LXR linux/drivers/power/rx51

   1/*
   2 * Nokia RX-51 battery driver
   3 *
   4 * Copyright (C) 2012  Pali Rohár <pali.rohar@gmail.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License along
  17 * with this program; if not, write to the Free Software Foundation, Inc.,
  18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21#include <linux/module.h>
  22#include <linux/param.h>
  23#include <linux/platform_device.h>
  24#include <linux/power_supply.h>
  25#include <linux/slab.h>
  26#include <linux/i2c/twl4030-madc.h>
  27#include <linux/iio/consumer.h>
  28#include <linux/of.h>
  29
  30struct rx51_device_info {
  31        struct device *dev;
  32        struct power_supply *bat;
  33        struct power_supply_desc bat_desc;
  34        struct iio_channel *channel_temp;
  35        struct iio_channel *channel_bsi;
  36        struct iio_channel *channel_vbat;
  37};
  38
  39/*
  40 * Read ADCIN channel value, code copied from maemo kernel
  41 */
  42static int rx51_battery_read_adc(struct iio_channel *channel)
  43{
  44        int val, err;
  45        err = iio_read_channel_average_raw(channel, &val);
  46        if (err < 0)
  47                return err;
  48        return val;
  49}
  50
  51/*
  52 * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage
  53 * This conversion formula was extracted from maemo program bsi-read
  54 */
  55static int rx51_battery_read_voltage(struct rx51_device_info *di)
  56{
  57        int voltage = rx51_battery_read_adc(di->channel_vbat);
  58
  59        if (voltage < 0) {
  60                dev_err(di->dev, "Could not read ADC: %d\n", voltage);
  61                return voltage;
  62        }
  63
  64        return 1000 * (10000 * voltage / 1705);
  65}
  66
  67/*
  68 * Temperature look-up tables
  69 * TEMP = (1/(t1 + 1/298) - 273.15)
  70 * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255))
  71 * Formula is based on experimental data, RX-51 CAL data, maemo program bme
  72 * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671
  73 */
  74
  75/*
  76 * Table1 (temperature for first 25 RAW values)
  77 * Usage: TEMP = rx51_temp_table1[RAW]
  78 *   RAW is between 1 and 24
  79 *   TEMP is between 201 C and 55 C
  80 */
  81static u8 rx51_temp_table1[] = {
  82        255, 201, 159, 138, 124, 114, 106,  99,  94,  89,  85,  82,  78,  75,
  83         73,  70,  68,  66,  64,  62,  61,  59,  57,  56,  55
  84};
  85
  86/*
  87 * Table2 (lowest RAW value for temperature)
  88 * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first]
  89 *   TEMP is between 53 C and -32 C
  90 *   RAW is between 25 and 993
  91 */
  92#define rx51_temp_table2_first 53
  93static u16 rx51_temp_table2[] = {
  94         25,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  39,
  95         40,  41,  43,  44,  46,  48,  49,  51,  53,  55,  57,  59,  61,  64,
  96         66,  69,  71,  74,  77,  80,  83,  86,  90,  94,  97, 101, 106, 110,
  97        115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211,
  98        221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415,
  99        437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885,
 100        937, 993, 1024
 101};
 102
 103/*
 104 * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius
 105 * Use Temperature look-up tables for conversation
 106 */
 107static int rx51_battery_read_temperature(struct rx51_device_info *di)
 108{
 109        int min = 0;
 110        int max = ARRAY_SIZE(rx51_temp_table2) - 1;
 111        int raw = rx51_battery_read_adc(di->channel_temp);
 112
 113        if (raw < 0)
 114                dev_err(di->dev, "Could not read ADC: %d\n", raw);
 115
 116        /* Zero and negative values are undefined */
 117        if (raw <= 0)
 118                return INT_MAX;
 119
 120        /* ADC channels are 10 bit, higher value are undefined */
 121        if (raw >= (1 << 10))
 122                return INT_MIN;
 123
 124        /* First check for temperature in first direct table */
 125        if (raw < ARRAY_SIZE(rx51_temp_table1))
 126                return rx51_temp_table1[raw] * 10;
 127
 128        /* Binary search RAW value in second inverse table */
 129        while (max - min > 1) {
 130                int mid = (max + min) / 2;
 131                if (rx51_temp_table2[mid] <= raw)
 132                        min = mid;
 133                else if (rx51_temp_table2[mid] > raw)
 134                        max = mid;
 135                if (rx51_temp_table2[mid] == raw)
 136                        break;
 137        }
 138
 139        return (rx51_temp_table2_first - min) * 10;
 140}
 141
