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11#include <linux/devm-helpers.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of_device.h>
15#include <linux/types.h>
16#include <linux/errno.h>
17#include <linux/swab.h>
18#include <linux/i2c.h>
19#include <linux/delay.h>
20#include <linux/power_supply.h>
21#include <linux/slab.h>
22
23#define I16_MSB(x) ((x >> 8) & 0xFF)
24#define I16_LSB(x) (x & 0xFF)
25
26#define LTC294X_WORK_DELAY 10
27
28#define LTC294X_MAX_VALUE 0xFFFF
29#define LTC294X_MID_SUPPLY 0x7FFF
30
31#define LTC2941_MAX_PRESCALER_EXP 7
32#define LTC2943_MAX_PRESCALER_EXP 6
33
34enum ltc294x_reg {
35 LTC294X_REG_STATUS = 0x00,
36 LTC294X_REG_CONTROL = 0x01,
37 LTC294X_REG_ACC_CHARGE_MSB = 0x02,
38 LTC294X_REG_ACC_CHARGE_LSB = 0x03,
39 LTC294X_REG_CHARGE_THR_HIGH_MSB = 0x04,
40 LTC294X_REG_CHARGE_THR_HIGH_LSB = 0x05,
41 LTC294X_REG_CHARGE_THR_LOW_MSB = 0x06,
42 LTC294X_REG_CHARGE_THR_LOW_LSB = 0x07,
43 LTC294X_REG_VOLTAGE_MSB = 0x08,
44 LTC294X_REG_VOLTAGE_LSB = 0x09,
45 LTC2942_REG_TEMPERATURE_MSB = 0x0C,
46 LTC2942_REG_TEMPERATURE_LSB = 0x0D,
47 LTC2943_REG_CURRENT_MSB = 0x0E,
48 LTC2943_REG_CURRENT_LSB = 0x0F,
49 LTC2943_REG_TEMPERATURE_MSB = 0x14,
50 LTC2943_REG_TEMPERATURE_LSB = 0x15,
51};
52
53enum ltc294x_id {
54 LTC2941_ID,
55 LTC2942_ID,
56 LTC2943_ID,
57 LTC2944_ID,
58};
59
60#define LTC2941_REG_STATUS_CHIP_ID BIT(7)
61
62#define LTC2942_REG_CONTROL_MODE_SCAN (BIT(7) | BIT(6))
63#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
64#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3))
65#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
66#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
67 ((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
68#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED 0
69#define LTC294X_REG_CONTROL_ADC_DISABLE(x) ((x) & ~(BIT(7) | BIT(6)))
70
71struct ltc294x_info {
72 struct i2c_client *client;
73 struct power_supply *supply;
74 struct power_supply_desc supply_desc;
75 struct delayed_work work;
76 enum ltc294x_id id;
77 int charge;
78 int r_sense;
79 int Qlsb;
80};
81
82static inline int convert_bin_to_uAh(
83 const struct ltc294x_info *info, int Q)
84{
85 return ((Q * (info->Qlsb / 10))) / 100;
86}
87
88static inline int convert_uAh_to_bin(
89 const struct ltc294x_info *info, int uAh)
90{
91 int Q;
92
93 Q = (uAh * 100) / (info->Qlsb/10);
94 return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
95}
96
97static int ltc294x_read_regs(struct i2c_client *client,
98 enum ltc294x_reg reg, u8 *buf, int num_regs)
99{
100 int ret;
101 struct i2c_msg msgs[2] = { };
102 u8 reg_start = reg;
103
104 msgs[0].addr = client->addr;
105 msgs[0].len = 1;
106 msgs[0].buf = ®_start;
107
108 msgs[1].addr = client->addr;
109 msgs[1].len = num_regs;
110 msgs[1].buf = buf;
111 msgs[1].flags = I2C_M_RD;
112
113 ret = i2c_transfer(client->adapter, &msgs[0], 2);
114 if (ret < 0) {
115 dev_err(&client->dev, "ltc2941 read_reg failed!\n");
116 return ret;
117 }
118
119 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
120 __func__, reg, num_regs, *buf);
121
122 return 0;
123}
124
125static int ltc294x_write_regs(struct i2c_client *client,
126 enum ltc294x_reg reg, const u8 *buf, int num_regs)
127{
128 int ret;
129 u8 reg_start = reg;
130
131 ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
132 if (ret < 0) {
133 dev_err(&client->dev, "ltc2941 write_reg failed!\n");
