Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
/*
 * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
 *
 * Copyright (C) 2009 Bluewater Systems Ltd
 *
 * Author: Ryan Mallon
 *
 * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/swab.h>
#include <linux/i2c.h>
#include <linux/idr.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/ds2782_battery.h>

#define DS2782_REG_RARC		0x06	/* Remaining active relative capacity */

#define DS278x_REG_VOLT_MSB	0x0c
#define DS278x_REG_TEMP_MSB	0x0a
#define DS278x_REG_CURRENT_MSB	0x0e

/* EEPROM Block */
#define DS2782_REG_RSNSP	0x69	/* Sense resistor value */

/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
#define DS2782_CURRENT_UNITS	1563

#define DS2786_REG_RARC		0x02	/* Remaining active relative capacity */

#define DS2786_CURRENT_UNITS	25

struct ds278x_info;

struct ds278x_battery_ops {
	int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
	int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
	int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
};

#define to_ds278x_info(x) container_of(x, struct ds278x_info, battery)

struct ds278x_info {
	struct i2c_client	*client;
	struct power_supply	battery;
	struct ds278x_battery_ops  *ops;
	int			id;
	int                     rsns;
};

static DEFINE_IDR(battery_id);
static DEFINE_MUTEX(battery_lock);

static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
{
	int ret;

	ret = i2c_smbus_read_byte_data(info->client, reg);
	if (ret < 0) {
		dev_err(&info->client->dev, "register read failed\n");
		return ret;
	}

	*val = ret;
	return 0;
}

static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
				    s16 *val)
{
	int ret;

	ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb));
	if (ret < 0) {
		dev_err(&info->client->dev, "register read failed\n");
		return ret;
	}

	*val = ret;
	return 0;
}

static int ds278x_get_temp(struct ds278x_info *info, int *temp)
{
	s16 raw;
	int err;

	/*
	 * Temperature is measured in units of 0.125 degrees celcius, the
	 * power_supply class measures temperature in tenths of degrees
	 * celsius. The temperature value is stored as a 10 bit number, plus
	 * sign in the upper bits of a 16 bit register.
	 */
	err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
	if (err)
		return err;
	*temp = ((raw / 32) * 125) / 100;
	return 0;
}

static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
{
	int sense_res;
	int err;
	u8 sense_res_raw;
	s16 raw;

	/*
	 * The units of measurement for current are dependent on the value of
	 * the sense resistor.
	 */
	err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
	if (err)
		return err;
	if (sense_res_raw == 0) {
		dev_err(&info->client->dev, "sense resistor value is 0\n");
		return -ENXIO;
	}
	sense_res = 1000 / sense_res_raw;

	dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
		sense_res);
	err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
	if (err)
		return err;
	*current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
	return 0;
}

static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
{
	s16 raw;
	int err;

	/*
	 * Voltage is measured in units of 4.88mV. The voltage is stored as
	 * a 10-bit number plus sign, in the upper bits of a 16-bit register
	 */
	err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
	if (err)
		return err;
	*voltage_uV = (raw / 32) * 4800;
	return 0;
}

static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
{
	int err;
	u8 raw;

	err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
	if (err)
		return err;
	*capacity = raw;
	return 0;
}

static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
{
	int err;
	s16 raw;

	err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
	if (err)
		return err;
	*current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
	return 0;
}

static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
{
	s16 raw;
	int err;

	/*
	 * Voltage is measured in units of 1.22mV. The voltage is stored as
	 * a 10-bit number plus sign, in the upper bits of a 16-bit register
	 */
	err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
	if (err)
		return err;
	*voltage_uV = (raw / 8) * 1220;
	return 0;
}

static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
{
	int err;
	u8 raw;

	err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
	if (err)
		return err;
	/* Relative capacity is displayed with resolution 0.5 % */
	*capacity = raw/2 ;
	return 0;
}

static int ds278x_get_status(struct ds278x_info *info, int *status)
{
	int err;
	int current_uA;
	int capacity;

	err = info->ops->get_battery_current(info, &current_uA);
	if (err)
		return err;

	err = info->ops->get_battery_capacity(info, &capacity);
	if (err)
		return err;

	if (capacity == 100)
		*status = POWER_SUPPLY_STATUS_FULL;
	else if (current_uA == 0)
		*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
	else if (current_uA < 0)
		*status = POWER_SUPPLY_STATUS_DISCHARGING;
	else
		*status = POWER_SUPPLY_STATUS_CHARGING;

	return 0;
}

static int ds278x_battery_get_property(struct power_supply *psy,
				       enum power_supply_property prop,
				       union power_supply_propval *val)
{
	struct ds278x_info *info = to_ds278x_info(psy);
	int ret;

	switch (prop) {
	case POWER_SUPPLY_PROP_STATUS:
		ret = ds278x_get_status(info, &val->intval);
		break;

	case POWER_SUPPLY_PROP_CAPACITY:
		ret = info->ops->get_battery_capacity(info, &val->intval);
		break;

