1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /*
3  * LTC2992 - Dual Wide Range Power Monitor
4  *
5  * Copyright 2020 Analog Devices Inc.
6  */
7 
8 #include <linux/bitfield.h>
9 #include <linux/bitops.h>
10 #include <linux/err.h>
11 #include <linux/gpio/driver.h>
12 #include <linux/hwmon.h>
13 #include <linux/i2c.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/property.h>
17 #include <linux/regmap.h>
18 
19 #define LTC2992_CTRLB			0x01
20 #define LTC2992_FAULT1			0x03
21 #define LTC2992_POWER1			0x05
22 #define LTC2992_POWER1_MAX		0x08
23 #define LTC2992_POWER1_MIN		0x0B
24 #define LTC2992_POWER1_MAX_THRESH	0x0E
25 #define LTC2992_POWER1_MIN_THRESH	0x11
26 #define LTC2992_DSENSE1			0x14
27 #define LTC2992_DSENSE1_MAX		0x16
28 #define LTC2992_DSENSE1_MIN		0x18
29 #define LTC2992_DSENSE1_MAX_THRESH	0x1A
30 #define LTC2992_DSENSE1_MIN_THRESH	0x1C
31 #define LTC2992_SENSE1			0x1E
32 #define LTC2992_SENSE1_MAX		0x20
33 #define LTC2992_SENSE1_MIN		0x22
34 #define LTC2992_SENSE1_MAX_THRESH	0x24
35 #define LTC2992_SENSE1_MIN_THRESH	0x26
36 #define LTC2992_G1			0x28
37 #define LTC2992_G1_MAX			0x2A
38 #define LTC2992_G1_MIN			0x2C
39 #define LTC2992_G1_MAX_THRESH		0x2E
40 #define LTC2992_G1_MIN_THRESH		0x30
41 #define LTC2992_FAULT2			0x35
42 #define LTC2992_G2			0x5A
43 #define LTC2992_G2_MAX			0x5C
44 #define LTC2992_G2_MIN			0x5E
45 #define LTC2992_G2_MAX_THRESH		0x60
46 #define LTC2992_G2_MIN_THRESH		0x62
47 #define LTC2992_G3			0x64
48 #define LTC2992_G3_MAX			0x66
49 #define LTC2992_G3_MIN			0x68
50 #define LTC2992_G3_MAX_THRESH		0x6A
51 #define LTC2992_G3_MIN_THRESH		0x6C
52 #define LTC2992_G4			0x6E
53 #define LTC2992_G4_MAX			0x70
54 #define LTC2992_G4_MIN			0x72
55 #define LTC2992_G4_MAX_THRESH		0x74
56 #define LTC2992_G4_MIN_THRESH		0x76
57 #define LTC2992_FAULT3			0x92
58 #define LTC2992_GPIO_STATUS		0x95
59 #define LTC2992_GPIO_IO_CTRL		0x96
60 #define LTC2992_GPIO_CTRL		0x97
61 
62 #define LTC2992_POWER(x)		(LTC2992_POWER1 + ((x) * 0x32))
63 #define LTC2992_POWER_MAX(x)		(LTC2992_POWER1_MAX + ((x) * 0x32))
64 #define LTC2992_POWER_MIN(x)		(LTC2992_POWER1_MIN + ((x) * 0x32))
65 #define LTC2992_POWER_MAX_THRESH(x)	(LTC2992_POWER1_MAX_THRESH + ((x) * 0x32))
66 #define LTC2992_POWER_MIN_THRESH(x)	(LTC2992_POWER1_MIN_THRESH + ((x) * 0x32))
67 #define LTC2992_DSENSE(x)		(LTC2992_DSENSE1 + ((x) * 0x32))
68 #define LTC2992_DSENSE_MAX(x)		(LTC2992_DSENSE1_MAX + ((x) * 0x32))
69 #define LTC2992_DSENSE_MIN(x)		(LTC2992_DSENSE1_MIN + ((x) * 0x32))
70 #define LTC2992_DSENSE_MAX_THRESH(x)	(LTC2992_DSENSE1_MAX_THRESH + ((x) * 0x32))
71 #define LTC2992_DSENSE_MIN_THRESH(x)	(LTC2992_DSENSE1_MIN_THRESH + ((x) * 0x32))
72 #define LTC2992_SENSE(x)		(LTC2992_SENSE1 + ((x) * 0x32))
73 #define LTC2992_SENSE_MAX(x)		(LTC2992_SENSE1_MAX + ((x) * 0x32))
74 #define LTC2992_SENSE_MIN(x)		(LTC2992_SENSE1_MIN + ((x) * 0x32))
75 #define LTC2992_SENSE_MAX_THRESH(x)	(LTC2992_SENSE1_MAX_THRESH + ((x) * 0x32))
76 #define LTC2992_SENSE_MIN_THRESH(x)	(LTC2992_SENSE1_MIN_THRESH + ((x) * 0x32))
77 #define LTC2992_POWER_FAULT(x)		(LTC2992_FAULT1 + ((x) * 0x32))
78 #define LTC2992_SENSE_FAULT(x)		(LTC2992_FAULT1 + ((x) * 0x32))
79 #define LTC2992_DSENSE_FAULT(x)		(LTC2992_FAULT1 + ((x) * 0x32))
80 
81 /* CTRLB register bitfields */
82 #define LTC2992_RESET_HISTORY		BIT(3)
83 
84 /* FAULT1 FAULT2 registers common bitfields */
85 #define LTC2992_POWER_FAULT_MSK(x)	(BIT(6) << (x))
86 #define LTC2992_DSENSE_FAULT_MSK(x)	(BIT(4) << (x))