134 return ret;
135 }
136
137 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
138 __func__, reg, num_regs, *buf);
139
140 return 0;
141}
142
143static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
144{
145 int ret;
146 u8 value;
147 u8 control;
148
149
150 ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
151 if (ret < 0) {
152 dev_err(&info->client->dev,
153 "Could not read registers from device\n");
154 goto error_exit;
155 }
156
157 control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
158 LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
159
160 switch (info->id) {
161 case LTC2942_ID:
162 control |= LTC2942_REG_CONTROL_MODE_SCAN;
163 break;
164 case LTC2943_ID:
165 case LTC2944_ID:
166 control |= LTC2943_REG_CONTROL_MODE_SCAN;
167 break;
168 default:
169 break;
170 }
171
172 if (value != control) {
173 ret = ltc294x_write_regs(info->client,
174 LTC294X_REG_CONTROL, &control, 1);
175 if (ret < 0) {
176 dev_err(&info->client->dev,
177 "Could not write register\n");
178 goto error_exit;
179 }
180 }
181
182 return 0;
183
184error_exit:
185 return ret;
186}
187
188static int ltc294x_read_charge_register(const struct ltc294x_info *info,
189 enum ltc294x_reg reg)
190 {
191 int ret;
192 u8 datar[2];
193
194 ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
195 if (ret < 0)
196 return ret;
197 return (datar[0] << 8) + datar[1];
198}
199
200static int ltc294x_get_charge(const struct ltc294x_info *info,
201 enum ltc294x_reg reg, int *val)
202{
203 int value = ltc294x_read_charge_register(info, reg);
204
205 if (value < 0)
206 return value;
207
208 if (info->Qlsb < 0)
209 value -= 0xFFFF;
210 *val = convert_bin_to_uAh(info, value);
211 return 0;
212}
213
214static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
215{
216 int ret;
217 u8 dataw[2];
218 u8 ctrl_reg;
219 s32 value;
220
221 value = convert_uAh_to_bin(info, val);
222
223 if (info->Qlsb < 0)
224 value += 0xFFFF;
225 if ((value < 0) || (value > 0xFFFF))
226 return -EINVAL;
227
228
229 ret = ltc294x_read_regs(info->client,
230 LTC294X_REG_CONTROL, &ctrl_reg, 1);
231 if (ret < 0)
232 return ret;
233
234 ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
235 ret = ltc294x_write_regs(info->client,
236 LTC294X_REG_CONTROL, &ctrl_reg, 1);
237 if (ret < 0)
238 return ret;
239
240 dataw[0] = I16_MSB(value);
241 dataw[1] = I16_LSB(value);
242 ret = ltc294x_write_regs(info->client,
243 LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
244 if (ret < 0)
245 goto error_exit;
246
247error_exit:
248 ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
249 ret = ltc294x_write_regs(info->client,
250 LTC294X_REG_CONTROL, &ctrl_reg, 1);
251
252 return ret < 0 ? ret : 0;
253}
254
255static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
256 enum ltc294x_reg reg, int val)
257{
258 u8 dataw[2];
259 s32 value;
260
261 value = convert_uAh_to_bin(info, val);
262
263 if (info->Qlsb < 0)
264 value += 0xFFFF;
265 if ((value < 0) || (value > 0xFFFF))
266 return -EINVAL;
267
268
269 dataw[0] = I16_MSB(value);
270 dataw[1] = I16_LSB(value);
271 return ltc294x_write_regs(info->client, reg, &dataw[0], 2);
272}
273
274static int ltc294x_get_charge_counter(
275 const struct ltc294x_info *info, int *val)
276{
277 int value = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
278
279 if (value < 0)
280 return value;
281 value -= LTC294X_MID_SUPPLY;
