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, MAX17042_VCELL)
 115                             * 625 / 8;
 116                 break;
 117         case POWER_SUPPLY_PROP_VOLTAGE_AVG:
 118                 val->intval = max17042_read_reg(chip->client, MAX17042_AvgVCELL)
 119                             * 625 / 8;
 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 *= 1562500 / chip->pdata->r_sns;
 156                 } else {
 157                         return -EINVAL;
 158                 }
 159                 break;
 160         case POWER_SUPPLY_PROP_CURRENT_AVG:
 161                 if (chip->pdata->enable_current_sense) {
 162                         val->intval = max17042_read_reg(chip->client,
 163                                         MAX17042_AvgCurrent);
 164                         if (val->intval & 0x8000) {
 165                                 /* Negative */
 166                                 val->intval = ~val->intval & 0x7fff;
 167                                 val->intval++;
 168                                 val->intval *= -1;
 169                         }
 170                         val->intval *= 1562500 / chip->pdata->r_sns;
 171                 } else {
 172                         return -EINVAL;
 173                 }
 174                 break;
 175         default:
 176                 return -EINVAL;
 177         }
 178         return 0;
 179 }
 180
 181 static int __devinit max17042_probe(struct i2c_client *client,
 182                         const struct i2c_device_id *id)
 183 {
 184         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 185         struct max17042_chip *chip;
 186         int ret;
 187
 188         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 189                 return -EIO;
 190
 191         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 192         if (!chip)
 193                 return -ENOMEM;
 194
 195         chip->client = client;
 196         chip->pdata = client->dev.platform_data;
 197
 198         i2c_set_clientdata(client, chip);
 199
 200         chip->battery.name              = "max17042_battery";
 201         chip->battery.type              = POWER_SUPPLY_TYPE_BATTERY;
 202         chip->battery.get_property      = max17042_get_property;
 203         chip->battery.properties        = max17042_battery_props;
 204         chip->battery.num_properties    = ARRAY_SIZE(max17042_battery_props);
 205
 206         /* When current is not measured,
 207          * CURRENT_NOW and CURRENT_AVG properties should be invisible. */
 208         if (!chip->pdata->enable_current_sense)
 209                 chip->battery.num_properties -= 2;
 210
 211         if (chip->pdata->r_sns == 0)
 212                 chip->pdata->r_sns = MAX17042_DEFAULT_SNS_RESISTOR;
 213
 214         ret = power_supply_register(&client->dev, &chip->battery);
 215         if (ret) {
 216                 dev_err(&client->dev, "failed: power supply register\n");
 217                 kfree(chip);
 218                 return ret;
 219         }
 220
 221         /* Initialize registers according to values from the platform data */
 222         if (chip->pdata->init_data)
 223                 max17042_set_reg(client, chip->pdata->init_data,
 224                                  chip->pdata->num_init_data);
 225
 226         if (!chip->pdata->enable_current_sense) {
 227                 max17042_write_reg(client, MAX17042_CGAIN, 0x0000);
 228                 max17042_write_reg(client, MAX17042_MiscCFG, 0x0003);
 229                 max17042_write_reg(client, MAX17042_LearnCFG, 0x0007);
 230         }
 231
 232         return 0;
 233 }
 234
 235 static int __devexit max17042_remove(struct i2c_client *client)
 236 {
 237         struct max17042_chip *chip = i2c_get_clientdata(client);
 238
 239         power_supply_unregister(&chip->battery);
 240         kfree(chip);
 241         return 0;
 242 }
 243
 244 static const struct i2c_device_id max17042_id[] = {
 245         { "max17042", 0 },
 246         { }
 247 };
 248 MODULE_DEVICE_TABLE(i2c, max17042_id);
 249
 250 static struct i2c_driver max17042_i2c_driver = {
 251         .driver = {
 252                 .name   = "max17042",
 253         },
 254         .probe          = max17042_probe,
 255         .remove         = __devexit_p(max17042_remove),
 256         .id_table       = max17042_id,
 257 };
 258
 259 static int __init max17042_init(void)
 260 {
 261         return i2c_add_driver(&max17042_i2c_driver);
 262 }
 263 module_init(max17042_init);
 264
 265 static void __exit max17042_exit(void)
 266 {
 267         i2c_del_driver(&max17042_i2c_driver);
 268 }
 269 module_exit(max17042_exit);
 270
 271 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 272 MODULE_DESCRIPTION("MAX17042 Fuel Gauge");
 273 MODULE_LICENSE("GPL");