87 #define LTC2992_SENSE_FAULT_MSK(x)	(BIT(2) << (x))
88 
89 /* FAULT1 bitfields */
90 #define LTC2992_GPIO1_FAULT_MSK(x)	(BIT(0) << (x))
91 
92 /* FAULT2 bitfields */
93 #define LTC2992_GPIO2_FAULT_MSK(x)	(BIT(0) << (x))
94 
95 /* FAULT3 bitfields */
96 #define LTC2992_GPIO3_FAULT_MSK(x)	(BIT(6) << (x))
97 #define LTC2992_GPIO4_FAULT_MSK(x)	(BIT(4) << (x))
98 
99 #define LTC2992_IADC_NANOV_LSB		12500
100 #define LTC2992_VADC_UV_LSB		25000
101 #define LTC2992_VADC_GPIO_UV_LSB	500
102 
103 #define LTC2992_GPIO_NR		4
104 #define LTC2992_GPIO1_BIT	7
105 #define LTC2992_GPIO2_BIT	6
106 #define LTC2992_GPIO3_BIT	0
107 #define LTC2992_GPIO4_BIT	6
108 #define LTC2992_GPIO_BIT(x)	(LTC2992_GPIO_NR - (x) - 1)
109 
110 struct ltc2992_state {
111 	struct i2c_client		*client;
112 	struct gpio_chip		gc;
113 	struct mutex			gpio_mutex; /* lock for gpio access */
114 	const char			*gpio_names[LTC2992_GPIO_NR];
115 	struct regmap			*regmap;
116 	u32				r_sense_uohm[2];
117 };
118 
119 struct ltc2992_gpio_regs {
120 	u8	data;
121 	u8	max;
122 	u8	min;
123 	u8	max_thresh;
124 	u8	min_thresh;
125 	u8	alarm;
126 	u8	min_alarm_msk;
127 	u8	max_alarm_msk;
128 	u8	ctrl;
129 	u8	ctrl_bit;
130 };
131 
132 static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
133 	{
134 		.data = LTC2992_G1,
135 		.max = LTC2992_G1_MAX,
136 		.min = LTC2992_G1_MIN,
137 		.max_thresh = LTC2992_G1_MAX_THRESH,
138 		.min_thresh = LTC2992_G1_MIN_THRESH,
139 		.alarm = LTC2992_FAULT1,
140 		.min_alarm_msk = LTC2992_GPIO1_FAULT_MSK(0),
141 		.max_alarm_msk = LTC2992_GPIO1_FAULT_MSK(1),
142 		.ctrl = LTC2992_GPIO_IO_CTRL,
143 		.ctrl_bit = LTC2992_GPIO1_BIT,
144 	},
145 	{
146 		.data = LTC2992_G2,
147 		.max = LTC2992_G2_MAX,
148 		.min = LTC2992_G2_MIN,
149 		.max_thresh = LTC2992_G2_MAX_THRESH,
150 		.min_thresh = LTC2992_G2_MIN_THRESH,
151 		.alarm = LTC2992_FAULT2,
152 		.min_alarm_msk = LTC2992_GPIO2_FAULT_MSK(0),
153 		.max_alarm_msk = LTC2992_GPIO2_FAULT_MSK(1),
154 		.ctrl = LTC2992_GPIO_IO_CTRL,
155 		.ctrl_bit = LTC2992_GPIO2_BIT,
156 	},
157 	{
158 		.data = LTC2992_G3,
159 		.max = LTC2992_G3_MAX,
160 		.min = LTC2992_G3_MIN,
161 		.max_thresh = LTC2992_G3_MAX_THRESH,
162 		.min_thresh = LTC2992_G3_MIN_THRESH,
163 		.alarm = LTC2992_FAULT3,
164 		.min_alarm_msk = LTC2992_GPIO3_FAULT_MSK(0),
165 		.max_alarm_msk = LTC2992_GPIO3_FAULT_MSK(1),
166 		.ctrl = LTC2992_GPIO_IO_CTRL,
167 		.ctrl_bit = LTC2992_GPIO3_BIT,
168 	},
169 	{
170 		.data = LTC2992_G4,
171 		.max = LTC2992_G4_MAX,
172 		.min = LTC2992_G4_MIN,
173 		.max_thresh = LTC2992_G4_MAX_THRESH,
174 		.min_thresh = LTC2992_G4_MIN_THRESH,
175 		.alarm = LTC2992_FAULT3,
176 		.min_alarm_msk = LTC2992_GPIO4_FAULT_MSK(0),
177 		.max_alarm_msk = LTC2992_GPIO4_FAULT_MSK(1),
178 		.ctrl = LTC2992_GPIO_CTRL,
179 		.ctrl_bit = LTC2992_GPIO4_BIT,
180 	},
181 };
182 
183 static const char *ltc2992_gpio_names[LTC2992_GPIO_NR] = {
184 	"GPIO1", "GPIO2", "GPIO3", "GPIO4",
185 };
186 
187 static int ltc2992_read_reg(struct ltc2992_state *st, u8 addr, const u8 reg_len)
188 {
189 	u8 regvals[4];
190 	int val;
191 	int ret;
192 	int i;
193 
194 	ret = regmap_bulk_read(st->regmap, addr, regvals, reg_len);
195 	if (ret < 0)
196 		return ret;
197 
198 	val = 0;
199 	for (i = 0; i < reg_len; i++)
200 		val |= regvals[reg_len - i - 1] << (i * 8);
201 
202 	return val;
203 }
204 
205 static int ltc2992_write_reg(struct ltc2992_state *st, u8 addr, const u8 reg_len, u32 val)
206 {
207 	u8 regvals[4];
208 	int i;
209 
