1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
4 *
5 * Copyright (C) 2009 Bluewater Systems Ltd
6 *
7 * Author: Ryan Mallon
8 *
9 * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
10 *
11 * UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru>
12 */
13
14#include <linux/devm-helpers.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/types.h>
18#include <linux/errno.h>
19#include <linux/swab.h>
20#include <linux/i2c.h>
21#include <linux/delay.h>
22#include <linux/idr.h>
23#include <linux/power_supply.h>
24#include <linux/slab.h>
25#include <linux/ds2782_battery.h>
26
27#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */
28
29#define DS278x_REG_VOLT_MSB 0x0c
30#define DS278x_REG_TEMP_MSB 0x0a
31#define DS278x_REG_CURRENT_MSB 0x0e
32
33/* EEPROM Block */
34#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
35
36/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
37#define DS2782_CURRENT_UNITS 1563
38
39#define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */
40
41#define DS2786_CURRENT_UNITS 25
42
43#define DS278x_DELAY 1000
44
45struct ds278x_info;
46
47struct ds278x_battery_ops {
48 int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
49 int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
50 int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
51};
52
53#define to_ds278x_info(x) power_supply_get_drvdata(x)
54
55struct ds278x_info {
56 struct i2c_client *client;
57 struct power_supply *battery;
58 struct power_supply_desc battery_desc;
59 const struct ds278x_battery_ops *ops;
60 struct delayed_work bat_work;
61 int rsns;
62 int capacity;
63 int status; /* State Of Charge */
64};
65
66static DEFINE_IDA(battery_id);
67
68static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
69{
70 int ret;
71
72 ret = i2c_smbus_read_byte_data(client: info->client, command: reg);
73 if (ret < 0) {
74 dev_err(&info->client->dev, "register read failed\n");
75 return ret;
76 }
77
78 *val = ret;
79 return 0;
80}
81
82static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
83 s16 *val)
84{
85 int ret;
86
87 ret = i2c_smbus_read_word_data(client: info->client, command: reg_msb);
88 if (ret < 0) {
89 dev_err(&info->client->dev, "register read failed\n");
90 return ret;
91 }
92
93 *val = swab16(ret);
94 return 0;
95}
96
97static int ds278x_get_temp(struct ds278x_info *info, int *temp)
98{
99 s16 raw;
100 int err;
101
102 /*
103 * Temperature is measured in units of 0.125 degrees celcius, the
104 * power_supply class measures temperature in tenths of degrees
105 * celsius. The temperature value is stored as a 10 bit number, plus
106 * sign in the upper bits of a 16 bit register.
107 */
108 err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, val: &raw);
109 if (err)
110 return err;
111 *temp = ((raw / 32) * 125) / 100;
112 return 0;
113}
114
115static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
116{
117 int sense_res;
118 int err;
119 u8 sense_res_raw;
120 s16 raw;
121
122 /*
123 * The units of measurement for current are dependent on the value of
124 * the sense resistor.
125 */
126 err = ds278x_read_reg(info, DS2782_REG_RSNSP, val: &sense_res_raw);
127 if (err)
128 return err;
129 if (sense_res_raw == 0) {
130 dev_err(&info->client->dev, "sense resistor value is 0\n");
131 return -ENXIO;
132 }
133 sense_res = 1000 / sense_res_raw;
134
135 dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
136 sense_res);
137 err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, val: &raw);
138 if (err)
139 return err;
140 *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
141 return 0;
142}
143
144static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
145{
146 s16 raw;
147 int err;
148
149 /*
150 * Voltage is measured in units of 4.88mV. The voltage is stored as
151 * a 10-bit number plus sign, in the upper bits of a 16-bit register
152 */
153 err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, val: &raw);
