SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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         struct bq27x00_access_methods   *bus;
  53         struct power_supply     bat;
  54
  55         struct i2c_client       *client;
  56 };
  57
  58 static enum power_supply_property bq27x00_battery_props[] = {
  59         POWER_SUPPLY_PROP_PRESENT,
  60         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  61         POWER_SUPPLY_PROP_CURRENT_NOW,
  62         POWER_SUPPLY_PROP_CAPACITY,
  63         POWER_SUPPLY_PROP_TEMP,
  64 };
  65
  66 /*
  67  * Common code for BQ27x00 devices
  68  */
  69
  70 static int bq27x00_read(u8 reg, int *rt_value, int b_single,
  71                         struct bq27x00_device_info *di)
  72 {
  73         return di->bus->read(reg, rt_value, b_single, di);
  74 }
  75
  76 /*
  77  * Return the battery temperature in tenths of degree Celsius
  78  * Or < 0 if something fails.
  79  */
  80 static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
  81 {
  82         int ret;
  83         int temp = 0;
  84
  85         ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
  86         if (ret) {
  87                 dev_err(di->dev, "error reading temperature\n");
  88                 return ret;
  89         }
  90
  91         return ((temp >> 2) - 273) * 10;
  92 }
  93
  94 /*
  95  * Return the battery Voltage in milivolts
  96  * Or < 0 if something fails.
  97  */
  98 static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
  99 {
 100         int ret;
 101         int volt = 0;
 102
 103         ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
 104         if (ret) {
 105                 dev_err(di->dev, "error reading voltage\n");
 106                 return ret;
 107         }
 108
 109         return volt;
 110 }
 111
 112 /*
 113  * Return the battery average current
 114  * Note that current can be negative signed as well
 115  * Or 0 if something fails.
 116  */
 117 static int bq27x00_battery_current(struct bq27x00_device_info *di)
 118 {
 119         int ret;
 120         int curr = 0;
 121         int flags = 0;
 122
 123         ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
 124         if (ret) {
 125                 dev_err(di->dev, "error reading current\n");
 126                 return 0;
 127         }
 128         ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
 129         if (ret < 0) {
 130                 dev_err(di->dev, "error reading flags\n");
 131                 return 0;
 132         }
 133         if ((flags & (1 << 7)) != 0) {
 134                 dev_dbg(di->dev, "negative current!\n");
 135                 return -curr;
 136         }
 137         return curr;
 138 }
 139
 140 /*
 141  * Return the battery Relative State-of-Charge
 142  * Or < 0 if something fails.
 143  */
 144 static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
 145 {
 146         int ret;
 147         int rsoc = 0;
 148
 149         ret = bq27x00_read(BQ27x00_REG_RSOC, &rsoc, 1, di);
 150         if (ret) {
 151                 dev_err(di->dev, "error reading relative State-of-Charge\n");
 152                 return ret;
 153         }
 154
 155         return rsoc;
 156 }
 157
 158 #define to_bq27x00_device_info(x) container_of((x), \
 159                                 struct bq27x00_device_info, bat);
 160
 161 static int bq27x00_battery_get_property(struct power_supply *psy,
 162                                         enum power_supply_property psp,
 163                                         union power_supply_propval *val)
 164 {
 165         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 166
 167         switch (psp) {
 168         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 169         case POWER_SUPPLY_PROP_PRESENT:
 170                 val->intval = bq27x00_battery_voltage(di);
 171                 if (psp == POWER_SUPPLY_PROP_PRESENT)
 172                         val->intval = val->intval <= 0 ? 0 : 1;
 173                 break;
 174         case POWER_SUPPLY_PROP_CURRENT_NOW:
 175                 val->intval = bq27x00_battery_current(di);
 176                 break;
 177         case POWER_SUPPLY_PROP_CAPACITY:
 178                 val->intval = bq27x00_battery_rsoc(di);
 179                 break;
 180         case POWER_SUPPLY_PROP_TEMP:
 181                 val->intval = bq27x00_battery_temperature(di);
 182                 break;
 183         default:
 184                 return -EINVAL;
 185         }
 186
 187         return 0;
 188 }
 189
 190 static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
 191 {
 192         di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
 193         di->bat.properties = bq27x00_battery_props;
 194         di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
 195         di->bat.get_property = bq27x00_battery_get_property;
 196         di->bat.external_power_changed = NULL;
 197 }
 198
 199 /*
 200  * BQ27200 specific code
 201  */
 202
 203 static int bq27200_read(u8 reg, int *rt_value, int b_single,
 204                         struct bq27x00_device_info *di)
 205 {
