drivers/power/max17042_battery.c

   1 /*
   2  * Fuel gauge driver for Maxim 17042 / 8966 / 8997
   3  *  Note that Maxim 8966 and 8997 are mfd and this is its subdevice.
   4  *
   5  * Copyright (C) 2011 Samsung Electronics
   6  * MyungJoo Ham <myungjoo.ham@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  * This driver is based on max17040_battery.c
  23  */
  24
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28 #include <linux/i2c.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/power_supply.h>
  31 #include <linux/power/max17042_battery.h>
  32
  33 struct max17042_chip {
  34         struct i2c_client *client;
  35         struct power_supply battery;
  36         struct max17042_platform_data *pdata;
  37 };
  38
  39 static int max17042_write_reg(struct i2c_client *client, u8 reg, u16 value)
  40 {
  41         int ret = i2c_smbus_write_word_data(client, reg, value);
  42
  43         if (ret < 0)
  44                 dev_err(&client->dev, "%s: err %d\n", __func__, ret);
  45
  46         return ret;
  47 }
  48
  49 static int max17042_read_reg(struct i2c_client *client, u8 reg)
  50 {
  51         int ret = i2c_smbus_read_word_data(client, reg);
  52
  53         if (ret < 0)
  54                 dev_err(&client->dev, "%s: err %d\n", __func__, ret);
  55
  56         return ret;
  57 }
  58
  59 static void max17042_set_reg(struct i2c_client *client,
  60                              struct max17042_reg_data *data, int size)
  61 {
  62         int i;
  63
  64         for (i = 0; i < size; i++)
  65                 max17042_write_reg(client, data[i].addr, data[i].data);
  66 }
  67
  68 static enum power_supply_property max17042_battery_props[] = {
  69         POWER_SUPPLY_PROP_PRESENT,
  70         POWER_SUPPLY_PROP_CYCLE_COUNT,
  71         POWER_SUPPLY_PROP_VOLTAGE_MAX,
  72         POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
  73         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  74         POWER_SUPPLY_PROP_VOLTAGE_AVG,
  75         POWER_SUPPLY_PROP_CAPACITY,
  76         POWER_SUPPLY_PROP_CHARGE_FULL,
  77         POWER_SUPPLY_PROP_TEMP,
  78         POWER_SUPPLY_PROP_CURRENT_NOW,
  79         POWER_SUPPLY_PROP_CURRENT_AVG,
  80 };
  81
  82 static int max17042_get_property(struct power_supply *psy,
  83                             enum power_supply_property psp,
  84                             union power_supply_propval *val)
  85 {
  86         struct max17042_chip *chip = container_of(psy,
  87                                 struct max17042_chip, battery);
  88         int ret;
  89
  90         switch (psp) {
  91         case POWER_SUPPLY_PROP_PRESENT:
  92                 ret = max17042_read_reg(chip->client, MAX17042_STATUS);
  93                 if (ret < 0)
  94                         return ret;
  95
  96                 if (ret & MAX17042_STATUS_BattAbsent)
  97                         val->intval = 0;
  98                 else
  99                         val->intval = 1;
 100                 break;
 101         case POWER_SUPPLY_PROP_CYCLE_COUNT:
 102                 ret = max17042_read_reg(chip->client, MAX17042_Cycles);
 103                 if (ret < 0)
 104                         return ret;
 105
 106                 val->intval = ret;
 107                 break;
 108         case POWER_SUPPLY_PROP_VOLTAGE_MAX:
 109                 ret = max17042_read_reg(chip->client, MAX17042_MinMaxVolt);
 110                 if (ret < 0)
 111                         return ret;
 112
 113                 val->intval = ret >> 8;
 114                 val->intval *= 20000; /* Units of LSB = 20mV */
 115                 break;
 116         case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
 117                 ret = max17042_read_reg(chip->client, MAX17042_V_empty);
 118                 if (ret < 0)
 119                         return ret;
 120
 121                 val->intval = ret >> 7;
 122                 val->intval *= 10000; /* Units of LSB = 10mV */
 123                 break;
 124         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 125                 ret = max17042_read_reg(chip->client, MAX17042_VCELL);
 126                 if (ret < 0)
 127                         return ret;
 128
 129                 val->intval = ret * 625 / 8;
 130                 break;
 131         case POWER_SUPPLY_PROP_VOLTAGE_AVG:
 132                 ret = max17042_read_reg(chip->client, MAX17042_AvgVCELL);
 133                 if (ret < 0)
 134                         return ret;
 135
 136                 val->intval = ret * 625 / 8;
 137                 break;
 138         case POWER_SUPPLY_PROP_CAPACITY:
 139                 ret = max17042_read_reg(chip->client, MAX17042_SOC);
 140                 if (ret < 0)
 141                         return ret;
 142
 143                 val->intval = ret >> 8;
 144                 break;
 145         case POWER_SUPPLY_PROP_CHARGE_FULL:
 146                 ret = max17042_read_reg(chip->client, MAX17042_RepSOC);
 147                 if (ret < 0)
 148                         return ret;
 149
 150                 if ((ret >> 8) >= MAX17042_BATTERY_FULL)
 151                         val->intval = 1;
 152                 else if (ret >= 0)
 153                         val->intval = 0;
 154                 break;
 155         case POWER_SUPPLY_PROP_TEMP:
 156                 ret = max17042_read_reg(chip->client, MAX17042_TEMP);
 157                 if (ret < 0)
 158                         return ret;
 159
 160                 val->intval = ret;
 161                 /* The value is signed. */
 162                 if (val->intval & 0x8000) {