210 	for (i = 0; i < reg_len; i++)
211 		regvals[reg_len - i - 1] = (val >> (i * 8)) & 0xFF;
212 
213 	return regmap_bulk_write(st->regmap, addr, regvals, reg_len);
214 }
215 
216 static int ltc2992_gpio_get(struct gpio_chip *chip, unsigned int offset)
217 {
218 	struct ltc2992_state *st = gpiochip_get_data(chip);
219 	unsigned long gpio_status;
220 	int reg;
221 
222 	mutex_lock(&st->gpio_mutex);
223 	reg = ltc2992_read_reg(st, LTC2992_GPIO_STATUS, 1);
224 	mutex_unlock(&st->gpio_mutex);
225 
226 	if (reg < 0)
227 		return reg;
228 
229 	gpio_status = reg;
230 
231 	return !test_bit(LTC2992_GPIO_BIT(offset), &gpio_status);
232 }
233 
234 static int ltc2992_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
235 				     unsigned long *bits)
236 {
237 	struct ltc2992_state *st = gpiochip_get_data(chip);
238 	unsigned long gpio_status;
239 	unsigned int gpio_nr;
240 	int reg;
241 
242 	mutex_lock(&st->gpio_mutex);
243 	reg = ltc2992_read_reg(st, LTC2992_GPIO_STATUS, 1);
244 	mutex_unlock(&st->gpio_mutex);
245 
246 	if (reg < 0)
247 		return reg;
248 
249 	gpio_status = reg;
250 
251 	for_each_set_bit(gpio_nr, mask, LTC2992_GPIO_NR) {
252 		if (test_bit(LTC2992_GPIO_BIT(gpio_nr), &gpio_status))
253 			set_bit(gpio_nr, bits);
254 	}
255 
256 	return 0;
257 }
258 
259 static int ltc2992_gpio_set(struct gpio_chip *chip, unsigned int offset,
260 			    int value)
261 {
262 	struct ltc2992_state *st = gpiochip_get_data(chip);
263 	unsigned long gpio_ctrl;
264 	int reg, ret;
265 
266 	mutex_lock(&st->gpio_mutex);
267 	reg = ltc2992_read_reg(st, ltc2992_gpio_addr_map[offset].ctrl, 1);
268 	if (reg < 0) {
269 		mutex_unlock(&st->gpio_mutex);
270 		return reg;
271 	}
272 
273 	gpio_ctrl = reg;
274 	assign_bit(ltc2992_gpio_addr_map[offset].ctrl_bit, &gpio_ctrl, value);
275 
276 	ret = ltc2992_write_reg(st, ltc2992_gpio_addr_map[offset].ctrl, 1,
277 				gpio_ctrl);
278 	mutex_unlock(&st->gpio_mutex);
279 
280 	return ret;
281 }
282 
283 static int ltc2992_gpio_set_multiple(struct gpio_chip *chip, unsigned long *mask,
284 				     unsigned long *bits)
285 {
286 	struct ltc2992_state *st = gpiochip_get_data(chip);
287 	unsigned long gpio_ctrl_io = 0;
288 	unsigned long gpio_ctrl = 0;
289 	unsigned int gpio_nr;
290 	int ret;
291 
292 	for_each_set_bit(gpio_nr, mask, LTC2992_GPIO_NR) {
293 		if (gpio_nr < 3)
294 			assign_bit(ltc2992_gpio_addr_map[gpio_nr].ctrl_bit, &gpio_ctrl_io, true);
295 
296 		if (gpio_nr == 3)
297 			assign_bit(ltc2992_gpio_addr_map[gpio_nr].ctrl_bit, &gpio_ctrl, true);
298 	}
299 
300 	mutex_lock(&st->gpio_mutex);
301 	ret = ltc2992_write_reg(st, LTC2992_GPIO_IO_CTRL, 1, gpio_ctrl_io);
302 	if (ret)
303 		goto out;
304 
305 	ret = ltc2992_write_reg(st, LTC2992_GPIO_CTRL, 1, gpio_ctrl);
306 out:
307 	mutex_unlock(&st->gpio_mutex);
308 	return ret;
309 }
310 
311 static int ltc2992_config_gpio(struct ltc2992_state *st)
312 {
313 	const char *name = dev_name(&st->client->dev);
314 	char *gpio_name;
315 	int ret;
316 	int i;
317 
318 	ret = ltc2992_write_reg(st, LTC2992_GPIO_IO_CTRL, 1, 0);
319 	if (ret < 0)
320 		return ret;
321 
322 	mutex_init(&st->gpio_mutex);
323 
324 	for (i = 0; i < ARRAY_SIZE(st->gpio_names); i++) {
325 		gpio_name = devm_kasprintf(&st->client->dev, GFP_KERNEL, "ltc2992-%x-%s",
326 					   st->client->addr, ltc2992_gpio_names[i]);
327 		if (!gpio_name)
328 			return -ENOMEM;
329 
330 		st->gpio_names[i] = gpio_name;
331 	}
332 
333 	st->gc.label = name;
334 	st->gc.parent = &st->client->dev;
