1 // SPDX-License-Identifier: GPL-2.0
2 //
3 //  max17040_battery.c
4 //  fuel-gauge systems for lithium-ion (Li+) batteries
5 //
6 //  Copyright (C) 2009 Samsung Electronics
7 //  Minkyu Kang <mk7.kang@samsung.com>
8 
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/platform_device.h>
12 #include <linux/mutex.h>
13 #include <linux/err.h>
14 #include <linux/i2c.h>
15 #include <linux/delay.h>
16 #include <linux/interrupt.h>
17 #include <linux/power_supply.h>
18 #include <linux/of_device.h>
19 #include <linux/regmap.h>
20 #include <linux/slab.h>
21 
22 #define MAX17040_VCELL	0x02
23 #define MAX17040_SOC	0x04
24 #define MAX17040_MODE	0x06
25 #define MAX17040_VER	0x08
26 #define MAX17040_CONFIG	0x0C
27 #define MAX17040_STATUS	0x1A
28 #define MAX17040_CMD	0xFE
29 
30 
31 #define MAX17040_DELAY		1000
32 #define MAX17040_BATTERY_FULL	95
33 #define MAX17040_RCOMP_DEFAULT  0x9700
34 
35 #define MAX17040_ATHD_MASK		0x3f
36 #define MAX17040_ALSC_MASK		0x40
37 #define MAX17040_ATHD_DEFAULT_POWER_UP	4
38 #define MAX17040_STATUS_HD_MASK		0x1000
39 #define MAX17040_STATUS_SC_MASK		0x2000
40 #define MAX17040_CFG_RCOMP_MASK		0xff00
41 
42 enum chip_id {
43 	ID_MAX17040,
44 	ID_MAX17041,
45 	ID_MAX17043,
46 	ID_MAX17044,
47 	ID_MAX17048,
48 	ID_MAX17049,
49 	ID_MAX17058,
50 	ID_MAX17059,
51 };
52 
53 /* values that differ by chip_id */
54 struct chip_data {
55 	u16 reset_val;
56 	u16 vcell_shift;
57 	u16 vcell_mul;
58 	u16 vcell_div;
59 	u8  has_low_soc_alert;
60 	u8  rcomp_bytes;
61 	u8  has_soc_alert;
62 };
63 
64 static struct chip_data max17040_family[] = {
65 	[ID_MAX17040] = {
66 		.reset_val = 0x0054,
67 		.vcell_shift = 4,
68 		.vcell_mul = 1250,
69 		.vcell_div = 1,
70 		.has_low_soc_alert = 0,
71 		.rcomp_bytes = 2,
72 		.has_soc_alert = 0,
73 	},
74 	[ID_MAX17041] = {
75 		.reset_val = 0x0054,
76 		.vcell_shift = 4,
77 		.vcell_mul = 2500,
78 		.vcell_div = 1,
79 		.has_low_soc_alert = 0,
80 		.rcomp_bytes = 2,
81 		.has_soc_alert = 0,
82 	},
83 	[ID_MAX17043] = {
84 		.reset_val = 0x0054,
85 		.vcell_shift = 4,
86 		.vcell_mul = 1250,
87 		.vcell_div = 1,
88 		.has_low_soc_alert = 1,
89 		.rcomp_bytes = 1,
90 		.has_soc_alert = 0,
91 	},
92 	[ID_MAX17044] = {
93 		.reset_val = 0x0054,
94 		.vcell_shift = 4,
95 		.vcell_mul = 2500,
96 		.vcell_div = 1,
97 		.has_low_soc_alert = 1,
98 		.rcomp_bytes = 1,
99 		.has_soc_alert = 0,
100 	},
101 	[ID_MAX17048] = {
102 		.reset_val = 0x5400,
103 		.vcell_shift = 0,
104 		.vcell_mul = 625,
105 		.vcell_div = 8,
106 		.has_low_soc_alert = 1,
107 		.rcomp_bytes = 1,
108 		.has_soc_alert = 1,
109 	},
110 	[ID_MAX17049] = {
111 		.reset_val = 0x5400,
112 		.vcell_shift = 0,
113 		.vcell_mul = 625,
114 		.vcell_div = 4,
115 		.has_low_soc_alert = 1,
116 		.rcomp_bytes = 1,
117 		.has_soc_alert = 1,
118 	},
119 	[ID_MAX17058] = {
120 		.reset_val = 0x5400,
121 		.vcell_shift = 0,
122 		.vcell_mul = 625,
123 		.vcell_div = 8,
124 		.has_low_soc_alert = 1,
125 		.rcomp_bytes = 1,
126 		.has_soc_alert = 0,
127 	},
128 	[ID_MAX17059] = {
129 		.reset_val = 0x5400,
130 		.vcell_shift = 0,
131 		.vcell_mul = 625,
132 		.vcell_div = 4,
133 		.has_low_soc_alert = 1,
134 		.rcomp_bytes = 1,
135 		.has_soc_alert = 0,
136 	},
137 };
138 
139 struct max17040_chip {
140 	struct i2c_client		*client;
141 	struct regmap			*regmap;
142 	struct delayed_work		work;
143 	struct power_supply		*battery;
144 	struct chip_data		data;
145 
