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 */
65 /* Addresses scanned */
66 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
67 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
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
75 /* Each client has this additional data */
77 struct i2c_client *client;
78 struct regmap *regmap;
80 u8 resolution; /* In bits, between 9 and 16 */
82 unsigned int sample_time; /* In ms */
85 /*-----------------------------------------------------------------------*/
87 static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
89 return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
92 static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
93 u32 attr, int channel, long *val)
95 struct lm75_data *data = dev_get_drvdata(dev);
102 case hwmon_chip_update_interval:
103 *val = data->sample_time;
111 case hwmon_temp_input:
117 case hwmon_temp_max_hyst:
123 err = regmap_read(data->regmap, reg, ®val);
127 *val = lm75_reg_to_mc(regval, data->resolution);
135 static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
136 u32 attr, int channel, long temp)
138 struct lm75_data *data = dev_get_drvdata(dev);
142 if (type != hwmon_temp)
149 case hwmon_temp_max_hyst:
157 * Resolution of limit registers is assumed to be the same as the
158 * temperature input register resolution unless given explicitly.
160 if (data->resolution_limits)
161 resolution = data->resolution_limits;
163 resolution = data->resolution;
165 temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
166 temp = DIV_ROUND_CLOSEST(temp << (resolution - 8),
167 1000) << (16 - resolution);
169 return regmap_write(data->regmap, reg, temp);
172 static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
173 u32 attr, int channel)
178 case hwmon_chip_update_interval:
184 case hwmon_temp_input:
187 case hwmon_temp_max_hyst:
188 return S_IRUGO | S_IWUSR;
197 /*-----------------------------------------------------------------------*/
199 /* device probe and removal */
201 /* chip configuration */
203 static const u32 lm75_chip_config[] = {
204 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
208 static const struct hwmon_channel_info lm75_chip = {
210 .config = lm75_chip_config,
213 static const u32 lm75_temp_config[] = {
214 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
218 static const struct hwmon_channel_info lm75_temp = {
220 .config = lm75_temp_config,
223 static const struct hwmon_channel_info *lm75_info[] = {
229 static const struct hwmon_ops lm75_hwmon_ops = {
230 .is_visible = lm75_is_visible,
235 static const struct hwmon_chip_info lm75_chip_info = {
236 .ops = &lm75_hwmon_ops,
240 static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
242 return reg != LM75_REG_TEMP;
245 static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
247 return reg == LM75_REG_TEMP;
250 static const struct regmap_config lm75_regmap_config = {
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,
262 static void lm75_remove(void *data)
264 struct lm75_data *lm75 = data;
265 struct i2c_client *client = lm75->client;
267 i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
271 lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
273 struct device *dev = &client->dev;
274 struct device *hwmon_dev;
275 struct lm75_data *data;
277 u8 set_mask, clr_mask;
281 if (client->dev.of_node)
282 kind = (enum lm75_type)of_device_get_match_data(&client->dev);
284 kind = id->driver_data;
286 if (!i2c_check_functionality(client->adapter,
287 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
290 data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
294 data->client = client;
296 data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
297 if (IS_ERR(data->regmap))
298 return PTR_ERR(data->regmap);
300 /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
301 * Then tweak to be more precise when appropriate.
304 clr_mask = LM75_SHUTDOWN; /* continuous conversions */
308 clr_mask |= 1 << 5; /* not one-shot mode */
309 data->resolution = 12;
310 data->sample_time = MSEC_PER_SEC / 8;
316 set_mask |= 2 << 5; /* 11-bit mode */
317 data->resolution = 11;
318 data->sample_time = MSEC_PER_SEC;
321 data->resolution = 9;
322 data->sample_time = MSEC_PER_SEC / 5;
325 set_mask |= 3 << 5; /* 12-bit mode */
326 data->resolution = 12;
327 data->sample_time = MSEC_PER_SEC / 4;
332 data->resolution = 9;
333 data->sample_time = MSEC_PER_SEC / 2;
336 data->resolution = 11;
337 data->sample_time = MSEC_PER_SEC / 4;
340 data->resolution = 9;
341 data->sample_time = MSEC_PER_SEC / 4;
344 data->resolution = 12;
345 data->resolution_limits = 9;
346 data->sample_time = MSEC_PER_SEC / 4;
349 data->resolution = 16;
350 data->sample_time = MSEC_PER_SEC / 8;
353 data->resolution = 9;
354 data->sample_time = MSEC_PER_SEC / 8;
357 data->resolution_limits = 9;
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 */
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;
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;