335 	st->gc.owner = THIS_MODULE;
336 	st->gc.can_sleep = true;
337 	st->gc.base = -1;
338 	st->gc.names = st->gpio_names;
339 	st->gc.ngpio = ARRAY_SIZE(st->gpio_names);
340 	st->gc.get = ltc2992_gpio_get;
341 	st->gc.get_multiple = ltc2992_gpio_get_multiple;
342 	st->gc.set_rv = ltc2992_gpio_set;
343 	st->gc.set_multiple_rv = ltc2992_gpio_set_multiple;
344 
345 	ret = devm_gpiochip_add_data(&st->client->dev, &st->gc, st);
346 	if (ret)
347 		dev_err(&st->client->dev, "GPIO registering failed (%d)\n", ret);
348 
349 	return ret;
350 }
351 
352 static umode_t ltc2992_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
353 				  int channel)
354 {
355 	const struct ltc2992_state *st = data;
356 
357 	switch (type) {
358 	case hwmon_chip:
359 		switch (attr) {
360 		case hwmon_chip_in_reset_history:
361 			return 0200;
362 		}
363 		break;
364 	case hwmon_in:
365 		switch (attr) {
366 		case hwmon_in_input:
367 		case hwmon_in_lowest:
368 		case hwmon_in_highest:
369 		case hwmon_in_min_alarm:
370 		case hwmon_in_max_alarm:
371 			return 0444;
372 		case hwmon_in_min:
373 		case hwmon_in_max:
374 			return 0644;
375 		}
376 		break;
377 	case hwmon_curr:
378 		switch (attr) {
379 		case hwmon_curr_input:
380 		case hwmon_curr_lowest:
381 		case hwmon_curr_highest:
382 		case hwmon_curr_min_alarm:
383 		case hwmon_curr_max_alarm:
384 			if (st->r_sense_uohm[channel])
385 				return 0444;
386 			break;
387 		case hwmon_curr_min:
388 		case hwmon_curr_max:
389 			if (st->r_sense_uohm[channel])
390 				return 0644;
391 			break;
392 		}
393 		break;
394 	case hwmon_power:
395 		switch (attr) {
396 		case hwmon_power_input:
397 		case hwmon_power_input_lowest:
398 		case hwmon_power_input_highest:
399 		case hwmon_power_min_alarm:
400 		case hwmon_power_max_alarm:
401 			if (st->r_sense_uohm[channel])
402 				return 0444;
403 			break;
404 		case hwmon_power_min:
405 		case hwmon_power_max:
406 			if (st->r_sense_uohm[channel])
407 				return 0644;
408 			break;
409 		}
410 		break;
411 	default:
412 		break;
413 	}
414 
415 	return 0;
416 }
417 
418 static int ltc2992_get_voltage(struct ltc2992_state *st, u32 reg, u32 scale, long *val)
419 {
420 	int reg_val;
421 
422 	reg_val = ltc2992_read_reg(st, reg, 2);
423 	if (reg_val < 0)
424 		return reg_val;
425 
426 	reg_val = reg_val >> 4;
427 	*val = DIV_ROUND_CLOSEST(reg_val * scale, 1000);
428 
429 	return 0;
430 }
431 
432 static int ltc2992_set_voltage(struct ltc2992_state *st, u32 reg, u32 scale, long val)
433 {
434 	val = DIV_ROUND_CLOSEST(val * 1000, scale);
435 	val = val << 4;
436 
437 	return ltc2992_write_reg(st, reg, 2, val);
438 }
439 
440 static int ltc2992_read_gpio_alarm(struct ltc2992_state *st, int nr_gpio, u32 attr, long *val)
441 {
442 	int reg_val;
443 	u32 mask;
444 
445 	if (attr == hwmon_in_max_alarm)
446 		mask = ltc2992_gpio_addr_map[nr_gpio].max_alarm_msk;
447 	else
448 		mask = ltc2992_gpio_addr_map[nr_gpio].min_alarm_msk;
449 
450 	reg_val = ltc2992_read_reg(st, ltc2992_gpio_addr_map[nr_gpio].alarm, 1);
451 	if (reg_val < 0)
452 		return reg_val;
453 
454 	*val = !!(reg_val & mask);
455 	reg_val &= ~mask;
456 
457 	return ltc2992_write_reg(st, ltc2992_gpio_addr_map[nr_gpio].alarm, 1, reg_val);
458 }
459 
460 static int ltc2992_read_gpios_in(struct device *dev, u32 attr, int nr_gpio, long *val)
461 {
462 	struct ltc2992_state *st = dev_get_drvdata(dev);
463 	u32 reg;
464 
465 	switch (attr) {
466 	case hwmon_in_input:
467 		reg = ltc2992_gpio_addr_map[nr_gpio].data;