146 	/* battery capacity */
147 	int soc;
148 	/* Low alert threshold from 32% to 1% of the State of Charge */
149 	u32 low_soc_alert;
150 	/* some devices return twice the capacity */
151 	bool quirk_double_soc;
152 	/* higher 8 bits for 17043+, 16 bits for 17040,41 */
153 	u16 rcomp;
154 };
155 
156 static int max17040_reset(struct max17040_chip *chip)
157 {
158 	return regmap_write(chip->regmap, MAX17040_CMD, chip->data.reset_val);
159 }
160 
161 static int max17040_set_low_soc_alert(struct max17040_chip *chip, u32 level)
162 {
163 	level = 32 - level * (chip->quirk_double_soc ? 2 : 1);
164 	return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
165 			MAX17040_ATHD_MASK, level);
166 }
167 
168 static int max17040_set_soc_alert(struct max17040_chip *chip, bool enable)
169 {
170 	return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
171 			MAX17040_ALSC_MASK, enable ? MAX17040_ALSC_MASK : 0);
172 }
173 
174 static int max17040_set_rcomp(struct max17040_chip *chip, u16 rcomp)
175 {
176 	u16 mask = chip->data.rcomp_bytes == 2 ?
177 		0xffff : MAX17040_CFG_RCOMP_MASK;
178 
179 	return regmap_update_bits(chip->regmap, MAX17040_CONFIG, mask, rcomp);
180 }
181 
182 static int max17040_raw_vcell_to_uvolts(struct max17040_chip *chip, u16 vcell)
183 {
184 	struct chip_data *d = &chip->data;
185 
186 	return (vcell >> d->vcell_shift) * d->vcell_mul / d->vcell_div;
187 }
188 
189 
190 static int max17040_get_vcell(struct max17040_chip *chip)
191 {
192 	u32 vcell;
193 
194 	regmap_read(chip->regmap, MAX17040_VCELL, &vcell);
195 
196 	return max17040_raw_vcell_to_uvolts(chip, vcell);
197 }
198 
199 static int max17040_get_soc(struct max17040_chip *chip)
200 {
201 	u32 soc;
202 
203 	regmap_read(chip->regmap, MAX17040_SOC, &soc);
204 
205 	return soc >> (chip->quirk_double_soc ? 9 : 8);
206 }
207 
208 static int max17040_get_version(struct max17040_chip *chip)
209 {
210 	int ret;
211 	u32 version;
212 
213 	ret = regmap_read(chip->regmap, MAX17040_VER, &version);
214 
215 	return ret ? ret : version;
216 }
217 
218 static int max17040_get_online(struct max17040_chip *chip)
219 {
220 	return 1;
221 }
222 
223 static int max17040_get_of_data(struct max17040_chip *chip)
224 {
225 	struct device *dev = &chip->client->dev;
226 	struct chip_data *data = &max17040_family[
227 		(uintptr_t) of_device_get_match_data(dev)];
228 	int rcomp_len;
229 	u8 rcomp[2];
230 
231 	chip->quirk_double_soc = device_property_read_bool(dev,
232 							   "maxim,double-soc");
233 
234 	chip->low_soc_alert = MAX17040_ATHD_DEFAULT_POWER_UP;
235 	device_property_read_u32(dev,
236 				 "maxim,alert-low-soc-level",
237 				 &chip->low_soc_alert);
238 
239 	if (chip->low_soc_alert <= 0 ||
240 	    chip->low_soc_alert > (chip->quirk_double_soc ? 16 : 32)) {
241 		dev_err(dev, "maxim,alert-low-soc-level out of bounds\n");
242 		return -EINVAL;
243 	}
244 
245 	rcomp_len = device_property_count_u8(dev, "maxim,rcomp");
246 	chip->rcomp = MAX17040_RCOMP_DEFAULT;
247 	if (rcomp_len == data->rcomp_bytes) {
248 		if (!device_property_read_u8_array(dev, "maxim,rcomp",
249 						   rcomp, rcomp_len))
250 			chip->rcomp = rcomp_len == 2 ? rcomp[0] << 8 | rcomp[1] :
251 				      rcomp[0] << 8;
252 	} else if (rcomp_len > 0) {
253 		dev_err(dev, "maxim,rcomp has incorrect length\n");
254 		return -EINVAL;
255 	}
256 
257 	return 0;
258 }
259 
260 static void max17040_check_changes(struct max17040_chip *chip)
