tmp101
510 .compatible = "ti,tmp105",
511 .data = (void *)tmp105
514 .compatible = "ti,tmp112",
515 .data = (void *)tmp112
518 .compatible = "ti,tmp175",
519 .data = (void *)tmp175
522 .compatible = "ti,tmp275",
523 .data = (void *)tmp275
526 .compatible = "ti,tmp75",
527 .data = (void *)tmp75
530 .compatible = "ti,tmp75c",
531 .data = (void *)tmp75c
535 MODULE_DEVICE_TABLE(of, lm75_of_match);
537 #define LM75A_ID 0xA1
539 /* Return 0 if detection is successful, -ENODEV otherwise */
540 static int lm75_detect(struct i2c_client *new_client,
541 struct i2c_board_info *info)
543 struct i2c_adapter *adapter = new_client->adapter;
548 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
549 I2C_FUNC_SMBUS_WORD_DATA))
553 * Now, we do the remaining detection. There is no identification-
554 * dedicated register so we have to rely on several tricks:
555 * unused bits, registers cycling over 8-address boundaries,
556 * addresses 0x04-0x07 returning the last read value.
557 * The cycling+unused addresses combination is not tested,
558 * since it would significantly slow the detection down and would
559 * hardly add any value.
561 * The National Semiconductor LM75A is different than earlier
562 * LM75s. It has an ID byte of 0xaX (where X is the chip
563 * revision, with 1 being the only revision in existence) in
564 * register 7, and unused registers return 0xff rather than the
567 * Note that this function only detects the original National
568 * Semiconductor LM75 and the LM75A. Clones from other vendors
569 * aren't detected, on purpose, because they are typically never
570 * found on PC hardware. They are found on embedded designs where
571 * they can be instantiated explicitly so detection is not needed.
572 * The absence of identification registers on all these clones
573 * would make their exhaustive detection very difficult and weak,
574 * and odds are that the driver would bind to unsupported devices.
578 conf = i2c_smbus_read_byte_data(new_client, 1);
582 /* First check for LM75A */
583 if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
584 /* LM75A returns 0xff on unused registers so
585 just to be sure we check for that too. */
586 if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
587 || i2c_smbus_read_byte_data(new_client, 5) != 0xff
588 || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
591 hyst = i2c_smbus_read_byte_data(new_client, 2);
592 os = i2c_smbus_read_byte_data(new_client, 3);
593 } else { /* Traditional style LM75 detection */
594 /* Unused addresses */
595 hyst = i2c_smbus_read_byte_data(new_client, 2);
596 if (i2c_smbus_read_byte_data(new_client, 4) != hyst
597 || i2c_smbus_read_byte_data(new_client, 5) != hyst
598 || i2c_smbus_read_byte_data(new_client, 6) != hyst
599 || i2c_smbus_read_byte_data(new_client, 7) != hyst)
601 os = i2c_smbus_read_byte_data(new_client, 3);
602 if (i2c_smbus_read_byte_data(new_client, 4) != os
603 || i2c_smbus_read_byte_data(new_client, 5) != os
604 || i2c_smbus_read_byte_data(new_client, 6) != os
605 || i2c_smbus_read_byte_data(new_client, 7) != os)
609 * It is very unlikely that this is a LM75 if both
610 * hysteresis and temperature limit registers are 0.
612 if (hyst == 0 && os == 0)
615 /* Addresses cycling */
616 for (i = 8; i <= 248; i += 40) {
617 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
618 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
619 || i2c_smbus_read_byte_data(new_client, i + 3) != os)
621 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
626 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
632 static int lm75_suspend(struct device *dev)
635 struct i2c_client *client = to_i2c_client(dev);
636 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
638 dev_dbg(&client->dev, "Can't read config? %d\n", status);
641 status = status | LM75_SHUTDOWN;
642 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
646 static int lm75_resume(struct device *dev)
649 struct i2c_client *client = to_i2c_client(dev);
650 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
652 dev_dbg(&client->dev, "Can't read config? %d\n", status);
655 status = status & ~LM75_SHUTDOWN;
656 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
660 static const struct dev_pm_ops lm75_dev_pm_ops = {
661 .suspend = lm75_suspend,
662 .resume = lm75_resume,
664 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
666 #define LM75_DEV_PM_OPS NULL
667 #endif /* CONFIG_PM */
669 static struct i2c_driver lm75_driver = {
670 .class = I2C_CLASS_HWMON,
673 .of_match_table = of_match_ptr(lm75_of_match),
674 .pm = LM75_DEV_PM_OPS,
677 .id_table = lm75_ids,
678 .detect = lm75_detect,
679 .address_list = normal_i2c,
682 module_i2c_driver(lm75_driver);
684 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
685 MODULE_DESCRIPTION("LM75 driver");
686 MODULE_LICENSE("GPL");