468 		break;
469 	case hwmon_in_lowest:
470 		reg = ltc2992_gpio_addr_map[nr_gpio].min;
471 		break;
472 	case hwmon_in_highest:
473 		reg = ltc2992_gpio_addr_map[nr_gpio].max;
474 		break;
475 	case hwmon_in_min:
476 		reg = ltc2992_gpio_addr_map[nr_gpio].min_thresh;
477 		break;
478 	case hwmon_in_max:
479 		reg = ltc2992_gpio_addr_map[nr_gpio].max_thresh;
480 		break;
481 	case hwmon_in_min_alarm:
482 	case hwmon_in_max_alarm:
483 		return ltc2992_read_gpio_alarm(st, nr_gpio, attr, val);
484 	default:
485 		return -EOPNOTSUPP;
486 	}
487 
488 	return ltc2992_get_voltage(st, reg, LTC2992_VADC_GPIO_UV_LSB, val);
489 }
490 
491 static int ltc2992_read_in_alarm(struct ltc2992_state *st, int channel, long *val, u32 attr)
492 {
493 	int reg_val;
494 	u32 mask;
495 
496 	if (attr == hwmon_in_max_alarm)
497 		mask = LTC2992_SENSE_FAULT_MSK(1);
498 	else
499 		mask = LTC2992_SENSE_FAULT_MSK(0);
500 
501 	reg_val = ltc2992_read_reg(st, LTC2992_SENSE_FAULT(channel), 1);
502 	if (reg_val < 0)
503 		return reg_val;
504 
505 	*val = !!(reg_val & mask);
506 	reg_val &= ~mask;
507 
508 	return ltc2992_write_reg(st, LTC2992_SENSE_FAULT(channel), 1, reg_val);
509 }
510 
511 static int ltc2992_read_in(struct device *dev, u32 attr, int channel, long *val)
512 {
513 	struct ltc2992_state *st = dev_get_drvdata(dev);
514 	u32 reg;
515 
516 	if (channel > 1)
517 		return ltc2992_read_gpios_in(dev, attr, channel - 2, val);
518 
519 	switch (attr) {
520 	case hwmon_in_input:
521 		reg = LTC2992_SENSE(channel);
522 		break;
523 	case hwmon_in_lowest:
524 		reg = LTC2992_SENSE_MIN(channel);
525 		break;
526 	case hwmon_in_highest:
527 		reg = LTC2992_SENSE_MAX(channel);
528 		break;
529 	case hwmon_in_min:
530 		reg = LTC2992_SENSE_MIN_THRESH(channel);
531 		break;
532 	case hwmon_in_max:
533 		reg = LTC2992_SENSE_MAX_THRESH(channel);
534 		break;
535 	case hwmon_in_min_alarm:
536 	case hwmon_in_max_alarm:
537 		return ltc2992_read_in_alarm(st, channel, val, attr);
538 	default:
539 		return -EOPNOTSUPP;
540 	}
541 
542 	return ltc2992_get_voltage(st, reg, LTC2992_VADC_UV_LSB, val);
543 }
544 
545 static int ltc2992_get_current(struct ltc2992_state *st, u32 reg, u32 channel, long *val)
546 {
547 	int reg_val;
548 
549 	reg_val = ltc2992_read_reg(st, reg, 2);
550 	if (reg_val < 0)
551 		return reg_val;
552 
553 	reg_val = reg_val >> 4;
554 	*val = DIV_ROUND_CLOSEST(reg_val * LTC2992_IADC_NANOV_LSB, st->r_sense_uohm[channel]);
555 
556 	return 0;
557 }
558 
559 static int ltc2992_set_current(struct ltc2992_state *st, u32 reg, u32 channel, long val)
560 {
561 	u32 reg_val;
562 
563 	reg_val = DIV_ROUND_CLOSEST(val * st->r_sense_uohm[channel], LTC2992_IADC_NANOV_LSB);
564 	reg_val = reg_val << 4;
565 
566 	return ltc2992_write_reg(st, reg, 2, reg_val);
567 }
568 
569 static int ltc2992_read_curr_alarm(struct ltc2992_state *st, int channel, long *val, u32 attr)
570 {
571 	int reg_val;
572 	u32 mask;
573 
574 	if (attr == hwmon_curr_max_alarm)
575 		mask = LTC2992_DSENSE_FAULT_MSK(1);
576 	else
577 		mask = LTC2992_DSENSE_FAULT_MSK(0);
578 
579 	reg_val = ltc2992_read_reg(st, LTC2992_DSENSE_FAULT(channel), 1);
580 	if (reg_val < 0)
581 		return reg_val;
582 
583 	*val = !!(reg_val & mask);
584 
585 	reg_val &= ~mask;
586 	return ltc2992_write_reg(st, LTC2992_DSENSE_FAULT(channel), 1, reg_val);
587 }
588 
589 static int ltc2992_read_curr(struct device *dev, u32 attr, int channel, long *val)
590 {
591 	struct ltc2992_state *st = dev_get_drvdata(dev);
