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/max17040_battery.h>
20#include <linux/regmap.h>
21#include <linux/slab.h>
22
23#define MAX17040_VCELL	0x02
24#define MAX17040_SOC	0x04
25#define MAX17040_MODE	0x06
26#define MAX17040_VER	0x08
27#define MAX17040_CONFIG	0x0C
28#define MAX17040_STATUS	0x1A
29#define MAX17040_CMD	0xFE
30
31
32#define MAX17040_DELAY		1000
33#define MAX17040_BATTERY_FULL	95
34#define MAX17040_RCOMP_DEFAULT  0x9700
35
36#define MAX17040_ATHD_MASK		0x3f
37#define MAX17040_ALSC_MASK		0x40
38#define MAX17040_ATHD_DEFAULT_POWER_UP	4
39#define MAX17040_STATUS_HD_MASK		0x1000
40#define MAX17040_STATUS_SC_MASK		0x2000
41#define MAX17040_CFG_RCOMP_MASK		0xff00
42
43enum chip_id {
44	ID_MAX17040,
45	ID_MAX17041,
46	ID_MAX17043,
47	ID_MAX17044,
48	ID_MAX17048,
49	ID_MAX17049,
50	ID_MAX17058,
51	ID_MAX17059,
52};
53
54/* values that differ by chip_id */
55struct chip_data {
56	u16 reset_val;
57	u16 vcell_shift;
58	u16 vcell_mul;
59	u16 vcell_div;
60	u8  has_low_soc_alert;
61	u8  rcomp_bytes;
62	u8  has_soc_alert;
63};
64
65static struct chip_data max17040_family[] = {
66	[ID_MAX17040] = {
67		.reset_val = 0x0054,
68		.vcell_shift = 4,
69		.vcell_mul = 1250,
70		.vcell_div = 1,
71		.has_low_soc_alert = 0,
72		.rcomp_bytes = 2,
73		.has_soc_alert = 0,
74	},
75	[ID_MAX17041] = {
76		.reset_val = 0x0054,
77		.vcell_shift = 4,
78		.vcell_mul = 2500,
79		.vcell_div = 1,
80		.has_low_soc_alert = 0,
81		.rcomp_bytes = 2,
82		.has_soc_alert = 0,
83	},
84	[ID_MAX17043] = {
85		.reset_val = 0x0054,
86		.vcell_shift = 4,
87		.vcell_mul = 1250,
88		.vcell_div = 1,
89		.has_low_soc_alert = 1,
90		.rcomp_bytes = 1,
91		.has_soc_alert = 0,
92	},
93	[ID_MAX17044] = {
94		.reset_val = 0x0054,
95		.vcell_shift = 4,
96		.vcell_mul = 2500,
97		.vcell_div = 1,
98		.has_low_soc_alert = 1,
99		.rcomp_bytes = 1,
100		.has_soc_alert = 0,
101	},
102	[ID_MAX17048] = {
103		.reset_val = 0x5400,
104		.vcell_shift = 0,
105		.vcell_mul = 625,
106		.vcell_div = 8,
107		.has_low_soc_alert = 1,
108		.rcomp_bytes = 1,
109		.has_soc_alert = 1,
110	},
111	[ID_MAX17049] = {
112		.reset_val = 0x5400,
113		.vcell_shift = 0,
114		.vcell_mul = 625,
115		.vcell_div = 4,
116		.has_low_soc_alert = 1,
117		.rcomp_bytes = 1,
118		.has_soc_alert = 1,
119	},
120	[ID_MAX17058] = {
121		.reset_val = 0x5400,
122		.vcell_shift = 0,
123		.vcell_mul = 625,
124		.vcell_div = 8,
125		.has_low_soc_alert = 1,
126		.rcomp_bytes = 1,
127		.has_soc_alert = 0,
128	},
129	[ID_MAX17059] = {
130		.reset_val = 0x5400,
131		.vcell_shift = 0,
132		.vcell_mul = 625,
133		.vcell_div = 4,
134		.has_low_soc_alert = 1,
135		.rcomp_bytes = 1,
136		.has_soc_alert = 0,
137	},
138};
139
140struct max17040_chip {
141	struct i2c_client		*client;
142	struct regmap			*regmap;
143	struct delayed_work		work;
144	struct power_supply		*battery;
145	struct max17040_platform_data	*pdata;
146	struct chip_data		data;
147
148	/* battery capacity */
149	int soc;
150	/* State Of Charge */
151	int status;
152	/* Low alert threshold from 32% to 1% of the State of Charge */
153	u32 low_soc_alert;
154	/* some devices return twice the capacity */
155	bool quirk_double_soc;
156	/* higher 8 bits for 17043+, 16 bits for 17040,41 */
157	u16 rcomp;
158};
159
160static int max17040_reset(struct max17040_chip *chip)
161{
