drivers/power/bq27x00_battery.c

   1 /*
   2  * BQ27x00 battery driver
   3  *
   4  * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
   5  * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
   6  *
   7  * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
   8  *
   9  * This package is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  *
  17  */
  18 #include <linux/module.h>
  19 #include <linux/param.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/delay.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/power_supply.h>
  25 #include <linux/idr.h>
  26 #include <linux/i2c.h>
  27 #include <linux/slab.h>
  28 #include <asm/unaligned.h>
  29
  30 #define DRIVER_VERSION                  "1.1.0"
  31
  32 #define BQ27x00_REG_TEMP                0x06
  33 #define BQ27x00_REG_VOLT                0x08
  34 #define BQ27x00_REG_AI                  0x14
  35 #define BQ27x00_REG_FLAGS               0x0A
  36 #define BQ27x00_REG_TTE                 0x16
  37 #define BQ27x00_REG_TTF                 0x18
  38 #define BQ27x00_REG_TTECP               0x26
  39
  40 #define BQ27000_REG_RSOC                0x0B /* Relative State-of-Charge */
  41 #define BQ27000_FLAG_CHGS               BIT(7)
  42
  43 #define BQ27500_REG_SOC                 0x2c
  44 #define BQ27500_FLAG_DSC                BIT(0)
  45 #define BQ27500_FLAG_FC                 BIT(9)
  46
  47 /* If the system has several batteries we need a different name for each
  48  * of them...
  49  */
  50 static DEFINE_IDR(battery_id);
  51 static DEFINE_MUTEX(battery_mutex);
  52
  53 struct bq27x00_device_info;
  54 struct bq27x00_access_methods {
  55         int (*read)(u8 reg, int *rt_value, int b_single,
  56                 struct bq27x00_device_info *di);
  57 };
  58
  59 enum bq27x00_chip { BQ27000, BQ27500 };
  60
  61 struct bq27x00_device_info {
  62         struct device           *dev;
  63         int                     id;
  64         struct bq27x00_access_methods   *bus;
  65         struct power_supply     bat;
  66         enum bq27x00_chip       chip;
  67
  68         struct i2c_client       *client;
  69 };
  70
  71 static enum power_supply_property bq27x00_battery_props[] = {
  72         POWER_SUPPLY_PROP_STATUS,
  73         POWER_SUPPLY_PROP_PRESENT,
  74         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  75         POWER_SUPPLY_PROP_CURRENT_NOW,
  76         POWER_SUPPLY_PROP_CAPACITY,
  77         POWER_SUPPLY_PROP_TEMP,
  78         POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
  79         POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
  80         POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
  81 };
  82
  83 /*
  84  * Common code for BQ27x00 devices
  85  */
  86
  87 static int bq27x00_read(u8 reg, int *rt_value, int b_single,
  88                         struct bq27x00_device_info *di)
  89 {
  90         return di->bus->read(reg, rt_value, b_single, di);
  91 }
  92
  93 /*
  94  * Return the battery temperature in tenths of degree Celsius
  95  * Or < 0 if something fails.
  96  */
  97 static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
  98 {
  99         int ret;
 100         int temp = 0;
 101
 102         ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
 103         if (ret) {
 104                 dev_err(di->dev, "error reading temperature\n");
 105                 return ret;
 106         }
 107
 108         if (di->chip == BQ27500)
 109                 return temp - 2731;
 110         else
 111                 return ((temp >> 2) - 273) * 10;
 112 }
 113
 114 /*
 115  * Return the battery Voltage in milivolts
 116  * Or < 0 if something fails.
 117  */
 118 static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
 119 {
 120         int ret;
 121         int volt = 0;
 122
 123         ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
 124         if (ret) {
 125                 dev_err(di->dev, "error reading voltage\n");
 126                 return ret;
 127         }
 128
 129         return volt * 1000;
 130 }
 131
 132 /*
 133  * Return the battery average current
 134  * Note that current can be negative signed as well
 135  * Or 0 if something fails.
 136  */
 137 static int bq27x00_battery_current(struct bq27x00_device_info *di)
 138 {
 139         int ret;
 140         int curr = 0;
 141         int flags = 0;
 142
 143         ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
 144         if (ret) {
 145                 dev_err(di->dev, "error reading current\n");
 146                 return 0;
 147         }
 148
 149         if (di->chip == BQ27500) {
 150                 /* bq27500 returns signed value */
 151                 curr = (int)(s16)curr;
 152         } else {
 153                 ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
 154                 if (ret < 0) {
 155                         dev_err(di->dev, "error reading flags\n");
 156                         return 0;
 157                 }
 158                 if (flags & BQ27000_FLAG_CHGS) {
 159                         dev_dbg(di->dev, "negative current!\n");
 160                         curr = -curr;
 161                 }
 162         }
 163
 164         return curr * 1000;
 165 }
 166
 167 /*
 168  * Return the battery Relative State-of-Charge
 169  * Or < 0 if something fails.