592 	u32 reg;
593 
594 	switch (attr) {
595 	case hwmon_curr_input:
596 		reg = LTC2992_DSENSE(channel);
597 		break;
598 	case hwmon_curr_lowest:
599 		reg = LTC2992_DSENSE_MIN(channel);
600 		break;
601 	case hwmon_curr_highest:
602 		reg = LTC2992_DSENSE_MAX(channel);
603 		break;
604 	case hwmon_curr_min:
605 		reg = LTC2992_DSENSE_MIN_THRESH(channel);
606 		break;
607 	case hwmon_curr_max:
608 		reg = LTC2992_DSENSE_MAX_THRESH(channel);
609 		break;
610 	case hwmon_curr_min_alarm:
611 	case hwmon_curr_max_alarm:
612 		return ltc2992_read_curr_alarm(st, channel, val, attr);
613 	default:
614 		return -EOPNOTSUPP;
615 	}
616 
617 	return ltc2992_get_current(st, reg, channel, val);
618 }
619 
620 static int ltc2992_get_power(struct ltc2992_state *st, u32 reg, u32 channel, long *val)
621 {
622 	int reg_val;
623 
624 	reg_val = ltc2992_read_reg(st, reg, 3);
625 	if (reg_val < 0)
626 		return reg_val;
627 
628 	*val = mul_u64_u32_div(reg_val, LTC2992_VADC_UV_LSB * LTC2992_IADC_NANOV_LSB,
629 			       st->r_sense_uohm[channel] * 1000);
630 
631 	return 0;
632 }
633 
634 static int ltc2992_set_power(struct ltc2992_state *st, u32 reg, u32 channel, long val)
635 {
636 	u32 reg_val;
637 
638 	reg_val = mul_u64_u32_div(val, st->r_sense_uohm[channel] * 1000,
639 				  LTC2992_VADC_UV_LSB * LTC2992_IADC_NANOV_LSB);
640 
641 	return ltc2992_write_reg(st, reg, 3, reg_val);
642 }
643 
644 static int ltc2992_read_power_alarm(struct ltc2992_state *st, int channel, long *val, u32 attr)
645 {
646 	int reg_val;
647 	u32 mask;
648 
649 	if (attr == hwmon_power_max_alarm)
650 		mask = LTC2992_POWER_FAULT_MSK(1);
651 	else
652 		mask = LTC2992_POWER_FAULT_MSK(0);
653 
654 	reg_val = ltc2992_read_reg(st, LTC2992_POWER_FAULT(channel), 1);
655 	if (reg_val < 0)
656 		return reg_val;
657 
658 	*val = !!(reg_val & mask);
659 	reg_val &= ~mask;
660 
661 	return ltc2992_write_reg(st, LTC2992_POWER_FAULT(channel), 1, reg_val);
662 }
663 
664 static int ltc2992_read_power(struct device *dev, u32 attr, int channel, long *val)
665 {
666 	struct ltc2992_state *st = dev_get_drvdata(dev);
667 	u32 reg;
668 
669 	switch (attr) {
670 	case hwmon_power_input:
671 		reg = LTC2992_POWER(channel);
672 		break;
673 	case hwmon_power_input_lowest:
674 		reg = LTC2992_POWER_MIN(channel);
675 		break;
676 	case hwmon_power_input_highest:
677 		reg = LTC2992_POWER_MAX(channel);
678 		break;
679 	case hwmon_power_min:
680 		reg = LTC2992_POWER_MIN_THRESH(channel);
681 		break;
682 	case hwmon_power_max:
683 		reg = LTC2992_POWER_MAX_THRESH(channel);
684 		break;
685 	case hwmon_power_min_alarm:
686 	case hwmon_power_max_alarm:
687 		return ltc2992_read_power_alarm(st, channel, val, attr);
688 	default:
689 		return -EOPNOTSUPP;
690 	}
691 
692 	return ltc2992_get_power(st, reg, channel, val);
693 }
694 
695 static int ltc2992_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
696 			long *val)
697 {
698 	switch (type) {
699 	case hwmon_in:
700 		return ltc2992_read_in(dev, attr, channel, val);
701 	case hwmon_curr:
702 		return ltc2992_read_curr(dev, attr, channel, val);
703 	case hwmon_power:
704 		return ltc2992_read_power(dev, attr, channel, val);
705 	default:
706 		return -EOPNOTSUPP;
707 	}
708 }
709 
710 static int ltc2992_write_curr(struct device *dev, u32 attr, int channel, long val)
711 {
712 	struct ltc2992_state *st = dev_get_drvdata(dev);
713 	u32 reg;
714 
715 	switch (attr) {
716 	case hwmon_curr_min:
717 		reg = LTC2992_DSENSE_MIN_THRESH(channel);
