max17040_battery.c

  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#include <linux/iio/consumer.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 chip_data		data;
146	struct iio_channel		*channel_temp;
147
148	/* battery capacity */
149	int soc;
150	/* Low alert threshold from 32% to 1% of the State of Charge */
151	u32 low_soc_alert;
152	/* some devices return twice the capacity */
153	bool quirk_double_soc;
154	/* higher 8 bits for 17043+, 16 bits for 17040,41 */
155	u16 rcomp;
156};
157
158static int max17040_reset(struct max17040_chip *chip)
159{
160	return regmap_write(chip->regmap, MAX17040_CMD, chip->data.reset_val);
161}
162
163static int max17040_set_low_soc_alert(struct max17040_chip *chip, u32 level)
164{
165	level = 32 - level * (chip->quirk_double_soc ? 2 : 1);
166	return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
167			MAX17040_ATHD_MASK, level);
168}
169
170static int max17040_set_soc_alert(struct max17040_chip *chip, bool enable)
171{
172	return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
173			MAX17040_ALSC_MASK, enable ? MAX17040_ALSC_MASK : 0);
174}
175
176static int max17040_set_rcomp(struct max17040_chip *chip, u16 rcomp)
177{
178	u16 mask = chip->data.rcomp_bytes == 2 ?
179		0xffff : MAX17040_CFG_RCOMP_MASK;
180
181	return regmap_update_bits(chip->regmap, MAX17040_CONFIG, mask, rcomp);
182}
183
184static int max17040_raw_vcell_to_uvolts(struct max17040_chip *chip, u16 vcell)
185{
186	struct chip_data *d = &chip->data;
187
188	return (vcell >> d->vcell_shift) * d->vcell_mul / d->vcell_div;
189}
190
191
192static int max17040_get_vcell(struct max17040_chip *chip)
193{
194	u32 vcell;
195
196	regmap_read(chip->regmap, MAX17040_VCELL, &vcell);
197
198	return max17040_raw_vcell_to_uvolts(chip, vcell);
199}
200
201static int max17040_get_soc(struct max17040_chip *chip)
202{
203	u32 soc;
204
205	regmap_read(chip->regmap, MAX17040_SOC, &soc);
206
207	return soc >> (chip->quirk_double_soc ? 9 : 8);
208}
209
210static int max17040_get_version(struct max17040_chip *chip)
211{
212	int ret;
213	u32 version;
214
215	ret = regmap_read(chip->regmap, MAX17040_VER, &version);
216
217	return ret ? ret : version;
218}
219
220static int max17040_get_online(struct max17040_chip *chip)
221{
222	return 1;
223}
224
225static int max17040_get_of_data(struct max17040_chip *chip)
226{
227	struct device *dev = &chip->client->dev;
228	struct chip_data *data = &max17040_family[
229		(uintptr_t) of_device_get_match_data(dev)];
230	int rcomp_len;
231	u8 rcomp[2];
232
233	chip->quirk_double_soc = device_property_read_bool(dev,
234							   "maxim,double-soc");
235
236	chip->low_soc_alert = MAX17040_ATHD_DEFAULT_POWER_UP;
237	device_property_read_u32(dev,
238				 "maxim,alert-low-soc-level",
239				 &chip->low_soc_alert);
240
241	if (chip->low_soc_alert <= 0 ||
242	    chip->low_soc_alert > (chip->quirk_double_soc ? 16 : 32)) {
243		dev_err(dev, "maxim,alert-low-soc-level out of bounds\n");
244		return -EINVAL;
245	}
246
247	rcomp_len = device_property_count_u8(dev, "maxim,rcomp");
248	chip->rcomp = MAX17040_RCOMP_DEFAULT;
249	if (rcomp_len == data->rcomp_bytes) {
250		if (!device_property_read_u8_array(dev, "maxim,rcomp",
251						   rcomp, rcomp_len))
252			chip->rcomp = rcomp_len == 2 ? rcomp[0] << 8 | rcomp[1] :
253				      rcomp[0] << 8;
254	} else if (rcomp_len > 0) {
255		dev_err(dev, "maxim,rcomp has incorrect length\n");
256		return -EINVAL;
257	}
258
259	return 0;
260}
261
262static void max17040_check_changes(struct max17040_chip *chip)
263{
264	chip->soc = max17040_get_soc(chip);
265}
266