162	return regmap_write(chip->regmap, MAX17040_CMD, chip->data.reset_val);
163}
164
165static int max17040_set_low_soc_alert(struct max17040_chip *chip, u32 level)
166{
167	level = 32 - level * (chip->quirk_double_soc ? 2 : 1);
168	return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
169			MAX17040_ATHD_MASK, level);
170}
171
172static int max17040_set_soc_alert(struct max17040_chip *chip, bool enable)
173{
174	return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
175			MAX17040_ALSC_MASK, enable ? MAX17040_ALSC_MASK : 0);
176}
177
178static int max17040_set_rcomp(struct max17040_chip *chip, u16 rcomp)
179{
180	u16 mask = chip->data.rcomp_bytes == 2 ?
181		0xffff : MAX17040_CFG_RCOMP_MASK;
182
183	return regmap_update_bits(chip->regmap, MAX17040_CONFIG, mask, rcomp);
184}
185
186static int max17040_raw_vcell_to_uvolts(struct max17040_chip *chip, u16 vcell)
187{
188	struct chip_data *d = &chip->data;
189
190	return (vcell >> d->vcell_shift) * d->vcell_mul / d->vcell_div;
191}
192
193
194static int max17040_get_vcell(struct max17040_chip *chip)
195{
196	u32 vcell;
197
198	regmap_read(chip->regmap, MAX17040_VCELL, &vcell);
199
200	return max17040_raw_vcell_to_uvolts(chip, vcell);
201}
202
203static int max17040_get_soc(struct max17040_chip *chip)
204{
205	u32 soc;
206
207	regmap_read(chip->regmap, MAX17040_SOC, &soc);
208
209	return soc >> (chip->quirk_double_soc ? 9 : 8);
210}
211
212static int max17040_get_version(struct max17040_chip *chip)
213{
214	int ret;
215	u32 version;
216
217	ret = regmap_read(chip->regmap, MAX17040_VER, &version);
218
219	return ret ? ret : version;
220}
221
222static int max17040_get_online(struct max17040_chip *chip)
223{
224	return chip->pdata && chip->pdata->battery_online ?
225		chip->pdata->battery_online() : 1;
226}
227
228static int max17040_get_status(struct max17040_chip *chip)
229{
230	if (!chip->pdata || !chip->pdata->charger_online
231			|| !chip->pdata->charger_enable)
232		return POWER_SUPPLY_STATUS_UNKNOWN;
233
234	if (max17040_get_soc(chip) > MAX17040_BATTERY_FULL)
235		return POWER_SUPPLY_STATUS_FULL;
236
237	if (chip->pdata->charger_online())
238		if (chip->pdata->charger_enable())
239			return POWER_SUPPLY_STATUS_CHARGING;
240		else
241			return POWER_SUPPLY_STATUS_NOT_CHARGING;
242	else
243		return POWER_SUPPLY_STATUS_DISCHARGING;
244}
245
246static int max17040_get_of_data(struct max17040_chip *chip)
247{
248	struct device *dev = &chip->client->dev;
249	struct chip_data *data = &max17040_family[
250		(uintptr_t) of_device_get_match_data(dev)];
251	int rcomp_len;
252	u8 rcomp[2];
253
254	chip->quirk_double_soc = device_property_read_bool(dev,
255							   "maxim,double-soc");
256
257	chip->low_soc_alert = MAX17040_ATHD_DEFAULT_POWER_UP;
258	device_property_read_u32(dev,
259				 "maxim,alert-low-soc-level",
260				 &chip->low_soc_alert);
261
262	if (chip->low_soc_alert <= 0 ||
263	    chip->low_soc_alert > (chip->quirk_double_soc ? 16 : 32)) {
264		dev_err(dev, "maxim,alert-low-soc-level out of bounds\n");
265		return -EINVAL;
266	}
267
268	rcomp_len = device_property_count_u8(dev, "maxim,rcomp");
269	chip->rcomp = MAX17040_RCOMP_DEFAULT;
270	if (rcomp_len == data->rcomp_bytes) {
271		device_property_read_u8_array(dev, "maxim,rcomp",
272					      rcomp, rcomp_len);
273		chip->rcomp = rcomp_len == 2 ?