 170  */
 171 static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
 172 {
 173         int ret;
 174         int rsoc = 0;
 175
 176         if (di->chip == BQ27500)
 177                 ret = bq27x00_read(BQ27500_REG_SOC, &rsoc, 0, di);
 178         else
 179                 ret = bq27x00_read(BQ27000_REG_RSOC, &rsoc, 1, di);
 180         if (ret) {
 181                 dev_err(di->dev, "error reading relative State-of-Charge\n");
 182                 return ret;
 183         }
 184
 185         return rsoc;
 186 }
 187
 188 static int bq27x00_battery_status(struct bq27x00_device_info *di,
 189                                   union power_supply_propval *val)
 190 {
 191         int flags = 0;
 192         int status;
 193         int ret;
 194
 195         ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
 196         if (ret < 0) {
 197                 dev_err(di->dev, "error reading flags\n");
 198                 return ret;
 199         }
 200
 201         if (di->chip == BQ27500) {
 202                 if (flags & BQ27500_FLAG_FC)
 203                         status = POWER_SUPPLY_STATUS_FULL;
 204                 else if (flags & BQ27500_FLAG_DSC)
 205                         status = POWER_SUPPLY_STATUS_DISCHARGING;
 206                 else
 207                         status = POWER_SUPPLY_STATUS_CHARGING;
 208         } else {
 209                 if (flags & BQ27000_FLAG_CHGS)
 210                         status = POWER_SUPPLY_STATUS_CHARGING;
 211                 else
 212                         status = POWER_SUPPLY_STATUS_DISCHARGING;
 213         }
 214
 215         val->intval = status;
 216         return 0;
 217 }
 218
 219 /*
 220  * Read a time register.
 221  * Return < 0 if something fails.
 222  */
 223 static int bq27x00_battery_time(struct bq27x00_device_info *di, int reg,
 224                                 union power_supply_propval *val)
 225 {
 226         int tval = 0;
 227         int ret;
 228
 229         ret = bq27x00_read(reg, &tval, 0, di);
 230         if (ret) {
 231                 dev_err(di->dev, "error reading register %02x\n", reg);
 232                 return ret;
 233         }
 234
 235         if (tval == 65535)
 236                 return -ENODATA;
 237
 238         val->intval = tval * 60;
 239         return 0;
 240 }
 241
 242 #define to_bq27x00_device_info(x) container_of((x), \
 243                                 struct bq27x00_device_info, bat);
 244
 245 static int bq27x00_battery_get_property(struct power_supply *psy,
 246                                         enum power_supply_property psp,
 247                                         union power_supply_propval *val)
 248 {
 249         int ret = 0;
 250         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 251
 252         switch (psp) {
 253         case POWER_SUPPLY_PROP_STATUS:
 254                 ret = bq27x00_battery_status(di, val);
 255                 break;
 256         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 257         case POWER_SUPPLY_PROP_PRESENT:
 258                 val->intval = bq27x00_battery_voltage(di);
 259                 if (psp == POWER_SUPPLY_PROP_PRESENT)
 260                         val->intval = val->intval <= 0 ? 0 : 1;
 261                 break;
 262         case POWER_SUPPLY_PROP_CURRENT_NOW:
 263                 val->intval = bq27x00_battery_current(di);
 264                 break;
 265         case POWER_SUPPLY_PROP_CAPACITY:
 266                 val->intval = bq27x00_battery_rsoc(di);
 267                 break;
 268         case POWER_SUPPLY_PROP_TEMP:
 269                 val->intval = bq27x00_battery_temperature(di);
 270                 break;
 271         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
 272                 ret = bq27x00_battery_time(di, BQ27x00_REG_TTE, val);
 273                 break;
 274         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 275                 ret = bq27x00_battery_time(di, BQ27x00_REG_TTECP, val);
 276                 break;
 277         case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
 278                 ret = bq27x00_battery_time(di, BQ27x00_REG_TTF, val);
 279                 break;
 280         default:
 281                 return -EINVAL;
 282         }
 283
 284         return ret;
 285 }
 286
 287 static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
 288 {
 289         di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
 290         di->bat.properties = bq27x00_battery_props;
 291         di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
 292         di->bat.get_property = bq27x00_battery_get_property;
 293         di->bat.external_power_changed = NULL;
 294 }
 295
 296 /*
 297  * i2c specific code
 298  */
 299
 300 static int bq27x00_read_i2c(u8 reg, int *rt_value, int b_single,
 301                         struct bq27x00_device_info *di)
 302 {
 303         struct i2c_client *client = di->client;
 304         struct i2c_msg msg[1];
 305         unsigned char data[2];
 306         int err;
 307
 308         if (!client->adapter)
