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/slab.h>
  27 #include <linux/i2c.h>
  28 #include <linux/mod_devicetable.h>
  29 #include <linux/power_supply.h>
  30 #include <linux/power/max17042_battery.h>
  31
  32 struct max17042_chip {
  33         struct i2c_client *client;
  34         struct power_supply battery;
  35         struct max17042_platform_data *pdata;
  36 };
  37
  38 static int max17042_write_reg(struct i2c_client *client, u8 reg, u16 value)
  39 {
  40         int ret = i2c_smbus_write_word_data(client, reg, value);
  41
  42         if (ret < 0)
  43                 dev_err(&client->dev, "%s: err %d\n", __func__, ret);
  44
  45         return ret;
  46 }
  47
  48 static int max17042_read_reg(struct i2c_client *client, u8 reg)
  49 {
  50         int ret = i2c_smbus_read_word_data(client, reg);
  51
  52         if (ret < 0)
  53                 dev_err(&client->dev, "%s: err %d\n", __func__, ret);
  54
  55         return ret;
  56 }
  57
  58 static void max17042_set_reg(struct i2c_client *client,
  59                              struct max17042_reg_data *data, int size)
  60 {
  61         int i;
  62
  63         for (i = 0; i < size; i++)
  64                 max17042_write_reg(client, data[i].addr, data[i].data);
  65 }
  66
  67 static enum power_supply_property max17042_battery_props[] = {
  68         POWER_SUPPLY_PROP_PRESENT,
  69         POWER_SUPPLY_PROP_CYCLE_COUNT,
  70         POWER_SUPPLY_PROP_VOLTAGE_MAX,
  71         POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
  72         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  73         POWER_SUPPLY_PROP_VOLTAGE_AVG,
  74         POWER_SUPPLY_PROP_CAPACITY,
  75         POWER_SUPPLY_PROP_CHARGE_FULL,
  76         POWER_SUPPLY_PROP_TEMP,
  77         POWER_SUPPLY_PROP_CURRENT_NOW,
  78         POWER_SUPPLY_PROP_CURRENT_AVG,
  79 };
  80
  81 static int max17042_get_property(struct power_supply *psy,
  82                             enum power_supply_property psp,
  83                             union power_supply_propval *val)
  84 {
  85         struct max17042_chip *chip = container_of(psy,
  86                                 struct max17042_chip, battery);
  87
  88         switch (psp) {
  89         case POWER_SUPPLY_PROP_PRESENT:
  90                 val->intval = max17042_read_reg(chip->client,
  91                                 MAX17042_STATUS);
  92                 if (val->intval & MAX17042_STATUS_BattAbsent)
  93                         val->intval = 0;
  94                 else
  95                         val->intval = 1;
  96                 break;
  97         case POWER_SUPPLY_PROP_CYCLE_COUNT:
  98                 val->intval = max17042_read_reg(chip->client,
  99                                 MAX17042_Cycles);
 100                 break;
 101         case POWER_SUPPLY_PROP_VOLTAGE_MAX:
 102                 val->intval = max17042_read_reg(chip->client,
 103                                 MAX17042_MinMaxVolt);
 104                 val->intval >>= 8;
 105                 val->intval *= 20000; /* Units of LSB = 20mV */
 106                 break;
 107         case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
 108                 val->intval = max17042_read_reg(chip->client,
 109                                 MAX17042_V_empty);
 110                 val->intval >>= 7;
 111                 val->intval *= 10000; /* Units of LSB = 10mV */
 112                 break;
 113         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 114                 val->intval = max17042_read_reg(chip->client,
 115                                 MAX17042_VCELL) * 83; /* 1000 / 12 = 83 */
 116                 break;
 117         case POWER_SUPPLY_PROP_VOLTAGE_AVG:
 118                 val->intval = max17042_read_reg(chip->client,
 119                                 MAX17042_AvgVCELL) * 83;
 120                 break;
 121         case POWER_SUPPLY_PROP_CAPACITY:
 122                 val->intval = max17042_read_reg(chip->client,
 123                                 MAX17042_SOC) / 256;
 124                 break;
 125         case POWER_SUPPLY_PROP_CHARGE_FULL:
 126                 val->intval = max17042_read_reg(chip->client,
 127                                 MAX17042_RepSOC);
 128                 if ((val->intval / 256) >= MAX17042_BATTERY_FULL)
 129                         val->intval = 1;
 130                 else if (val->intval >= 0)
 131                         val->intval = 0;
 132                 break;
 133         case POWER_SUPPLY_PROP_TEMP:
 134                 val->intval = max17042_read_reg(chip->client,
 135                                 MAX17042_TEMP);
 136                 /* The value is signed. */
 137                 if (val->intval & 0x8000) {
 138                         val->intval = (0x7fff & ~val->intval) + 1;
 139                         val->intval *= -1;
 140                 }
 141                 /* The value is converted into deci-centigrade scale */
 142                 /* Units of LSB = 1 / 256 degree Celsius */
 143                 val->intval = val->intval * 10 / 256;
 144                 break;