274			rcomp[0] << 8 | rcomp[1] :
275			rcomp[0] << 8;
276	} else if (rcomp_len > 0) {
277		dev_err(dev, "maxim,rcomp has incorrect length\n");
278		return -EINVAL;
279	}
280
281	return 0;
282}
283
284static void max17040_check_changes(struct max17040_chip *chip)
285{
286	chip->soc = max17040_get_soc(chip);
287	chip->status = max17040_get_status(chip);
288}
289
290static void max17040_queue_work(struct max17040_chip *chip)
291{
292	queue_delayed_work(system_power_efficient_wq, &chip->work,
293			   MAX17040_DELAY);
294}
295
296static void max17040_stop_work(void *data)
297{
298	struct max17040_chip *chip = data;
299
300	cancel_delayed_work_sync(&chip->work);
301}
302
303static void max17040_work(struct work_struct *work)
304{
305	struct max17040_chip *chip;
306	int last_soc, last_status;
307
308	chip = container_of(work, struct max17040_chip, work.work);
309
310	/* store SOC and status to check changes */
311	last_soc = chip->soc;
312	last_status = chip->status;
313	max17040_check_changes(chip);
314
315	/* check changes and send uevent */
316	if (last_soc != chip->soc || last_status != chip->status)
317		power_supply_changed(chip->battery);
318
319	max17040_queue_work(chip);
320}
321
322/* Returns true if alert cause was SOC change, not low SOC */
323static bool max17040_handle_soc_alert(struct max17040_chip *chip)
324{
325	bool ret = true;
326	u32 data;
327
328	regmap_read(chip->regmap, MAX17040_STATUS, &data);
329
330	if (data & MAX17040_STATUS_HD_MASK) {
331		// this alert was caused by low soc
332		ret = false;
333	}
334	if (data & MAX17040_STATUS_SC_MASK) {
335		// soc change bit -- deassert to mark as handled
336		regmap_write(chip->regmap, MAX17040_STATUS,
337				data & ~MAX17040_STATUS_SC_MASK);
338	}
339
340	return ret;
341}
342
343static irqreturn_t max17040_thread_handler(int id, void *dev)
344{
345	struct max17040_chip *chip = dev;
346
347	if (!(chip->data.has_soc_alert && max17040_handle_soc_alert(chip)))
348		dev_warn(&chip->client->dev, "IRQ: Alert battery low level\n");
349
350	/* read registers */
351	max17040_check_changes(chip);
352
353	/* send uevent */
354	power_supply_changed(chip->battery);
355
356	/* reset alert bit */
357	max17040_set_low_soc_alert(chip, chip->low_soc_alert);
358
359	return IRQ_HANDLED;
360}
361
362static int max17040_enable_alert_irq(struct max17040_chip *chip)
363{
364	struct i2c_client *client = chip->client;
365	unsigned int flags;
366	int ret;
367
368	flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
369	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
370					max17040_thread_handler, flags,
371					chip->battery->desc->name, chip);
372
373	return ret;
374}
375
376static int max17040_prop_writeable(struct power_supply *psy,
377				   enum power_supply_property psp)
378{
379	switch (psp) {
380	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
381		return 1;
382	default:
383		return 0;
384	}
385}
386
387static int max17040_set_property(struct power_supply *psy,
388			    enum power_supply_property psp,
389			    const union power_supply_propval *val)
390{
391	struct max17040_chip *chip = power_supply_get_drvdata(psy);
392	int ret;
393
394	switch (psp) {
395	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
396		/* alert threshold can be programmed from 1% up to 16/32% */
397		if ((val->intval < 1) ||
398		    (val->intval > (chip->quirk_double_soc ? 16 : 32))) {
399			ret = -EINVAL;
400			break;
401		}
402		ret = max17040_set_low_soc_alert(chip, val->intval);
403		chip->low_soc_alert = val->intval;
404		break;
