aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/max6620.c
blob: 202b6438179d1fe3f745c3b9796ff2eb7fb2462f (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for Maxim MAX6620
 *
 * Originally from L. Grunenberg.
 * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de>
 *
 * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved.
 *
 * based on code written by :
 * 2007 by Hans J. Koch <hjk@hansjkoch.de>
 * John Morris <john.morris@spirentcom.com>
 * Copyright (c) 2003 Spirent Communications
 * and Claus Gindhart <claus.gindhart@kontron.com>
 *
 * This module has only been tested with the MAX6620 chip.
 *
 * The datasheet was last seen at:
 *
 *        http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
 *
 */

#include <linux/bits.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/slab.h>

/*
 * MAX 6620 registers
 */

#define MAX6620_REG_CONFIG	0x00
#define MAX6620_REG_FAULT	0x01
#define MAX6620_REG_CONF_FAN0	0x02
#define MAX6620_REG_CONF_FAN1	0x03
#define MAX6620_REG_CONF_FAN2	0x04
#define MAX6620_REG_CONF_FAN3	0x05
#define MAX6620_REG_DYN_FAN0	0x06
#define MAX6620_REG_DYN_FAN1	0x07
#define MAX6620_REG_DYN_FAN2	0x08
#define MAX6620_REG_DYN_FAN3	0x09
#define MAX6620_REG_TACH0	0x10
#define MAX6620_REG_TACH1	0x12
#define MAX6620_REG_TACH2	0x14
#define MAX6620_REG_TACH3	0x16
#define MAX6620_REG_VOLT0	0x18
#define MAX6620_REG_VOLT1	0x1A
#define MAX6620_REG_VOLT2	0x1C
#define MAX6620_REG_VOLT3	0x1E
#define MAX6620_REG_TAR0	0x20
#define MAX6620_REG_TAR1	0x22
#define MAX6620_REG_TAR2	0x24
#define MAX6620_REG_TAR3	0x26
#define MAX6620_REG_DAC0	0x28
#define MAX6620_REG_DAC1	0x2A
#define MAX6620_REG_DAC2	0x2C
#define MAX6620_REG_DAC3	0x2E

/*
 * Config register bits
 */

#define MAX6620_CFG_RUN		BIT(7)
#define MAX6620_CFG_POR		BIT(6)
#define MAX6620_CFG_TIMEOUT	BIT(5)
#define MAX6620_CFG_FULLFAN	BIT(4)
#define MAX6620_CFG_OSC		BIT(3)
#define MAX6620_CFG_WD_MASK	(BIT(2) | BIT(1))
#define MAX6620_CFG_WD_2	BIT(1)
#define MAX6620_CFG_WD_6	BIT(2)
#define MAX6620_CFG_WD10	(BIT(2) | BIT(1))
#define MAX6620_CFG_WD		BIT(0)

/*
 * Failure status register bits
 */

#define MAX6620_FAIL_TACH0	BIT(4)
#define MAX6620_FAIL_TACH1	BIT(5)
#define MAX6620_FAIL_TACH2	BIT(6)
#define MAX6620_FAIL_TACH3	BIT(7)
#define MAX6620_FAIL_MASK0	BIT(0)
#define MAX6620_FAIL_MASK1	BIT(1)
#define MAX6620_FAIL_MASK2	BIT(2)
#define MAX6620_FAIL_MASK3	BIT(3)

#define MAX6620_CLOCK_FREQ	8192 /* Clock frequency in Hz */
#define MAX6620_PULSE_PER_REV	2 /* Tachometer pulses per revolution */

/* Minimum and maximum values of the FAN-RPM */
#define FAN_RPM_MIN	240
#define FAN_RPM_MAX	30000

static const u8 config_reg[] = {
	MAX6620_REG_CONF_FAN0,
	MAX6620_REG_CONF_FAN1,
	MAX6620_REG_CONF_FAN2,
	MAX6620_REG_CONF_FAN3,
};

static const u8 dyn_reg[] = {
	MAX6620_REG_DYN_FAN0,
	MAX6620_REG_DYN_FAN1,
	MAX6620_REG_DYN_FAN2,
	MAX6620_REG_DYN_FAN3,
};

static const u8 tach_reg[] = {
	MAX6620_REG_TACH0,
	MAX6620_REG_TACH1,
	MAX6620_REG_TACH2,
	MAX6620_REG_TACH3,
};

static const u8 target_reg[] = {
	MAX6620_REG_TAR0,
	MAX6620_REG_TAR1,
	MAX6620_REG_TAR2,
	MAX6620_REG_TAR3,
};

