linux/drivers/power/twl4030_madc_battery.c
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   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/i2c/twl4030-madc.h>
  21#include <linux/power/twl4030_madc_battery.h>
  22
  23struct twl4030_madc_battery {
  24        struct power_supply psy;
  25        struct twl4030_madc_bat_platform_data *pdata;
  26};
  27
  28static enum power_supply_property twl4030_madc_bat_props[] = {
  29        POWER_SUPPLY_PROP_PRESENT,
  30        POWER_SUPPLY_PROP_STATUS,
  31        POWER_SUPPLY_PROP_TECHNOLOGY,
  32        POWER_SUPPLY_PROP_VOLTAGE_NOW,
  33        POWER_SUPPLY_PROP_CURRENT_NOW,
  34        POWER_SUPPLY_PROP_CAPACITY,
  35        POWER_SUPPLY_PROP_CHARGE_FULL,
  36        POWER_SUPPLY_PROP_CHARGE_NOW,
  37        POWER_SUPPLY_PROP_TEMP,
  38        POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
  39};
  40
  41static int madc_read(int index)
  42{
  43        struct twl4030_madc_request req;
  44        int val;
  45
  46        req.channels = index;
  47        req.method = TWL4030_MADC_SW2;
  48        req.type = TWL4030_MADC_WAIT;
  49        req.do_avg = 0;
  50        req.raw = false;
  51        req.func_cb = NULL;
  52
  53        val = twl4030_madc_conversion(&req);
  54        if (val < 0)
  55                return val;
  56
  57        return req.rbuf[ffs(index) - 1];
  58}
  59
  60static int twl4030_madc_bat_get_charging_status(void)
  61{
  62        return (madc_read(TWL4030_MADC_ICHG) > 0) ? 1 : 0;
  63}
  64
  65static int twl4030_madc_bat_get_voltage(void)
  66{
  67        return madc_read(TWL4030_MADC_VBAT);
  68}
  69
  70static int twl4030_madc_bat_get_current(void)
  71{
  72        return madc_read(TWL4030_MADC_ICHG) * 1000;
  73}
  74
  75static int twl4030_madc_bat_get_temp(void)
  76{
  77        return madc_read(TWL4030_MADC_BTEMP) * 10;
  78}
  79
  80static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
  81                                        int volt)
  82{
  83        struct twl4030_madc_bat_calibration *calibration;
  84        int i, res = 0;
  85
  86        /* choose charging curve */
  87        if (twl4030_madc_bat_get_charging_status())
  88                calibration = bat->pdata->charging;
  89        else
  90                calibration = bat->pdata->discharging;
  91
  92        if (volt > calibration[0].voltage) {
  93                res = calibration[0].level;
  94        } else {
  95                for (i = 0; calibration[i+1].voltage >= 0; i++) {
  96                        if (volt <= calibration[i].voltage &&
  97                                        volt >= calibration[i+1].voltage) {
  98                                /* interval found - interpolate within range */
  99                                res = calibration[i].level -
 100                                        ((calibration[i].voltage - volt) *
 101                                        (calibration[i].level -
 102                                        calibration[i+1].level)) /
 103                                        (calibration[i].voltage -
 104                                        calibration[i+1].voltage);
 105                                break;
 106                        }
 107                }
 108        }
 109        return res;
 110}
 111
 112static int twl4030_madc_bat_get_property(struct power_supply *psy,
 113                                        enum power_supply_property psp,
 114                                        union power_supply_propval *val)
 115{
 116        struct twl4030_madc_battery *bat = container_of(psy,
 117                                        struct twl4030_madc_battery, psy);
 118
 119        switch (psp) {
 120        case POWER_SUPPLY_PROP_STATUS:
 121                if (twl4030_madc_bat_voltscale(bat,
 122                                twl4030_madc_bat_get_voltage()) > 95)
 123                        val->intval = POWER_SUPPLY_STATUS_FULL;
 124                else {
 125                        if (twl4030_madc_bat_get_charging_status())
 126                                val->intval = POWER_SUPPLY_STATUS_CHARGING;
 127                        else
 128                                val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
 129                }
 130                break;
 131        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 132                val->intval = twl4030_madc_bat_get_voltage() * 1000;