	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = info->ops->get_battery_voltage(info, &val->intval);
		break;

	case POWER_SUPPLY_PROP_CURRENT_NOW:
		ret = info->ops->get_battery_current(info, &val->intval);
		break;

	case POWER_SUPPLY_PROP_TEMP:
		ret = ds278x_get_temp(info, &val->intval);
		break;

	default:
		ret = -EINVAL;
	}

	return ret;
}

static enum power_supply_property ds278x_battery_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_TEMP,
};

static void ds278x_power_supply_init(struct power_supply *battery)
{
	battery->type			= POWER_SUPPLY_TYPE_BATTERY;
	battery->properties		= ds278x_battery_props;
	battery->num_properties		= ARRAY_SIZE(ds278x_battery_props);
	battery->get_property		= ds278x_battery_get_property;
	battery->external_power_changed	= NULL;
}

static int ds278x_battery_remove(struct i2c_client *client)
{
	struct ds278x_info *info = i2c_get_clientdata(client);

	power_supply_unregister(&info->battery);
	kfree(info->battery.name);

	mutex_lock(&battery_lock);
	idr_remove(&battery_id, info->id);
	mutex_unlock(&battery_lock);

	kfree(info);
	return 0;
}

enum ds278x_num_id {
	DS2782 = 0,
	DS2786,
};

static struct ds278x_battery_ops ds278x_ops[] = {
	[DS2782] = {
		.get_battery_current  = ds2782_get_current,
		.get_battery_voltage  = ds2782_get_voltage,
		.get_battery_capacity = ds2782_get_capacity,
	},
	[DS2786] = {
		.get_battery_current  = ds2786_get_current,
		.get_battery_voltage  = ds2786_get_voltage,
		.get_battery_capacity = ds2786_get_capacity,
	}
};

static int ds278x_battery_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	struct ds278x_platform_data *pdata = client->dev.platform_data;
	struct ds278x_info *info;
	int ret;
	int num;

	/*
	 * ds2786 should have the sense resistor value set
	 * in the platform data
	 */
	if (id->driver_data == DS2786 && !pdata) {
		dev_err(&client->dev, "missing platform data for ds2786\n");
		return -EINVAL;
	}

	/* Get an ID for this battery */
	ret = idr_pre_get(&battery_id, GFP_KERNEL);
	if (ret == 0) {
		ret = -ENOMEM;
		goto fail_id;
	}

	mutex_lock(&battery_lock);
	ret = idr_get_new(&battery_id, client, &num);
	mutex_unlock(&battery_lock);
	if (ret < 0)
		goto fail_id;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info) {
		ret = -ENOMEM;
		goto fail_info;
	}

	info->battery.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num);
	if (!info->battery.name) {
		ret = -ENOMEM;
		goto fail_name;
	}

	if (id->driver_data == DS2786)
		info->rsns = pdata->rsns;

	i2c_set_clientdata(client, info);
	info->client = client;
	info->id = num;
	info->ops  = &ds278x_ops[id->driver_data];
	ds278x_power_supply_init(&info->battery);

	ret = power_supply_register(&client->dev, &info->battery);
	if (ret) {
		dev_err(&client->dev, "failed to register battery\n");
		goto fail_register;
	}

	return 0;

fail_register:
	kfree(info->battery.name);
fail_name:
	kfree(info);
fail_info:
	mutex_lock(&battery_lock);
	idr_remove(&battery_id, num);
	mutex_unlock(&battery_lock);
fail_id:
	return ret;
}

static const struct i2c_device_id ds278x_id[] = {
	{"ds2782", DS2782},
	{"ds2786", DS2786},
	{},
};
MODULE_DEVICE_TABLE(i2c, ds278x_id);

static struct i2c_driver ds278x_battery_driver = {
	.driver 	= {
		.name	= "ds2782-battery",
	},
	.probe		= ds278x_battery_probe,
	.remove		= ds278x_battery_remove,
	.id_table	= ds278x_id,
};

static int __init ds278x_init(void)
{
	return i2c_add_driver(&ds278x_battery_driver);
}
module_init(ds278x_init);

static void __exit ds278x_exit(void)
{
	i2c_del_driver(&ds278x_battery_driver);
}
module_exit(ds278x_exit);

MODULE_AUTHOR("Ryan Mallon");
MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
MODULE_LICENSE("GPL");