summaryrefslogtreecommitdiff
path: root/drivers/hwmon/emc2103.c
blob: 60eddc7b027089fb035bc838b43c2684d8d1e6ce (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
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * emc2103.c - Support for SMSC EMC2103
 * Copyright (c) 2010 SMSC
 */

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

/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x2E, I2C_CLIENT_END };

static const u8 REG_TEMP[4] = { 0x00, 0x02, 0x04, 0x06 };
static const u8 REG_TEMP_MIN[4] = { 0x3c, 0x38, 0x39, 0x3a };
static const u8 REG_TEMP_MAX[4] = { 0x34, 0x30, 0x31, 0x32 };

#define REG_CONF1		0x20
#define REG_TEMP_MAX_ALARM	0x24
#define REG_TEMP_MIN_ALARM	0x25
#define REG_FAN_CONF1		0x42
#define REG_FAN_TARGET_LO	0x4c
#define REG_FAN_TARGET_HI	0x4d
#define REG_FAN_TACH_HI		0x4e
#define REG_FAN_TACH_LO		0x4f
#define REG_PRODUCT_ID		0xfd
#define REG_MFG_ID		0xfe

/* equation 4 from datasheet: rpm = (3932160 * multipler) / count */
#define FAN_RPM_FACTOR		3932160

/*
 * 2103-2 and 2103-4's 3rd temperature sensor can be connected to two diodes
 * in anti-parallel mode, and in this configuration both can be read
 * independently (so we have 4 temperature inputs).  The device can't
 * detect if it's connected in this mode, so we have to manually enable
 * it.  Default is to leave the device in the state it's already in (-1).
 * This parameter allows APD mode to be optionally forced on or off
 */
static int apd = -1;
module_param(apd, bint, 0);
MODULE_PARM_DESC(apd, "Set to zero to disable anti-parallel diode mode");

struct temperature {
	s8	degrees;
	u8	fraction;	/* 0-7 multiples of 0.125 */
};

struct emc2103_data {
	struct i2c_client	*client;
	const struct		attribute_group *groups[4];
	struct mutex		update_lock;
	bool			valid;		/* registers are valid */
	bool			fan_rpm_control;
	int			temp_count;	/* num of temp sensors */
	unsigned long		last_updated;	/* in jiffies */
	struct temperature	temp[4];	/* internal + 3 external */
	s8			temp_min[4];	/* no fractional part */
	s8			temp_max[4];    /* no fractional part */
	u8			temp_min_alarm;
	u8			temp_max_alarm;
	u8			fan_multiplier;
	u16			fan_tach;
	u16			fan_target;
};

static int read_u8_from_i2c(struct i2c_client *client, u8 i2c_reg, u8 *output)
{
	int status = i2c_smbus_read_byte_data(client, i2c_reg);
	if (status < 0) {
		dev_warn(&client->dev, "reg 0x%02x, err %d\n",
			i2c_reg, status);
	} else {
		*output = status;
	}
	return status;
}

static void read_temp_from_i2c(struct i2c_client *client, u8 i2c_reg,
			       struct temperature *temp)
{
	u8 degrees, fractional;

	if (read_u8_from_i2c(client, i2c_reg, &degrees) < 0)
		return;

	if (read_u8_from_i2c(client, i2c_reg + 1, &fractional) < 0)
		return;

	temp->degrees = degrees;
	temp->fraction = (fractional & 0xe0) >> 5;
}

static void read_fan_from_i2c(struct i2c_client *client, u16 *output,
			      u8 hi_addr, u8 lo_addr)
{
	u8 high_byte, lo_byte;

	if (read_u8_from_i2c(client, hi_addr, &high_byte) < 0)
		return;

	if (read_u8_from_i2c(client, lo_addr, &lo_byte) < 0)
		return;

	*output = ((u16)high_byte << 5) | (lo_byte >> 3);
}

static void write_fan_target_to_i2c(struct i2c_client *client, u16 new_target)
{
	u8 high_byte = (new_target & 0x1fe0) >> 5;
	u8 low_byte = (new_target & 0x001f) << 3;
	i2c_smbus_write_byte_data(client, REG_FAN_TARGET_LO, low_byte);
	i2c_smbus_write_byte_data(client, REG_FAN_TARGET_HI, high_byte);
}

static void read_fan_config_from_i2c(struct i2c_client *client)

