drivers/power/ds2782_battery.c

   1 /*
   2  * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
   3  *
   4  * Copyright (C) 2009 Bluewater Systems Ltd
   5  *
   6  * Author: Ryan Mallon
   7  *
   8  * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
   9  *
  10  * UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/types.h>
  21 #include <linux/errno.h>
  22 #include <linux/swab.h>
  23 #include <linux/i2c.h>
  24 #include <linux/delay.h>
  25 #include <linux/idr.h>
  26 #include <linux/power_supply.h>
  27 #include <linux/slab.h>
  28 #include <linux/ds2782_battery.h>
  29
  30 #define DS2782_REG_RARC         0x06    /* Remaining active relative capacity */
  31
  32 #define DS278x_REG_VOLT_MSB     0x0c
  33 #define DS278x_REG_TEMP_MSB     0x0a
  34 #define DS278x_REG_CURRENT_MSB  0x0e
  35
  36 /* EEPROM Block */
  37 #define DS2782_REG_RSNSP        0x69    /* Sense resistor value */
  38
  39 /* Current unit measurement in uA for a 1 milli-ohm sense resistor */
  40 #define DS2782_CURRENT_UNITS    1563
  41
  42 #define DS2786_REG_RARC         0x02    /* Remaining active relative capacity */
  43
  44 #define DS2786_CURRENT_UNITS    25
  45
  46 #define DS278x_DELAY            1000
  47
  48 struct ds278x_info;
  49
  50 struct ds278x_battery_ops {
  51         int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
  52         int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
  53         int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
  54 };
  55
  56 #define to_ds278x_info(x) power_supply_get_drvdata(x)
  57
  58 struct ds278x_info {
  59         struct i2c_client       *client;
  60         struct power_supply     *battery;
  61         struct power_supply_desc        battery_desc;
  62         struct ds278x_battery_ops  *ops;
  63         struct delayed_work     bat_work;
  64         int                     id;
  65         int                     rsns;
  66         int                     capacity;
  67         int                     status;         /* State Of Charge */
  68 };
  69
  70 static DEFINE_IDR(battery_id);
  71 static DEFINE_MUTEX(battery_lock);
  72
  73 static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
  74 {
  75         int ret;
  76
  77         ret = i2c_smbus_read_byte_data(info->client, reg);
  78         if (ret < 0) {
  79                 dev_err(&info->client->dev, "register read failed\n");
  80                 return ret;
  81         }
  82
  83         *val = ret;
  84         return 0;
  85 }
  86
  87 static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
  88                                     s16 *val)
  89 {
  90         int ret;
  91
  92         ret = i2c_smbus_read_word_data(info->client, reg_msb);
  93         if (ret < 0) {
  94                 dev_err(&info->client->dev, "register read failed\n");
  95                 return ret;
  96         }
  97
  98         *val = swab16(ret);
  99         return 0;
 100 }
 101
 102 static int ds278x_get_temp(struct ds278x_info *info, int *temp)
 103 {
 104         s16 raw;
 105         int err;
 106
 107         /*
 108          * Temperature is measured in units of 0.125 degrees celcius, the
 109          * power_supply class measures temperature in tenths of degrees
 110          * celsius. The temperature value is stored as a 10 bit number, plus
 111          * sign in the upper bits of a 16 bit register.
 112          */
 113         err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
 114         if (err)
 115                 return err;
 116         *temp = ((raw / 32) * 125) / 100;
 117         return 0;
 118 }
 119
 120 static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
 121 {
 122         int sense_res;
 123         int err;
 124         u8 sense_res_raw;
 125         s16 raw;
 126
 127         /*
 128          * The units of measurement for current are dependent on the value of
 129          * the sense resistor.
