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10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/types.h>
13#include <linux/errno.h>
14#include <linux/swab.h>
15#include <linux/i2c.h>
16#include <linux/delay.h>
17#include <linux/idr.h>
18#include <linux/power_supply.h>
19#include <linux/slab.h>
20
21#define I16_MSB(x) ((x >> 8) & 0xFF)
22#define I16_LSB(x) (x & 0xFF)
23
24#define LTC294X_WORK_DELAY 10
25
26#define LTC294X_MAX_VALUE 0xFFFF
27#define LTC294X_MID_SUPPLY 0x7FFF
28
29#define LTC2941_MAX_PRESCALER_EXP 7
30#define LTC2943_MAX_PRESCALER_EXP 6
31
32enum ltc294x_reg {
33 LTC294X_REG_STATUS = 0x00,
34 LTC294X_REG_CONTROL = 0x01,
35 LTC294X_REG_ACC_CHARGE_MSB = 0x02,
36 LTC294X_REG_ACC_CHARGE_LSB = 0x03,
37 LTC294X_REG_THRESH_HIGH_MSB = 0x04,
38 LTC294X_REG_THRESH_HIGH_LSB = 0x05,
39 LTC294X_REG_THRESH_LOW_MSB = 0x06,
40 LTC294X_REG_THRESH_LOW_LSB = 0x07,
41 LTC294X_REG_VOLTAGE_MSB = 0x08,
42 LTC294X_REG_VOLTAGE_LSB = 0x09,
43 LTC294X_REG_CURRENT_MSB = 0x0E,
44 LTC294X_REG_CURRENT_LSB = 0x0F,
45 LTC294X_REG_TEMPERATURE_MSB = 0x14,
46 LTC294X_REG_TEMPERATURE_LSB = 0x15,
47};
48
49#define LTC2943_REG_CONTROL_MODE_MASK (BIT(7) | BIT(6))
50#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
51#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3))
52#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
53#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
54 ((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
55#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED 0
56
57#define LTC2941_NUM_REGS 0x08
58#define LTC2943_NUM_REGS 0x18
59
60struct ltc294x_info {
61 struct i2c_client *client;
62 struct power_supply supply;
63 struct delayed_work work;
64 int num_regs;
65 int id;
66 int charge;
67 int r_sense;
68 int Qlsb;
69};
70
71static DEFINE_IDR(ltc294x_id);
72static DEFINE_MUTEX(ltc294x_lock);
73
74static inline int convert_bin_to_uAh(
75 const struct ltc294x_info *info, int Q)
76{
77 return ((Q * (info->Qlsb / 10))) / 100;
78}
79
80static inline int convert_uAh_to_bin(
81 const struct ltc294x_info *info, int uAh)
82{
83 int Q;
84
85 Q = (uAh * 100) / (info->Qlsb/10);
86 return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
87}
88
89static int ltc294x_read_regs(struct i2c_client *client,
90 enum ltc294x_reg reg, u8 *buf, int num_regs)
91{
92 int ret;
93 struct i2c_msg msgs[2] = { };
94 u8 reg_start = reg;
95
96 msgs[0].addr = client->addr;
97 msgs[0].len = 1;
98 msgs[0].buf = ®_start;
99
100 msgs[1].addr = client->addr;
101 msgs[1].len = num_regs;
102 msgs[1].buf = buf;
103 msgs[1].flags = I2C_M_RD;
104
105 ret = i2c_transfer(client->adapter, &msgs[0], 2);
106 if (ret < 0) {
107 dev_err(&client->dev, "ltc2941 read_reg failed!\n");
108 return ret;
109 }
110
111 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
112 __func__, reg, num_regs, *buf);
113
114 return 0;
115}
116
117static int ltc294x_write_regs(struct i2c_client *client,
118 enum ltc294x_reg reg, const u8 *buf, int num_regs)
119{
120 int ret;
121 u8 reg_start = reg;
122
123 ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
124 if (ret < 0) {
125 dev_err(&client->dev, "ltc2941 write_reg failed!\n");
126 return ret;
127 }
128
129 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
130 __func__, reg, num_regs, *buf);
131
132 return 0;
133}
134
135static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
136{
137 int ret;
138 u8 value;
139 u8 control;
140
141
142 ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
143 if (ret < 0) {
144 dev_err(&info->client->dev,