{
	struct emc2103_data *data = i2c_get_clientdata(client);
	u8 conf1;

	if (read_u8_from_i2c(client, REG_FAN_CONF1, &conf1) < 0)
		return;

	data->fan_multiplier = 1 << ((conf1 & 0x60) >> 5);
	data->fan_rpm_control = (conf1 & 0x80) != 0;
}

static struct emc2103_data *emc2103_update_device(struct device *dev)
{
	struct emc2103_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	    || !data->valid) {
		int i;

		for (i = 0; i < data->temp_count; i++) {
			read_temp_from_i2c(client, REG_TEMP[i], &data->temp[i]);
			read_u8_from_i2c(client, REG_TEMP_MIN[i],
				&data->temp_min[i]);
			read_u8_from_i2c(client, REG_TEMP_MAX[i],
				&data->temp_max[i]);
		}

		read_u8_from_i2c(client, REG_TEMP_MIN_ALARM,
			&data->temp_min_alarm);
		read_u8_from_i2c(client, REG_TEMP_MAX_ALARM,
			&data->temp_max_alarm);

		read_fan_from_i2c(client, &data->fan_tach,
			REG_FAN_TACH_HI, REG_FAN_TACH_LO);
		read_fan_from_i2c(client, &data->fan_target,
			REG_FAN_TARGET_HI, REG_FAN_TARGET_LO);
		read_fan_config_from_i2c(client);

		data->last_updated = jiffies;
		data->valid = true;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

static ssize_t
temp_show(struct device *dev, struct device_attribute *da, char *buf)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = emc2103_update_device(dev);
	int millidegrees = data->temp[nr].degrees * 1000
		+ data->temp[nr].fraction * 125;
	return sprintf(buf, "%d\n", millidegrees);
}

static ssize_t
temp_min_show(struct device *dev, struct device_attribute *da, char *buf)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = emc2103_update_device(dev);
	int millidegrees = data->temp_min[nr] * 1000;
	return sprintf(buf, "%d\n", millidegrees);
}

static ssize_t
temp_max_show(struct device *dev, struct device_attribute *da, char *buf)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = emc2103_update_device(dev);
	int millidegrees = data->temp_max[nr] * 1000;
	return sprintf(buf, "%d\n", millidegrees);
}

static ssize_t
temp_fault_show(struct device *dev, struct device_attribute *da, char *buf)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = emc2103_update_device(dev);
	bool fault = (data->temp[nr].degrees == -128);
	return sprintf(buf, "%d\n", fault ? 1 : 0);
}

static ssize_t
temp_min_alarm_show(struct device *dev, struct device_attribute *da,
		    char *buf)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = emc2103_update_device(dev);
	bool alarm = data->temp_min_alarm & (1 << nr);
	return sprintf(buf, "%d\n", alarm ? 1 : 0);
}

static ssize_t
temp_max_alarm_show(struct device *dev, struct device_attribute *da,
		    char *buf)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = emc2103_update_device(dev);
	bool alarm = data->temp_max_alarm & (1 << nr);
	return sprintf(buf, "%d\n", alarm ? 1 : 0);
}

static ssize_t temp_min_store(struct device *dev, struct device_attribute *da,
			      const char *buf, size_t count)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	long val;

	int result = kstrtol(buf, 10, &val);
	if (result < 0)
		return result;

	val = DIV_ROUND_CLOSEST(clamp_val(val, -63000, 127000), 1000);

	mutex_lock(&data->update_lock);
	data->temp_min[nr] = val;
	i2c_smbus_write_byte_data(client, REG_TEMP_MIN[nr], val);
	mutex_unlock(&data->update_lock);

	return count;
}

static ssize_t temp_max_store(struct device *dev, struct device_attribute *da,
			      const char *buf, size_t count)
{
	int nr = to_sensor_dev_attr(da)->index;
	struct emc2103_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	long val;

	int result = kstrtol(buf, 10, &val);
	if (result < 0)
		return result;

	val = DIV_ROUND_CLOSEST(clamp_val(val, -63000, 127000), 1000);