405	default:
406		ret = -EINVAL;
407	}
408
409	return ret;
410}
411
412static int max17040_get_property(struct power_supply *psy,
413			    enum power_supply_property psp,
414			    union power_supply_propval *val)
415{
416	struct max17040_chip *chip = power_supply_get_drvdata(psy);
417
418	switch (psp) {
419	case POWER_SUPPLY_PROP_STATUS:
420		val->intval = max17040_get_status(chip);
421		break;
422	case POWER_SUPPLY_PROP_ONLINE:
423		val->intval = max17040_get_online(chip);
424		break;
425	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
426		val->intval = max17040_get_vcell(chip);
427		break;
428	case POWER_SUPPLY_PROP_CAPACITY:
429		val->intval = max17040_get_soc(chip);
430		break;
431	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
432		val->intval = chip->low_soc_alert;
433		break;
434	default:
435		return -EINVAL;
436	}
437	return 0;
438}
439
440static const struct regmap_config max17040_regmap = {
441	.reg_bits	= 8,
442	.reg_stride	= 2,
443	.val_bits	= 16,
444	.val_format_endian = REGMAP_ENDIAN_BIG,
445};
446
447static enum power_supply_property max17040_battery_props[] = {
448	POWER_SUPPLY_PROP_STATUS,
449	POWER_SUPPLY_PROP_ONLINE,
450	POWER_SUPPLY_PROP_VOLTAGE_NOW,
451	POWER_SUPPLY_PROP_CAPACITY,
452	POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN,
453};
454
455static const struct power_supply_desc max17040_battery_desc = {
456	.name			= "battery",
457	.type			= POWER_SUPPLY_TYPE_BATTERY,
458	.get_property		= max17040_get_property,
459	.set_property		= max17040_set_property,
460	.property_is_writeable  = max17040_prop_writeable,
461	.properties		= max17040_battery_props,
462	.num_properties		= ARRAY_SIZE(max17040_battery_props),
463};
464
465static int max17040_probe(struct i2c_client *client,
466			const struct i2c_device_id *id)
467{
468	struct i2c_adapter *adapter = client->adapter;
469	struct power_supply_config psy_cfg = {};
470	struct max17040_chip *chip;
471	enum chip_id chip_id;
472	bool enable_irq = false;
473	int ret;
474
475	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
476		return -EIO;
477
478	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
479	if (!chip)
480		return -ENOMEM;
481
482	chip->client = client;
483	chip->regmap = devm_regmap_init_i2c(client, &max17040_regmap);
484	chip->pdata = client->dev.platform_data;
485	if (IS_ERR(chip->regmap))
486		return PTR_ERR(chip->regmap);
487	chip_id = (enum chip_id) id->driver_data;
488	if (client->dev.of_node) {
489		ret = max17040_get_of_data(chip);
490		if (ret)
491			return ret;
492		chip_id = (enum chip_id) (uintptr_t)
493			of_device_get_match_data(&client->dev);
494	}
495	chip->data = max17040_family[chip_id];
496
497	i2c_set_clientdata(client, chip);
498	psy_cfg.drv_data = chip;
499
500	chip->battery = devm_power_supply_register(&client->dev,
501				&max17040_battery_desc, &psy_cfg);
502	if (IS_ERR(chip->battery)) {
503		dev_err(&client->dev, "failed: power supply register\n");
504		return PTR_ERR(chip->battery);
505	}
506
507	ret = max17040_get_version(chip);
508	if (ret < 0)
509		return ret;
510	dev_dbg(&chip->client->dev, "MAX17040 Fuel-Gauge Ver 0x%x\n", ret);
511
512	if (chip_id == ID_MAX17040 || chip_id == ID_MAX17041)
513		max17040_reset(chip);
514
515	max17040_set_rcomp(chip, chip->rcomp);
516
517	/* check interrupt */
518	if (client->irq && chip->data.has_low_soc_alert) {
519		ret = max17040_set_low_soc_alert(chip, chip->low_soc_alert);
520		if (ret) {
521			dev_err(&client->dev,
522				"Failed to set low SOC alert: err %d\n", ret);
523			return ret;
