summaryrefslogtreecommitdiff
path: root/drivers/hwmon/tmp108.c
blob: 91bb946392869e5002097fdfa2f371dacc466f25 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
/* Texas Instruments TMP108 SMBus temperature sensor driver
 *
 * Copyright (C) 2016 John Muir <john@jmuir.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#define	DRIVER_NAME "tmp108"

#define	TMP108_REG_TEMP		0x00
#define	TMP108_REG_CONF		0x01
#define	TMP108_REG_TLOW		0x02
#define	TMP108_REG_THIGH	0x03

#define TMP108_TEMP_MIN_MC	-50000 /* Minimum millicelcius. */
#define TMP108_TEMP_MAX_MC	127937 /* Maximum millicelcius. */

/* Configuration register bits.
 * Note: these bit definitions are byte swapped.
 */
#define TMP108_CONF_M0		0x0100 /* Sensor mode. */
#define TMP108_CONF_M1		0x0200
#define TMP108_CONF_TM		0x0400 /* Thermostat mode. */
#define TMP108_CONF_FL		0x0800 /* Watchdog flag - TLOW */
#define TMP108_CONF_FH		0x1000 /* Watchdog flag - THIGH */
#define TMP108_CONF_CR0		0x2000 /* Conversion rate. */
#define TMP108_CONF_CR1		0x4000
#define TMP108_CONF_ID		0x8000
#define TMP108_CONF_HYS0	0x0010 /* Hysteresis. */
#define TMP108_CONF_HYS1	0x0020
#define TMP108_CONF_POL		0x0080 /* Polarity of alert. */

/* Defaults set by the hardware upon reset. */
#define TMP108_CONF_DEFAULTS		(TMP108_CONF_CR0 | TMP108_CONF_TM |\
					 TMP108_CONF_HYS0 | TMP108_CONF_M1)
/* These bits are read-only. */
#define TMP108_CONF_READ_ONLY		(TMP108_CONF_FL | TMP108_CONF_FH |\
					 TMP108_CONF_ID)

#define TMP108_CONF_MODE_MASK		(TMP108_CONF_M0|TMP108_CONF_M1)
#define TMP108_MODE_SHUTDOWN		0x0000
#define TMP108_MODE_ONE_SHOT		TMP108_CONF_M0
#define TMP108_MODE_CONTINUOUS		TMP108_CONF_M1		/* Default */
					/* When M1 is set, M0 is ignored. */

#define TMP108_CONF_CONVRATE_MASK	(TMP108_CONF_CR0|TMP108_CONF_CR1)
#define TMP108_CONVRATE_0P25HZ		0x0000
#define TMP108_CONVRATE_1HZ		TMP108_CONF_CR0		/* Default */
#define TMP108_CONVRATE_4HZ		TMP108_CONF_CR1
#define TMP108_CONVRATE_16HZ		(TMP108_CONF_CR0|TMP108_CONF_CR1)

#define TMP108_CONF_HYSTERESIS_MASK	(TMP108_CONF_HYS0|TMP108_CONF_HYS1)
#define TMP108_HYSTERESIS_0C		0x0000
#define TMP108_HYSTERESIS_1C		TMP108_CONF_HYS0	/* Default */
#define TMP108_HYSTERESIS_2C		TMP108_CONF_HYS1
#define TMP108_HYSTERESIS_4C		(TMP108_CONF_HYS0|TMP108_CONF_HYS1)

#define TMP108_CONVERSION_TIME_MS	30	/* in milli-seconds */

struct tmp108 {
	struct regmap *regmap;
	u16 orig_config;
	unsigned long ready_time;
};

/* convert 12-bit TMP108 register value to milliCelsius */
static inline int tmp108_temp_reg_to_mC(s16 val)
{
	return (val & ~0x0f) * 1000 / 256;
}