267static void max17040_queue_work(struct max17040_chip *chip)
268{
269	queue_delayed_work(system_power_efficient_wq, &chip->work,
270			   MAX17040_DELAY);
271}
272
273static void max17040_stop_work(void *data)
274{
275	struct max17040_chip *chip = data;
276
277	cancel_delayed_work_sync(&chip->work);
278}
279
280static void max17040_work(struct work_struct *work)
281{
282	struct max17040_chip *chip;
283	int last_soc;
284
285	chip = container_of(work, struct max17040_chip, work.work);
286
287	/* store SOC to check changes */
288	last_soc = chip->soc;
289	max17040_check_changes(chip);
290
291	/* check changes and send uevent */
292	if (last_soc != chip->soc)
293		power_supply_changed(chip->battery);
294
295	max17040_queue_work(chip);
296}
297
298/* Returns true if alert cause was SOC change, not low SOC */
299static bool max17040_handle_soc_alert(struct max17040_chip *chip)
300{
301	bool ret = true;
302	u32 data;
303
304	regmap_read(chip->regmap, MAX17040_STATUS, &data);
305
306	if (data & MAX17040_STATUS_HD_MASK) {
307		// this alert was caused by low soc
308		ret = false;
309	}
310	if (data & MAX17040_STATUS_SC_MASK) {
311		// soc change bit -- deassert to mark as handled
312		regmap_write(chip->regmap, MAX17040_STATUS,
313				data & ~MAX17040_STATUS_SC_MASK);
314	}
315
316	return ret;
317}
318
319static irqreturn_t max17040_thread_handler(int id, void *dev)
320{
321	struct max17040_chip *chip = dev;
322
323	if (!(chip->data.has_soc_alert && max17040_handle_soc_alert(chip)))
324		dev_warn(&chip->client->dev, "IRQ: Alert battery low level\n");
325
326	/* read registers */
327	max17040_check_changes(chip);
328
329	/* send uevent */
330	power_supply_changed(chip->battery);
331
332	/* reset alert bit */
333	max17040_set_low_soc_alert(chip, chip->low_soc_alert);
334
335	return IRQ_HANDLED;
336}
337
338static int max17040_enable_alert_irq(struct max17040_chip *chip)
339{
340	struct i2c_client *client = chip->client;
341	int ret;
342
343	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
344					max17040_thread_handler, IRQF_ONESHOT,
345					chip->battery->desc->name, chip);
346
347	return ret;
348}
349
350static int max17040_prop_writeable(struct power_supply *psy,
351				   enum power_supply_property psp)
352{
353	switch (psp) {
354	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
355		return 1;
356	default:
357		return 0;
358	}
359}
360
361static int max17040_set_property(struct power_supply *psy,
362			    enum power_supply_property psp,
363			    const union power_supply_propval *val)
364{
365	struct max17040_chip *chip = power_supply_get_drvdata(psy);
366	int ret;
367
368	switch (psp) {
369	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
370		/* alert threshold can be programmed from 1% up to 16/32% */
371		if ((val->intval < 1) ||
372		    (val->intval > (chip->quirk_double_soc ? 16 : 32))) {
373			ret = -EINVAL;
374			break;
375		}
376		ret = max17040_set_low_soc_alert(chip, val->intval);
377		chip->low_soc_alert = val->intval;
378		break;
379	default:
380		ret = -EINVAL;
381	}
382
383	return ret;
384}
385
386static int max17040_get_property(struct power_supply *psy,
387			    enum power_supply_property psp,
388			    union power_supply_propval *val)
389{
390	struct max17040_chip *chip = power_supply_get_drvdata(psy);
391	int ret;
392
393	switch (psp) {
394	case POWER_SUPPLY_PROP_ONLINE:
395	case POWER_SUPPLY_PROP_PRESENT:
396		val->intval = max17040_get_online(chip);
397		break;
398	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
399		val->intval = max17040_get_vcell(chip);
400		break;
401	case POWER_SUPPLY_PROP_CAPACITY:
