aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/ltc2945.c
blob: 45b87a863cae45222523f0569585cf3617518c70 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for Linear Technology LTC2945 I2C Power Monitor
 *
 * Copyright (c) 2014 Guenter Roeck
 */

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

/* chip registers */
#define LTC2945_CONTROL			0x00
#define LTC2945_ALERT			0x01
#define LTC2945_STATUS			0x02
#define LTC2945_FAULT			0x03
#define LTC2945_POWER_H			0x05
#define LTC2945_MAX_POWER_H		0x08
#define LTC2945_MIN_POWER_H		0x0b
#define LTC2945_MAX_POWER_THRES_H	0x0e
#define LTC2945_MIN_POWER_THRES_H	0x11
#define LTC2945_SENSE_H			0x14
#define LTC2945_MAX_SENSE_H		0x16
#define LTC2945_MIN_SENSE_H		0x18
#define LTC2945_MAX_SENSE_THRES_H	0x1a
#define LTC2945_MIN_SENSE_THRES_H	0x1c
#define LTC2945_VIN_H			0x1e
#define LTC2945_MAX_VIN_H		0x20
#define LTC2945_MIN_VIN_H		0x22
#define LTC2945_MAX_VIN_THRES_H		0x24
#define LTC2945_MIN_VIN_THRES_H		0x26
#define LTC2945_ADIN_H			0x28
#define LTC2945_MAX_ADIN_H		0x2a
#define LTC2945_MIN_ADIN_H		0x2c
#define LTC2945_MAX_ADIN_THRES_H	0x2e
#define LTC2945_MIN_ADIN_THRES_H	0x30
#define LTC2945_MIN_ADIN_THRES_L	0x31

/* Fault register bits */

#define FAULT_ADIN_UV		(1 << 0)
#define FAULT_ADIN_OV		(1 << 1)
#define FAULT_VIN_UV		(1 << 2)
#define FAULT_VIN_OV		(1 << 3)
#define FAULT_SENSE_UV		(1 << 4)
#define FAULT_SENSE_OV		(1 << 5)
#define FAULT_POWER_UV		(1 << 6)
#define FAULT_POWER_OV		(1 << 7)

/* Control register bits */

#define CONTROL_MULT_SELECT	(1 << 0)
#define CONTROL_TEST_MODE	(1 << 4)

static const struct of_device_id __maybe_unused ltc2945_of_match[] = {
	{ .compatible = "adi,ltc2945" },
	{ }
};
MODULE_DEVICE_TABLE(of, ltc2945_of_match);

/**
 * struct ltc2945_data - LTC2945 device data
 * @regmap: regmap device
 * @shunt_resistor: shunt resistor value in micro ohms (1000 by default)
 */
struct ltc2945_data {
	struct regmap *regmap;
	u32 shunt_resistor;
};

static inline bool is_power_reg(u8 reg)
{
	return reg < LTC2945_SENSE_H;
}

/* Return the value from the given register in uW, mV, or mA */
static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
{
	struct ltc2945_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u32 shunt_resistor = data->shunt_resistor;
	unsigned int control;
	u8 buf[3];
	long long val;
	int ret;

	ret = regmap_bulk_read(regmap, reg, buf,
			       is_power_reg(reg) ? 3 : 2);
	if (ret < 0)
		return ret;

	if (is_power_reg(reg)) {
		/* 24-bit power */
		val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
	} else {
		/* 12-bit current, voltage */
		val = (buf[0] << 4) + (buf[1] >> 4);
	}

