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10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/of_device.h>
13#include <linux/types.h>
14#include <linux/errno.h>
15#include <linux/swab.h>
16#include <linux/i2c.h>
17#include <linux/delay.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 power_supply_desc supply_desc;
64 struct delayed_work work;
65 unsigned long num_regs;
66 int charge;
67 int r_sense;
68 int Qlsb;
69};
70
71static inline int convert_bin_to_uAh(
72 const struct ltc294x_info *info, int Q)
73{
74 return ((Q * (info->Qlsb / 10))) / 100;
75}
76
77static inline int convert_uAh_to_bin(
78 const struct ltc294x_info *info, int uAh)
79{
80 int Q;
81
82 Q = (uAh * 100) / (info->Qlsb/10);
83 return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
84}
85
86static int ltc294x_read_regs(struct i2c_client *client,
87 enum ltc294x_reg reg, u8 *buf, int num_regs)
88{
89 int ret;
90 struct i2c_msg msgs[2] = { };
91 u8 reg_start = reg;
92
93 msgs[0].addr = client->addr;
94 msgs[0].len = 1;
95 msgs[0].buf = ®_start;
96
97 msgs[1].addr = client->addr;
98 msgs[1].len = num_regs;
99 msgs[1].buf = buf;
100 msgs[1].flags = I2C_M_RD;
101
102 ret = i2c_transfer(client->adapter, &msgs[0], 2);
103 if (ret < 0) {
104 dev_err(&client->dev, "ltc2941 read_reg failed!\n");
105 return ret;
106 }
107
108 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
109 __func__, reg, num_regs, *buf);
110
111 return 0;
112}
113
114static int ltc294x_write_regs(struct i2c_client *client,
115 enum ltc294x_reg reg, const u8 *buf, int num_regs)
116{
117 int ret;
118 u8 reg_start = reg;
119
120 ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
121 if (ret < 0) {
122 dev_err(&client->dev, "ltc2941 write_reg failed!\n");
123 return ret;
124 }
125
126 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
127 __func__, reg, num_regs, *buf);
128
129 return 0;
130}
131
132static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
133{
134 int ret;
135 u8 value;
136 u8 control;
137
138
139 ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
140 if (ret < 0) {
141 dev_err(&info->client->dev,
142 "Could not read registers from device\n");
143 goto error_exit;
144 }
145
146 control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
147 LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
148
149 if (info->num_regs == LTC2943_NUM_REGS)
150 control |= LTC2943_REG_CONTROL_MODE_SCAN;
151
152 if (value != control) {
153 ret = ltc294x_write_regs(info->client,
154 LTC294X_REG_CONTROL, &control, 1);
155 if (ret < 0) {
156 dev_err(&info->client->dev,
157 "Could not write register\n");
158 goto error_exit;
159 }
160 }
161
162 return 0;
163
164error_exit:
165 return ret;
166}
167
168static int ltc294x_read_charge_register(const struct ltc294x_info *info)
169{
170 int ret;
171 u8 datar[2];
172
173 ret = ltc294x_read_regs(info->client,
174 LTC294X_REG_ACC_CHARGE_MSB, &datar[0], 2);
175 if (ret < 0)
176 return ret;
177 return (datar[0] << 8) + datar[1];
178}
179
180static int ltc294x_get_charge_now(const struct ltc294x_info *info, int *val)
181{
182 int value = ltc294x_read_charge_register(info);
183
184 if (value < 0)
185 return value;
186
187 if (info->Qlsb < 0)
188 value -= 0xFFFF;
189 *val = convert_bin_to_uAh(info, value);
190 return 0;
191}
192
193static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
194{
195 int ret;
196 u8 dataw[2];
197 u8 ctrl_reg;
198 s32 value;
199
200 value = convert_uAh_to_bin(info, val);
201
202 if (info->Qlsb < 0)
203 value += 0xFFFF;
204 if ((value < 0) || (value > 0xFFFF))
205 return -EINVAL;
206
207
208 ret = ltc294x_read_regs(info->client,
209 LTC294X_REG_CONTROL, &ctrl_reg, 1);
210 if (ret < 0)
211 return ret;
212
213 ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
214 ret = ltc294x_write_regs(info->client,
215 LTC294X_REG_CONTROL, &ctrl_reg, 1);
216 if (ret < 0)
217 return ret;
218
219 dataw[0] = I16_MSB(value);
220 dataw[1] = I16_LSB(value);
221 ret = ltc294x_write_regs(info->client,
222 LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
223 if (ret < 0)
224 goto error_exit;
225
226error_exit:
227 ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
228 ret = ltc294x_write_regs(info->client,