 163                         val->intval = (0x7fff & ~val->intval) + 1;
 164                         val->intval *= -1;
 165                 }
 166                 /* The value is converted into deci-centigrade scale */
 167                 /* Units of LSB = 1 / 256 degree Celsius */
 168                 val->intval = val->intval * 10 / 256;
 169                 break;
 170         case POWER_SUPPLY_PROP_CURRENT_NOW:
 171                 if (chip->pdata->enable_current_sense) {
 172                         ret = max17042_read_reg(chip->client, MAX17042_Current);
 173                         if (ret < 0)
 174                                 return ret;
 175
 176                         val->intval = ret;
 177                         if (val->intval & 0x8000) {
 178                                 /* Negative */
 179                                 val->intval = ~val->intval & 0x7fff;
 180                                 val->intval++;
 181                                 val->intval *= -1;
 182                         }
 183                         val->intval *= 1562500 / chip->pdata->r_sns;
 184                 } else {
 185                         return -EINVAL;
 186                 }
 187                 break;
 188         case POWER_SUPPLY_PROP_CURRENT_AVG:
 189                 if (chip->pdata->enable_current_sense) {
 190                         ret = max17042_read_reg(chip->client,
 191                                                 MAX17042_AvgCurrent);
 192                         if (ret < 0)
 193                                 return ret;
 194
 195                         val->intval = ret;
 196                         if (val->intval & 0x8000) {
 197                                 /* Negative */
 198                                 val->intval = ~val->intval & 0x7fff;
 199                                 val->intval++;
 200                                 val->intval *= -1;
 201                         }
 202                         val->intval *= 1562500 / chip->pdata->r_sns;
 203                 } else {
 204                         return -EINVAL;
 205                 }
 206                 break;
 207         default:
 208                 return -EINVAL;
 209         }
 210         return 0;
 211 }
 212
 213 static int __devinit max17042_probe(struct i2c_client *client,
 214                         const struct i2c_device_id *id)
 215 {
 216         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 217         struct max17042_chip *chip;
 218         int ret;
 219
 220         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 221                 return -EIO;
 222
 223         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 224         if (!chip)
 225                 return -ENOMEM;
 226
 227         chip->client = client;
 228         chip->pdata = client->dev.platform_data;
 229
 230         i2c_set_clientdata(client, chip);
 231
 232         chip->battery.name              = "max17042_battery";
 233         chip->battery.type              = POWER_SUPPLY_TYPE_BATTERY;
 234         chip->battery.get_property      = max17042_get_property;
 235         chip->battery.properties        = max17042_battery_props;
 236         chip->battery.num_properties    = ARRAY_SIZE(max17042_battery_props);
 237
 238         /* When current is not measured,
 239          * CURRENT_NOW and CURRENT_AVG properties should be invisible. */
 240         if (!chip->pdata->enable_current_sense)
 241                 chip->battery.num_properties -= 2;
 242
 243         if (chip->pdata->r_sns == 0)
 244                 chip->pdata->r_sns = MAX17042_DEFAULT_SNS_RESISTOR;
 245
 246         ret = power_supply_register(&client->dev, &chip->battery);
 247         if (ret) {
 248                 dev_err(&client->dev, "failed: power supply register\n");
 249                 kfree(chip);
 250                 return ret;
 251         }
 252
 253         /* Initialize registers according to values from the platform data */
 254         if (chip->pdata->init_data)
 255                 max17042_set_reg(client, chip->pdata->init_data,
 256                                  chip->pdata->num_init_data);
 257
 258         if (!chip->pdata->enable_current_sense) {
 259                 max17042_write_reg(client, MAX17042_CGAIN, 0x0000);
 260                 max17042_write_reg(client, MAX17042_MiscCFG, 0x0003);
 261                 max17042_write_reg(client, MAX17042_LearnCFG, 0x0007);
 262         }
 263
 264         return 0;
 265 }
 266
 267 static int __devexit max17042_remove(struct i2c_client *client)
 268 {
 269         struct max17042_chip *chip = i2c_get_clientdata(client);
 270
 271         power_supply_unregister(&chip->battery);
 272         kfree(chip);
 273         return 0;
 274 }
 275
 276 static const struct i2c_device_id max17042_id[] = {
 277         { "max17042", 0 },
 278         { }
 279 };
 280 MODULE_DEVICE_TABLE(i2c, max17042_id);
 281
 282 static struct i2c_driver max17042_i2c_driver = {
 283         .driver = {
 284                 .name   = "max17042",
 285         },
 286         .probe          = max17042_probe,
 287         .remove         = __devexit_p(max17042_remove),
 288         .id_table       = max17042_id,
 289 };
 290
 291 static int __init max17042_init(void)
 292 {
 293         return i2c_add_driver(&max17042_i2c_driver);
 294 }
 295 module_init(max17042_init);
 296
 297 static void __exit max17042_exit(void)
 298 {
 299         i2c_del_driver(&max17042_i2c_driver);
 300 }
 301 module_exit(max17042_exit);
 302
 303 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 304 MODULE_DESCRIPTION("MAX17042 Fuel Gauge");
 305 MODULE_LICENSE("GPL");