/*
 * Client data (each client gets its own)
 */

struct max6620_data {
	struct i2c_client *client;
	struct mutex update_lock;
	bool valid; /* false until following fields are valid */
	unsigned long last_updated; /* in jiffies */

	/* register values */
	u8 fancfg[4];
	u8 fandyn[4];
	u8 fault;
	u16 tach[4];
	u16 target[4];
};

static u8 max6620_fan_div_from_reg(u8 val)
{
	return BIT((val & 0xE0) >> 5);
}

static u16 max6620_fan_rpm_to_tach(u8 div, int rpm)
{
	return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV);
}

static int max6620_fan_tach_to_rpm(u8 div, u16 tach)
{
	return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV);
}

static int max6620_update_device(struct device *dev)
{
	struct max6620_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int i;
	int ret = 0;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
		for (i = 0; i < 4; i++) {
			ret = i2c_smbus_read_byte_data(client, config_reg[i]);
			if (ret < 0)
				goto error;
			data->fancfg[i] = ret;

			ret = i2c_smbus_read_byte_data(client, dyn_reg[i]);
			if (ret < 0)
				goto error;
			data->fandyn[i] = ret;

			ret = i2c_smbus_read_byte_data(client, tach_reg[i]);
			if (ret < 0)
				goto error;
			data->tach[i] = (ret << 3) & 0x7f8;
			ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1);
			if (ret < 0)
				goto error;
			data->tach[i] |= (ret >> 5) & 0x7;

			ret = i2c_smbus_read_byte_data(client, target_reg[i]);
			if (ret < 0)
				goto error;
			data->target[i] = (ret << 3) & 0x7f8;
			ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1);
			if (ret < 0)
				goto error;
			data->target[i] |= (ret >> 5) & 0x7;
		}

		/*
		 * Alarms are cleared on read in case the condition that
		 * caused the alarm is removed. Keep the value latched here
		 * for providing the register through different alarm files.
		 */
		ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT);
		if (ret < 0)
			goto error;
		data->fault |= (ret >> 4) & (ret & 0x0F);

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

error:
	mutex_unlock(&data->update_lock);
	return ret;
}

static umode_t
max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
		   int channel)
{
	switch (type) {
	case hwmon_fan:
		switch (attr) {
		case hwmon_fan_alarm:
		case hwmon_fan_input:
			return 0444;
		case hwmon_fan_div:
		case hwmon_fan_target:
			return 0644;
		default:
			break;
		}
		break;
	default:
		break;
	}

	return 0;
}

static int
max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
	     int channel, long *val)
{
	struct max6620_data *data;
	struct i2c_client *client;
	int ret;
	u8 div;
	u8 val1;
	u8 val2;

	ret = max6620_update_device(dev);
	if (ret < 0)
		return ret;
	data = dev_get_drvdata(dev);
	client = data->client;

	switch (type) {
	case hwmon_fan:
		switch (attr) {
		case hwmon_fan_alarm:
			mutex_lock(&data->update_lock);
			*val = !!(data->fault & BIT(channel));

			/* Setting TACH count to re-enable fan fault detection */
			if (*val == 1) {
				val1 = (data->target[channel] >> 3) & 0xff;
				val2 = (data->target[channel] << 5) & 0xe0;
				ret = i2c_smbus_write_byte_data(client,
								target_reg[channel], val1);
				if (ret < 0) {
					mutex_unlock(&data->update_lock);
					return ret;
				}
				ret = i2c_smbus_write_byte_data(client,
								target_reg[channel] + 1, val2);
				if (ret < 0) {
					mutex_unlock(&data->update_lock);
					return ret;
				}

				data->fault &= ~BIT(channel);
			}
			mutex_unlock(&data->update_lock);