	mutex_lock(&data->update_lock);
	data->temp_max[nr] = val;
	i2c_smbus_write_byte_data(client, REG_TEMP_MAX[nr], val);
	mutex_unlock(&data->update_lock);

	return count;
}

static ssize_t
fan1_input_show(struct device *dev, struct device_attribute *da, char *buf)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	int rpm = 0;
	if (data->fan_tach != 0)
		rpm = (FAN_RPM_FACTOR * data->fan_multiplier) / data->fan_tach;
	return sprintf(buf, "%d\n", rpm);
}

static ssize_t
fan1_div_show(struct device *dev, struct device_attribute *da, char *buf)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	int fan_div = 8 / data->fan_multiplier;
	return sprintf(buf, "%d\n", fan_div);
}

/*
 * Note: we also update the fan target here, because its value is
 * determined in part by the fan clock divider.  This follows the principle
 * of least surprise; the user doesn't expect the fan target to change just
 * because the divider changed.
 */
static ssize_t fan1_div_store(struct device *dev, struct device_attribute *da,
			      const char *buf, size_t count)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	struct i2c_client *client = data->client;
	int new_range_bits, old_div = 8 / data->fan_multiplier;
	long new_div;

	int status = kstrtol(buf, 10, &new_div);
	if (status < 0)
		return status;

	if (new_div == old_div) /* No change */
		return count;

	switch (new_div) {
	case 1:
		new_range_bits = 3;
		break;
	case 2:
		new_range_bits = 2;
		break;
	case 4:
		new_range_bits = 1;
		break;
	case 8:
		new_range_bits = 0;
		break;
	default:
		return -EINVAL;
	}

	mutex_lock(&data->update_lock);

	status = i2c_smbus_read_byte_data(client, REG_FAN_CONF1);
	if (status < 0) {
		dev_dbg(&client->dev, "reg 0x%02x, err %d\n",
			REG_FAN_CONF1, status);
		mutex_unlock(&data->update_lock);
		return status;
	}
	status &= 0x9F;
	status |= (new_range_bits << 5);
	i2c_smbus_write_byte_data(client, REG_FAN_CONF1, status);

	data->fan_multiplier = 8 / new_div;

	/* update fan target if high byte is not disabled */
	if ((data->fan_target & 0x1fe0) != 0x1fe0) {
		u16 new_target = (data->fan_target * old_div) / new_div;
		data->fan_target = min(new_target, (u16)0x1fff);
		write_fan_target_to_i2c(client, data->fan_target);
	}

	/* invalidate data to force re-read from hardware */
	data->valid = false;

	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t
fan1_target_show(struct device *dev, struct device_attribute *da, char *buf)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	int rpm = 0;

	/* high byte of 0xff indicates disabled so return 0 */
	if ((data->fan_target != 0) && ((data->fan_target & 0x1fe0) != 0x1fe0))
		rpm = (FAN_RPM_FACTOR * data->fan_multiplier)
			/ data->fan_target;

	return sprintf(buf, "%d\n", rpm);
}

static ssize_t fan1_target_store(struct device *dev,
				 struct device_attribute *da, const char *buf,
				 size_t count)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	struct i2c_client *client = data->client;
	unsigned long rpm_target;

	int result = kstrtoul(buf, 10, &rpm_target);
	if (result < 0)
		return result;

	/* Datasheet states 16384 as maximum RPM target (table 3.2) */
	rpm_target = clamp_val(rpm_target, 0, 16384);

	mutex_lock(&data->update_lock);

	if (rpm_target == 0)
		data->fan_target = 0x1fff;
	else
		data->fan_target = clamp_val(
			(FAN_RPM_FACTOR * data->fan_multiplier) / rpm_target,
			0, 0x1fff);

	write_fan_target_to_i2c(client, data->fan_target);