154 if (err)
155 return err;
156 *voltage_uV = (raw / 32) * 4800;
157 return 0;
158}
159
160static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
161{
162 int err;
163 u8 raw;
164
165 err = ds278x_read_reg(info, DS2782_REG_RARC, val: &raw);
166 if (err)
167 return err;
168 *capacity = raw;
169 return 0;
170}
171
172static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
173{
174 int err;
175 s16 raw;
176
177 err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, val: &raw);
178 if (err)
179 return err;
180 *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
181 return 0;
182}
183
184static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
185{
186 s16 raw;
187 int err;
188
189 /*
190 * Voltage is measured in units of 1.22mV. The voltage is stored as
191 * a 12-bit number plus sign, in the upper bits of a 16-bit register
192 */
193 err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, val: &raw);
194 if (err)
195 return err;
196 *voltage_uV = (raw / 8) * 1220;
197 return 0;
198}
199
200static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
201{
202 int err;
203 u8 raw;
204
205 err = ds278x_read_reg(info, DS2786_REG_RARC, val: &raw);
206 if (err)
207 return err;
208 /* Relative capacity is displayed with resolution 0.5 % */
209 *capacity = raw/2 ;
210 return 0;
211}
212
213static int ds278x_get_status(struct ds278x_info *info, int *status)
214{
215 int err;
216 int current_uA;
217 int capacity;
218
219 err = info->ops->get_battery_current(info, &current_uA);
220 if (err)
221 return err;
222
223 err = info->ops->get_battery_capacity(info, &capacity);
224 if (err)
225 return err;
226
227 info->capacity = capacity;
228
229 if (capacity == 100)
230 *status = POWER_SUPPLY_STATUS_FULL;
231 else if (current_uA == 0)
232 *status = POWER_SUPPLY_STATUS_NOT_CHARGING;
233 else if (current_uA < 0)
234 *status = POWER_SUPPLY_STATUS_DISCHARGING;
235 else
236 *status = POWER_SUPPLY_STATUS_CHARGING;
237
238 return 0;
239}
240
241static int ds278x_battery_get_property(struct power_supply *psy,
242 enum power_supply_property prop,
243 union power_supply_propval *val)
244{
245 struct ds278x_info *info = to_ds278x_info(psy);
246 int ret;
247
248 switch (prop) {
249 case POWER_SUPPLY_PROP_STATUS:
250 ret = ds278x_get_status(info, status: &val->intval);
251 break;
252
253 case POWER_SUPPLY_PROP_CAPACITY:
254 ret = info->ops->get_battery_capacity(info, &val->intval);
255 break;
256
257 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
258 ret = info->ops->get_battery_voltage(info, &val->intval);
259 break;
260
261 case POWER_SUPPLY_PROP_CURRENT_NOW:
262 ret = info->ops->get_battery_current(info, &val->intval);
263 break;
264
265 case POWER_SUPPLY_PROP_TEMP:
266 ret = ds278x_get_temp(info, temp: &val->intval);
267 break;
268
269 default:
270 ret = -EINVAL;
271 }
272
273 return ret;
274}
275
276static void ds278x_bat_update(struct ds278x_info *info)
277{
278 int old_status = info->status;
279 int old_capacity = info->capacity;
280
281 ds278x_get_status(info, status: &info->status);
282
283 if ((old_status != info->status) || (old_capacity != info->capacity))
284 power_supply_changed(psy: info->battery);
285}
286
287static void ds278x_bat_work(struct work_struct *work)
288{
289 struct ds278x_info *info;
290
291 info = container_of(work, struct ds278x_info, bat_work.work);
292 ds278x_bat_update(info);
293
294 schedule_delayed_work(dwork: &info->bat_work, DS278x_DELAY);
295}
296
297static enum power_supply_property ds278x_battery_props[] = {
298 POWER_SUPPLY_PROP_STATUS,
299 POWER_SUPPLY_PROP_CAPACITY,
300 POWER_SUPPLY_PROP_VOLTAGE_NOW,
301 POWER_SUPPLY_PROP_CURRENT_NOW,
302 POWER_SUPPLY_PROP_TEMP,
303};
304
305static void ds278x_power_supply_init(struct power_supply_desc *battery)
306{
307 battery->type = POWER_SUPPLY_TYPE_BATTERY;
308 battery->properties = ds278x_battery_props;