718 		break;
719 	case hwmon_curr_max:
720 		reg = LTC2992_DSENSE_MAX_THRESH(channel);
721 		break;
722 	default:
723 		return -EOPNOTSUPP;
724 	}
725 
726 	return ltc2992_set_current(st, reg, channel, val);
727 }
728 
729 static int ltc2992_write_gpios_in(struct device *dev, u32 attr, int nr_gpio, long val)
730 {
731 	struct ltc2992_state *st = dev_get_drvdata(dev);
732 	u32 reg;
733 
734 	switch (attr) {
735 	case hwmon_in_min:
736 		reg = ltc2992_gpio_addr_map[nr_gpio].min_thresh;
737 		break;
738 	case hwmon_in_max:
739 		reg = ltc2992_gpio_addr_map[nr_gpio].max_thresh;
740 		break;
741 	default:
742 		return -EOPNOTSUPP;
743 	}
744 
745 	return ltc2992_set_voltage(st, reg, LTC2992_VADC_GPIO_UV_LSB, val);
746 }
747 
748 static int ltc2992_write_in(struct device *dev, u32 attr, int channel, long val)
749 {
750 	struct ltc2992_state *st = dev_get_drvdata(dev);
751 	u32 reg;
752 
753 	if (channel > 1)
754 		return ltc2992_write_gpios_in(dev, attr, channel - 2, val);
755 
756 	switch (attr) {
757 	case hwmon_in_min:
758 		reg = LTC2992_SENSE_MIN_THRESH(channel);
759 		break;
760 	case hwmon_in_max:
761 		reg = LTC2992_SENSE_MAX_THRESH(channel);
762 		break;
763 	default:
764 		return -EOPNOTSUPP;
765 	}
766 
767 	return ltc2992_set_voltage(st, reg, LTC2992_VADC_UV_LSB, val);
768 }
769 
770 static int ltc2992_write_power(struct device *dev, u32 attr, int channel, long val)
771 {
772 	struct ltc2992_state *st = dev_get_drvdata(dev);
773 	u32 reg;
774 
775 	switch (attr) {
776 	case hwmon_power_min:
777 		reg = LTC2992_POWER_MIN_THRESH(channel);
778 		break;
779 	case hwmon_power_max:
780 		reg = LTC2992_POWER_MAX_THRESH(channel);
781 		break;
782 	default:
783 		return -EOPNOTSUPP;
784 	}
785 
786 	return ltc2992_set_power(st, reg, channel, val);
787 }
788 
789 static int ltc2992_write_chip(struct device *dev, u32 attr, int channel, long val)
790 {
791 	struct ltc2992_state *st = dev_get_drvdata(dev);
792 
793 	switch (attr) {
794 	case hwmon_chip_in_reset_history:
795 		return regmap_update_bits(st->regmap, LTC2992_CTRLB, LTC2992_RESET_HISTORY,
796 					  LTC2992_RESET_HISTORY);
797 	default:
798 		return -EOPNOTSUPP;
799 	}
800 }
801 
802 static int ltc2992_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
803 			 long val)
804 {
805 	switch (type) {
806 	case hwmon_chip:
807 		return ltc2992_write_chip(dev, attr, channel, val);
808 	case hwmon_in:
809 		return ltc2992_write_in(dev, attr, channel, val);
810 	case hwmon_curr:
811 		return ltc2992_write_curr(dev, attr, channel, val);
812 	case hwmon_power:
813 		return ltc2992_write_power(dev, attr, channel, val);
814 	default:
815 		return -EOPNOTSUPP;
816 	}
817 }
818 
819 static const struct hwmon_ops ltc2992_hwmon_ops = {
820 	.is_visible = ltc2992_is_visible,
821 	.read = ltc2992_read,
822 	.write = ltc2992_write,
823 };
824 
825 static const struct hwmon_channel_info * const ltc2992_info[] = {
826 	HWMON_CHANNEL_INFO(chip,
827 			   HWMON_C_IN_RESET_HISTORY),
828 	HWMON_CHANNEL_INFO(in,
829 			   HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN |
830 			   HWMON_I_MAX | HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
831 			   HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN |
832 			   HWMON_I_MAX | HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
833 			   HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN |
834 			   HWMON_I_MAX | HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
835 			   HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN |
