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
43 enum 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 */
55 struct 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
65 static 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
140 struct 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
max17040_reset(struct max17040_chip * chip)158 static int max17040_reset(struct max17040_chip *chip)
159 {
160 return regmap_write(chip->regmap, MAX17040_CMD, chip->data.reset_val);
161 }
162
max17040_set_low_soc_alert(struct max17040_chip * chip,u32 level)163 static 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
max17040_set_soc_alert(struct max17040_chip * chip,bool enable)170 static 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
max17040_set_rcomp(struct max17040_chip * chip,u16 rcomp)176 static 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
max17040_raw_vcell_to_uvolts(struct max17040_chip * chip,u16 vcell)184 static 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
max17040_get_vcell(struct max17040_chip * chip)192 static 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
max17040_get_soc(struct max17040_chip * chip)201 static 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
max17040_get_version(struct max17040_chip * chip)210 static 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
max17040_get_online(struct max17040_chip * chip)220 static int max17040_get_online(struct max17040_chip *chip)
221 {
222 return 1;
223 }
224
max17040_get_of_data(struct max17040_chip * chip)225 static 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
max17040_check_changes(struct max17040_chip * chip)262 static void max17040_check_changes(struct max17040_chip *chip)
263 {
264 chip->soc = max17040_get_soc(chip);
265 }
266
max17040_queue_work(struct max17040_chip * chip)267 static void max17040_queue_work(struct max17040_chip *chip)
268 {
269 queue_delayed_work(system_power_efficient_wq, &chip->work,
270 MAX17040_DELAY);
271 }
272
max17040_stop_work(void * data)273 static void max17040_stop_work(void *data)
274 {
275 struct max17040_chip *chip = data;
276
277 cancel_delayed_work_sync(&chip->work);
278 }
279
max17040_work(struct work_struct * work)280 static 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 */
max17040_handle_soc_alert(struct max17040_chip * chip)299 static 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
max17040_thread_handler(int id,void * dev)319 static 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
max17040_enable_alert_irq(struct max17040_chip * chip)338 static 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
max17040_prop_writeable(struct power_supply * psy,enum power_supply_property psp)350 static 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
max17040_set_property(struct power_supply * psy,enum power_supply_property psp,const union power_supply_propval * val)361 static 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
max17040_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)386 static 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
392 switch (psp) {
393 case POWER_SUPPLY_PROP_ONLINE:
394 case POWER_SUPPLY_PROP_PRESENT:
395 val->intval = max17040_get_online(chip);
396 break;
397 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
398 val->intval = max17040_get_vcell(chip);
399 break;
400 case POWER_SUPPLY_PROP_CAPACITY:
401 val->intval = max17040_get_soc(chip);
402 break;
403 case POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN:
404 val->intval = chip->low_soc_alert;
405 break;
406 case POWER_SUPPLY_PROP_STATUS:
407 power_supply_get_property_from_supplier(psy, psp, val);
408 break;
409 case POWER_SUPPLY_PROP_TEMP:
410 if (!chip->channel_temp)
411 return -ENODATA;
412
413 iio_read_channel_processed_scale(chip->channel_temp,
414 &val->intval, 10);
415 break;
416 default:
417 return -EINVAL;
418 }
419 return 0;
420 }
421
422 static const struct regmap_config max17040_regmap = {
423 .reg_bits = 8,
424 .reg_stride = 2,
425 .val_bits = 16,
426 .val_format_endian = REGMAP_ENDIAN_BIG,
427 };
428
429 static enum power_supply_property max17040_battery_props[] = {
430 POWER_SUPPLY_PROP_ONLINE,
431 POWER_SUPPLY_PROP_PRESENT,
432 POWER_SUPPLY_PROP_VOLTAGE_NOW,
433 POWER_SUPPLY_PROP_CAPACITY,
434 POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN,
435 POWER_SUPPLY_PROP_STATUS,
436 POWER_SUPPLY_PROP_TEMP,
437 };
438
439 static const struct power_supply_desc max17040_battery_desc = {
440 .name = "battery",
441 .type = POWER_SUPPLY_TYPE_BATTERY,
442 .get_property = max17040_get_property,
443 .set_property = max17040_set_property,
444 .property_is_writeable = max17040_prop_writeable,
445 .properties = max17040_battery_props,
446 .num_properties = ARRAY_SIZE(max17040_battery_props),
447 };
448
max17040_probe(struct i2c_client * client)449 static int max17040_probe(struct i2c_client *client)
450 {
451 const struct i2c_device_id *id = i2c_client_get_device_id(client);
452 struct i2c_adapter *adapter = client->adapter;
453 struct power_supply_config psy_cfg = {};
454 struct max17040_chip *chip;
455 enum chip_id chip_id;
456 bool enable_irq = false;
457 int ret;
458
459 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
460 return -EIO;
461
462 chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