 309                 return -ENODEV;
 310
 311         msg->addr = client->addr;
 312         msg->flags = 0;
 313         msg->len = 1;
 314         msg->buf = data;
 315
 316         data[0] = reg;
 317         err = i2c_transfer(client->adapter, msg, 1);
 318
 319         if (err >= 0) {
 320                 if (!b_single)
 321                         msg->len = 2;
 322                 else
 323                         msg->len = 1;
 324
 325                 msg->flags = I2C_M_RD;
 326                 err = i2c_transfer(client->adapter, msg, 1);
 327                 if (err >= 0) {
 328                         if (!b_single)
 329                                 *rt_value = get_unaligned_le16(data);
 330                         else
 331                                 *rt_value = data[0];
 332
 333                         return 0;
 334                 }
 335         }
 336         return err;
 337 }
 338
 339 static int bq27x00_battery_probe(struct i2c_client *client,
 340                                  const struct i2c_device_id *id)
 341 {
 342         char *name;
 343         struct bq27x00_device_info *di;
 344         struct bq27x00_access_methods *bus;
 345         int num;
 346         int retval = 0;
 347
 348         /* Get new ID for the new battery device */
 349         retval = idr_pre_get(&battery_id, GFP_KERNEL);
 350         if (retval == 0)
 351                 return -ENOMEM;
 352         mutex_lock(&battery_mutex);
 353         retval = idr_get_new(&battery_id, client, &num);
 354         mutex_unlock(&battery_mutex);
 355         if (retval < 0)
 356                 return retval;
 357
 358         name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
 359         if (!name) {
 360                 dev_err(&client->dev, "failed to allocate device name\n");
 361                 retval = -ENOMEM;
 362                 goto batt_failed_1;
 363         }
 364
 365         di = kzalloc(sizeof(*di), GFP_KERNEL);
 366         if (!di) {
 367                 dev_err(&client->dev, "failed to allocate device info data\n");
 368                 retval = -ENOMEM;
 369                 goto batt_failed_2;
 370         }
 371         di->id = num;
 372         di->chip = id->driver_data;
 373
 374         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
 375         if (!bus) {
 376                 dev_err(&client->dev, "failed to allocate access method "
 377                                         "data\n");
 378                 retval = -ENOMEM;
 379                 goto batt_failed_3;
 380         }
 381
 382         i2c_set_clientdata(client, di);
 383         di->dev = &client->dev;
 384         di->bat.name = name;
 385         bus->read = &bq27x00_read_i2c;
 386         di->bus = bus;
 387         di->client = client;
 388
 389         bq27x00_powersupply_init(di);
 390
 391         retval = power_supply_register(&client->dev, &di->bat);
 392         if (retval) {
 393                 dev_err(&client->dev, "failed to register battery\n");
 394                 goto batt_failed_4;
 395         }
 396
 397         dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 398
 399         return 0;
 400
 401 batt_failed_4:
 402         kfree(bus);
 403 batt_failed_3:
 404         kfree(di);
 405 batt_failed_2:
 406         kfree(name);
 407 batt_failed_1:
 408         mutex_lock(&battery_mutex);
 409         idr_remove(&battery_id, num);
 410         mutex_unlock(&battery_mutex);
 411
 412         return retval;
 413 }
 414
 415 static int bq27x00_battery_remove(struct i2c_client *client)
 416 {
 417         struct bq27x00_device_info *di = i2c_get_clientdata(client);
 418
 419         power_supply_unregister(&di->bat);
 420
 421         kfree(di->bat.name);
 422
 423         mutex_lock(&battery_mutex);
 424         idr_remove(&battery_id, di->id);
 425         mutex_unlock(&battery_mutex);
 426
 427         kfree(di);
 428
 429         return 0;
 430 }
 431
 432 /*
 433  * Module stuff
 434  */
 435
 436 static const struct i2c_device_id bq27x00_id[] = {
 437         { "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */
 438         { "bq27500", BQ27500 },
 439         {},
 440 };
 441
 442 static struct i2c_driver bq27x00_battery_driver = {
 443         .driver = {
 444                 .name = "bq27x00-battery",
 445         },
 446         .probe = bq27x00_battery_probe,
 447         .remove = bq27x00_battery_remove,
 448         .id_table = bq27x00_id,
 449 };
 450
 451 static int __init bq27x00_battery_init(void)
 452 {
 453         int ret;
 454
 455         ret = i2c_add_driver(&bq27x00_battery_driver);
 456         if (ret)
 457                 printk(KERN_ERR "Unable to register BQ27x00 driver\n");
 458
 459         return ret;
 460 }
 461 module_init(bq27x00_battery_init);
 462
 463 static void __exit bq27x00_battery_exit(void)
 464 {
 465         i2c_del_driver(&bq27x00_battery_driver);
 466 }
 467 module_exit(bq27x00_battery_exit);
 468
 469 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 470 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 471 MODULE_LICENSE("GPL");