145 "Could not read registers from device\n");
146 goto error_exit;
147 }
148
149 control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
150 LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
151
152 if (info->num_regs == LTC2943_NUM_REGS)
153 control |= LTC2943_REG_CONTROL_MODE_SCAN;
154
155 if (value != control) {
156 ret = ltc294x_write_regs(info->client,
157 LTC294X_REG_CONTROL, &control, 1);
158 if (ret < 0) {
159 dev_err(&info->client->dev,
160 "Could not write register\n");
161 goto error_exit;
162 }
163 }
164
165 return 0;
166
167error_exit:
168 return ret;
169}
170
171static int ltc294x_read_charge_register(const struct ltc294x_info *info)
172{
173 int ret;
174 u8 datar[2];
175
176 ret = ltc294x_read_regs(info->client,
177 LTC294X_REG_ACC_CHARGE_MSB, &datar[0], 2);
178 if (ret < 0)
179 return ret;
180 return (datar[0] << 8) + datar[1];
181}
182
183static int ltc294x_get_charge_now(const struct ltc294x_info *info, int *val)
184{
185 int value = ltc294x_read_charge_register(info);
186
187 if (value < 0)
188 return value;
189
190 if (info->Qlsb < 0)
191 value -= 0xFFFF;
192 *val = convert_bin_to_uAh(info, value);
193 return 0;
194}
195
196static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
197{
198 int ret;
199 u8 dataw[2];
200 u8 ctrl_reg;
201 s32 value;
202
203 value = convert_uAh_to_bin(info, val);
204
205 if (info->Qlsb < 0)
206 value += 0xFFFF;
207 if ((value < 0) || (value > 0xFFFF))
208 return -EINVAL;
209
210
211 ret = ltc294x_read_regs(info->client,
212 LTC294X_REG_CONTROL, &ctrl_reg, 1);
213 if (ret < 0)
214 return ret;
215
216 ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
217 ret = ltc294x_write_regs(info->client,
218 LTC294X_REG_CONTROL, &ctrl_reg, 1);
219 if (ret < 0)
220 return ret;
221
222 dataw[0] = I16_MSB(value);
223 dataw[1] = I16_LSB(value);
224 ret = ltc294x_write_regs(info->client,
225 LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
226 if (ret < 0)
227 goto error_exit;
228
229error_exit:
230 ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
231 ret = ltc294x_write_regs(info->client,
232 LTC294X_REG_CONTROL, &ctrl_reg, 1);
233
234 return ret < 0 ? ret : 0;
235}
236
237static int ltc294x_get_charge_counter(
238 const struct ltc294x_info *info, int *val)
239{
240 int value = ltc294x_read_charge_register(info);
241
242 if (value < 0)
243 return value;
244 value -= LTC294X_MID_SUPPLY;
245 *val = convert_bin_to_uAh(info, value);
246 return 0;
247}
248
249static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
250{
251 int ret;
252 u8 datar[2];
253 u32 value;
254
255 ret = ltc294x_read_regs(info->client,
256 LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
257 value = (datar[0] << 8) | datar[1];
258 *val = ((value * 23600) / 0xFFFF) * 1000;
259 return ret;
260}
261
262static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
263{
264 int ret;
265 u8 datar[2];
266 s32 value;
267
268 ret = ltc294x_read_regs(info->client,
269 LTC294X_REG_CURRENT_MSB, &datar[0], 2);
270 value = (datar[0] << 8) | datar[1];
271 value -= 0x7FFF;
272
273
274
275 *val = 1000 * ((60000 * value) / (info->r_sense * 0x7FFF));
276 return ret;
277}
278
279static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
280{
281 int ret;
282 u8 datar[2];
283 u32 value;
284
285 ret = ltc294x_read_regs(info->client,
286 LTC294X_REG_TEMPERATURE_MSB, &datar[0], 2);
287 value = (datar[0] << 8) | datar[1];
288
289 *val = (((51000 * value) / 0xFFFF) - 27215);
290 return ret;
291}
292
293static int ltc294x_get_property(struct power_supply *psy,