	switch (reg) {
	case LTC2945_POWER_H:
	case LTC2945_MAX_POWER_H:
	case LTC2945_MIN_POWER_H:
	case LTC2945_MAX_POWER_THRES_H:
	case LTC2945_MIN_POWER_THRES_H:
		/*
		 * Convert to uW
		 * Control register bit 0 selects if voltage at SENSE+/VDD
		 * or voltage at ADIN is used to measure power.
		 */
		ret = regmap_read(regmap, LTC2945_CONTROL, &control);
		if (ret < 0)
			return ret;
		if (control & CONTROL_MULT_SELECT) {
			/* 25 mV * 25 uV = 0.625 uV resolution. */
			val *= 625LL;
		} else {
			/* 0.5 mV * 25 uV = 0.0125 uV resolution. */
			val = (val * 25LL) >> 1;
		}
		val *= 1000;
		/* Overflow check: Assuming max 24-bit power, val is at most 53 bits right now. */
		val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
		/*
		 * Overflow check: After division, depending on shunt resistor,
		 * val can still be > 32 bits so returning long long makes sense
		 */

		break;
	case LTC2945_VIN_H:
	case LTC2945_MAX_VIN_H:
	case LTC2945_MIN_VIN_H:
	case LTC2945_MAX_VIN_THRES_H:
	case LTC2945_MIN_VIN_THRES_H:
		/* 25 mV resolution. Convert to mV. */
		val *= 25;
		break;
	case LTC2945_ADIN_H:
	case LTC2945_MAX_ADIN_H:
	case LTC2945_MIN_ADIN_THRES_H:
	case LTC2945_MAX_ADIN_THRES_H:
	case LTC2945_MIN_ADIN_H:
		/* 0.5mV resolution. Convert to mV. */
		val = val >> 1;
		break;
	case LTC2945_SENSE_H:
	case LTC2945_MAX_SENSE_H:
	case LTC2945_MIN_SENSE_H:
	case LTC2945_MAX_SENSE_THRES_H:
	case LTC2945_MIN_SENSE_THRES_H:
		/* 25 uV resolution. Convert to mA. */
		val *= 25 * 1000;
		/* Overflow check: Assuming max 12-bit sense, val is at most 27 bits right now */
		val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
		/* Overflow check: After division, <= 27 bits */
		break;
	default:
		return -EINVAL;
	}
	return val;
}

static long long ltc2945_val_to_reg(struct device *dev, u8 reg,
				    unsigned long long val)
{
	struct ltc2945_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u32 shunt_resistor = data->shunt_resistor;
	unsigned int control;
	int ret;

	/* Ensure we don't overflow */
	val = clamp_val(val, 0, U32_MAX);

	switch (reg) {
	case LTC2945_POWER_H:
	case LTC2945_MAX_POWER_H:
	case LTC2945_MIN_POWER_H:
	case LTC2945_MAX_POWER_THRES_H:
	case LTC2945_MIN_POWER_THRES_H:
		/*
		 * Control register bit 0 selects if voltage at SENSE+/VDD
		 * or voltage at ADIN is used to measure power, which in turn
		 * determines register calculations.
		 */
		ret = regmap_read(regmap, LTC2945_CONTROL, &control);
		if (ret < 0)
			return ret;
		if (control & CONTROL_MULT_SELECT) {
			/* 25 mV * 25 uV = 0.625 uV resolution. */
			val *= shunt_resistor;
			/* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
			val = DIV_ROUND_CLOSEST_ULL(val, 625 * 1000);
			/* Overflow check: val is now <= 44 bits */
		} else {
			/* 0.5 mV * 25 uV = 0.0125 uV resolution. */
			val *= shunt_resistor;
			/* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
			val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000) * 2;
			/* Overflow check: val is now <= 51 bits */
		}
		break;
	case LTC2945_VIN_H:
	case LTC2945_MAX_VIN_H:
	case LTC2945_MIN_VIN_H:
	case LTC2945_MAX_VIN_THRES_H:
	case LTC2945_MIN_VIN_THRES_H:
		/* 25 mV resolution. */
		val = DIV_ROUND_CLOSEST_ULL(val, 25);
		break;
	case LTC2945_ADIN_H:
	case LTC2945_MAX_ADIN_H:
	case LTC2945_MIN_ADIN_THRES_H:
	case LTC2945_MAX_ADIN_THRES_H:
	case LTC2945_MIN_ADIN_H:
		/* 0.5mV resolution. */
		val *= 2;
		break;
	case LTC2945_SENSE_H:
	case LTC2945_MAX_SENSE_H:
	case LTC2945_MIN_SENSE_H:
	case LTC2945_MAX_SENSE_THRES_H:
	case LTC2945_MIN_SENSE_THRES_H:
		/* 25 uV resolution. Convert to  mA. */
		val *= shunt_resistor;
		/* Overflow check: Assuming 32-bit val and 32-bit shunt resistor, val is 64bits */
		val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000);
		/* Overflow check: val is now <= 50 bits */
		break;
	default:
		return -EINVAL;
	}
	return val;
}