836 			   HWMON_I_MAX | HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
837 			   HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN |
838 			   HWMON_I_MAX | HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
839 			   HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN |
840 			   HWMON_I_MAX | HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM),
841 	HWMON_CHANNEL_INFO(curr,
842 			   HWMON_C_INPUT | HWMON_C_LOWEST | HWMON_C_HIGHEST | HWMON_C_MIN |
843 			   HWMON_C_MAX | HWMON_C_MIN_ALARM | HWMON_C_MAX_ALARM,
844 			   HWMON_C_INPUT | HWMON_C_LOWEST | HWMON_C_HIGHEST | HWMON_C_MIN |
845 			   HWMON_C_MAX | HWMON_C_MIN_ALARM | HWMON_C_MAX_ALARM),
846 	HWMON_CHANNEL_INFO(power,
847 			   HWMON_P_INPUT | HWMON_P_INPUT_LOWEST | HWMON_P_INPUT_HIGHEST |
848 			   HWMON_P_MIN | HWMON_P_MAX | HWMON_P_MIN_ALARM | HWMON_P_MAX_ALARM,
849 			   HWMON_P_INPUT | HWMON_P_INPUT_LOWEST | HWMON_P_INPUT_HIGHEST |
850 			   HWMON_P_MIN | HWMON_P_MAX | HWMON_P_MIN_ALARM | HWMON_P_MAX_ALARM),
851 	NULL
852 };
853 
854 static const struct hwmon_chip_info ltc2992_chip_info = {
855 	.ops = &ltc2992_hwmon_ops,
856 	.info = ltc2992_info,
857 };
858 
859 static const struct regmap_config ltc2992_regmap_config = {
860 	.reg_bits = 8,
861 	.val_bits = 8,
862 	.max_register = 0xE8,
863 };
864 
865 static int ltc2992_parse_dt(struct ltc2992_state *st)
866 {
867 	u32 addr;
868 	u32 val;
869 	int ret;
870 
871 	device_for_each_child_node_scoped(&st->client->dev, child) {
872 		ret = fwnode_property_read_u32(child, "reg", &addr);
873 		if (ret < 0)
874 			return ret;
875 
876 		if (addr > 1)
877 			return -EINVAL;
878 
879 		ret = fwnode_property_read_u32(child, "shunt-resistor-micro-ohms", &val);
880 		if (!ret) {
881 			if (!val)
882 				return dev_err_probe(&st->client->dev, -EINVAL,
883 						     "shunt resistor value cannot be zero\n");
884 
885 			st->r_sense_uohm[addr] = val;
886 		}
887 	}
888 
889 	return 0;
890 }
891 
892 static int ltc2992_i2c_probe(struct i2c_client *client)
893 {
894 	struct device *hwmon_dev;
895 	struct ltc2992_state *st;
896 	int ret;
897 
898 	st = devm_kzalloc(&client->dev, sizeof(*st), GFP_KERNEL);
899 	if (!st)
900 		return -ENOMEM;
901 
902 	st->client = client;
903 	st->regmap = devm_regmap_init_i2c(client, &ltc2992_regmap_config);
904 	if (IS_ERR(st->regmap))
905 		return PTR_ERR(st->regmap);
906 
907 	ret = ltc2992_parse_dt(st);
908 	if (ret < 0)
909 		return ret;
910 
911 	ret = ltc2992_config_gpio(st);
912 	if (ret < 0)
913 		return ret;
914 
915 	hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, client->name, st,
916 							 &ltc2992_chip_info, NULL);
917 
918 	return PTR_ERR_OR_ZERO(hwmon_dev);
919 }
920 
921 static const struct of_device_id ltc2992_of_match[] = {
922 	{ .compatible = "adi,ltc2992" },
923 	{ }
924 };
925 MODULE_DEVICE_TABLE(of, ltc2992_of_match);
926 
927 static const struct i2c_device_id ltc2992_i2c_id[] = {
928 	{"ltc2992"},
929 	{}
930 };
931 MODULE_DEVICE_TABLE(i2c, ltc2992_i2c_id);
932 
933 static struct i2c_driver ltc2992_i2c_driver = {
934 	.driver = {
935 		.name = "ltc2992",
936 		.of_match_table = ltc2992_of_match,
937 	},
938 	.probe = ltc2992_i2c_probe,
939 	.id_table = ltc2992_i2c_id,
940 };
941 
942 module_i2c_driver(ltc2992_i2c_driver);
943 
944 MODULE_AUTHOR("Alexandru Tachici <alexandru.tachici@analog.com>");
945 MODULE_DESCRIPTION("Hwmon driver for Linear Technology 2992");
946 MODULE_LICENSE("Dual BSD/GPL");
947