382 clr_mask |= 1 << 5; /* not one-shot mode */
383 data->resolution = 12;
384 data->sample_time = MSEC_PER_SEC / 4;
388 /* configure as specified */
389 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
391 dev_dbg(dev, "Can't read config? %d\n", status);
394 data->orig_conf = status;
395 new = status & ~clr_mask;
398 i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
400 err = devm_add_action_or_reset(dev, lm75_remove, data);
404 dev_dbg(dev, "Config %02x\n", new);
406 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
407 data, &lm75_chip_info,
409 if (IS_ERR(hwmon_dev))
410 return PTR_ERR(hwmon_dev);
412 dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
417 static const struct i2c_device_id lm75_ids[] = {
419 { "ds1775", ds1775, },
421 { "ds7505", ds7505, },
426 { "max6625", max6625, },
427 { "max6626", max6626, },
428 { "max31725", max31725, },
429 { "max31726", max31725, },
430 { "mcp980x", mcp980x, },
431 { "stds75", stds75, },
432 { "stlm75", stlm75, },
434 { "tmp100", tmp100, },
435 { "tmp101", tmp101, },
436 { "tmp105", tmp105, },
437 { "tmp112", tmp112, },
438 { "tmp175", tmp175, },
439 { "tmp275", tmp275, },
441 { "tmp75c", tmp75c, },
444 MODULE_DEVICE_TABLE(i2c, lm75_ids);
446 static const struct of_device_id lm75_of_match[] = {
448 .compatible = "adi,adt75",
449 .data = (void *)adt75
452 .compatible = "dallas,ds1775",
453 .data = (void *)ds1775
456 .compatible = "dallas,ds75",
460 .compatible = "dallas,ds7505",
461 .data = (void *)ds7505
464 .compatible = "gmt,g751",
468 .compatible = "national,lm75",
472 .compatible = "national,lm75a",
473 .data = (void *)lm75a
476 .compatible = "national,lm75b",
477 .data = (void *)lm75b
480 .compatible = "maxim,max6625",
481 .data = (void *)max6625
484 .compatible = "maxim,max6626",
485 .data = (void *)max6626
488 .compatible = "maxim,max31725",
489 .data = (void *)max31725
492 .compatible = "maxim,max31726",
493 .data = (void *)max31725
496 .compatible = "maxim,mcp980x",
497 .data = (void *)mcp980x
500 .compatible = "st,stds75",
501 .data = (void *)stds75
504 .compatible = "st,stlm75",
505 .data = (void *)stlm75
508 .compatible = "microchip,tcn75",
509 .data = (void *)tcn75
512 .compatible = "ti,tmp100",
513 .data = (void *)tmp100
516 .compatible = "ti,tmp101",
517 .data = (void *)tmp101
520 .compatible = "ti,tmp105",
521 .data = (void *)tmp105
524 .compatible = "ti,tmp112",
525 .data = (void *)tmp112
528 .compatible = "ti,tmp175",
529 .data = (void *)tmp175
532 .compatible = "ti,tmp275",
533 .data = (void *)tmp275
536 .compatible = "ti,tmp75",
537 .data = (void *)tmp75
540 .compatible = "ti,tmp75c",
541 .data = (void *)tmp75c
545 MODULE_DEVICE_TABLE(of, lm75_of_match);
547 #define LM75A_ID 0xA1
549 /* Return 0 if detection is successful, -ENODEV otherwise */
550 static int lm75_detect(struct i2c_client *new_client,
551 struct i2c_board_info *info)
553 struct i2c_adapter *adapter = new_client->adapter;
558 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
559 I2C_FUNC_SMBUS_WORD_DATA))
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.
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
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.
588 conf = i2c_smbus_read_byte_data(new_client, 1);
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)
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)
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)
619 * It is very unlikely that this is a LM75 if both
620 * hysteresis and temperature limit registers are 0.
622 if (hyst == 0 && os == 0)
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)
631 if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
636 strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
642 static int lm75_suspend(struct device *dev)
645 struct i2c_client *client = to_i2c_client(dev);
646 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
648 dev_dbg(&client->dev, "Can't read config? %d\n", status);
651 status = status | LM75_SHUTDOWN;
652 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
656 static int lm75_resume(struct device *dev)
659 struct i2c_client *client = to_i2c_client(dev);
660 status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
662 dev_dbg(&client->dev, "Can't read config? %d\n", status);
665 status = status & ~LM75_SHUTDOWN;
666 i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
670 static const struct dev_pm_ops lm75_dev_pm_ops = {
671 .suspend = lm75_suspend,
672 .resume = lm75_resume,
674 #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
676 #define LM75_DEV_PM_OPS NULL
677 #endif /* CONFIG_PM */
679 static struct i2c_driver lm75_driver = {
680 .class = I2C_CLASS_HWMON,
683 .of_match_table = of_match_ptr(lm75_of_match),
684 .pm = LM75_DEV_PM_OPS,
687 .id_table = lm75_ids,
688 .detect = lm75_detect,
689 .address_list = normal_i2c,
692 module_i2c_driver(lm75_driver);
694 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
695 MODULE_DESCRIPTION("LM75 driver");
696 MODULE_LICENSE("GPL");