282 *val = convert_bin_to_uAh(info, value);
283 return 0;
284}
285
286static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
287{
288 int ret;
289 u8 datar[2];
290 u32 value;
291
292 ret = ltc294x_read_regs(info->client,
293 LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
294 value = (datar[0] << 8) | datar[1];
295 switch (info->id) {
296 case LTC2943_ID:
297 value *= 23600 * 2;
298 value /= 0xFFFF;
299 value *= 1000 / 2;
300 break;
301 case LTC2944_ID:
302 value *= 70800 / 5*4;
303 value /= 0xFFFF;
304 value *= 1000 * 5/4;
305 break;
306 default:
307 value *= 6000 * 10;
308 value /= 0xFFFF;
309 value *= 1000 / 10;
310 break;
311 }
312 *val = value;
313 return ret;
314}
315
316static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
317{
318 int ret;
319 u8 datar[2];
320 s32 value;
321
322 ret = ltc294x_read_regs(info->client,
323 LTC2943_REG_CURRENT_MSB, &datar[0], 2);
324 value = (datar[0] << 8) | datar[1];
325 value -= 0x7FFF;
326 if (info->id == LTC2944_ID)
327 value *= 64000;
328 else
329 value *= 60000;
330
331
332
333 *val = 1000 * (value / (info->r_sense * 0x7FFF));
334 return ret;
335}
336
337static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
338{
339 enum ltc294x_reg reg;
340 int ret;
341 u8 datar[2];
342 u32 value;
343
344 if (info->id == LTC2942_ID) {
345 reg = LTC2942_REG_TEMPERATURE_MSB;
346 value = 6000;
347 } else {
348 reg = LTC2943_REG_TEMPERATURE_MSB;
349 value = 5100;
350 }
351 ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
352 value *= (datar[0] << 8) | datar[1];
353
354 *val = value / 0xFFFF - 2722;
355 return ret;
356}
357
358static int ltc294x_get_property(struct power_supply *psy,
359 enum power_supply_property prop,
360 union power_supply_propval *val)
361{
362 struct ltc294x_info *info = power_supply_get_drvdata(psy);
363
364 switch (prop) {
365 case POWER_SUPPLY_PROP_CHARGE_FULL:
366 return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_HIGH_MSB,
367 &val->intval);
368 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
369 return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_LOW_MSB,
370 &val->intval);
371 case POWER_SUPPLY_PROP_CHARGE_NOW:
372 return ltc294x_get_charge(info, LTC294X_REG_ACC_CHARGE_MSB,
373 &val->intval);
374 case POWER_SUPPLY_PROP_CHARGE_COUNTER:
375 return ltc294x_get_charge_counter(info, &val->intval);
376 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
377 return ltc294x_get_voltage(info, &val->intval);
378 case POWER_SUPPLY_PROP_CURRENT_NOW:
379 return ltc294x_get_current(info, &val->intval);
380 case POWER_SUPPLY_PROP_TEMP:
381 return ltc294x_get_temperature(info, &val->intval);
382 default:
383 return -EINVAL;
384 }
385}
386
387static int ltc294x_set_property(struct power_supply *psy,
388 enum power_supply_property psp,
389 const union power_supply_propval *val)
390{
391 struct ltc294x_info *info = power_supply_get_drvdata(psy);
392
393 switch (psp) {
394 case POWER_SUPPLY_PROP_CHARGE_FULL:
395 return ltc294x_set_charge_thr(info,
396 LTC294X_REG_CHARGE_THR_HIGH_MSB, val->intval);
397 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
398 return ltc294x_set_charge_thr(info,
399 LTC294X_REG_CHARGE_THR_LOW_MSB, val->intval);
400 case POWER_SUPPLY_PROP_CHARGE_NOW:
401 return ltc294x_set_charge_now(info, val->intval);
402 default:
403 return -EPERM;
404 }
405}
406
407static int ltc294x_property_is_writeable(