261 {
262 	chip->soc = max17040_get_soc(chip);
263 }
264 
265 static void max17040_queue_work(struct max17040_chip *chip)
266 {
267 	queue_delayed_work(system_power_efficient_wq, &chip->work,
268 			   MAX17040_DELAY);
269 }
270 
271 static void max17040_stop_work(void *data)
272 {
273 	struct max17040_chip *chip = data;
274 
275 	cancel_delayed_work_sync(&chip->work);
276 }
277 
278 static void max17040_work(struct work_struct *work)
279 {
280 	struct max17040_chip *chip;
281 	int last_soc;
282 
283 	chip = container_of(work, struct max17040_chip, work.work);
284 
285 	/* store SOC to check changes */
286 	last_soc = chip->soc;
287 	max17040_check_changes(chip);
288 
289 	/* check changes and send uevent */
290 	if (last_soc != chip->soc)
291 		power_supply_changed(chip->battery);
292 
293 	max17040_queue_work(chip);
294 }
295 
296 /* Returns true if alert cause was SOC change, not low SOC */
297 static bool max17040_handle_soc_alert(struct max17040_chip *chip)
298 {
299 	bool ret = true;
300 	u32 data;
301 
302 	regmap_read(chip->regmap, MAX17040_STATUS, &data);
303 
304 	if (data & MAX17040_STATUS_HD_MASK) {
305 		// this alert was caused by low soc
306 		ret = false;
307 	}
308 	if (data & MAX17040_STATUS_SC_MASK) {
309 		// soc change bit -- deassert to mark as handled
310 		regmap_write(chip->regmap, MAX17040_STATUS,
311 				data & ~MAX17040_STATUS_SC_MASK);
312 	}
313 
314 	return ret;
315 }
316 
317 static irqreturn_t max17040_thread_handler(int id, void *dev)
318 {
319 	struct max17040_chip *chip = dev;
320 
321 	if (!(chip->data.has_soc_alert && max17040_handle_soc_alert(chip)))
322 		dev_warn(&chip->client->dev, "IRQ: Alert battery low level\n");
323 
324 	/* read registers */
325 	max17040_check_changes(chip);
326 
327 	/* send uevent */
328 	power_supply_changed(chip->battery);
329 
330 	/* reset alert bit */
331 	max17040_set_low_soc_alert(chip, chip->low_soc_alert);
332 
333 	return IRQ_HANDLED;
334 }
335 
336 static int max17040_enable_alert_irq(struct max17040_chip *chip)
337 {
338 	struct i2c_client *client = chip->client;
339 	int ret;
340 
341 	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
342 					max17040_thread_handler, IRQF_ONESHOT,
343 					chip->battery->desc->name, chip);
344 
345 	return ret;
346 }
347 
348 static int max17040_prop_writeable(struct power_supply *psy,
349 				   enum power_supply_property psp)
350 {
351 	switch (psp) {
352 	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
353 		return 1;
354 	default:
355 		return 0;
356 	}
357 }
358 
359 static int max17040_set_property(struct power_supply *psy,
360 			    enum power_supply_property psp,
361 			    const union power_supply_propval *val)
362 {
363 	struct max17040_chip *chip = power_supply_get_drvdata(psy);
364 	int ret;
365 
366 	switch (psp) {
367 	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
368 		/* alert threshold can be programmed from 1% up to 16/32% */
369 		if ((val->intval < 1) ||
370 		    (val->intval > (chip->quirk_double_soc ? 16 : 32))) {
371 			ret = -EINVAL;
372 			break;
373 		}
374 		ret = max17040_set_low_soc_alert(chip, val->intval);
375 		chip->low_soc_alert = val->intval;
376 		break;
377 	default:
378 		ret = -EINVAL;
379 	}
380 
381 	return ret;
382 }
383 
384 static int max17040_get_property(struct power_supply *psy,
385 			    enum power_supply_property psp,
386 			    union power_supply_propval *val)
