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 <asm/unaligned.h>
  28
  29 #define DRIVER_VERSION                  "1.0.0"
  30
  31 #define BQ27x00_REG_TEMP                0x06
  32 #define BQ27x00_REG_VOLT                0x08
  33 #define BQ27x00_REG_RSOC                0x0B /* Relative State-of-Charge */
  34 #define BQ27x00_REG_AI                  0x14
  35 #define BQ27x00_REG_FLAGS               0x0A
  36
  37 /* If the system has several batteries we need a different name for each
  38  * of them...
  39  */
  40 static DEFINE_IDR(battery_id);
  41 static DEFINE_MUTEX(battery_mutex);
  42
  43 struct bq27x00_device_info;
  44 struct bq27x00_access_methods {
  45         int (*read)(u8 reg, int *rt_value, int b_single,
  46                 struct bq27x00_device_info *di);
  47 };
  48
  49 struct bq27x00_device_info {
  50         struct device           *dev;
  51         int                     id;
  52         int                     voltage_uV;
  53         int                     current_uA;
  54         int                     temp_C;
  55         int                     charge_rsoc;
  56         struct bq27x00_access_methods   *bus;
  57         struct power_supply     bat;
  58
  59         struct i2c_client       *client;
  60 };
  61
  62 static enum power_supply_property bq27x00_battery_props[] = {
  63         POWER_SUPPLY_PROP_PRESENT,
  64         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  65         POWER_SUPPLY_PROP_CURRENT_NOW,
  66         POWER_SUPPLY_PROP_CAPACITY,
  67         POWER_SUPPLY_PROP_TEMP,
  68 };
  69
  70 /*
  71  * Common code for BQ27x00 devices
  72  */
  73
  74 static int bq27x00_read(u8 reg, int *rt_value, int b_single,
  75                         struct bq27x00_device_info *di)
  76 {
  77         int ret;
  78
  79         ret = di->bus->read(reg, rt_value, b_single, di);
  80         *rt_value = be16_to_cpu(*rt_value);
  81
  82         return ret;
  83 }
  84
  85 /*
  86  * Return the battery temperature in Celsius degrees
  87  * Or < 0 if something fails.
  88  */
  89 static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
  90 {
  91         int ret;
  92         int temp = 0;
  93
  94         ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
  95         if (ret) {
  96                 dev_err(di->dev, "error reading temperature\n");
  97                 return ret;
  98         }
  99
 100         return (temp >> 2) - 273;
 101 }
 102
 103 /*
 104  * Return the battery Voltage in milivolts
 105  * Or < 0 if something fails.
 106  */
 107 static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
 108 {
 109         int ret;
 110         int volt = 0;
 111
 112         ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
 113         if (ret) {
 114                 dev_err(di->dev, "error reading voltage\n");
 115                 return ret;
 116         }
 117
 118         return volt;
 119 }
 120
 121 /*
 122  * Return the battery average current
 123  * Note that current can be negative signed as well
 124  * Or 0 if something fails.
 125  */
 126 static int bq27x00_battery_current(struct bq27x00_device_info *di)
 127 {
 128         int ret;
 129         int curr = 0;
 130         int flags = 0;
 131
 132         ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
 133         if (ret) {
 134                 dev_err(di->dev, "error reading current\n");
 135                 return 0;
 136         }
 137         ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
 138         if (ret < 0) {
 139                 dev_err(di->dev, "error reading flags\n");
 140                 return 0;
 141         }
 142         if ((flags & (1 << 7)) != 0) {
 143                 dev_dbg(di->dev, "negative current!\n");
 144                 return -curr;
 145         }
 146         return curr;
 147 }
 148
 149 /*
 150  * Return the battery Relative State-of-Charge
 151  * Or < 0 if something fails.
 152  */
 153 static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
 154 {
 155         int ret;
 156         int rsoc = 0;
 157
 158         ret = bq27x00_read(BQ27x00_REG_RSOC, &rsoc, 1, di);
 159         if (ret) {
 160                 dev_err(di->dev, "error reading relative State-of-Charge\n");
 161                 return ret;
 162         }
 163
 164         return rsoc >> 8;
 165 }
 166
 167 #define to_bq27x00_device_info(x) container_of((x), \
 168                                 struct bq27x00_device_info, bat);
 169
 170 static int bq27x00_battery_get_property(struct power_supply *psy,
 171                                         enum power_supply_property psp,
 172                                         union power_supply_propval *val)
 173 {
 174         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 175
 176         switch (psp) {
 177         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 178         case POWER_SUPPLY_PROP_PRESENT:
 179                 val->intval = bq27x00_battery_voltage(di);
 180                 if (psp == POWER_SUPPLY_PROP_PRESENT)
 181                         val->intval = val->intval <= 0 ? 0 : 1;
 182                 break;
 183         case POWER_SUPPLY_PROP_CURRENT_NOW:
 184                 val->intval = bq27x00_battery_current(di);
 185                 break;
 186         case POWER_SUPPLY_PROP_CAPACITY:
 187                 val->intval = bq27x00_battery_rsoc(di);
 188                 break;
 189         case POWER_SUPPLY_PROP_TEMP:
 190                 val->intval = bq27x00_battery_temperature(di);
 191                 break;
 192         default:
 193                 return -EINVAL;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
 200 {