 145         case POWER_SUPPLY_PROP_CURRENT_NOW:
 146                 if (chip->pdata->enable_current_sense) {
 147                         val->intval = max17042_read_reg(chip->client,
 148                                         MAX17042_Current);
 149                         if (val->intval & 0x8000) {
 150                                 /* Negative */
 151                                 val->intval = ~val->intval & 0x7fff;
 152                                 val->intval++;
 153                                 val->intval *= -1;
 154                         }
 155                         val->intval >>= 4;
 156                         val->intval *= 1000000 * 25 / chip->pdata->r_sns;
 157                 } else {
 158                         return -EINVAL;
 159                 }
 160                 break;
 161         case POWER_SUPPLY_PROP_CURRENT_AVG:
 162                 if (chip->pdata->enable_current_sense) {
 163                         val->intval = max17042_read_reg(chip->client,
 164                                         MAX17042_AvgCurrent);
 165                         if (val->intval & 0x8000) {
 166                                 /* Negative */
 167                                 val->intval = ~val->intval & 0x7fff;
 168                                 val->intval++;
 169                                 val->intval *= -1;
 170                         }
 171                         val->intval *= 1562500 / chip->pdata->r_sns;
 172                 } else {
 173                         return -EINVAL;
 174                 }
 175                 break;
 176         default:
 177                 return -EINVAL;
 178         }
 179         return 0;
 180 }
 181
 182 static int __devinit max17042_probe(struct i2c_client *client,
 183                         const struct i2c_device_id *id)
 184 {
 185         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 186         struct max17042_chip *chip;
 187         int ret;
 188
 189         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 190                 return -EIO;
 191
 192         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 193         if (!chip)
 194                 return -ENOMEM;
 195
 196         chip->client = client;
 197         chip->pdata = client->dev.platform_data;
 198
 199         i2c_set_clientdata(client, chip);
 200
 201         chip->battery.name              = "max17042_battery";
 202         chip->battery.type              = POWER_SUPPLY_TYPE_BATTERY;
 203         chip->battery.get_property      = max17042_get_property;
 204         chip->battery.properties        = max17042_battery_props;
 205         chip->battery.num_properties    = ARRAY_SIZE(max17042_battery_props);
 206
 207         /* When current is not measured,
 208          * CURRENT_NOW and CURRENT_AVG properties should be invisible. */
 209         if (!chip->pdata->enable_current_sense)
 210                 chip->battery.num_properties -= 2;
 211
 212         ret = power_supply_register(&client->dev, &chip->battery);
 213         if (ret) {
 214                 dev_err(&client->dev, "failed: power supply register\n");
 215                 kfree(chip);
 216                 return ret;
 217         }
 218
 219         /* Initialize registers according to values from the platform data */
 220         if (chip->pdata->init_data)
 221                 max17042_set_reg(client, chip->pdata->init_data,
 222                                  chip->pdata->num_init_data);
 223
 224         if (!chip->pdata->enable_current_sense) {
 225                 max17042_write_reg(client, MAX17042_CGAIN, 0x0000);
 226                 max17042_write_reg(client, MAX17042_MiscCFG, 0x0003);
 227                 max17042_write_reg(client, MAX17042_LearnCFG, 0x0007);
 228         } else {
 229                 if (chip->pdata->r_sns == 0)
 230                         chip->pdata->r_sns = MAX17042_DEFAULT_SNS_RESISTOR;
 231         }
 232
 233         return 0;
 234 }
 235
 236 static int __devexit max17042_remove(struct i2c_client *client)
 237 {
 238         struct max17042_chip *chip = i2c_get_clientdata(client);
 239
 240         power_supply_unregister(&chip->battery);
 241         kfree(chip);
 242         return 0;
 243 }
 244
 245 static const struct i2c_device_id max17042_id[] = {
 246         { "max17042", 0 },
 247         { }
 248 };
 249 MODULE_DEVICE_TABLE(i2c, max17042_id);
 250
 251 static struct i2c_driver max17042_i2c_driver = {
 252         .driver = {
 253                 .name   = "max17042",
 254         },
 255         .probe          = max17042_probe,
 256         .remove         = __devexit_p(max17042_remove),
 257         .id_table       = max17042_id,
 258 };
 259
 260 static int __init max17042_init(void)
 261 {
 262         return i2c_add_driver(&max17042_i2c_driver);
 263 }
 264 module_init(max17042_init);
 265
 266 static void __exit max17042_exit(void)
 267 {
 268         i2c_del_driver(&max17042_i2c_driver);
 269 }
 270 module_exit(max17042_exit);
 271
 272 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 273 MODULE_DESCRIPTION("MAX17042 Fuel Gauge");
 274 MODULE_LICENSE("GPL");