294 enum power_supply_property prop,
295 union power_supply_propval *val)
296{
297 struct ltc294x_info *info =
298 container_of(psy, struct ltc294x_info, supply);
299
300 switch (prop) {
301 case POWER_SUPPLY_PROP_CHARGE_NOW:
302 return ltc294x_get_charge_now(info, &val->intval);
303 case POWER_SUPPLY_PROP_CHARGE_COUNTER:
304 return ltc294x_get_charge_counter(info, &val->intval);
305 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
306 return ltc294x_get_voltage(info, &val->intval);
307 case POWER_SUPPLY_PROP_CURRENT_NOW:
308 return ltc294x_get_current(info, &val->intval);
309 case POWER_SUPPLY_PROP_TEMP:
310 return ltc294x_get_temperature(info, &val->intval);
311 default:
312 return -EINVAL;
313 }
314}
315
316static int ltc294x_set_property(struct power_supply *psy,
317 enum power_supply_property psp,
318 const union power_supply_propval *val)
319{
320 struct ltc294x_info *info =
321 container_of(psy, struct ltc294x_info, supply);
322
323 switch (psp) {
324 case POWER_SUPPLY_PROP_CHARGE_NOW:
325 return ltc294x_set_charge_now(info, val->intval);
326 default:
327 return -EPERM;
328 }
329}
330
331static int ltc294x_property_is_writeable(
332 struct power_supply *psy, enum power_supply_property psp)
333{
334 switch (psp) {
335 case POWER_SUPPLY_PROP_CHARGE_NOW:
336 return 1;
337 default:
338 return 0;
339 }
340}
341
342static void ltc294x_update(struct ltc294x_info *info)
343{
344 int charge = ltc294x_read_charge_register(info);
345
346 if (charge != info->charge) {
347 info->charge = charge;
348 power_supply_changed(&info->supply);
349 }
350}
351
352static void ltc294x_work(struct work_struct *work)
353{
354 struct ltc294x_info *info;
355
356 info = container_of(work, struct ltc294x_info, work.work);
357 ltc294x_update(info);
358 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
359}
360
361static enum power_supply_property ltc294x_properties[] = {
362 POWER_SUPPLY_PROP_CHARGE_COUNTER,
363 POWER_SUPPLY_PROP_CHARGE_NOW,
364 POWER_SUPPLY_PROP_VOLTAGE_NOW,
365 POWER_SUPPLY_PROP_CURRENT_NOW,
366 POWER_SUPPLY_PROP_TEMP,
367};
368
369static int ltc294x_i2c_remove(struct i2c_client *client)
370{
371 struct ltc294x_info *info = i2c_get_clientdata(client);
372
373 cancel_delayed_work(&info->work);
374 power_supply_unregister(&info->supply);
375 kfree(info->supply.name);
376 mutex_lock(<c294x_lock);
377 idr_remove(<c294x_id, info->id);
378 mutex_unlock(<c294x_lock);
379 return 0;
380}
381
382static int ltc294x_i2c_probe(struct i2c_client *client,
383 const struct i2c_device_id *id)
384{
385 struct ltc294x_info *info;
386 int ret;
387 int num;
388 u32 prescaler_exp;
389 s32 r_sense;
390 struct device_node *np;
391
392 mutex_lock(<c294x_lock);
393 ret = idr_alloc(<c294x_id, client, 0, 0, GFP_KERNEL);
394 mutex_unlock(<c294x_lock);
395 if (ret < 0)
396 goto fail_id;
397
398 num = ret;
399
400 info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
401 if (info == NULL) {
402 ret = -ENOMEM;
403 goto fail_info;
404 }
405
406 i2c_set_clientdata(client, info);
407
408 info->num_regs = id->driver_data;
409 info->supply.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num);
410 if (!info->supply.name) {
411 ret = -ENOMEM;
412 goto fail_name;
413 }
414
415 np = of_node_get(client->dev.of_node);
416
417
418
419 ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
420 if (ret < 0) {
421 dev_err(&client->dev,
422 "Could not find lltc,resistor-sense in devicetree\n");
423 goto fail_name;
424 }
425 info->r_sense = r_sense;
426
427 ret = of_property_read_u32(np, "lltc,prescaler-exponent",
428 &prescaler_exp);