/* convert milliCelsius to left adjusted 12-bit TMP108 register value */
static inline u16 tmp108_mC_to_temp_reg(int val)
{
	return (val * 256) / 1000;
}

static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
		       u32 attr, int channel, long *temp)
{
	struct tmp108 *tmp108 = dev_get_drvdata(dev);
	unsigned int regval;
	int err, hyst;

	if (type == hwmon_chip) {
		if (attr == hwmon_chip_update_interval) {
			err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
					  &regval);
			if (err < 0)
				return err;
			switch (regval & TMP108_CONF_CONVRATE_MASK) {
			case TMP108_CONVRATE_0P25HZ:
			default:
				*temp = 4000;
				break;
			case TMP108_CONVRATE_1HZ:
				*temp = 1000;
				break;
			case TMP108_CONVRATE_4HZ:
				*temp = 250;
				break;
			case TMP108_CONVRATE_16HZ:
				*temp = 63;
				break;
			}
			return 0;
		}
		return -EOPNOTSUPP;
	}

	switch (attr) {
	case hwmon_temp_input:
		/* Is it too early to return a conversion ? */
		if (time_before(jiffies, tmp108->ready_time)) {
			dev_dbg(dev, "%s: Conversion not ready yet..\n",
				__func__);
			return -EAGAIN;
		}
		err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, &regval);
		if (err < 0)
			return err;
		*temp = tmp108_temp_reg_to_mC(regval);
		break;
	case hwmon_temp_min:
	case hwmon_temp_max:
		err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
				  TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
		if (err < 0)
			return err;
		*temp = tmp108_temp_reg_to_mC(regval);
		break;
	case hwmon_temp_min_alarm:
	case hwmon_temp_max_alarm:
		err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
		if (err < 0)
			return err;
		*temp = !!(regval & (attr == hwmon_temp_min_alarm ?
				     TMP108_CONF_FL : TMP108_CONF_FH));
		break;
	case hwmon_temp_min_hyst:
	case hwmon_temp_max_hyst:
		err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
		if (err < 0)
			return err;
		switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
		case TMP108_HYSTERESIS_0C:
		default:
			hyst = 0;
			break;
		case TMP108_HYSTERESIS_1C:
			hyst = 1000;
			break;
		case TMP108_HYSTERESIS_2C:
			hyst = 2000;
			break;
		case TMP108_HYSTERESIS_4C:
			hyst = 4000;
			break;
		}
		err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
				  TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
		if (err < 0)
			return err;
		*temp = tmp108_temp_reg_to_mC(regval);
		if (attr == hwmon_temp_min_hyst)
			*temp += hyst;
		else
			*temp -= hyst;
		break;
	default:
		return -EOPNOTSUPP;
	}

	return 0;
}

static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
			u32 attr, int channel, long temp)
{
	struct tmp108 *tmp108 = dev_get_drvdata(dev);
	u32 regval, mask;
	int err;

	if (type == hwmon_chip) {
		if (attr == hwmon_chip_update_interval) {
			if (temp < 156)
				mask = TMP108_CONVRATE_16HZ;
			else if (temp < 625)
				mask = TMP108_CONVRATE_4HZ;
			else if (temp < 2500)
				mask = TMP108_CONVRATE_1HZ;
			else
				mask = TMP108_CONVRATE_0P25HZ;
			return regmap_update_bits(tmp108->regmap,
						  TMP108_REG_CONF,
						  TMP108_CONF_CONVRATE_MASK,
						  mask);
		}
		return -EOPNOTSUPP;
	}

	switch (attr) {
	case hwmon_temp_min:
	case hwmon_temp_max:
		temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
		return regmap_write(tmp108->regmap,
				    attr == hwmon_temp_min ?
					TMP108_REG_TLOW : TMP108_REG_THIGH,
				    tmp108_mC_to_temp_reg(temp));
	case hwmon_temp_min_hyst:
	case hwmon_temp_max_hyst:
		temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
		err = regmap_read(tmp108->regmap,
				  attr == hwmon_temp_min_hyst ?
					TMP108_REG_TLOW : TMP108_REG_THIGH,
				  &regval);
		if (err < 0)
			return err;
		if (attr == hwmon_temp_min_hyst)
			temp -= tmp108_temp_reg_to_mC(regval);
		else
			temp = tmp108_temp_reg_to_mC(regval) - temp;
		if (temp < 500)
			mask = TMP108_HYSTERESIS_0C;
		else if (temp < 1500)
			mask = TMP108_HYSTERESIS_1C;
		else if (temp < 3000)
			mask = TMP108_HYSTERESIS_2C;
		else
			mask = TMP108_HYSTERESIS_4C;
		return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
					  TMP108_CONF_HYSTERESIS_MASK, mask);
	default:
		return -EOPNOTSUPP;
	}
}

static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
				 u32 attr, int channel)
{
	if (type == hwmon_chip && attr == hwmon_chip_update_interval)
		return 0644;

	if (type != hwmon_temp)
		return 0;