408 struct power_supply *psy, enum power_supply_property psp)
409{
410 switch (psp) {
411 case POWER_SUPPLY_PROP_CHARGE_FULL:
412 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
413 case POWER_SUPPLY_PROP_CHARGE_NOW:
414 return 1;
415 default:
416 return 0;
417 }
418}
419
420static void ltc294x_update(struct ltc294x_info *info)
421{
422 int charge = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
423
424 if (charge != info->charge) {
425 info->charge = charge;
426 power_supply_changed(info->supply);
427 }
428}
429
430static void ltc294x_work(struct work_struct *work)
431{
432 struct ltc294x_info *info;
433
434 info = container_of(work, struct ltc294x_info, work.work);
435 ltc294x_update(info);
436 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
437}
438
439static enum power_supply_property ltc294x_properties[] = {
440 POWER_SUPPLY_PROP_CHARGE_COUNTER,
441 POWER_SUPPLY_PROP_CHARGE_FULL,
442 POWER_SUPPLY_PROP_CHARGE_EMPTY,
443 POWER_SUPPLY_PROP_CHARGE_NOW,
444 POWER_SUPPLY_PROP_VOLTAGE_NOW,
445 POWER_SUPPLY_PROP_TEMP,
446 POWER_SUPPLY_PROP_CURRENT_NOW,
447};
448
449static int ltc294x_i2c_probe(struct i2c_client *client,
450 const struct i2c_device_id *id)
451{
452 struct power_supply_config psy_cfg = {};
453 struct ltc294x_info *info;
454 struct device_node *np;
455 int ret;
456 u32 prescaler_exp;
457 s32 r_sense;
458 u8 status;
459
460 info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
461 if (info == NULL)
462 return -ENOMEM;
463
464 i2c_set_clientdata(client, info);
465
466 np = of_node_get(client->dev.of_node);
467
468 info->id = (enum ltc294x_id) (uintptr_t) of_device_get_match_data(
469 &client->dev);
470 info->supply_desc.name = np->name;
471
472
473
474 ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
475 if (ret < 0) {
476 dev_err(&client->dev,
477 "Could not find lltc,resistor-sense in devicetree\n");
478 return ret;
479 }
480 info->r_sense = r_sense;
481
482 ret = of_property_read_u32(np, "lltc,prescaler-exponent",
483 &prescaler_exp);
484 if (ret < 0) {
485 dev_warn(&client->dev,
486 "lltc,prescaler-exponent not in devicetree\n");
487 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
488 }
489
490 if (info->id == LTC2943_ID) {
491 if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
492 prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
493 info->Qlsb = ((340 * 50000) / r_sense) /
494 (4096 / (1 << (2*prescaler_exp)));
495 } else {
496 if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
497 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
498 info->Qlsb = ((85 * 50000) / r_sense) /
499 (128 / (1 << prescaler_exp));
500 }
501
502
503 if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
504 ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
505 if (ret < 0) {
506 dev_err(&client->dev,
507 "Could not read status register\n");
508 return ret;
509 }
510 if (status & LTC2941_REG_STATUS_CHIP_ID)
511 info->id = LTC2941_ID;
512 else
513 info->id = LTC2942_ID;
514 }
515
516 info->client = client;
517 info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
518 info->supply_desc.properties = ltc294x_properties;
519 switch (info->id) {
520 case LTC2944_ID:
521 case LTC2943_ID:
522 info->supply_desc.num_properties =
523 ARRAY_SIZE(ltc294x_properties);
524 break;
525 case LTC2942_ID:
526 info->supply_desc.num_properties =
527 ARRAY_SIZE(ltc294x_properties) - 1;
528 break;
529 case LTC2941_ID:
