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.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
42enum 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 */
54struct 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
64static 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
139struct 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
156static int max17040_reset(struct max17040_chip *chip)
157{
158	return regmap_write(chip->regmap, MAX17040_CMD, chip->data.reset_val);
159}
160
161static 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
168static 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
174static 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
182static 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
190static 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
199static 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
208static 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
218static int max17040_get_online(struct max17040_chip *chip)
219{
220	return 1;
221}
222
223static 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
260static void max17040_check_changes(struct max17040_chip *chip)
261{
262	chip->soc = max17040_get_soc(chip);
263}
264
265static void max17040_queue_work(struct max17040_chip *chip)
266{
267	queue_delayed_work(system_power_efficient_wq, &chip->work,
268			   MAX17040_DELAY);
269}
270
271static void max17040_stop_work(void *data)
272{
273	struct max17040_chip *chip = data;
274
275	cancel_delayed_work_sync(&chip->work);
276}
277
278static 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 */
297static 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
317static 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
336static 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
348static 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
359static 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
384static 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
409static 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
416static 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
423static 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
433static int max17040_probe(struct i2c_client *client)
434{
435	const struct i2c_device_id *id = i2c_client_get_device_id(client);
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	if (IS_ERR(chip->regmap))
453		return PTR_ERR(chip->regmap);
454	chip_id = (enum chip_id) id->driver_data;
455	if (client->dev.of_node) {
456		ret = max17040_get_of_data(chip);
457		if (ret)
458			return ret;
459		chip_id = (uintptr_t)of_device_get_match_data(&client->dev);
460	}
461	chip->data = max17040_family[chip_id];
462
463	i2c_set_clientdata(client, chip);
464	psy_cfg.drv_data = chip;
465
466	chip->battery = devm_power_supply_register(&client->dev,
467				&max17040_battery_desc, &psy_cfg);
468	if (IS_ERR(chip->battery)) {
469		dev_err(&client->dev, "failed: power supply register\n");
470		return PTR_ERR(chip->battery);
471	}
472
473	ret = max17040_get_version(chip);
474	if (ret < 0)
475		return ret;
476	dev_dbg(&chip->client->dev, "MAX17040 Fuel-Gauge Ver 0x%x\n", ret);
477
478	if (chip_id == ID_MAX17040 || chip_id == ID_MAX17041)
479		max17040_reset(chip);
480
481	max17040_set_rcomp(chip, chip->rcomp);
482
483	/* check interrupt */
484	if (client->irq && chip->data.has_low_soc_alert) {
485		ret = max17040_set_low_soc_alert(chip, chip->low_soc_alert);
486		if (ret) {
487			dev_err(&client->dev,
488				"Failed to set low SOC alert: err %d\n", ret);
489			return ret;
490		}
491
492		enable_irq = true;
493	}
494
495	if (client->irq && chip->data.has_soc_alert) {
496		ret = max17040_set_soc_alert(chip, 1);
497		if (ret) {
498			dev_err(&client->dev,
499				"Failed to set SOC alert: err %d\n", ret);
500			return ret;
501		}
502		enable_irq = true;
503	} else {
504		/* soc alerts negate the need for polling */
505		INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
506		ret = devm_add_action(&client->dev, max17040_stop_work, chip);
507		if (ret)
508			return ret;
509		max17040_queue_work(chip);
510	}
511
512	if (enable_irq) {
513		ret = max17040_enable_alert_irq(chip);
514		if (ret) {
515			client->irq = 0;
516			dev_warn(&client->dev,
517				 "Failed to get IRQ err %d\n", ret);
518		}
519	}
520
521	return 0;
522}
523
524#ifdef CONFIG_PM_SLEEP
525
526static int max17040_suspend(struct device *dev)
527{
528	struct i2c_client *client = to_i2c_client(dev);
529	struct max17040_chip *chip = i2c_get_clientdata(client);
530
531	if (client->irq && chip->data.has_soc_alert)
532		// disable soc alert to prevent wakeup
533		max17040_set_soc_alert(chip, 0);
534	else
535		cancel_delayed_work(&chip->work);
536
537	if (client->irq && device_may_wakeup(dev))
538		enable_irq_wake(client->irq);
539
540	return 0;
541}
542
543static int max17040_resume(struct device *dev)
544{
545	struct i2c_client *client = to_i2c_client(dev);
546	struct max17040_chip *chip = i2c_get_clientdata(client);
547
548	if (client->irq && device_may_wakeup(dev))
549		disable_irq_wake(client->irq);
550
551	if (client->irq && chip->data.has_soc_alert)
552		max17040_set_soc_alert(chip, 1);
553	else
554		max17040_queue_work(chip);
555
556	return 0;
557}
558
559static SIMPLE_DEV_PM_OPS(max17040_pm_ops, max17040_suspend, max17040_resume);
560#define MAX17040_PM_OPS (&max17040_pm_ops)
561
562#else
563
564#define MAX17040_PM_OPS NULL
565
566#endif /* CONFIG_PM_SLEEP */
567
568static const struct i2c_device_id max17040_id[] = {
569	{ "max17040", ID_MAX17040 },
570	{ "max17041", ID_MAX17041 },
571	{ "max17043", ID_MAX17043 },
572	{ "max77836-battery", ID_MAX17043 },
573	{ "max17044", ID_MAX17044 },
574	{ "max17048", ID_MAX17048 },
575	{ "max17049", ID_MAX17049 },
576	{ "max17058", ID_MAX17058 },
577	{ "max17059", ID_MAX17059 },
578	{ /* sentinel */ }
579};
580MODULE_DEVICE_TABLE(i2c, max17040_id);
581
582static const struct of_device_id max17040_of_match[] = {
583	{ .compatible = "maxim,max17040", .data = (void *) ID_MAX17040 },
584	{ .compatible = "maxim,max17041", .data = (void *) ID_MAX17041 },
585	{ .compatible = "maxim,max17043", .data = (void *) ID_MAX17043 },
586	{ .compatible = "maxim,max77836-battery", .data = (void *) ID_MAX17043 },
587	{ .compatible = "maxim,max17044", .data = (void *) ID_MAX17044 },
588	{ .compatible = "maxim,max17048", .data = (void *) ID_MAX17048 },
589	{ .compatible = "maxim,max17049", .data = (void *) ID_MAX17049 },
590	{ .compatible = "maxim,max17058", .data = (void *) ID_MAX17058 },
591	{ .compatible = "maxim,max17059", .data = (void *) ID_MAX17059 },
592	{ /* sentinel */ },
593};
594MODULE_DEVICE_TABLE(of, max17040_of_match);
595
596static struct i2c_driver max17040_i2c_driver = {
597	.driver	= {
598		.name	= "max17040",
599		.of_match_table = max17040_of_match,
600		.pm	= MAX17040_PM_OPS,
601	},
602	.probe		= max17040_probe,
603	.id_table	= max17040_id,
604};
605module_i2c_driver(max17040_i2c_driver);
606
607MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
608MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
609MODULE_LICENSE("GPL");
610