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/kernel.h>
15#include <linux/module.h>
16#include <linux/types.h>
17#include <linux/errno.h>
18#include <linux/swab.h>
19#include <linux/i2c.h>
20#include <linux/delay.h>
21#include <linux/idr.h>
22#include <linux/power_supply.h>
23#include <linux/slab.h>
24#include <linux/ds2782_battery.h>
25
26#define DS2782_REG_RARC		0x06	/* Remaining active relative capacity */
27
28#define DS278x_REG_VOLT_MSB	0x0c
29#define DS278x_REG_TEMP_MSB	0x0a
30#define DS278x_REG_CURRENT_MSB	0x0e
31
32/* EEPROM Block */
33#define DS2782_REG_RSNSP	0x69	/* Sense resistor value */
34
35/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
36#define DS2782_CURRENT_UNITS	1563
37
38#define DS2786_REG_RARC		0x02	/* Remaining active relative capacity */
39
40#define DS2786_CURRENT_UNITS	25
41
42#define DS278x_DELAY		1000
43
44struct ds278x_info;
45
46struct ds278x_battery_ops {
47	int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
48	int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
49	int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
50};
51
52#define to_ds278x_info(x) power_supply_get_drvdata(x)
53
54struct ds278x_info {
55	struct i2c_client	*client;
56	struct power_supply	*battery;
57	struct power_supply_desc	battery_desc;
58	const struct ds278x_battery_ops *ops;
59	struct delayed_work	bat_work;
60	int			id;
61	int                     rsns;
62	int			capacity;
63	int			status;		/* State Of Charge */
64};
65
66static DEFINE_IDR(battery_id);
67static DEFINE_MUTEX(battery_lock);
68
69static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
70{
71	int ret;
72
73	ret = i2c_smbus_read_byte_data(info->client, reg);
74	if (ret < 0) {
75		dev_err(&info->client->dev, "register read failed\n");
76		return ret;
77	}
78
79	*val = ret;
80	return 0;
81}
82
83static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
84				    s16 *val)
85{
86	int ret;
87
88	ret = i2c_smbus_read_word_data(info->client, reg_msb);
89	if (ret < 0) {
90		dev_err(&info->client->dev, "register read failed\n");
91		return ret;
92	}
93
94	*val = swab16(ret);
95	return 0;
96}
97
98static int ds278x_get_temp(struct ds278x_info *info, int *temp)
99{
100	s16 raw;
101	int err;
102
103	/*
104	 * Temperature is measured in units of 0.125 degrees celcius, the
105	 * power_supply class measures temperature in tenths of degrees
106	 * celsius. The temperature value is stored as a 10 bit number, plus
107	 * sign in the upper bits of a 16 bit register.
108	 */
109	err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
110	if (err)
111		return err;
112	*temp = ((raw / 32) * 125) / 100;
113	return 0;
114}
115
116static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
117{
118	int sense_res;
119	int err;
120	u8 sense_res_raw;
121	s16 raw;
122
123	/*
124	 * The units of measurement for current are dependent on the value of
125	 * the sense resistor.