387 {
388 	struct max17040_chip *chip = power_supply_get_drvdata(psy);
389 
390 	switch (psp) {
391 	case POWER_SUPPLY_PROP_ONLINE:
392 		val->intval = max17040_get_online(chip);
393 		break;
394 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
395 		val->intval = max17040_get_vcell(chip);
396 		break;
397 	case POWER_SUPPLY_PROP_CAPACITY:
398 		val->intval = max17040_get_soc(chip);
399 		break;
400 	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
401 		val->intval = chip->low_soc_alert;
402 		break;
403 	default:
404 		return -EINVAL;
405 	}
406 	return 0;
407 }
408 
409 static const struct regmap_config max17040_regmap = {
410 	.reg_bits	= 8,
411 	.reg_stride	= 2,
412 	.val_bits	= 16,
413 	.val_format_endian = REGMAP_ENDIAN_BIG,
414 };
415 
416 static enum power_supply_property max17040_battery_props[] = {
417 	POWER_SUPPLY_PROP_ONLINE,
418 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
419 	POWER_SUPPLY_PROP_CAPACITY,
420 	POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN,
421 };
422 
423 static const struct power_supply_desc max17040_battery_desc = {
424 	.name			= "battery",
425 	.type			= POWER_SUPPLY_TYPE_BATTERY,
426 	.get_property		= max17040_get_property,
427 	.set_property		= max17040_set_property,
428 	.property_is_writeable  = max17040_prop_writeable,
429 	.properties		= max17040_battery_props,
430 	.num_properties		= ARRAY_SIZE(max17040_battery_props),
431 };
432 
433 static int max17040_probe(struct i2c_client *client,
434 			const struct i2c_device_id *id)
435 {
436 	struct i2c_adapter *adapter = client->adapter;
437 	struct power_supply_config psy_cfg = {};
438 	struct max17040_chip *chip;
439 	enum chip_id chip_id;
440 	bool enable_irq = false;
441 	int ret;
442 
443 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
444 		return -EIO;
445 
446 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
447 	if (!chip)
448 		return -ENOMEM;
449 
450 	chip->client = client;
451 	chip->regmap = devm_regmap_init_i2c(client, &max17040_regmap);
452 	chip_id = (enum chip_id) id->driver_data;
453 	if (client->dev.of_node) {
454 		ret = max17040_get_of_data(chip);
455 		if (ret)
456 			return ret;
457 		chip_id = (uintptr_t)of_device_get_match_data(&client->dev);
458 	}
459 	chip->data = max17040_family[chip_id];
460 
461 	i2c_set_clientdata(client, chip);
462 	psy_cfg.drv_data = chip;
463 
464 	chip->battery = devm_power_supply_register(&client->dev,
465 				&max17040_battery_desc, &psy_cfg);
466 	if (IS_ERR(chip->battery)) {
467 		dev_err(&client->dev, "failed: power supply register\n");
468 		return PTR_ERR(chip->battery);
469 	}
470 
471 	ret = max17040_get_version(chip);
472 	if (ret < 0)
473 		return ret;
474 	dev_dbg(&chip->client->dev, "MAX17040 Fuel-Gauge Ver 0x%x\n", ret);
475 
476 	if (chip_id == ID_MAX17040 || chip_id == ID_MAX17041)
477 		max17040_reset(chip);
478 
479 	max17040_set_rcomp(chip, chip->rcomp);
480 
481 	/* check interrupt */
482 	if (client->irq && chip->data.has_low_soc_alert) {
483 		ret = max17040_set_low_soc_alert(chip, chip->low_soc_alert);
484 		if (ret) {
485 			dev_err(&client->dev,
486 				"Failed to set low SOC alert: err %d\n", ret);
487 			return ret;
488 		}
489 
490 		enable_irq = true;
491 	}
492 
493 	if (client->irq && chip->data.has_soc_alert) {
494 		ret = max17040_set_soc_alert(chip, 1);
495 		if (ret) {
496 			dev_err(&client->dev,
497 				"Failed to set SOC alert: err %d\n", ret);