402		val->intval = max17040_get_soc(chip);
403		break;
404	case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
405		val->intval = chip->low_soc_alert;
406		break;
407	case POWER_SUPPLY_PROP_STATUS:
408		power_supply_get_property_from_supplier(psy, psp, val);
409		break;
410	case POWER_SUPPLY_PROP_TEMP:
411		if (!chip->channel_temp)
412			return -ENODATA;
413
414		ret = iio_read_channel_processed(chip->channel_temp, &val->intval);
415		if (ret)
416			return ret;
417
418		val->intval /= 100; /* Convert from milli- to deci-degree */
419
420		break;
421	default:
422		return -EINVAL;
423	}
424	return 0;
425}
426
427static const struct regmap_config max17040_regmap = {
428	.reg_bits	= 8,
429	.reg_stride	= 2,
430	.val_bits	= 16,
431	.val_format_endian = REGMAP_ENDIAN_BIG,
432};
433
434static enum power_supply_property max17040_battery_props[] = {
435	POWER_SUPPLY_PROP_ONLINE,
436	POWER_SUPPLY_PROP_PRESENT,
437	POWER_SUPPLY_PROP_VOLTAGE_NOW,
438	POWER_SUPPLY_PROP_CAPACITY,
439	POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN,
440	POWER_SUPPLY_PROP_STATUS,
441	POWER_SUPPLY_PROP_TEMP,
442};
443
444static const struct power_supply_desc max17040_battery_desc = {
445	.name			= "battery",
446	.type			= POWER_SUPPLY_TYPE_BATTERY,
447	.get_property		= max17040_get_property,
448	.set_property		= max17040_set_property,
449	.property_is_writeable  = max17040_prop_writeable,
450	.properties		= max17040_battery_props,
451	.num_properties		= ARRAY_SIZE(max17040_battery_props),
452};
453
454static int max17040_probe(struct i2c_client *client)
455{
456	const struct i2c_device_id *id = i2c_client_get_device_id(client);
457	struct i2c_adapter *adapter = client->adapter;
458	struct power_supply_config psy_cfg = {};
459	struct max17040_chip *chip;
460	enum chip_id chip_id;
461	bool enable_irq = false;
462	int ret;
463
464	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
465		return -EIO;
466
467	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
468	if (!chip)
469		return -ENOMEM;
470
471	chip->client = client;
472	chip->regmap = devm_regmap_init_i2c(client, &max17040_regmap);
473	if (IS_ERR(chip->regmap))
474		return PTR_ERR(chip->regmap);
475	chip_id = (enum chip_id) id->driver_data;
476	if (client->dev.of_node) {
477		ret = max17040_get_of_data(chip);
478		if (ret)
479			return ret;
480		chip_id = (uintptr_t)of_device_get_match_data(&client->dev);
481	}
482	chip->data = max17040_family[chip_id];
483
484	i2c_set_clientdata(client, chip);
485	psy_cfg.drv_data = chip;
486
487	/* Switch to devm_iio_channel_get_optional when available  */
488	chip->channel_temp = devm_iio_channel_get(&client->dev, "temp");
489	if (IS_ERR(chip->channel_temp)) {
490		ret = PTR_ERR(chip->channel_temp);
491		if (ret != -ENODEV)
492			return dev_err_probe(&client->dev, PTR_ERR(chip->channel_temp),
493					     "failed to get temp\n");
494		else
495			chip->channel_temp = NULL;
496	}
497
498	chip->battery = devm_power_supply_register(&client->dev,
499				&max17040_battery_desc, &psy_cfg);
500	if (IS_ERR(chip->battery)) {
501		dev_err(&client->dev, "failed: power supply register\n");
502		return PTR_ERR(chip->battery);
503	}
504
505	ret = max17040_get_version(chip);
506	if (ret < 0)
507		return ret;
508	dev_dbg(&chip->client->dev, "MAX17040 Fuel-Gauge Ver 0x%x\n", ret);
509
510	if (chip_id == ID_MAX17040 || chip_id == ID_MAX17041)
511		max17040_reset(chip);
512
513	max17040_set_rcomp(chip, chip->rcomp);
514
515	/* check interrupt */
516	if (client->irq && chip->data.has_low_soc_alert) {
517		ret = max17040_set_low_soc_alert(chip, chip->low_soc_alert);
518		if (ret) {
519			dev_err(&client->dev,