524		}
525
526		enable_irq = true;
527	}
528
529	if (client->irq && chip->data.has_soc_alert) {
530		ret = max17040_set_soc_alert(chip, 1);
531		if (ret) {
532			dev_err(&client->dev,
533				"Failed to set SOC alert: err %d\n", ret);
534			return ret;
535		}
536		enable_irq = true;
537	} else {
538		/* soc alerts negate the need for polling */
539		INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
540		ret = devm_add_action(&client->dev, max17040_stop_work, chip);
541		if (ret)
542			return ret;
543		max17040_queue_work(chip);
544	}
545
546	if (enable_irq) {
547		ret = max17040_enable_alert_irq(chip);
548		if (ret) {
549			client->irq = 0;
550			dev_warn(&client->dev,
551				 "Failed to get IRQ err %d\n", ret);
552		}
553	}
554
555	return 0;
556}
557
558#ifdef CONFIG_PM_SLEEP
559
560static int max17040_suspend(struct device *dev)
561{
562	struct i2c_client *client = to_i2c_client(dev);
563	struct max17040_chip *chip = i2c_get_clientdata(client);
564
565	if (client->irq && chip->data.has_soc_alert)
566		// disable soc alert to prevent wakeup
567		max17040_set_soc_alert(chip, 0);
568	else
569		cancel_delayed_work(&chip->work);
570
571	if (client->irq && device_may_wakeup(dev))
572		enable_irq_wake(client->irq);
573
574	return 0;
575}
576
577static int max17040_resume(struct device *dev)
578{
579	struct i2c_client *client = to_i2c_client(dev);
580	struct max17040_chip *chip = i2c_get_clientdata(client);
581
582	if (client->irq && device_may_wakeup(dev))
583		disable_irq_wake(client->irq);
584
585	if (client->irq && chip->data.has_soc_alert)
586		max17040_set_soc_alert(chip, 1);
587	else
588		max17040_queue_work(chip);
589
590	return 0;
591}
592
593static SIMPLE_DEV_PM_OPS(max17040_pm_ops, max17040_suspend, max17040_resume);
594#define MAX17040_PM_OPS (&max17040_pm_ops)
595
596#else
597
598#define MAX17040_PM_OPS NULL
599
600#endif /* CONFIG_PM_SLEEP */
601
602static const struct i2c_device_id max17040_id[] = {
603	{ "max17040", ID_MAX17040 },
604	{ "max17041", ID_MAX17041 },
605	{ "max17043", ID_MAX17043 },
606	{ "max77836-battery", ID_MAX17043 },
607	{ "max17044", ID_MAX17044 },
608	{ "max17048", ID_MAX17048 },
609	{ "max17049", ID_MAX17049 },
610	{ "max17058", ID_MAX17058 },
611	{ "max17059", ID_MAX17059 },
612	{ /* sentinel */ }
613};
614MODULE_DEVICE_TABLE(i2c, max17040_id);
615
616static const struct of_device_id max17040_of_match[] = {
617	{ .compatible = "maxim,max17040", .data = (void *) ID_MAX17040 },
618	{ .compatible = "maxim,max17041", .data = (void *) ID_MAX17041 },
619	{ .compatible = "maxim,max17043", .data = (void *) ID_MAX17043 },
620	{ .compatible = "maxim,max77836-battery", .data = (void *) ID_MAX17043 },
621	{ .compatible = "maxim,max17044", .data = (void *) ID_MAX17044 },
622	{ .compatible = "maxim,max17048", .data = (void *) ID_MAX17048 },
623	{ .compatible = "maxim,max17049", .data = (void *) ID_MAX17049 },
624	{ .compatible = "maxim,max17058", .data = (void *) ID_MAX17058 },
625	{ .compatible = "maxim,max17059", .data = (void *) ID_MAX17059 },
626	{ /* sentinel */ },
627};
628MODULE_DEVICE_TABLE(of, max17040_of_match);
629
630static struct i2c_driver max17040_i2c_driver = {
631	.driver	= {
632		.name	= "max17040",
633		.of_match_table = max17040_of_match,
634		.pm	= MAX17040_PM_OPS,
635	},
636	.probe		= max17040_probe,
637	.id_table	= max17040_id,
638};
639module_i2c_driver(max17040_i2c_driver);
640
641MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
642MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
643MODULE_LICENSE("GPL");
644