	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t
fan1_fault_show(struct device *dev, struct device_attribute *da, char *buf)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	bool fault = ((data->fan_tach & 0x1fe0) == 0x1fe0);
	return sprintf(buf, "%d\n", fault ? 1 : 0);
}

static ssize_t
pwm1_enable_show(struct device *dev, struct device_attribute *da, char *buf)
{
	struct emc2103_data *data = emc2103_update_device(dev);
	return sprintf(buf, "%d\n", data->fan_rpm_control ? 3 : 0);
}

static ssize_t pwm1_enable_store(struct device *dev,
				 struct device_attribute *da, const char *buf,
				 size_t count)
{
	struct emc2103_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	long new_value;
	u8 conf_reg;

	int result = kstrtol(buf, 10, &new_value);
	if (result < 0)
		return result;

	mutex_lock(&data->update_lock);
	switch (new_value) {
	case 0:
		data->fan_rpm_control = false;
		break;
	case 3:
		data->fan_rpm_control = true;
		break;
	default:
		count = -EINVAL;
		goto err;
	}

	result = read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg);
	if (result < 0) {
		count = result;
		goto err;
	}

	if (data->fan_rpm_control)
		conf_reg |= 0x80;
	else
		conf_reg &= ~0x80;

	i2c_smbus_write_byte_data(client, REG_FAN_CONF1, conf_reg);
err:
	mutex_unlock(&data->update_lock);
	return count;
}

static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
static SENSOR_DEVICE_ATTR_RW(temp1_min, temp_min, 0);
static SENSOR_DEVICE_ATTR_RW(temp1_max, temp_max, 0);
static SENSOR_DEVICE_ATTR_RO(temp1_fault, temp_fault, 0);
static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, temp_min_alarm, 0);
static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, temp_max_alarm, 0);

static SENSOR_DEVICE_ATTR_RO(temp2_input, temp, 1);
static SENSOR_DEVICE_ATTR_RW(temp2_min, temp_min, 1);
static SENSOR_DEVICE_ATTR_RW(temp2_max, temp_max, 1);
static SENSOR_DEVICE_ATTR_RO(temp2_fault, temp_fault, 1);
static SENSOR_DEVICE_ATTR_RO(temp2_min_alarm, temp_min_alarm, 1);
static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, temp_max_alarm, 1);

static SENSOR_DEVICE_ATTR_RO(temp3_input, temp, 2);
static SENSOR_DEVICE_ATTR_RW(temp3_min, temp_min, 2);
static SENSOR_DEVICE_ATTR_RW(temp3_max, temp_max, 2);
static SENSOR_DEVICE_ATTR_RO(temp3_fault, temp_fault, 2);
static SENSOR_DEVICE_ATTR_RO(temp3_min_alarm, temp_min_alarm, 2);
static SENSOR_DEVICE_ATTR_RO(temp3_max_alarm, temp_max_alarm, 2);

static SENSOR_DEVICE_ATTR_RO(temp4_input, temp, 3);
static SENSOR_DEVICE_ATTR_RW(temp4_min, temp_min, 3);
static SENSOR_DEVICE_ATTR_RW(temp4_max, temp_max, 3);
static SENSOR_DEVICE_ATTR_RO(temp4_fault, temp_fault, 3);
static SENSOR_DEVICE_ATTR_RO(temp4_min_alarm, temp_min_alarm, 3);
static SENSOR_DEVICE_ATTR_RO(temp4_max_alarm, temp_max_alarm, 3);

static DEVICE_ATTR_RO(fan1_input);
static DEVICE_ATTR_RW(fan1_div);
static DEVICE_ATTR_RW(fan1_target);
static DEVICE_ATTR_RO(fan1_fault);

static DEVICE_ATTR_RW(pwm1_enable);

/* sensors present on all models */
static struct attribute *emc2103_attributes[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_fault.dev_attr.attr,
	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp2_input.dev_attr.attr,
	&sensor_dev_attr_temp2_min.dev_attr.attr,
	&sensor_dev_attr_temp2_max.dev_attr.attr,
	&sensor_dev_attr_temp2_fault.dev_attr.attr,
	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
	&dev_attr_fan1_input.attr,
	&dev_attr_fan1_div.attr,
	&dev_attr_fan1_target.attr,
	&dev_attr_fan1_fault.attr,
	&dev_attr_pwm1_enable.attr,
	NULL
};