229 LTC294X_REG_CONTROL, &ctrl_reg, 1);
230
231 return ret < 0 ? ret : 0;
232}
233
234static int ltc294x_get_charge_counter(
235 const struct ltc294x_info *info, int *val)
236{
237 int value = ltc294x_read_charge_register(info);
238
239 if (value < 0)
240 return value;
241 value -= LTC294X_MID_SUPPLY;
242 *val = convert_bin_to_uAh(info, value);
243 return 0;
244}
245
246static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
247{
248 int ret;
249 u8 datar[2];
250 u32 value;
251
252 ret = ltc294x_read_regs(info->client,
253 LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
254 value = (datar[0] << 8) | datar[1];
255 *val = ((value * 23600) / 0xFFFF) * 1000;
256 return ret;
257}
258
259static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
260{
261 int ret;
262 u8 datar[2];
263 s32 value;
264
265 ret = ltc294x_read_regs(info->client,
266 LTC294X_REG_CURRENT_MSB, &datar[0], 2);
267 value = (datar[0] << 8) | datar[1];
268 value -= 0x7FFF;
269
270
271
272 *val = 1000 * ((60000 * value) / (info->r_sense * 0x7FFF));
273 return ret;
274}
275
276static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
277{
278 int ret;
279 u8 datar[2];
280 u32 value;
281
282 ret = ltc294x_read_regs(info->client,
283 LTC294X_REG_TEMPERATURE_MSB, &datar[0], 2);
284 value = (datar[0] << 8) | datar[1];
285
286 *val = (((51000 * value) / 0xFFFF) - 27215);
287 return ret;
288}
289
290static int ltc294x_get_property(struct power_supply *psy,
291 enum power_supply_property prop,
292 union power_supply_propval *val)
293{
294 struct ltc294x_info *info = power_supply_get_drvdata(psy);
295
296 switch (prop) {
297 case POWER_SUPPLY_PROP_CHARGE_NOW:
298 return ltc294x_get_charge_now(info, &val->intval);
299 case POWER_SUPPLY_PROP_CHARGE_COUNTER:
300 return ltc294x_get_charge_counter(info, &val->intval);
301 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
302 return ltc294x_get_voltage(info, &val->intval);
303 case POWER_SUPPLY_PROP_CURRENT_NOW:
304 return ltc294x_get_current(info, &val->intval);
305 case POWER_SUPPLY_PROP_TEMP:
306 return ltc294x_get_temperature(info, &val->intval);
307 default:
308 return -EINVAL;
309 }
310}
311
312static int ltc294x_set_property(struct power_supply *psy,
313 enum power_supply_property psp,
314 const union power_supply_propval *val)
315{
316 struct ltc294x_info *info = power_supply_get_drvdata(psy);
317
318 switch (psp) {
319 case POWER_SUPPLY_PROP_CHARGE_NOW:
320 return ltc294x_set_charge_now(info, val->intval);
321 default:
322 return -EPERM;
323 }
324}
325
326static int ltc294x_property_is_writeable(
327 struct power_supply *psy, enum power_supply_property psp)
328{
329 switch (psp) {
330 case POWER_SUPPLY_PROP_CHARGE_NOW:
331 return 1;
332 default:
333 return 0;
334 }
335}
336
337static void ltc294x_update(struct ltc294x_info *info)
338{
339 int charge = ltc294x_read_charge_register(info);
340
341 if (charge != info->charge) {
342 info->charge = charge;
343 power_supply_changed(info->supply);
344 }
345}
346
347static void ltc294x_work(struct work_struct *work)
348{
349 struct ltc294x_info *info;
350
351 info = container_of(work, struct ltc294x_info, work.work);
352 ltc294x_update(info);
353 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
354}
355
356static enum power_supply_property ltc294x_properties[] = {
357 POWER_SUPPLY_PROP_CHARGE_COUNTER,
358 POWER_SUPPLY_PROP_CHARGE_NOW,
359 POWER_SUPPLY_PROP_VOLTAGE_NOW,
360 POWER_SUPPLY_PROP_CURRENT_NOW,
361 POWER_SUPPLY_PROP_TEMP,
362};
363
364static int ltc294x_i2c_remove(struct i2c_client *client)
365{
366 struct ltc294x_info *info = i2c_get_clientdata(client);
367
368 cancel_delayed_work(&info->work);
369 power_supply_unregister(info->supply);
370 return 0;
371}
372
373static int ltc294x_i2c_probe(struct i2c_client *client,
374 const struct i2c_device_id *id)
375{
376 struct power_supply_config psy_cfg = {};
377 struct ltc294x_info *info;
378 int ret;
379 u32 prescaler_exp;
380 s32 r_sense;
381 struct device_node *np;
382
383 info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
384 if (info == NULL)
385 return -ENOMEM;
386
387 i2c_set_clientdata(client, info);
388
389 np = of_node_get(client->dev.of_node);
390