 206         struct i2c_client *client = di->client;
 207         struct i2c_msg msg[1];
 208         unsigned char data[2];
 209         int err;
 210
 211         if (!client->adapter)
 212                 return -ENODEV;
 213
 214         msg->addr = client->addr;
 215         msg->flags = 0;
 216         msg->len = 1;
 217         msg->buf = data;
 218
 219         data[0] = reg;
 220         err = i2c_transfer(client->adapter, msg, 1);
 221
 222         if (err >= 0) {
 223                 if (!b_single)
 224                         msg->len = 2;
 225                 else
 226                         msg->len = 1;
 227
 228                 msg->flags = I2C_M_RD;
 229                 err = i2c_transfer(client->adapter, msg, 1);
 230                 if (err >= 0) {
 231                         if (!b_single)
 232                                 *rt_value = get_unaligned_le16(data);
 233                         else
 234                                 *rt_value = data[0];
 235
 236                         return 0;
 237                 }
 238         }
 239         return err;
 240 }
 241
 242 static int bq27200_battery_probe(struct i2c_client *client,
 243                                  const struct i2c_device_id *id)
 244 {
 245         char *name;
 246         struct bq27x00_device_info *di;
 247         struct bq27x00_access_methods *bus;
 248         int num;
 249         int retval = 0;
 250
 251         /* Get new ID for the new battery device */
 252         retval = idr_pre_get(&battery_id, GFP_KERNEL);
 253         if (retval == 0)
 254                 return -ENOMEM;
 255         mutex_lock(&battery_mutex);
 256         retval = idr_get_new(&battery_id, client, &num);
 257         mutex_unlock(&battery_mutex);
 258         if (retval < 0)
 259                 return retval;
 260
 261         name = kasprintf(GFP_KERNEL, "bq27200-%d", num);
 262         if (!name) {
 263                 dev_err(&client->dev, "failed to allocate device name\n");
 264                 retval = -ENOMEM;
 265                 goto batt_failed_1;
 266         }
 267
 268         di = kzalloc(sizeof(*di), GFP_KERNEL);
 269         if (!di) {
 270                 dev_err(&client->dev, "failed to allocate device info data\n");
 271                 retval = -ENOMEM;
 272                 goto batt_failed_2;
 273         }
 274         di->id = num;
 275
 276         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
 277         if (!bus) {
 278                 dev_err(&client->dev, "failed to allocate access method "
 279                                         "data\n");
 280                 retval = -ENOMEM;
 281                 goto batt_failed_3;
 282         }
 283
 284         i2c_set_clientdata(client, di);
 285         di->dev = &client->dev;
 286         di->bat.name = name;
 287         bus->read = &bq27200_read;
 288         di->bus = bus;
 289         di->client = client;
 290
 291         bq27x00_powersupply_init(di);
 292
 293         retval = power_supply_register(&client->dev, &di->bat);
 294         if (retval) {
 295                 dev_err(&client->dev, "failed to register battery\n");
 296                 goto batt_failed_4;
 297         }
 298
 299         dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 300
 301         return 0;
 302
 303 batt_failed_4:
 304         kfree(bus);
 305 batt_failed_3:
 306         kfree(di);
 307 batt_failed_2:
 308         kfree(name);
 309 batt_failed_1:
 310         mutex_lock(&battery_mutex);
 311         idr_remove(&battery_id, num);
 312         mutex_unlock(&battery_mutex);
 313
 314         return retval;
 315 }
 316
 317 static int bq27200_battery_remove(struct i2c_client *client)
 318 {
 319         struct bq27x00_device_info *di = i2c_get_clientdata(client);
 320
 321         power_supply_unregister(&di->bat);
 322
 323         kfree(di->bat.name);
 324
 325         mutex_lock(&battery_mutex);
 326         idr_remove(&battery_id, di->id);
 327         mutex_unlock(&battery_mutex);
 328
 329         kfree(di);
 330
 331         return 0;
 332 }
 333
 334 /*
 335  * Module stuff
 336  */
 337
 338 static const struct i2c_device_id bq27200_id[] = {
 339         { "bq27200", 0 },
 340         {},
 341 };
 342
 343 static struct i2c_driver bq27200_battery_driver = {
 344         .driver = {
 345                 .name = "bq27200-battery",
 346         },
 347         .probe = bq27200_battery_probe,
 348         .remove = bq27200_battery_remove,
 349         .id_table = bq27200_id,
 350 };
 351
 352 static int __init bq27x00_battery_init(void)
 353 {
 354         int ret;
 355
 356         ret = i2c_add_driver(&bq27200_battery_driver);
 357         if (ret)
 358                 printk(KERN_ERR "Unable to register BQ27200 driver\n");
 359
 360         return ret;
 361 }
 362 module_init(bq27x00_battery_init);
 363
 364 static void __exit bq27x00_battery_exit(void)
 365 {
 366         i2c_del_driver(&bq27200_battery_driver);
 367 }
 368 module_exit(bq27x00_battery_exit);
 369
 370 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 371 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 372 MODULE_LICENSE("GPL");