309 battery->num_properties = ARRAY_SIZE(ds278x_battery_props);
310 battery->get_property = ds278x_battery_get_property;
311 battery->external_power_changed = NULL;
312}
313
314#ifdef CONFIG_PM_SLEEP
315
316static int ds278x_suspend(struct device *dev)
317{
318 struct i2c_client *client = to_i2c_client(dev);
319 struct ds278x_info *info = i2c_get_clientdata(client);
320
321 cancel_delayed_work(dwork: &info->bat_work);
322 return 0;
323}
324
325static int ds278x_resume(struct device *dev)
326{
327 struct i2c_client *client = to_i2c_client(dev);
328 struct ds278x_info *info = i2c_get_clientdata(client);
329
330 schedule_delayed_work(dwork: &info->bat_work, DS278x_DELAY);
331 return 0;
332}
333#endif /* CONFIG_PM_SLEEP */
334
335static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);
336
337enum ds278x_num_id {
338 DS2782 = 0,
339 DS2786,
340};
341
342static const struct ds278x_battery_ops ds278x_ops[] = {
343 [DS2782] = {
344 .get_battery_current = ds2782_get_current,
345 .get_battery_voltage = ds2782_get_voltage,
346 .get_battery_capacity = ds2782_get_capacity,
347 },
348 [DS2786] = {
349 .get_battery_current = ds2786_get_current,
350 .get_battery_voltage = ds2786_get_voltage,
351 .get_battery_capacity = ds2786_get_capacity,
352 }
353};
354
355static void ds278x_free_ida(void *data)
356{
357 int num = (uintptr_t)data;
358
359 ida_free(&battery_id, id: num);
360}
361
362static int ds278x_battery_probe(struct i2c_client *client)
363{
364 const struct i2c_device_id *id = i2c_client_get_device_id(client);
365 struct ds278x_platform_data *pdata = client->dev.platform_data;
366 struct power_supply_config psy_cfg = {};
367 struct ds278x_info *info;
368 int ret;
369 int num;
370
371 /*
372 * ds2786 should have the sense resistor value set
373 * in the platform data
374 */
375 if (id->driver_data == DS2786 && !pdata) {
376 dev_err(&client->dev, "missing platform data for ds2786\n");
377 return -EINVAL;
378 }
379
380 /* Get an ID for this battery */
381 num = ida_alloc(ida: &battery_id, GFP_KERNEL);
382 if (num < 0)
383 return num;
384 ret = devm_add_action_or_reset(&client->dev, ds278x_free_ida, (void *)(uintptr_t)num);
385 if (ret)
386 return ret;
387
388 info = devm_kzalloc(dev: &client->dev, size: sizeof(*info), GFP_KERNEL);
389 if (!info)
390 return -ENOMEM;
391
392 info->battery_desc.name = devm_kasprintf(dev: &client->dev, GFP_KERNEL,
393 fmt: "%s-%d", client->name, num);
394 if (!info->battery_desc.name)
395 return -ENOMEM;
396
397 if (id->driver_data == DS2786)
398 info->rsns = pdata->rsns;
399
400 i2c_set_clientdata(client, data: info);
401 info->client = client;
402 info->ops = &ds278x_ops[id->driver_data];
403 ds278x_power_supply_init(battery: &info->battery_desc);
404 psy_cfg.drv_data = info;
405
406 info->capacity = 100;
407 info->status = POWER_SUPPLY_STATUS_FULL;
408
409 info->battery = devm_power_supply_register(parent: &client->dev,
410 desc: &info->battery_desc,
411 cfg: &psy_cfg);
412 if (IS_ERR(ptr: info->battery)) {
413 dev_err(&client->dev, "failed to register battery\n");
414 return PTR_ERR(ptr: info->battery);
415 }
416
417 ret = devm_delayed_work_autocancel(dev: &client->dev, w: &info->bat_work, worker: ds278x_bat_work);
418 if (ret)
419 return ret;
420 schedule_delayed_work(dwork: &info->bat_work, DS278x_DELAY);
421
422 return 0;
423}
424
425static const struct i2c_device_id ds278x_id[] = {
426 {"ds2782", DS2782},
427 {"ds2786", DS2786},
428 {},
429};
430MODULE_DEVICE_TABLE(i2c, ds278x_id);
431
432static struct i2c_driver ds278x_battery_driver = {
433 .driver = {
434 .name = "ds2782-battery",
435 .pm = &ds278x_battery_pm_ops,
436 },
437 .probe = ds278x_battery_probe,
438 .id_table = ds278x_id,
439};
440module_i2c_driver(ds278x_battery_driver);
441
442MODULE_AUTHOR("Ryan Mallon");
443MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC driver");
444MODULE_LICENSE("GPL");
445

source code of linux/drivers/power/supply/ds2782_battery.c