			break;
		case hwmon_fan_div:
			*val = max6620_fan_div_from_reg(data->fandyn[channel]);
			break;
		case hwmon_fan_input:
			if (data->tach[channel] == 0) {
				*val = 0;
			} else {
				div = max6620_fan_div_from_reg(data->fandyn[channel]);
				*val = max6620_fan_tach_to_rpm(div, data->tach[channel]);
			}
			break;
		case hwmon_fan_target:
			if (data->target[channel] == 0) {
				*val = 0;
			} else {
				div = max6620_fan_div_from_reg(data->fandyn[channel]);
				*val = max6620_fan_tach_to_rpm(div, data->target[channel]);
			}
			break;
		default:
			return -EOPNOTSUPP;
		}
		break;

	default:
		return -EOPNOTSUPP;
	}

	return 0;
}

static int
max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
	      int channel, long val)
{
	struct max6620_data *data;
	struct i2c_client *client;
	int ret;
	u8 div;
	u16 tach;
	u8 val1;
	u8 val2;

	ret = max6620_update_device(dev);
	if (ret < 0)
		return ret;
	data = dev_get_drvdata(dev);
	client = data->client;
	mutex_lock(&data->update_lock);

	switch (type) {
	case hwmon_fan:
		switch (attr) {
		case hwmon_fan_div:
			switch (val) {
			case 1:
				div = 0;
				break;
			case 2:
				div = 1;
				break;
			case 4:
				div = 2;
				break;
			case 8:
				div = 3;
				break;
			case 16:
				div = 4;
				break;
			case 32:
				div = 5;
				break;
			default:
				ret = -EINVAL;
				goto error;
			}
			data->fandyn[channel] &= 0x1F;
			data->fandyn[channel] |= div << 5;
			ret = i2c_smbus_write_byte_data(client, dyn_reg[channel],
							data->fandyn[channel]);
			break;
		case hwmon_fan_target:
			val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
			div = max6620_fan_div_from_reg(data->fandyn[channel]);
			tach = max6620_fan_rpm_to_tach(div, val);
			val1 = (tach >> 3) & 0xff;
			val2 = (tach << 5) & 0xe0;
			ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1);
			if (ret < 0)
				break;
			ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2);
			if (ret < 0)
				break;

			/* Setting TACH count re-enables fan fault detection */
			data->fault &= ~BIT(channel);

			break;
		default:
			ret = -EOPNOTSUPP;
			break;
		}
		break;

	default:
		ret = -EOPNOTSUPP;
		break;
	}

error:
	mutex_unlock(&data->update_lock);
	return ret;
}

static const struct hwmon_channel_info *max6620_info[] = {
	HWMON_CHANNEL_INFO(fan,
			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM),
	NULL
};

static const struct hwmon_ops max6620_hwmon_ops = {
	.read = max6620_read,
	.write = max6620_write,
	.is_visible = max6620_is_visible,
};

static const struct hwmon_chip_info max6620_chip_info = {
	.ops = &max6620_hwmon_ops,
	.info = max6620_info,
};

static int max6620_init_client(struct max6620_data *data)
{
	struct i2c_client *client = data->client;
	int config;
	int err;
	int i;
	int reg;

	config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG);
	if (config < 0) {
		dev_err(&client->dev, "Error reading config, aborting.\n");
		return config;
	}

	/*
	 * Set bit 4, disable other fans from going full speed on a fail
	 * failure.
	 */
	err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10);
	if (err < 0) {
		dev_err(&client->dev, "Config write error, aborting.\n");
		return err;
	}

	for (i = 0; i < 4; i++) {
		reg = i2c_smbus_read_byte_data(client, config_reg[i]);
		if (reg < 0)
			return reg;
		data->fancfg[i] = reg;

		/* Enable RPM mode */
		data->fancfg[i] |= 0xa8;
		err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
		if (err < 0)
			return err;

		/* 2 counts (001) and Rate change 100 (0.125 secs) */
		data->fandyn[i] = 0x30;
		err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
		if (err < 0)
			return err;
	}
	return 0;
}

static int max6620_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct max6620_data *data;
	struct device *hwmon_dev;
	int err;

	data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

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

	err = max6620_init_client(data);
	if (err)
		return err;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
							 data,
							 &max6620_chip_info,
							 NULL);

	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id max6620_id[] = {
	{ "max6620", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, max6620_id);

static struct i2c_driver max6620_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "max6620",
	},
	.probe_new	= max6620_probe,
	.id_table	= max6620_id,
};

module_i2c_driver(max6620_driver);

MODULE_AUTHOR("Lucas Grunenberg");
MODULE_DESCRIPTION("MAX6620 sensor driver");
MODULE_LICENSE("GPL");