 130          */
 131         err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
 132         if (err)
 133                 return err;
 134         if (sense_res_raw == 0) {
 135                 dev_err(&info->client->dev, "sense resistor value is 0\n");
 136                 return -ENXIO;
 137         }
 138         sense_res = 1000 / sense_res_raw;
 139
 140         dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
 141                 sense_res);
 142         err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
 143         if (err)
 144                 return err;
 145         *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
 146         return 0;
 147 }
 148
 149 static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
 150 {
 151         s16 raw;
 152         int err;
 153
 154         /*
 155          * Voltage is measured in units of 4.88mV. The voltage is stored as
 156          * a 10-bit number plus sign, in the upper bits of a 16-bit register
 157          */
 158         err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
 159         if (err)
 160                 return err;
 161         *voltage_uV = (raw / 32) * 4800;
 162         return 0;
 163 }
 164
 165 static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
 166 {
 167         int err;
 168         u8 raw;
 169
 170         err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
 171         if (err)
 172                 return err;
 173         *capacity = raw;
 174         return 0;
 175 }
 176
 177 static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
 178 {
 179         int err;
 180         s16 raw;
 181
 182         err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
 183         if (err)
 184                 return err;
 185         *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
 186         return 0;
 187 }
 188
 189 static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
 190 {
 191         s16 raw;
 192         int err;
 193
 194         /*
 195          * Voltage is measured in units of 1.22mV. The voltage is stored as
 196          * a 12-bit number plus sign, in the upper bits of a 16-bit register
 197          */
 198         err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
 199         if (err)
 200                 return err;
 201         *voltage_uV = (raw / 8) * 1220;
 202         return 0;
 203 }
 204
 205 static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
 206 {
 207         int err;
 208         u8 raw;
 209
 210         err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
 211         if (err)
 212                 return err;
 213         /* Relative capacity is displayed with resolution 0.5 % */
 214         *capacity = raw/2 ;
 215         return 0;
 216 }
 217
 218 static int ds278x_get_status(struct ds278x_info *info, int *status)
 219 {
 220         int err;
 221         int current_uA;
 222         int capacity;
 223
 224         err = info->ops->get_battery_current(info, &current_uA);
 225         if (err)
 226                 return err;
 227
 228         err = info->ops->get_battery_capacity(info, &capacity);
 229         if (err)
 230                 return err;
 231
 232         info->capacity = capacity;
 233
 234         if (capacity == 100)
 235                 *status = POWER_SUPPLY_STATUS_FULL;
 236         else if (current_uA == 0)
 237                 *status = POWER_SUPPLY_STATUS_NOT_CHARGING;
 238         else if (current_uA < 0)
 239                 *status = POWER_SUPPLY_STATUS_DISCHARGING;
 240         else
 241                 *status = POWER_SUPPLY_STATUS_CHARGING;
 242
 243         return 0;
 244 }
 245
 246 static int ds278x_battery_get_property(struct power_supply *psy,
 247                                        enum power_supply_property prop,
 248                                        union power_supply_propval *val)
 249 {
 250         struct ds278x_info *info = to_ds278x_info(psy);
 251         int ret;
 252
 253         switch (prop) {
 254         case POWER_SUPPLY_PROP_STATUS:
 255                 ret = ds278x_get_status(info, &val->intval);
 256                 break;
 257
 258         case POWER_SUPPLY_PROP_CAPACITY:
 259                 ret = info->ops->get_battery_capacity(info, &val->intval);
 260                 break;
 261
 262         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 263                 ret = info->ops->get_battery_voltage(info, &val->intval);
 264                 break;
 265
 266         case POWER_SUPPLY_PROP_CURRENT_NOW:
 267                 ret = info->ops->get_battery_current(info, &val->intval);
 268                 break;
 269
 270         case POWER_SUPPLY_PROP_TEMP:
 271                 ret = ds278x_get_temp(info, &val->intval);
 272                 break;
 273
 274         default:
 275                 ret = -EINVAL;
 276         }
 277
 278         return ret;
 279 }
 280
 281 static void ds278x_bat_update(struct ds278x_info *info)
 282 {
 283         int old_status = info->status;
 284         int old_capacity = info->capacity;
 285
 286         ds278x_get_status(info, &info->status);
 287
 288         if ((old_status != info->status) || (old_capacity != info->capacity))
 289                 power_supply_changed(info->battery);
 290 }
 291
 292 static void ds278x_bat_work(struct work_struct *work)
 293 {
 294         struct ds278x_info *info;
 295
 296         info = container_of(work, struct ds278x_info, bat_work.work);
 297         ds278x_bat_update(info);
 298
 299         schedule_delayed_work(&info->bat_work, DS278x_DELAY);
 300 }
 301
 302 static enum power_supply_property ds278x_battery_props[] = {
 303         POWER_SUPPLY_PROP_STATUS,
 304         POWER_SUPPLY_PROP_CAPACITY,
 305         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 306         POWER_SUPPLY_PROP_CURRENT_NOW,