126	 */
127	err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
128	if (err)
129		return err;
130	if (sense_res_raw == 0) {
131		dev_err(&info->client->dev, "sense resistor value is 0\n");
132		return -ENXIO;
133	}
134	sense_res = 1000 / sense_res_raw;
135
136	dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
137		sense_res);
138	err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
139	if (err)
140		return err;
141	*current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
142	return 0;
143}
144
145static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
146{
147	s16 raw;
148	int err;
149
150	/*
151	 * Voltage is measured in units of 4.88mV. The voltage is stored as
152	 * a 10-bit number plus sign, in the upper bits of a 16-bit register
153	 */
154	err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
155	if (err)
156		return err;
157	*voltage_uV = (raw / 32) * 4800;
158	return 0;
159}
160
161static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
162{
163	int err;
164	u8 raw;
165
166	err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
167	if (err)
168		return err;
169	*capacity = raw;
170	return 0;
171}
172
173static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
174{
175	int err;
176	s16 raw;
177
178	err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
179	if (err)
180		return err;
181	*current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
182	return 0;
183}
184
185static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
186{
187	s16 raw;
188	int err;
189
190	/*
191	 * Voltage is measured in units of 1.22mV. The voltage is stored as
192	 * a 12-bit number plus sign, in the upper bits of a 16-bit register
193	 */
194	err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
195	if (err)
196		return err;
197	*voltage_uV = (raw / 8) * 1220;
198	return 0;
199}
200
201static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
202{
203	int err;
204	u8 raw;
205
206	err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
207	if (err)
208		return err;
209	/* Relative capacity is displayed with resolution 0.5 % */
210	*capacity = raw/2 ;
211	return 0;
212}
213
214static int ds278x_get_status(struct ds278x_info *info, int *status)
215{
216	int err;
217	int current_uA;
218	int capacity;
219
220	err = info->ops->get_battery_current(info, &current_uA);
221	if (err)
222		return err;
223
224	err = info->ops->get_battery_capacity(info, &capacity);
225	if (err)
226		return err;
227
228	info->capacity = capacity;
229
230	if (capacity == 100)
231		*status = POWER_SUPPLY_STATUS_FULL;
232	else if (current_uA == 0)
233		*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
234	else if (current_uA < 0)
235		*status = POWER_SUPPLY_STATUS_DISCHARGING;
236	else
237		*status = POWER_SUPPLY_STATUS_CHARGING;
238
239	return 0;
240}
241
242static int ds278x_battery_get_property(struct power_supply *psy,
243				       enum power_supply_property prop,
244				       union power_supply_propval *val)
245{
246	struct ds278x_info *info = to_ds278x_info(psy);
247	int ret;
248
249	switch (prop) {
250	case POWER_SUPPLY_PROP_STATUS:
251		ret = ds278x_get_status(info, &val->intval);
252		break;
253
254	case POWER_SUPPLY_PROP_CAPACITY:
255		ret = info->ops->get_battery_capacity(info, &val->intval);
256		break;
257
258	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
259		ret = info->ops->get_battery_voltage(info, &val->intval);
260		break;
261
262	case POWER_SUPPLY_PROP_CURRENT_NOW:
263		ret = info->ops->get_battery_current(info, &val->intval);
264		break;
265
266	case POWER_SUPPLY_PROP_TEMP:
267		ret = ds278x_get_temp(info, &val->intval);
268		break;
269
270	default:
271		ret = -EINVAL;
272	}
273
274	return ret;
275}
276
277static void ds278x_bat_update(struct ds278x_info *info)
278{
279	int old_status = info->status;
280	int old_capacity = info->capacity;
281
282	ds278x_get_status(info, &info->status);
283
284	if ((old_status != info->status) || (old_capacity != info->capacity))
285		power_supply_changed(info->battery);
286}
287
288static void ds278x_bat_work(struct work_struct *work)
289{
290	struct ds278x_info *info;
291
292	info = container_of(work, struct ds278x_info, bat_work.work);
293	ds278x_bat_update(info);
294
295	schedule_delayed_work(&info->bat_work, DS278x_DELAY);
296}
297
298static enum power_supply_property ds278x_battery_props[] = {
299	POWER_SUPPLY_PROP_STATUS,
300	POWER_SUPPLY_PROP_CAPACITY,
301	POWER_SUPPLY_PROP_VOLTAGE_NOW,
302	POWER_SUPPLY_PROP_CURRENT_NOW,
303	POWER_SUPPLY_PROP_TEMP,
304};
305
