drivers/power/supply/twl4030_madc_battery.c

   1 /*
   2  * Dumb driver for LiIon batteries using TWL4030 madc.
   3  *
   4  * Copyright 2013 Golden Delicious Computers
   5  * Lukas Märdian <lukas@goldelico.com>
   6  *
   7  * Based on dumb driver for gta01 battery
   8  * Copyright 2009 Openmoko, Inc
   9  * Balaji Rao <balajirrao@openmoko.org>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/param.h>
  14 #include <linux/delay.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/power_supply.h>
  18 #include <linux/slab.h>
  19 #include <linux/sort.h>
  20 #include <linux/power/twl4030_madc_battery.h>
  21 #include <linux/iio/consumer.h>
  22
  23 struct twl4030_madc_battery {
  24         struct power_supply *psy;
  25         struct twl4030_madc_bat_platform_data *pdata;
  26         struct iio_channel *channel_temp;
  27         struct iio_channel *channel_ichg;
  28         struct iio_channel *channel_vbat;
  29 };
  30
  31 static enum power_supply_property twl4030_madc_bat_props[] = {
  32         POWER_SUPPLY_PROP_PRESENT,
  33         POWER_SUPPLY_PROP_STATUS,
  34         POWER_SUPPLY_PROP_TECHNOLOGY,
  35         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  36         POWER_SUPPLY_PROP_CURRENT_NOW,
  37         POWER_SUPPLY_PROP_CAPACITY,
  38         POWER_SUPPLY_PROP_CHARGE_FULL,
  39         POWER_SUPPLY_PROP_CHARGE_NOW,
  40         POWER_SUPPLY_PROP_TEMP,
  41         POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
  42 };
  43
  44 static int madc_read(struct iio_channel *channel)
  45 {
  46         int val, err;
  47         err = iio_read_channel_processed(channel, &val);
  48         if (err < 0)
  49                 return err;
  50
  51         return val;
  52 }
  53
  54 static int twl4030_madc_bat_get_charging_status(struct twl4030_madc_battery *bt)
  55 {
  56         return (madc_read(bt->channel_ichg) > 0) ? 1 : 0;
  57 }
  58
  59 static int twl4030_madc_bat_get_voltage(struct twl4030_madc_battery *bt)
  60 {
  61         return madc_read(bt->channel_vbat);
  62 }
  63
  64 static int twl4030_madc_bat_get_current(struct twl4030_madc_battery *bt)
  65 {
  66         return madc_read(bt->channel_ichg) * 1000;
  67 }
  68
  69 static int twl4030_madc_bat_get_temp(struct twl4030_madc_battery *bt)
  70 {
  71         return madc_read(bt->channel_temp) * 10;
  72 }
  73
  74 static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
  75                                         int volt)
  76 {
  77         struct twl4030_madc_bat_calibration *calibration;
  78         int i, res = 0;
  79
  80         /* choose charging curve */
  81         if (twl4030_madc_bat_get_charging_status(bat))
  82                 calibration = bat->pdata->charging;
  83         else
  84                 calibration = bat->pdata->discharging;
  85
  86         if (volt > calibration[0].voltage) {
  87                 res = calibration[0].level;
  88         } else {
  89                 for (i = 0; calibration[i+1].voltage >= 0; i++) {
  90                         if (volt <= calibration[i].voltage &&
  91                                         volt >= calibration[i+1].voltage) {
  92                                 /* interval found - interpolate within range */
  93                                 res = calibration[i].level -
  94                                         ((calibration[i].voltage - volt) *
  95                                         (calibration[i].level -
  96                                         calibration[i+1].level)) /
  97                                         (calibration[i].voltage -
  98                                         calibration[i+1].voltage);
  99                                 break;
 100                         }
 101                 }
 102         }
 103         return res;
 104 }
 105
 106 static int twl4030_madc_bat_get_property(struct power_supply *psy,
 107                                         enum power_supply_property psp,
 108                                         union power_supply_propval *val)
 109 {
 110         struct twl4030_madc_battery *bat = power_supply_get_drvdata(psy);
 111
 112         switch (psp) {
 113         case POWER_SUPPLY_PROP_STATUS:
 114                 if (twl4030_madc_bat_voltscale(bat,
 115                                 twl4030_madc_bat_get_voltage(bat)) > 95)
 116                         val->intval = POWER_SUPPLY_STATUS_FULL;
 117                 else {
 118                         if (twl4030_madc_bat_get_charging_status(bat))
 119                                 val->intval = POWER_SUPPLY_STATUS_CHARGING;
 120                         else
 121                                 val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
 122                 }
 123                 break;
 124         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 125                 val->intval = twl4030_madc_bat_get_voltage(bat) * 1000;
 126                 break;
 127         case POWER_SUPPLY_PROP_TECHNOLOGY:
 128                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 129                 break;
 130         case POWER_SUPPLY_PROP_CURRENT_NOW:
 131                 val->intval = twl4030_madc_bat_get_current(bat);
 132                 break;
 133         case POWER_SUPPLY_PROP_PRESENT:
 134                 /* assume battery is always present */
 135                 val->intval = 1;
 136                 break;
 137         case POWER_SUPPLY_PROP_CHARGE_NOW: {
 138                         int percent = twl4030_madc_bat_voltscale(bat,
 139                                         twl4030_madc_bat_get_voltage(bat));