429 if (ret < 0) {
430 dev_warn(&client->dev,
431 "lltc,prescaler-exponent not in devicetree\n");
432 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
433 }
434
435 if (info->num_regs == LTC2943_NUM_REGS) {
436 if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
437 prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
438 info->Qlsb = ((340 * 50000) / r_sense) /
439 (4096 / (1 << (2*prescaler_exp)));
440 } else {
441 if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
442 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
443 info->Qlsb = ((58 * 50000) / r_sense) /
444 (128 / (1 << prescaler_exp));
445 }
446
447 info->client = client;
448 info->id = num;
449 info->supply.type = POWER_SUPPLY_TYPE_BATTERY;
450 info->supply.properties = ltc294x_properties;
451 if (info->num_regs >= LTC294X_REG_TEMPERATURE_LSB)
452 info->supply.num_properties =
453 ARRAY_SIZE(ltc294x_properties);
454 else if (info->num_regs >= LTC294X_REG_CURRENT_LSB)
455 info->supply.num_properties =
456 ARRAY_SIZE(ltc294x_properties) - 1;
457 else if (info->num_regs >= LTC294X_REG_VOLTAGE_LSB)
458 info->supply.num_properties =
459 ARRAY_SIZE(ltc294x_properties) - 2;
460 else
461 info->supply.num_properties =
462 ARRAY_SIZE(ltc294x_properties) - 3;
463 info->supply.get_property = ltc294x_get_property;
464 info->supply.set_property = ltc294x_set_property;
465 info->supply.property_is_writeable = ltc294x_property_is_writeable;
466 info->supply.external_power_changed = NULL;
467
468 INIT_DELAYED_WORK(&info->work, ltc294x_work);
469
470 ret = ltc294x_reset(info, prescaler_exp);
471 if (ret < 0) {
472 dev_err(&client->dev, "Communication with chip failed\n");
473 goto fail_comm;
474 }
475
476 ret = power_supply_register(&client->dev, &info->supply);
477 if (ret) {
478 dev_err(&client->dev, "failed to register ltc2941\n");
479 goto fail_register;
480 } else {
481 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
482 }
483
484 return 0;
485
486fail_register:
487 kfree(info->supply.name);
488fail_comm:
489fail_name:
490fail_info:
491 mutex_lock(<c294x_lock);
492 idr_remove(<c294x_id, num);
493 mutex_unlock(<c294x_lock);
494fail_id:
495 return ret;
496}
497
498#ifdef CONFIG_PM_SLEEP
499
500static int ltc294x_suspend(struct device *dev)
501{
502 struct i2c_client *client = to_i2c_client(dev);
503 struct ltc294x_info *info = i2c_get_clientdata(client);
504
505 cancel_delayed_work(&info->work);
506 return 0;
507}
508
509static int ltc294x_resume(struct device *dev)
510{
511 struct i2c_client *client = to_i2c_client(dev);
512 struct ltc294x_info *info = i2c_get_clientdata(client);
513
514 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
515 return 0;
516}
517
518static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
519#define LTC294X_PM_OPS (<c294x_pm_ops)
520
521#else
522#define LTC294X_PM_OPS NULL
523#endif
524
525
526static const struct i2c_device_id ltc294x_i2c_id[] = {
527 {"ltc2941", LTC2941_NUM_REGS},
528 {"ltc2943", LTC2943_NUM_REGS},
529 { },
530};
531MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
532
533static struct i2c_driver ltc294x_driver = {
534 .driver = {
535 .name = "LTC2941",
536 .pm = LTC294X_PM_OPS,
537 },
538 .probe = ltc294x_i2c_probe,
539 .remove = ltc294x_i2c_remove,
540 .id_table = ltc294x_i2c_id,
541};
542module_i2c_driver(ltc294x_driver);
543
544MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
545MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
546MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver");
547MODULE_LICENSE("GPL");
548