	switch (attr) {
	case hwmon_temp_input:
	case hwmon_temp_min_alarm:
	case hwmon_temp_max_alarm:
		return 0444;
	case hwmon_temp_min:
	case hwmon_temp_max:
	case hwmon_temp_min_hyst:
	case hwmon_temp_max_hyst:
		return 0644;
	default:
		return 0;
	}
}

static u32 tmp108_chip_config[] = {
	HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
	0
};

static const struct hwmon_channel_info tmp108_chip = {
	.type = hwmon_chip,
	.config = tmp108_chip_config,
};

static u32 tmp108_temp_config[] = {
	HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_MIN_HYST
		| HWMON_T_MAX_HYST | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
	0
};

static const struct hwmon_channel_info tmp108_temp = {
	.type = hwmon_temp,
	.config = tmp108_temp_config,
};

static const struct hwmon_channel_info *tmp108_info[] = {
	&tmp108_chip,
	&tmp108_temp,
	NULL
};

static const struct hwmon_ops tmp108_hwmon_ops = {
	.is_visible = tmp108_is_visible,
	.read = tmp108_read,
	.write = tmp108_write,
};

static const struct hwmon_chip_info tmp108_chip_info = {
	.ops = &tmp108_hwmon_ops,
	.info = tmp108_info,
};

static void tmp108_restore_config(void *data)
{
	struct tmp108 *tmp108 = data;

	regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
}

static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
{
	return reg != TMP108_REG_TEMP;
}

static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
{
	/* Configuration register must be volatile to enable FL and FH. */
	return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
}

static const struct regmap_config tmp108_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.max_register = TMP108_REG_THIGH,
	.writeable_reg = tmp108_is_writeable_reg,
	.volatile_reg = tmp108_is_volatile_reg,
	.val_format_endian = REGMAP_ENDIAN_BIG,
	.cache_type = REGCACHE_RBTREE,
	.use_single_rw = true,
};

static int tmp108_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct tmp108 *tmp108;
	int err;
	u32 config;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_WORD_DATA)) {
		dev_err(dev,
			"adapter doesn't support SMBus word transactions\n");
		return -ENODEV;
	}

	tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
	if (!tmp108)
		return -ENOMEM;

	dev_set_drvdata(dev, tmp108);

	tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
	if (IS_ERR(tmp108->regmap)) {
		err = PTR_ERR(tmp108->regmap);
		dev_err(dev, "regmap init failed: %d", err);
		return err;
	}

	err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
	if (err < 0) {
		dev_err(dev, "error reading config register: %d", err);
		return err;
	}
	tmp108->orig_config = config;

	/* Only continuous mode is supported. */
	config &= ~TMP108_CONF_MODE_MASK;
	config |= TMP108_MODE_CONTINUOUS;

	/* Only comparator mode is supported. */
	config &= ~TMP108_CONF_TM;

	err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
	if (err < 0) {
		dev_err(dev, "error writing config register: %d", err);
		return err;
	}

	tmp108->ready_time = jiffies;
	if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
	    TMP108_MODE_SHUTDOWN)
		tmp108->ready_time +=
			msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);

	err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
	if (err) {
		dev_err(dev, "add action or reset failed: %d", err);
		return err;
	}

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
							 tmp108,
							 &tmp108_chip_info,
							 NULL);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static int __maybe_unused tmp108_suspend(struct device *dev)
{
	struct tmp108 *tmp108 = dev_get_drvdata(dev);

	return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
				  TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
}

static int __maybe_unused tmp108_resume(struct device *dev)
{
	struct tmp108 *tmp108 = dev_get_drvdata(dev);
	int err;

	err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
				 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
	tmp108->ready_time = jiffies +
			     msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
	return err;
}

static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);

static const struct i2c_device_id tmp108_i2c_ids[] = {
	{ "tmp108", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);

#ifdef CONFIG_OF
static const struct of_device_id tmp108_of_ids[] = {
	{ .compatible = "ti,tmp108", },
	{}
};
MODULE_DEVICE_TABLE(of, tmp108_of_ids);
#endif

static struct i2c_driver tmp108_driver = {
	.driver = {
		.name	= DRIVER_NAME,
		.pm	= &tmp108_dev_pm_ops,
		.of_match_table = of_match_ptr(tmp108_of_ids),
	},
	.probe		= tmp108_probe,
	.id_table	= tmp108_i2c_ids,
};

module_i2c_driver(tmp108_driver);

MODULE_AUTHOR("John Muir <john@jmuir.com>");
MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
MODULE_LICENSE("GPL");