 140                         val->intval = (percent * bat->pdata->capacity) / 100;
 141                         break;
 142                 }
 143         case POWER_SUPPLY_PROP_CAPACITY:
 144                 val->intval = twl4030_madc_bat_voltscale(bat,
 145                                         twl4030_madc_bat_get_voltage(bat));
 146                 break;
 147         case POWER_SUPPLY_PROP_CHARGE_FULL:
 148                 val->intval = bat->pdata->capacity;
 149                 break;
 150         case POWER_SUPPLY_PROP_TEMP:
 151                 val->intval = twl4030_madc_bat_get_temp(bat);
 152                 break;
 153         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
 154                         int percent = twl4030_madc_bat_voltscale(bat,
 155                                         twl4030_madc_bat_get_voltage(bat));
 156                         /* in mAh */
 157                         int chg = (percent * (bat->pdata->capacity/1000))/100;
 158
 159                         /* assume discharge with 400 mA (ca. 1.5W) */
 160                         val->intval = (3600l * chg) / 400;
 161                         break;
 162                 }
 163         default:
 164                 return -EINVAL;
 165         }
 166
 167         return 0;
 168 }
 169
 170 static void twl4030_madc_bat_ext_changed(struct power_supply *psy)
 171 {
 172         power_supply_changed(psy);
 173 }
 174
 175 static const struct power_supply_desc twl4030_madc_bat_desc = {
 176         .name                   = "twl4030_battery",
 177         .type                   = POWER_SUPPLY_TYPE_BATTERY,
 178         .properties             = twl4030_madc_bat_props,
 179         .num_properties         = ARRAY_SIZE(twl4030_madc_bat_props),
 180         .get_property           = twl4030_madc_bat_get_property,
 181         .external_power_changed = twl4030_madc_bat_ext_changed,
 182
 183 };
 184
 185 static int twl4030_cmp(const void *a, const void *b)
 186 {
 187         return ((struct twl4030_madc_bat_calibration *)b)->voltage -
 188                 ((struct twl4030_madc_bat_calibration *)a)->voltage;
 189 }
 190
 191 static int twl4030_madc_battery_probe(struct platform_device *pdev)
 192 {
 193         struct twl4030_madc_battery *twl4030_madc_bat;
 194         struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
 195         struct power_supply_config psy_cfg = {};
 196         int ret = 0;
 197
 198         twl4030_madc_bat = devm_kzalloc(&pdev->dev, sizeof(*twl4030_madc_bat),
 199                                 GFP_KERNEL);
 200         if (!twl4030_madc_bat)
 201                 return -ENOMEM;
 202
 203         twl4030_madc_bat->channel_temp = iio_channel_get(&pdev->dev, "temp");
 204         if (IS_ERR(twl4030_madc_bat->channel_temp)) {
 205                 ret = PTR_ERR(twl4030_madc_bat->channel_temp);
 206                 goto err;
 207         }
 208
 209         twl4030_madc_bat->channel_ichg = iio_channel_get(&pdev->dev, "ichg");
 210         if (IS_ERR(twl4030_madc_bat->channel_ichg)) {
 211                 ret = PTR_ERR(twl4030_madc_bat->channel_ichg);
 212                 goto err_temp;
 213         }
 214
 215         twl4030_madc_bat->channel_vbat = iio_channel_get(&pdev->dev, "vbat");
 216         if (IS_ERR(twl4030_madc_bat->channel_vbat)) {
 217                 ret = PTR_ERR(twl4030_madc_bat->channel_vbat);
 218                 goto err_ichg;
 219         }
 220
 221         /* sort charging and discharging calibration data */
 222         sort(pdata->charging, pdata->charging_size,
 223                 sizeof(struct twl4030_madc_bat_calibration),
 224                 twl4030_cmp, NULL);
 225         sort(pdata->discharging, pdata->discharging_size,
 226                 sizeof(struct twl4030_madc_bat_calibration),
 227                 twl4030_cmp, NULL);
 228
 229         twl4030_madc_bat->pdata = pdata;
 230         platform_set_drvdata(pdev, twl4030_madc_bat);
 231         psy_cfg.drv_data = twl4030_madc_bat;
 232         twl4030_madc_bat->psy = power_supply_register(&pdev->dev,
 233                                                       &twl4030_madc_bat_desc,
 234                                                       &psy_cfg);
 235         if (IS_ERR(twl4030_madc_bat->psy)) {
 236                 ret = PTR_ERR(twl4030_madc_bat->psy);
 237                 goto err_vbat;
 238         }
 239
 240         return 0;
 241
 242 err_vbat:
 243         iio_channel_release(twl4030_madc_bat->channel_vbat);
 244 err_ichg:
 245         iio_channel_release(twl4030_madc_bat->channel_ichg);
 246 err_temp:
 247         iio_channel_release(twl4030_madc_bat->channel_temp);
 248 err:
 249         return ret;
 250 }
 251
 252 static int twl4030_madc_battery_remove(struct platform_device *pdev)
 253 {
 254         struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
 255
 256         power_supply_unregister(bat->psy);
 257
 258         iio_channel_release(bat->channel_vbat);
 259         iio_channel_release(bat->channel_ichg);
 260         iio_channel_release(bat->channel_temp);
 261
 262         return 0;
 263 }
 264
 265 static struct platform_driver twl4030_madc_battery_driver = {
 266         .driver = {
 267                 .name = "twl4030_madc_battery",
 268         },
 269         .probe  = twl4030_madc_battery_probe,
 270         .remove = twl4030_madc_battery_remove,
 271 };
 272 module_platform_driver(twl4030_madc_battery_driver);
 273
 274 MODULE_LICENSE("GPL");
 275 MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
 276 MODULE_DESCRIPTION("twl4030_madc battery driver");
 277 MODULE_ALIAS("platform:twl4030_madc_battery");