static ssize_t ltc2945_value_show(struct device *dev,
				  struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	long long value;

	value = ltc2945_reg_to_val(dev, attr->index);
	if (value < 0)
		return value;
	return sysfs_emit(buf, "%lld\n", value);
}

static ssize_t ltc2945_value_store(struct device *dev,
				   struct device_attribute *da,
				   const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ltc2945_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u8 reg = attr->index;
	unsigned int val;
	u8 regbuf[3];
	int num_regs;
	long long regval;
	int ret;

	ret = kstrtouint(buf, 10, &val);
	if (ret)
		return ret;

	/* convert to register value, then clamp and write result */
	regval = ltc2945_val_to_reg(dev, reg, val);
	if (regval < 0)
		return regval;
	if (is_power_reg(reg)) {
		regval = clamp_val(regval, 0, 0xffffff);
		regbuf[0] = regval >> 16;
		regbuf[1] = (regval >> 8) & 0xff;
		regbuf[2] = regval;
		num_regs = 3;
	} else {
		regval = clamp_val(regval, 0, 0xfff) << 4;
		regbuf[0] = regval >> 8;
		regbuf[1] = regval & 0xff;
		num_regs = 2;
	}
	ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
	return ret < 0 ? ret : count;
}

static ssize_t ltc2945_history_store(struct device *dev,
				     struct device_attribute *da,
				     const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ltc2945_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u8 reg = attr->index;
	int num_regs = is_power_reg(reg) ? 3 : 2;
	u8 buf_min[3] = { 0xff, 0xff, 0xff };
	u8 buf_max[3] = { 0, 0, 0 };
	unsigned long val;
	int ret;

	ret = kstrtoul(buf, 10, &val);
	if (ret)
		return ret;
	if (val != 1)
		return -EINVAL;

	ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
				 CONTROL_TEST_MODE);

	/* Reset minimum */
	ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
	if (ret)
		return ret;

	switch (reg) {
	case LTC2945_MIN_POWER_H:
		reg = LTC2945_MAX_POWER_H;
		break;
	case LTC2945_MIN_SENSE_H:
		reg = LTC2945_MAX_SENSE_H;
		break;
	case LTC2945_MIN_VIN_H:
		reg = LTC2945_MAX_VIN_H;
		break;
	case LTC2945_MIN_ADIN_H:
		reg = LTC2945_MAX_ADIN_H;
		break;
	default:
		WARN_ONCE(1, "Bad register: 0x%x\n", reg);
		return -EINVAL;
	}
	/* Reset maximum */
	ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);

	/* Try resetting test mode even if there was an error */
	regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);

	return ret ? : count;
}

static ssize_t ltc2945_bool_show(struct device *dev,
				 struct device_attribute *da, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ltc2945_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	unsigned int fault;
	int ret;

	ret = regmap_read(regmap, LTC2945_FAULT, &fault);
	if (ret < 0)
		return ret;

	fault &= attr->index;
	if (fault)		/* Clear reported faults in chip register */
		regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);

	return sysfs_emit(buf, "%d\n", !!fault);
}

/* Input voltages */

static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H);
static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H);
static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H);
static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H);
static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H);
static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history,
			     LTC2945_MIN_VIN_H);

static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H);
static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H);
static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H);
static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H);
static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H);
static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history,
			     LTC2945_MIN_ADIN_H);