 307         POWER_SUPPLY_PROP_TEMP,
 308 };
 309
 310 static void ds278x_power_supply_init(struct power_supply_desc *battery)
 311 {
 312         battery->type                   = POWER_SUPPLY_TYPE_BATTERY;
 313         battery->properties             = ds278x_battery_props;
 314         battery->num_properties         = ARRAY_SIZE(ds278x_battery_props);
 315         battery->get_property           = ds278x_battery_get_property;
 316         battery->external_power_changed = NULL;
 317 }
 318
 319 static int ds278x_battery_remove(struct i2c_client *client)
 320 {
 321         struct ds278x_info *info = i2c_get_clientdata(client);
 322
 323         power_supply_unregister(info->battery);
 324         kfree(info->battery_desc.name);
 325
 326         mutex_lock(&battery_lock);
 327         idr_remove(&battery_id, info->id);
 328         mutex_unlock(&battery_lock);
 329
 330         cancel_delayed_work(&info->bat_work);
 331
 332         kfree(info);
 333         return 0;
 334 }
 335
 336 #ifdef CONFIG_PM_SLEEP
 337
 338 static int ds278x_suspend(struct device *dev)
 339 {
 340         struct i2c_client *client = to_i2c_client(dev);
 341         struct ds278x_info *info = i2c_get_clientdata(client);
 342
 343         cancel_delayed_work(&info->bat_work);
 344         return 0;
 345 }
 346
 347 static int ds278x_resume(struct device *dev)
 348 {
 349         struct i2c_client *client = to_i2c_client(dev);
 350         struct ds278x_info *info = i2c_get_clientdata(client);
 351
 352         schedule_delayed_work(&info->bat_work, DS278x_DELAY);
 353         return 0;
 354 }
 355 #endif /* CONFIG_PM_SLEEP */
 356
 357 static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);
 358
 359 enum ds278x_num_id {
 360         DS2782 = 0,
 361         DS2786,
 362 };
 363
 364 static struct ds278x_battery_ops ds278x_ops[] = {
 365         [DS2782] = {
 366                 .get_battery_current  = ds2782_get_current,
 367                 .get_battery_voltage  = ds2782_get_voltage,
 368                 .get_battery_capacity = ds2782_get_capacity,
 369         },
 370         [DS2786] = {
 371                 .get_battery_current  = ds2786_get_current,
 372                 .get_battery_voltage  = ds2786_get_voltage,
 373                 .get_battery_capacity = ds2786_get_capacity,
 374         }
 375 };
 376
 377 static int ds278x_battery_probe(struct i2c_client *client,
 378                                 const struct i2c_device_id *id)
 379 {
 380         struct ds278x_platform_data *pdata = client->dev.platform_data;
 381         struct power_supply_config psy_cfg = {};
 382         struct ds278x_info *info;
 383         int ret;
 384         int num;
 385
 386         /*
 387          * ds2786 should have the sense resistor value set
 388          * in the platform data
 389          */
 390         if (id->driver_data == DS2786 && !pdata) {
 391                 dev_err(&client->dev, "missing platform data for ds2786\n");
 392                 return -EINVAL;
 393         }
 394
 395         /* Get an ID for this battery */
 396         mutex_lock(&battery_lock);
 397         ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL);
 398         mutex_unlock(&battery_lock);
 399         if (ret < 0)
 400                 goto fail_id;
 401         num = ret;
 402
 403         info = kzalloc(sizeof(*info), GFP_KERNEL);
 404         if (!info) {
 405                 ret = -ENOMEM;
 406                 goto fail_info;
 407         }
 408
 409         info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d",
 410                                             client->name, num);
 411         if (!info->battery_desc.name) {
 412                 ret = -ENOMEM;
 413                 goto fail_name;
 414         }
 415
 416         if (id->driver_data == DS2786)
 417                 info->rsns = pdata->rsns;
 418
 419         i2c_set_clientdata(client, info);
 420         info->client = client;
 421         info->id = num;
 422         info->ops  = &ds278x_ops[id->driver_data];
 423         ds278x_power_supply_init(&info->battery_desc);
 424         psy_cfg.drv_data = info;
 425
 426         info->capacity = 100;
 427         info->status = POWER_SUPPLY_STATUS_FULL;
 428
 429         INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work);
 430
 431         info->battery = power_supply_register(&client->dev,
 432                                               &info->battery_desc, &psy_cfg);
 433         if (IS_ERR(info->battery)) {
 434                 dev_err(&client->dev, "failed to register battery\n");
 435                 ret = PTR_ERR(info->battery);
 436                 goto fail_register;
 437         } else {
 438                 schedule_delayed_work(&info->bat_work, DS278x_DELAY);
 439         }
 440
 441         return 0;
 442
 443 fail_register:
 444         kfree(info->battery_desc.name);
 445 fail_name:
 446         kfree(info);
 447 fail_info:
 448         mutex_lock(&battery_lock);
 449         idr_remove(&battery_id, num);
 450         mutex_unlock(&battery_lock);
 451 fail_id:
 452         return ret;
 453 }
 454
 455 static const struct i2c_device_id ds278x_id[] = {
 456         {"ds2782", DS2782},
 457         {"ds2786", DS2786},
 458         {},
 459 };
 460 MODULE_DEVICE_TABLE(i2c, ds278x_id);
 461
 462 static struct i2c_driver ds278x_battery_driver = {
 463         .driver         = {
 464                 .name   = "ds2782-battery",
 465                 .pm     = &ds278x_battery_pm_ops,
 466         },
 467         .probe          = ds278x_battery_probe,
 468         .remove         = ds278x_battery_remove,
 469         .id_table       = ds278x_id,
 470 };
 471 module_i2c_driver(ds278x_battery_driver);
 472
 473 MODULE_AUTHOR("Ryan Mallon");
 474 MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
 475 MODULE_LICENSE("GPL");