530 default:
531 info->supply_desc.num_properties =
532 ARRAY_SIZE(ltc294x_properties) - 3;
533 break;
534 }
535 info->supply_desc.get_property = ltc294x_get_property;
536 info->supply_desc.set_property = ltc294x_set_property;
537 info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
538 info->supply_desc.external_power_changed = NULL;
539
540 psy_cfg.drv_data = info;
541
542 ret = devm_delayed_work_autocancel(&client->dev, &info->work,
543 ltc294x_work);
544 if (ret)
545 return ret;
546
547 ret = ltc294x_reset(info, prescaler_exp);
548 if (ret < 0) {
549 dev_err(&client->dev, "Communication with chip failed\n");
550 return ret;
551 }
552
553 info->supply = devm_power_supply_register(&client->dev,
554 &info->supply_desc, &psy_cfg);
555 if (IS_ERR(info->supply)) {
556 dev_err(&client->dev, "failed to register ltc2941\n");
557 return PTR_ERR(info->supply);
558 } else {
559 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
560 }
561
562 return 0;
563}
564
565static void ltc294x_i2c_shutdown(struct i2c_client *client)
566{
567 struct ltc294x_info *info = i2c_get_clientdata(client);
568 int ret;
569 u8 value;
570 u8 control;
571
572
573 if (info->id == LTC2941_ID)
574 return;
575
576
577 ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
578 if (ret < 0)
579 return;
580
581
582 control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
583 if (control != value)
584 ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,
585 &control, 1);
586}
587
588#ifdef CONFIG_PM_SLEEP
589
590static int ltc294x_suspend(struct device *dev)
591{
592 struct i2c_client *client = to_i2c_client(dev);
593 struct ltc294x_info *info = i2c_get_clientdata(client);
594
595 cancel_delayed_work(&info->work);
596 return 0;
597}
598
599static int ltc294x_resume(struct device *dev)
600{
601 struct i2c_client *client = to_i2c_client(dev);
602 struct ltc294x_info *info = i2c_get_clientdata(client);
603
604 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
605 return 0;
606}
607
608static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
609#define LTC294X_PM_OPS (<c294x_pm_ops)
610
611#else
612#define LTC294X_PM_OPS NULL
613#endif
614
615
616static const struct i2c_device_id ltc294x_i2c_id[] = {
617 { "ltc2941", LTC2941_ID, },
618 { "ltc2942", LTC2942_ID, },
619 { "ltc2943", LTC2943_ID, },
620 { "ltc2944", LTC2944_ID, },
621 { },
622};
623MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
624
625static const struct of_device_id ltc294x_i2c_of_match[] = {
626 {
627 .compatible = "lltc,ltc2941",
628 .data = (void *)LTC2941_ID,
629 },
630 {
631 .compatible = "lltc,ltc2942",
632 .data = (void *)LTC2942_ID,
633 },
634 {
635 .compatible = "lltc,ltc2943",
636 .data = (void *)LTC2943_ID,
637 },
638 {
639 .compatible = "lltc,ltc2944",
640 .data = (void *)LTC2944_ID,
641 },
642 { },
643};
644MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
645
646static struct i2c_driver ltc294x_driver = {
647 .driver = {
648 .name = "LTC2941",
649 .of_match_table = ltc294x_i2c_of_match,
650 .pm = LTC294X_PM_OPS,
651 },
652 .probe = ltc294x_i2c_probe,
653 .shutdown = ltc294x_i2c_shutdown,
654 .id_table = ltc294x_i2c_id,
655};
656module_i2c_driver(ltc294x_driver);
657
658MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
659MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
660MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
661MODULE_LICENSE("GPL");
662