/* Voltage alarms */

static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV);
static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV);
static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV);
static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV);

/* Currents (via sense resistor) */

static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H);
static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value,
			     LTC2945_MIN_SENSE_THRES_H);
static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value,
			     LTC2945_MAX_SENSE_THRES_H);
static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H);
static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value,
			     LTC2945_MAX_SENSE_H);
static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history,
			     LTC2945_MIN_SENSE_H);

/* Current alarms */

static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV);
static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV);

/* Power */

static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H);
static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value,
			     LTC2945_MIN_POWER_THRES_H);
static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value,
			     LTC2945_MAX_POWER_THRES_H);
static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value,
			     LTC2945_MIN_POWER_H);
static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value,
			     LTC2945_MAX_POWER_H);
static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history,
			     LTC2945_MIN_POWER_H);

/* Power alarms */

static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV);
static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV);

static struct attribute *ltc2945_attrs[] = {
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in1_min.dev_attr.attr,
	&sensor_dev_attr_in1_max.dev_attr.attr,
	&sensor_dev_attr_in1_lowest.dev_attr.attr,
	&sensor_dev_attr_in1_highest.dev_attr.attr,
	&sensor_dev_attr_in1_reset_history.dev_attr.attr,
	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,

	&sensor_dev_attr_in2_input.dev_attr.attr,
	&sensor_dev_attr_in2_min.dev_attr.attr,
	&sensor_dev_attr_in2_max.dev_attr.attr,
	&sensor_dev_attr_in2_lowest.dev_attr.attr,
	&sensor_dev_attr_in2_highest.dev_attr.attr,
	&sensor_dev_attr_in2_reset_history.dev_attr.attr,
	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,

	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_curr1_min.dev_attr.attr,
	&sensor_dev_attr_curr1_max.dev_attr.attr,
	&sensor_dev_attr_curr1_lowest.dev_attr.attr,
	&sensor_dev_attr_curr1_highest.dev_attr.attr,
	&sensor_dev_attr_curr1_reset_history.dev_attr.attr,
	&sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,

	&sensor_dev_attr_power1_input.dev_attr.attr,
	&sensor_dev_attr_power1_min.dev_attr.attr,
	&sensor_dev_attr_power1_max.dev_attr.attr,
	&sensor_dev_attr_power1_input_lowest.dev_attr.attr,
	&sensor_dev_attr_power1_input_highest.dev_attr.attr,
	&sensor_dev_attr_power1_reset_history.dev_attr.attr,
	&sensor_dev_attr_power1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_power1_max_alarm.dev_attr.attr,

	NULL,
};
ATTRIBUTE_GROUPS(ltc2945);

static const struct regmap_config ltc2945_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = LTC2945_MIN_ADIN_THRES_L,
};

static int ltc2945_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct regmap *regmap;
	struct ltc2945_data *data;

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

	regmap = devm_regmap_init_i2c(client, &ltc2945_regmap_config);
	if (IS_ERR(regmap)) {
		dev_err(dev, "failed to allocate register map\n");
		return PTR_ERR(regmap);
	}

	data->regmap = regmap;
	if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
				     &data->shunt_resistor))
		data->shunt_resistor = 1000;

	if (data->shunt_resistor == 0)
		return -EINVAL;

	/* Clear faults */
	regmap_write(regmap, LTC2945_FAULT, 0x00);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
							   data,
							   ltc2945_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id ltc2945_id[] = {
	{"ltc2945", 0},
	{ }
};

MODULE_DEVICE_TABLE(i2c, ltc2945_id);

static struct i2c_driver ltc2945_driver = {
	.driver = {
		.name = "ltc2945",
		.of_match_table = of_match_ptr(ltc2945_of_match),
	},
	.probe = ltc2945_probe,
	.id_table = ltc2945_id,
};

module_i2c_driver(ltc2945_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("LTC2945 driver");
MODULE_LICENSE("GPL");