463 if (!chip)
464 return -ENOMEM;
465
466 chip->client = client;
467 chip->regmap = devm_regmap_init_i2c(client, &max17040_regmap);
468 if (IS_ERR(chip->regmap))
469 return PTR_ERR(chip->regmap);
470 chip_id = (enum chip_id) id->driver_data;
471 if (client->dev.of_node) {
472 ret = max17040_get_of_data(chip);
473 if (ret)
474 return ret;
475 chip_id = (uintptr_t)of_device_get_match_data(&client->dev);
476 }
477 chip->data = max17040_family[chip_id];
478
479 i2c_set_clientdata(client, chip);
480 psy_cfg.drv_data = chip;
481
482 /* Switch to devm_iio_channel_get_optional when available */
483 chip->channel_temp = devm_iio_channel_get(&client->dev, "temp");
484 if (IS_ERR(chip->channel_temp)) {
485 ret = PTR_ERR(chip->channel_temp);
486 if (ret != -ENODEV)
487 return dev_err_probe(&client->dev, PTR_ERR(chip->channel_temp),
488 "failed to get temp\n");
489 else
490 chip->channel_temp = NULL;
491 }
492
493 chip->battery = devm_power_supply_register(&client->dev,
494 &max17040_battery_desc, &psy_cfg);
495 if (IS_ERR(chip->battery)) {
496 dev_err(&client->dev, "failed: power supply register\n");
497 return PTR_ERR(chip->battery);
498 }
499
500 ret = max17040_get_version(chip);
501 if (ret < 0)
502 return ret;
503 dev_dbg(&chip->client->dev, "MAX17040 Fuel-Gauge Ver 0x%x\n", ret);
504
505 if (chip_id == ID_MAX17040 || chip_id == ID_MAX17041)
506 max17040_reset(chip);
507
508 max17040_set_rcomp(chip, chip->rcomp);
509
510 /* check interrupt */
511 if (client->irq && chip->data.has_low_soc_alert) {
512 ret = max17040_set_low_soc_alert(chip, chip->low_soc_alert);
513 if (ret) {
514 dev_err(&client->dev,
515 "Failed to set low SOC alert: err %d\n", ret);
516 return ret;
517 }
518
519 enable_irq = true;
520 }
521
522 if (client->irq && chip->data.has_soc_alert) {
523 ret = max17040_set_soc_alert(chip, 1);
524 if (ret) {
525 dev_err(&client->dev,
526 "Failed to set SOC alert: err %d\n", ret);
527 return ret;
528 }
529 enable_irq = true;
530 } else {
531 /* soc alerts negate the need for polling */
532 INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
533 ret = devm_add_action(&client->dev, max17040_stop_work, chip);
534 if (ret)
535 return ret;
536 max17040_queue_work(chip);
537 }
538
539 if (enable_irq) {
540 ret = max17040_enable_alert_irq(chip);
541 if (ret) {
542 client->irq = 0;
543 dev_warn(&client->dev,
544 "Failed to get IRQ err %d\n", ret);
545 }
546 }
547
548 return 0;
549 }
550
551 #ifdef CONFIG_PM_SLEEP
552
max17040_suspend(struct device * dev)553 static int max17040_suspend(struct device *dev)
554 {
555 struct i2c_client *client = to_i2c_client(dev);
556 struct max17040_chip *chip = i2c_get_clientdata(client);
557
558 if (client->irq && chip->data.has_soc_alert)
559 // disable soc alert to prevent wakeup
560 max17040_set_soc_alert(chip, 0);
561 else
562 cancel_delayed_work(&chip->work);
563
564 if (client->irq && device_may_wakeup(dev))
565 enable_irq_wake(client->irq);
566
567 return 0;
568 }
569
max17040_resume(struct device * dev)570 static int max17040_resume(struct device *dev)
571 {
572 struct i2c_client *client = to_i2c_client(dev);
573 struct max17040_chip *chip = i2c_get_clientdata(client);
574
575 if (client->irq && device_may_wakeup(dev))
576 disable_irq_wake(client->irq);
577
578 if (client->irq && chip->data.has_soc_alert)
579 max17040_set_soc_alert(chip, 1);
580 else
581 max17040_queue_work(chip);
582
583 return 0;
584 }
585
586 static SIMPLE_DEV_PM_OPS(max17040_pm_ops, max17040_suspend, max17040_resume);
587 #define MAX17040_PM_OPS (&max17040_pm_ops)
588
589 #else
590
591 #define MAX17040_PM_OPS NULL
592
593 #endif /* CONFIG_PM_SLEEP */
594
595 static const struct i2c_device_id max17040_id[] = {
596 { "max17040", ID_MAX17040 },
597 { "max17041", ID_MAX17041 },
598 { "max17043", ID_MAX17043 },
599 { "max77836-battery", ID_MAX17043 },
600 { "max17044", ID_MAX17044 },
601 { "max17048", ID_MAX17048 },
602 { "max17049", ID_MAX17049 },
603 { "max17058", ID_MAX17058 },
604 { "max17059", ID_MAX17059 },
605 { /* sentinel */ }
606 };
607 MODULE_DEVICE_TABLE(i2c, max17040_id);
608
609 static const struct of_device_id max17040_of_match[] = {
610 { .compatible = "maxim,max17040", .data = (void *) ID_MAX17040 },
611 { .compatible = "maxim,max17041", .data = (void *) ID_MAX17041 },
612 { .compatible = "maxim,max17043", .data = (void *) ID_MAX17043 },
613 { .compatible = "maxim,max77836-battery", .data = (void *) ID_MAX17043 },
614 { .compatible = "maxim,max17044", .data = (void *) ID_MAX17044 },
615 { .compatible = "maxim,max17048", .data = (void *) ID_MAX17048 },
616 { .compatible = "maxim,max17049", .data = (void *) ID_MAX17049 },
617 { .compatible = "maxim,max17058", .data = (void *) ID_MAX17058 },
618 { .compatible = "maxim,max17059", .data = (void *) ID_MAX17059 },
619 { /* sentinel */ },
620 };
621 MODULE_DEVICE_TABLE(of, max17040_of_match);
622
623 static struct i2c_driver max17040_i2c_driver = {
624 .driver = {
625 .name = "max17040",
626 .of_match_table = max17040_of_match,
627 .pm = MAX17040_PM_OPS,
628 },
629 .probe = max17040_probe,
630 .id_table = max17040_id,
631 };
632 module_i2c_driver(max17040_i2c_driver);
633
634 MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
635 MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
636 MODULE_LICENSE("GPL");
637