520				"Failed to set low SOC alert: err %d\n", ret);
521			return ret;
522		}
523
524		enable_irq = true;
525	}
526
527	if (client->irq && chip->data.has_soc_alert) {
528		ret = max17040_set_soc_alert(chip, 1);
529		if (ret) {
530			dev_err(&client->dev,
531				"Failed to set SOC alert: err %d\n", ret);
532			return ret;
533		}
534		enable_irq = true;
535	} else {
536		/* soc alerts negate the need for polling */
537		INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
538		ret = devm_add_action(&client->dev, max17040_stop_work, chip);
539		if (ret)
540			return ret;
541		max17040_queue_work(chip);
542	}
543
544	if (enable_irq) {
545		ret = max17040_enable_alert_irq(chip);
546		if (ret) {
547			client->irq = 0;
548			dev_warn(&client->dev,
549				 "Failed to get IRQ err %d\n", ret);
550		}
551	}
552
553	return 0;
554}
555
556#ifdef CONFIG_PM_SLEEP
557
558static int max17040_suspend(struct device *dev)
559{
560	struct i2c_client *client = to_i2c_client(dev);
561	struct max17040_chip *chip = i2c_get_clientdata(client);
562
563	if (client->irq && chip->data.has_soc_alert)
564		// disable soc alert to prevent wakeup
565		max17040_set_soc_alert(chip, 0);
566	else
567		cancel_delayed_work(&chip->work);
568
569	if (client->irq && device_may_wakeup(dev))
570		enable_irq_wake(client->irq);
571
572	return 0;
573}
574
575static int max17040_resume(struct device *dev)
576{
577	struct i2c_client *client = to_i2c_client(dev);
578	struct max17040_chip *chip = i2c_get_clientdata(client);
579
580	if (client->irq && device_may_wakeup(dev))
581		disable_irq_wake(client->irq);
582
583	if (client->irq && chip->data.has_soc_alert)
584		max17040_set_soc_alert(chip, 1);
585	else
586		max17040_queue_work(chip);
587
588	return 0;
589}
590
591static SIMPLE_DEV_PM_OPS(max17040_pm_ops, max17040_suspend, max17040_resume);
592#define MAX17040_PM_OPS (&max17040_pm_ops)
593
594#else
595
596#define MAX17040_PM_OPS NULL
597
598#endif /* CONFIG_PM_SLEEP */
599
600static const struct i2c_device_id max17040_id[] = {
601	{ "max17040", ID_MAX17040 },
602	{ "max17041", ID_MAX17041 },
603	{ "max17043", ID_MAX17043 },
604	{ "max77836-battery", ID_MAX17043 },
605	{ "max17044", ID_MAX17044 },
606	{ "max17048", ID_MAX17048 },
607	{ "max17049", ID_MAX17049 },
608	{ "max17058", ID_MAX17058 },
609	{ "max17059", ID_MAX17059 },
610	{ /* sentinel */ }
611};
612MODULE_DEVICE_TABLE(i2c, max17040_id);
613
614static const struct of_device_id max17040_of_match[] = {
615	{ .compatible = "maxim,max17040", .data = (void *) ID_MAX17040 },
616	{ .compatible = "maxim,max17041", .data = (void *) ID_MAX17041 },
617	{ .compatible = "maxim,max17043", .data = (void *) ID_MAX17043 },
618	{ .compatible = "maxim,max77836-battery", .data = (void *) ID_MAX17043 },
619	{ .compatible = "maxim,max17044", .data = (void *) ID_MAX17044 },
620	{ .compatible = "maxim,max17048", .data = (void *) ID_MAX17048 },
621	{ .compatible = "maxim,max17049", .data = (void *) ID_MAX17049 },
622	{ .compatible = "maxim,max17058", .data = (void *) ID_MAX17058 },
623	{ .compatible = "maxim,max17059", .data = (void *) ID_MAX17059 },
624	{ /* sentinel */ },
625};
626MODULE_DEVICE_TABLE(of, max17040_of_match);
627
628static struct i2c_driver max17040_i2c_driver = {
629	.driver	= {
630		.name	= "max17040",
631		.of_match_table = max17040_of_match,
632		.pm	= MAX17040_PM_OPS,
633	},
634	.probe		= max17040_probe,
635	.id_table	= max17040_id,
636};
637module_i2c_driver(max17040_i2c_driver);
638
639MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
640MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
641MODULE_LICENSE("GPL");