drivers/power/supply/ds2782_battery.c

   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
  44 struct ds278x_info;
  45
  46 struct 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
  54 struct 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
  66 static DEFINE_IDR(battery_id);
  67 static DEFINE_MUTEX(battery_lock);
  68
  69 static 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
  83 static 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
  98 static 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
 116 static 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
 145 static 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
 161 static 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
 173 static 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
 185 static 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
 201 static 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
 214 static 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
 242 static 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
 277 static 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
 288 static 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
 298 static 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
 306 static 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
 315 static 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
 332 static 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
 341 static 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
 351 static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);
 352
 353 enum ds278x_num_id {
 354         DS2782 = 0,
 355         DS2786,
 356 };
 357
 358 static 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
 371 static 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
 437 fail_register:
 438         kfree(info->battery_desc.name);
 439 fail_name:
 440         kfree(info);
 441 fail_info:
 442         mutex_lock(&battery_lock);
 443         idr_remove(&battery_id, num);
 444         mutex_unlock(&battery_lock);
 445 fail_id:
 446         return ret;
 447 }
 448
 449 static const struct i2c_device_id ds278x_id[] = {
 450         {"ds2782", DS2782},
 451         {"ds2786", DS2786},
 452         {},
 453 };
 454 MODULE_DEVICE_TABLE(i2c, ds278x_id);
 455
 456 static 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 };
 465 module_i2c_driver(ds278x_battery_driver);
 466
 467 MODULE_AUTHOR("Ryan Mallon");
 468 MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC driver");
 469 MODULE_LICENSE("GPL");