 133                break;
 134        case POWER_SUPPLY_PROP_TECHNOLOGY:
 135                val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 136                break;
 137        case POWER_SUPPLY_PROP_CURRENT_NOW:
 138                val->intval = twl4030_madc_bat_get_current();
 139                break;
 140        case POWER_SUPPLY_PROP_PRESENT:
 141                /* assume battery is always present */
 142                val->intval = 1;
 143                break;
 144        case POWER_SUPPLY_PROP_CHARGE_NOW: {
 145                        int percent = twl4030_madc_bat_voltscale(bat,
 146                                        twl4030_madc_bat_get_voltage());
 147                        val->intval = (percent * bat->pdata->capacity) / 100;
 148                        break;
 149                }
 150        case POWER_SUPPLY_PROP_CAPACITY:
 151                val->intval = twl4030_madc_bat_voltscale(bat,
 152                                        twl4030_madc_bat_get_voltage());
 153                break;
 154        case POWER_SUPPLY_PROP_CHARGE_FULL:
 155                val->intval = bat->pdata->capacity;
 156                break;
 157        case POWER_SUPPLY_PROP_TEMP:
 158                val->intval = twl4030_madc_bat_get_temp();
 159                break;
 160        case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
 161                        int percent = twl4030_madc_bat_voltscale(bat,
 162                                        twl4030_madc_bat_get_voltage());
 163                        /* in mAh */
 164                        int chg = (percent * (bat->pdata->capacity/1000))/100;
 165
 166                        /* assume discharge with 400 mA (ca. 1.5W) */
 167                        val->intval = (3600l * chg) / 400;
 168                        break;
 169                }
 170        default:
 171                return -EINVAL;
 172        }
 173
 174        return 0;
 175}
 176
 177static void twl4030_madc_bat_ext_changed(struct power_supply *psy)
 178{
 179        struct twl4030_madc_battery *bat = container_of(psy,
 180                                        struct twl4030_madc_battery, psy);
 181
 182        power_supply_changed(&bat->psy);
 183}
 184
 185static 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
 191static 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
 196        twl4030_madc_bat = kzalloc(sizeof(*twl4030_madc_bat), GFP_KERNEL);
 197        if (!twl4030_madc_bat)
 198                return -ENOMEM;
 199
 200        twl4030_madc_bat->psy.name = "twl4030_battery";
 201        twl4030_madc_bat->psy.type = POWER_SUPPLY_TYPE_BATTERY;
 202        twl4030_madc_bat->psy.properties = twl4030_madc_bat_props;
 203        twl4030_madc_bat->psy.num_properties =
 204                                        ARRAY_SIZE(twl4030_madc_bat_props);
 205        twl4030_madc_bat->psy.get_property = twl4030_madc_bat_get_property;
 206        twl4030_madc_bat->psy.external_power_changed =
 207                                        twl4030_madc_bat_ext_changed;
 208
 209        /* sort charging and discharging calibration data */
 210        sort(pdata->charging, pdata->charging_size,
 211                sizeof(struct twl4030_madc_bat_calibration),
 212                twl4030_cmp, NULL);
 213        sort(pdata->discharging, pdata->discharging_size,
 214                sizeof(struct twl4030_madc_bat_calibration),
 215                twl4030_cmp, NULL);
 216
 217        twl4030_madc_bat->pdata = pdata;
 218        platform_set_drvdata(pdev, twl4030_madc_bat);
 219        power_supply_register(&pdev->dev, &twl4030_madc_bat->psy);
 220
 221        return 0;
 222}
 223
 224static int twl4030_madc_battery_remove(struct platform_device *pdev)
 225{
 226        struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
 227
 228        power_supply_unregister(&bat->psy);
 229        kfree(bat);
 230
 231        return 0;
 232}
 233
 234static struct platform_driver twl4030_madc_battery_driver = {
 235        .driver = {
 236                .name = "twl4030_madc_battery",
 237        },
 238        .probe  = twl4030_madc_battery_probe,
 239        .remove = twl4030_madc_battery_remove,
 240};
 241module_platform_driver(twl4030_madc_battery_driver);
 242
 243MODULE_LICENSE("GPL");
 244MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
 245MODULE_DESCRIPTION("twl4030_madc battery driver");
 246
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