/* extra temperature sensors only present on 2103-2 and 2103-4 */
static struct attribute *emc2103_attributes_temp3[] = {
	&sensor_dev_attr_temp3_input.dev_attr.attr,
	&sensor_dev_attr_temp3_min.dev_attr.attr,
	&sensor_dev_attr_temp3_max.dev_attr.attr,
	&sensor_dev_attr_temp3_fault.dev_attr.attr,
	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
	NULL
};

/* extra temperature sensors only present on 2103-2 and 2103-4 in APD mode */
static struct attribute *emc2103_attributes_temp4[] = {
	&sensor_dev_attr_temp4_input.dev_attr.attr,
	&sensor_dev_attr_temp4_min.dev_attr.attr,
	&sensor_dev_attr_temp4_max.dev_attr.attr,
	&sensor_dev_attr_temp4_fault.dev_attr.attr,
	&sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
	NULL
};

static const struct attribute_group emc2103_group = {
	.attrs = emc2103_attributes,
};

static const struct attribute_group emc2103_temp3_group = {
	.attrs = emc2103_attributes_temp3,
};

static const struct attribute_group emc2103_temp4_group = {
	.attrs = emc2103_attributes_temp4,
};

static int
emc2103_probe(struct i2c_client *client)
{
	struct emc2103_data *data;
	struct device *hwmon_dev;
	int status, idx = 0;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -EIO;

	data = devm_kzalloc(&client->dev, sizeof(struct emc2103_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);
	data->client = client;
	mutex_init(&data->update_lock);

	/* 2103-2 and 2103-4 have 3 external diodes, 2103-1 has 1 */
	status = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
	if (status == 0x24) {
		/* 2103-1 only has 1 external diode */
		data->temp_count = 2;
	} else {
		/* 2103-2 and 2103-4 have 3 or 4 external diodes */
		status = i2c_smbus_read_byte_data(client, REG_CONF1);
		if (status < 0) {
			dev_dbg(&client->dev, "reg 0x%02x, err %d\n", REG_CONF1,
				status);
			return status;
		}

		/* detect current state of hardware */
		data->temp_count = (status & 0x01) ? 4 : 3;

		/* force APD state if module parameter is set */
		if (apd == 0) {
			/* force APD mode off */
			data->temp_count = 3;
			status &= ~(0x01);
			i2c_smbus_write_byte_data(client, REG_CONF1, status);
		} else if (apd == 1) {
			/* force APD mode on */
			data->temp_count = 4;
			status |= 0x01;
			i2c_smbus_write_byte_data(client, REG_CONF1, status);
		}
	}

	/* sysfs hooks */
	data->groups[idx++] = &emc2103_group;
	if (data->temp_count >= 3)
		data->groups[idx++] = &emc2103_temp3_group;
	if (data->temp_count == 4)
		data->groups[idx++] = &emc2103_temp4_group;

	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
							   client->name, data,
							   data->groups);
	if (IS_ERR(hwmon_dev))
		return PTR_ERR(hwmon_dev);

	dev_info(&client->dev, "%s: sensor '%s'\n",
		 dev_name(hwmon_dev), client->name);

	return 0;
}

static const struct i2c_device_id emc2103_ids[] = {
	{ "emc2103" },
	{ /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, emc2103_ids);

/* Return 0 if detection is successful, -ENODEV otherwise */
static int
emc2103_detect(struct i2c_client *new_client, struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = new_client->adapter;
	int manufacturer, product;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -ENODEV;

	manufacturer = i2c_smbus_read_byte_data(new_client, REG_MFG_ID);
	if (manufacturer != 0x5D)
		return -ENODEV;

	product = i2c_smbus_read_byte_data(new_client, REG_PRODUCT_ID);
	if ((product != 0x24) && (product != 0x26))
		return -ENODEV;

	strscpy(info->type, "emc2103", I2C_NAME_SIZE);

	return 0;
}

static struct i2c_driver emc2103_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "emc2103",
	},
	.probe		= emc2103_probe,
	.id_table	= emc2103_ids,
	.detect		= emc2103_detect,
	.address_list	= normal_i2c,
};

module_i2c_driver(emc2103_driver);

MODULE_AUTHOR("Steve Glendinning <steve.glendinning@shawell.net>");
MODULE_DESCRIPTION("SMSC EMC2103 hwmon driver");
MODULE_LICENSE("GPL");