306static void ds278x_power_supply_init(struct power_supply_desc *battery)
307{
308	battery->type			= POWER_SUPPLY_TYPE_BATTERY;
309	battery->properties		= ds278x_battery_props;
310	battery->num_properties		= ARRAY_SIZE(ds278x_battery_props);
311	battery->get_property		= ds278x_battery_get_property;
312	battery->external_power_changed	= NULL;
313}
314
315static void ds278x_battery_remove(struct i2c_client *client)
316{
317	struct ds278x_info *info = i2c_get_clientdata(client);
318	int id = info->id;
319
320	power_supply_unregister(info->battery);
321	cancel_delayed_work_sync(&info->bat_work);
322	kfree(info->battery_desc.name);
323	kfree(info);
324
325	mutex_lock(&battery_lock);
326	idr_remove(&battery_id, id);
327	mutex_unlock(&battery_lock);
328}
329
330#ifdef CONFIG_PM_SLEEP
331
332static int ds278x_suspend(struct device *dev)
333{
334	struct i2c_client *client = to_i2c_client(dev);
335	struct ds278x_info *info = i2c_get_clientdata(client);
336
337	cancel_delayed_work(&info->bat_work);
338	return 0;
339}
340
341static int ds278x_resume(struct device *dev)
342{
343	struct i2c_client *client = to_i2c_client(dev);
344	struct ds278x_info *info = i2c_get_clientdata(client);
345
346	schedule_delayed_work(&info->bat_work, DS278x_DELAY);
347	return 0;
348}
349#endif /* CONFIG_PM_SLEEP */
350
351static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);
352
353enum ds278x_num_id {
354	DS2782 = 0,
355	DS2786,
356};
357
358static const struct ds278x_battery_ops ds278x_ops[] = {
359	[DS2782] = {
360		.get_battery_current  = ds2782_get_current,
361		.get_battery_voltage  = ds2782_get_voltage,
362		.get_battery_capacity = ds2782_get_capacity,
363	},
364	[DS2786] = {
365		.get_battery_current  = ds2786_get_current,
366		.get_battery_voltage  = ds2786_get_voltage,
367		.get_battery_capacity = ds2786_get_capacity,
368	}
369};
370
371static int ds278x_battery_probe(struct i2c_client *client)
372{
373	const struct i2c_device_id *id = i2c_client_get_device_id(client);
374	struct ds278x_platform_data *pdata = client->dev.platform_data;
375	struct power_supply_config psy_cfg = {};
376	struct ds278x_info *info;
377	int ret;
378	int num;
379
380	/*
381	 * ds2786 should have the sense resistor value set
382	 * in the platform data
383	 */
384	if (id->driver_data == DS2786 && !pdata) {
385		dev_err(&client->dev, "missing platform data for ds2786\n");
386		return -EINVAL;
387	}
388
389	/* Get an ID for this battery */
390	mutex_lock(&battery_lock);
391	ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL);
392	mutex_unlock(&battery_lock);
393	if (ret < 0)
394		goto fail_id;
395	num = ret;
396
397	info = kzalloc(sizeof(*info), GFP_KERNEL);
398	if (!info) {
399		ret = -ENOMEM;
400		goto fail_info;
401	}
402
403	info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d",
404					    client->name, num);
405	if (!info->battery_desc.name) {
406		ret = -ENOMEM;
407		goto fail_name;
408	}
409
410	if (id->driver_data == DS2786)
411		info->rsns = pdata->rsns;
412
413	i2c_set_clientdata(client, info);
414	info->client = client;
415	info->id = num;
416	info->ops  = &ds278x_ops[id->driver_data];
417	ds278x_power_supply_init(&info->battery_desc);
418	psy_cfg.drv_data = info;
419
420	info->capacity = 100;
421	info->status = POWER_SUPPLY_STATUS_FULL;
422
423	INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work);
424
425	info->battery = power_supply_register(&client->dev,
426					      &info->battery_desc, &psy_cfg);
427	if (IS_ERR(info->battery)) {
428		dev_err(&client->dev, "failed to register battery\n");
429		ret = PTR_ERR(info->battery);
430		goto fail_register;
431	} else {
432		schedule_delayed_work(&info->bat_work, DS278x_DELAY);
433	}
434
435	return 0;
436
437fail_register:
438	kfree(info->battery_desc.name);
439fail_name:
440	kfree(info);
441fail_info:
442	mutex_lock(&battery_lock);
443	idr_remove(&battery_id, num);
444	mutex_unlock(&battery_lock);
445fail_id:
446	return ret;
447}
448
449static const struct i2c_device_id ds278x_id[] = {
450	{"ds2782", DS2782},
451	{"ds2786", DS2786},
452	{},
453};
454MODULE_DEVICE_TABLE(i2c, ds278x_id);
455
456static struct i2c_driver ds278x_battery_driver = {
457	.driver 	= {
458		.name	= "ds2782-battery",
459		.pm	= &ds278x_battery_pm_ops,
460	},
461	.probe		= ds278x_battery_probe,
462	.remove		= ds278x_battery_remove,
463	.id_table	= ds278x_id,
464};
465module_i2c_driver(ds278x_battery_driver);
466
467MODULE_AUTHOR("Ryan Mallon");
468MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC driver");
469MODULE_LICENSE("GPL");
470