 201         di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
 202         di->bat.properties = bq27x00_battery_props;
 203         di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
 204         di->bat.get_property = bq27x00_battery_get_property;
 205         di->bat.external_power_changed = NULL;
 206 }
 207
 208 /*
 209  * BQ27200 specific code
 210  */
 211
 212 static int bq27200_read(u8 reg, int *rt_value, int b_single,
 213                         struct bq27x00_device_info *di)
 214 {
 215         struct i2c_client *client = di->client;
 216         struct i2c_msg msg[1];
 217         unsigned char data[2];
 218         int err;
 219
 220         if (!client->adapter)
 221                 return -ENODEV;
 222
 223         msg->addr = client->addr;
 224         msg->flags = 0;
 225         msg->len = 1;
 226         msg->buf = data;
 227
 228         data[0] = reg;
 229         err = i2c_transfer(client->adapter, msg, 1);
 230
 231         if (err >= 0) {
 232                 if (!b_single)
 233                         msg->len = 2;
 234                 else
 235                         msg->len = 1;
 236
 237                 msg->flags = I2C_M_RD;
 238                 err = i2c_transfer(client->adapter, msg, 1);
 239                 if (err >= 0) {
 240                         if (!b_single)
 241                                 *rt_value = get_unaligned_be16(data);
 242                         else
 243                                 *rt_value = data[0];
 244
 245                         return 0;
 246                 }
 247         }
 248         return err;
 249 }
 250
 251 static int bq27200_battery_probe(struct i2c_client *client,
 252                                  const struct i2c_device_id *id)
 253 {
 254         char *name;
 255         struct bq27x00_device_info *di;
 256         struct bq27x00_access_methods *bus;
 257         int num;
 258         int retval = 0;
 259
 260         /* Get new ID for the new battery device */
 261         retval = idr_pre_get(&battery_id, GFP_KERNEL);
 262         if (retval == 0)
 263                 return -ENOMEM;
 264         mutex_lock(&battery_mutex);
 265         retval = idr_get_new(&battery_id, client, &num);
 266         mutex_unlock(&battery_mutex);
 267         if (retval < 0)
 268                 return retval;
 269
 270         name = kasprintf(GFP_KERNEL, "bq27200-%d", num);
 271         if (!name) {
 272                 dev_err(&client->dev, "failed to allocate device name\n");
 273                 retval = -ENOMEM;
 274                 goto batt_failed_1;
 275         }
 276
 277         di = kzalloc(sizeof(*di), GFP_KERNEL);
 278         if (!di) {
 279                 dev_err(&client->dev, "failed to allocate device info data\n");
 280                 retval = -ENOMEM;
 281                 goto batt_failed_2;
 282         }
 283         di->id = num;
 284
 285         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
 286         if (!bus) {
 287                 dev_err(&client->dev, "failed to allocate access method "
 288                                         "data\n");
 289                 retval = -ENOMEM;
 290                 goto batt_failed_3;
 291         }
 292
 293         i2c_set_clientdata(client, di);
 294         di->dev = &client->dev;
 295         di->bat.name = name;
 296         bus->read = &bq27200_read;
 297         di->bus = bus;
 298         di->client = client;
 299
 300         bq27x00_powersupply_init(di);
 301
 302         retval = power_supply_register(&client->dev, &di->bat);
 303         if (retval) {
 304                 dev_err(&client->dev, "failed to register battery\n");
 305                 goto batt_failed_4;
 306         }
 307
 308         dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 309
 310         return 0;
 311
 312 batt_failed_4:
 313         kfree(bus);
 314 batt_failed_3:
 315         kfree(di);
 316 batt_failed_2:
 317         kfree(name);
 318 batt_failed_1:
 319         mutex_lock(&battery_mutex);
 320         idr_remove(&battery_id, num);
 321         mutex_unlock(&battery_mutex);
 322
 323         return retval;
 324 }
 325
 326 static int bq27200_battery_remove(struct i2c_client *client)
 327 {
 328         struct bq27x00_device_info *di = i2c_get_clientdata(client);
 329
 330         power_supply_unregister(&di->bat);
 331
 332         kfree(di->bat.name);
 333
 334         mutex_lock(&battery_mutex);
 335         idr_remove(&battery_id, di->id);
 336         mutex_unlock(&battery_mutex);
 337
 338         kfree(di);
 339
 340         return 0;
 341 }
 342
 343 /*
 344  * Module stuff
 345  */
 346
 347 static const struct i2c_device_id bq27200_id[] = {
 348         { "bq27200", 0 },
 349         {},
 350 };
 351
 352 static struct i2c_driver bq27200_battery_driver = {
 353         .driver = {
 354                 .name = "bq27200-battery",
 355         },
 356         .probe = bq27200_battery_probe,
 357         .remove = bq27200_battery_remove,
 358         .id_table = bq27200_id,
 359 };
 360
 361 static int __init bq27x00_battery_init(void)
 362 {
 363         int ret;
 364
 365         ret = i2c_add_driver(&bq27200_battery_driver);
 366         if (ret)
 367                 printk(KERN_ERR "Unable to register BQ27200 driver\n");
 368
 369         return ret;
 370 }
 371 module_init(bq27x00_battery_init);
 372
 373 static void __exit bq27x00_battery_exit(void)
 374 {
 375         i2c_del_driver(&bq27200_battery_driver);
 376 }
 377 module_exit(bq27x00_battery_exit);
 378
 379 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 380 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 381 MODULE_LICENSE("GPL");