498 			return ret;
499 		}
500 		enable_irq = true;
501 	} else {
502 		/* soc alerts negate the need for polling */
503 		INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
504 		ret = devm_add_action(&client->dev, max17040_stop_work, chip);
505 		if (ret)
506 			return ret;
507 		max17040_queue_work(chip);
508 	}
509 
510 	if (enable_irq) {
511 		ret = max17040_enable_alert_irq(chip);
512 		if (ret) {
513 			client->irq = 0;
514 			dev_warn(&client->dev,
515 				 "Failed to get IRQ err %d\n", ret);
516 		}
517 	}
518 
519 	return 0;
520 }
521 
522 #ifdef CONFIG_PM_SLEEP
523 
524 static int max17040_suspend(struct device *dev)
525 {
526 	struct i2c_client *client = to_i2c_client(dev);
527 	struct max17040_chip *chip = i2c_get_clientdata(client);
528 
529 	if (client->irq && chip->data.has_soc_alert)
530 		// disable soc alert to prevent wakeup
531 		max17040_set_soc_alert(chip, 0);
532 	else
533 		cancel_delayed_work(&chip->work);
534 
535 	if (client->irq && device_may_wakeup(dev))
536 		enable_irq_wake(client->irq);
537 
538 	return 0;
539 }
540 
541 static int max17040_resume(struct device *dev)
542 {
543 	struct i2c_client *client = to_i2c_client(dev);
544 	struct max17040_chip *chip = i2c_get_clientdata(client);
545 
546 	if (client->irq && device_may_wakeup(dev))
547 		disable_irq_wake(client->irq);
548 
549 	if (client->irq && chip->data.has_soc_alert)
550 		max17040_set_soc_alert(chip, 1);
551 	else
552 		max17040_queue_work(chip);
553 
554 	return 0;
555 }
556 
557 static SIMPLE_DEV_PM_OPS(max17040_pm_ops, max17040_suspend, max17040_resume);
558 #define MAX17040_PM_OPS (&max17040_pm_ops)
559 
560 #else
561 
562 #define MAX17040_PM_OPS NULL
563 
564 #endif /* CONFIG_PM_SLEEP */
565 
566 static const struct i2c_device_id max17040_id[] = {
567 	{ "max17040", ID_MAX17040 },
568 	{ "max17041", ID_MAX17041 },
569 	{ "max17043", ID_MAX17043 },
570 	{ "max77836-battery", ID_MAX17043 },
571 	{ "max17044", ID_MAX17044 },
572 	{ "max17048", ID_MAX17048 },
573 	{ "max17049", ID_MAX17049 },
574 	{ "max17058", ID_MAX17058 },
575 	{ "max17059", ID_MAX17059 },
576 	{ /* sentinel */ }
577 };
578 MODULE_DEVICE_TABLE(i2c, max17040_id);
579 
580 static const struct of_device_id max17040_of_match[] = {
581 	{ .compatible = "maxim,max17040", .data = (void *) ID_MAX17040 },
582 	{ .compatible = "maxim,max17041", .data = (void *) ID_MAX17041 },
583 	{ .compatible = "maxim,max17043", .data = (void *) ID_MAX17043 },
584 	{ .compatible = "maxim,max77836-battery", .data = (void *) ID_MAX17043 },
585 	{ .compatible = "maxim,max17044", .data = (void *) ID_MAX17044 },
586 	{ .compatible = "maxim,max17048", .data = (void *) ID_MAX17048 },
587 	{ .compatible = "maxim,max17049", .data = (void *) ID_MAX17049 },
588 	{ .compatible = "maxim,max17058", .data = (void *) ID_MAX17058 },
589 	{ .compatible = "maxim,max17059", .data = (void *) ID_MAX17059 },
590 	{ /* sentinel */ },
591 };
592 MODULE_DEVICE_TABLE(of, max17040_of_match);
593 
594 static struct i2c_driver max17040_i2c_driver = {
595 	.driver	= {
596 		.name	= "max17040",
597 		.of_match_table = max17040_of_match,
598 		.pm	= MAX17040_PM_OPS,
599 	},
600 	.probe		= max17040_probe,
601 	.id_table	= max17040_id,
602 };
603 module_i2c_driver(max17040_i2c_driver);
604 
605 MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
606 MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
607 MODULE_LICENSE("GPL");
608