391 info->num_regs = (unsigned long)of_device_get_match_data(&client->dev);
392 info->supply_desc.name = np->name;
393
394
395
396 ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
397 if (ret < 0) {
398 dev_err(&client->dev,
399 "Could not find lltc,resistor-sense in devicetree\n");
400 return ret;
401 }
402 info->r_sense = r_sense;
403
404 ret = of_property_read_u32(np, "lltc,prescaler-exponent",
405 &prescaler_exp);
406 if (ret < 0) {
407 dev_warn(&client->dev,
408 "lltc,prescaler-exponent not in devicetree\n");
409 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
410 }
411
412 if (info->num_regs == LTC2943_NUM_REGS) {
413 if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
414 prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
415 info->Qlsb = ((340 * 50000) / r_sense) /
416 (4096 / (1 << (2*prescaler_exp)));
417 } else {
418 if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
419 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
420 info->Qlsb = ((85 * 50000) / r_sense) /
421 (128 / (1 << prescaler_exp));
422 }
423
424 info->client = client;
425 info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
426 info->supply_desc.properties = ltc294x_properties;
427 if (info->num_regs >= LTC294X_REG_TEMPERATURE_LSB)
428 info->supply_desc.num_properties =
429 ARRAY_SIZE(ltc294x_properties);
430 else if (info->num_regs >= LTC294X_REG_CURRENT_LSB)
431 info->supply_desc.num_properties =
432 ARRAY_SIZE(ltc294x_properties) - 1;
433 else if (info->num_regs >= LTC294X_REG_VOLTAGE_LSB)
434 info->supply_desc.num_properties =
435 ARRAY_SIZE(ltc294x_properties) - 2;
436 else
437 info->supply_desc.num_properties =
438 ARRAY_SIZE(ltc294x_properties) - 3;
439 info->supply_desc.get_property = ltc294x_get_property;
440 info->supply_desc.set_property = ltc294x_set_property;
441 info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
442 info->supply_desc.external_power_changed = NULL;
443
444 psy_cfg.drv_data = info;
445
446 INIT_DELAYED_WORK(&info->work, ltc294x_work);
447
448 ret = ltc294x_reset(info, prescaler_exp);
449 if (ret < 0) {
450 dev_err(&client->dev, "Communication with chip failed\n");
451 return ret;
452 }
453
454 info->supply = power_supply_register(&client->dev, &info->supply_desc,
455 &psy_cfg);
456 if (IS_ERR(info->supply)) {
457 dev_err(&client->dev, "failed to register ltc2941\n");
458 return PTR_ERR(info->supply);
459 } else {
460 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
461 }
462
463 return 0;
464}
465
466#ifdef CONFIG_PM_SLEEP
467
468static int ltc294x_suspend(struct device *dev)
469{
470 struct i2c_client *client = to_i2c_client(dev);
471 struct ltc294x_info *info = i2c_get_clientdata(client);
472
473 cancel_delayed_work(&info->work);
474 return 0;
475}
476
477static int ltc294x_resume(struct device *dev)
478{
479 struct i2c_client *client = to_i2c_client(dev);
480 struct ltc294x_info *info = i2c_get_clientdata(client);
481
482 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
483 return 0;
484}
485
486static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
487#define LTC294X_PM_OPS (<c294x_pm_ops)
488
489#else
490#define LTC294X_PM_OPS NULL
491#endif
492
493
494static const struct i2c_device_id ltc294x_i2c_id[] = {
495 {"ltc2941", LTC2941_NUM_REGS},
496 {"ltc2943", LTC2943_NUM_REGS},
497 { },
498};
499MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
500
501static const struct of_device_id ltc294x_i2c_of_match[] = {
502 {
503 .compatible = "lltc,ltc2941",
504 .data = (void *)LTC2941_NUM_REGS
505 },
506 {
507 .compatible = "lltc,ltc2943",
508 .data = (void *)LTC2943_NUM_REGS
509 },
510 { },
511};
512MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
513
514static struct i2c_driver ltc294x_driver = {
515 .driver = {
516 .name = "LTC2941",
517 .of_match_table = ltc294x_i2c_of_match,
518 .pm = LTC294X_PM_OPS,
519 },
520 .probe = ltc294x_i2c_probe,
521 .remove = ltc294x_i2c_remove,
522 .id_table = ltc294x_i2c_id,
523};
524module_i2c_driver(ltc294x_driver);
525
526MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
527MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
528MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver");
529MODULE_LICENSE("GPL");
530