 142/*
 143 * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah
 144 * This conversion formula was extracted from maemo program bsi-read
 145 */
 146static int rx51_battery_read_capacity(struct rx51_device_info *di)
 147{
 148        int capacity = rx51_battery_read_adc(di->channel_bsi);
 149
 150        if (capacity < 0) {
 151                dev_err(di->dev, "Could not read ADC: %d\n", capacity);
 152                return capacity;
 153        }
 154
 155        return 1280 * (1200 * capacity)/(1024 - capacity);
 156}
 157
 158/*
 159 * Return power_supply property
 160 */
 161static int rx51_battery_get_property(struct power_supply *psy,
 162                                        enum power_supply_property psp,
 163                                        union power_supply_propval *val)
 164{
 165        struct rx51_device_info *di = power_supply_get_drvdata(psy);
 166
 167        switch (psp) {
 168        case POWER_SUPPLY_PROP_TECHNOLOGY:
 169                val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 170                break;
 171        case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
 172                val->intval = 4200000;
 173                break;
 174        case POWER_SUPPLY_PROP_PRESENT:
 175                val->intval = rx51_battery_read_voltage(di) ? 1 : 0;
 176                break;
 177        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 178                val->intval = rx51_battery_read_voltage(di);
 179                break;
 180        case POWER_SUPPLY_PROP_TEMP:
 181                val->intval = rx51_battery_read_temperature(di);
 182                break;
 183        case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 184                val->intval = rx51_battery_read_capacity(di);
 185                break;
 186        default:
 187                return -EINVAL;
 188        }
 189
 190        if (val->intval == INT_MAX || val->intval == INT_MIN)
 191                return -EINVAL;
 192
 193        return 0;
 194}
 195
 196static enum power_supply_property rx51_battery_props[] = {
 197        POWER_SUPPLY_PROP_TECHNOLOGY,
 198        POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
 199        POWER_SUPPLY_PROP_PRESENT,
 200        POWER_SUPPLY_PROP_VOLTAGE_NOW,
 201        POWER_SUPPLY_PROP_TEMP,
 202        POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 203};
 204
 205static int rx51_battery_probe(struct platform_device *pdev)
 206{
 207        struct power_supply_config psy_cfg = {};
 208        struct rx51_device_info *di;
 209        int ret;
 210
 211        di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL);
 212        if (!di)
 213                return -ENOMEM;
 214
 215        platform_set_drvdata(pdev, di);
 216
 217        di->dev = &pdev->dev;
 218        di->bat_desc.name = "rx51-battery";
 219        di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
 220        di->bat_desc.properties = rx51_battery_props;
 221        di->bat_desc.num_properties = ARRAY_SIZE(rx51_battery_props);
 222        di->bat_desc.get_property = rx51_battery_get_property;
 223
 224        psy_cfg.drv_data = di;
 225
 226        di->channel_temp = iio_channel_get(di->dev, "temp");
 227        if (IS_ERR(di->channel_temp)) {
 228                ret = PTR_ERR(di->channel_temp);
 229                goto error;
 230        }
 231
 232        di->channel_bsi  = iio_channel_get(di->dev, "bsi");
 233        if (IS_ERR(di->channel_bsi)) {
 234                ret = PTR_ERR(di->channel_bsi);
 235                goto error_channel_temp;
 236        }
 237
 238        di->channel_vbat = iio_channel_get(di->dev, "vbat");
 239        if (IS_ERR(di->channel_vbat)) {
 240                ret = PTR_ERR(di->channel_vbat);
 241                goto error_channel_bsi;
 242        }
 243
 244        di->bat = power_supply_register(di->dev, &di->bat_desc, &psy_cfg);
 245        if (IS_ERR(di->bat)) {
 246                ret = PTR_ERR(di->bat);
 247                goto error_channel_vbat;
 248        }
 249
 250        return 0;
 251
 252error_channel_vbat:
 253        iio_channel_release(di->channel_vbat);
 254error_channel_bsi:
 255        iio_channel_release(di->channel_bsi);
 256error_channel_temp:
 257        iio_channel_release(di->channel_temp);
 258error:
 259
 260        return ret;
 261}
 262
 263static int rx51_battery_remove(struct platform_device *pdev)
 264{
 265        struct rx51_device_info *di = platform_get_drvdata(pdev);
 266
 267        power_supply_unregister(di->bat);
 268
 269        iio_channel_release(di->channel_vbat);
 270        iio_channel_release(di->channel_bsi);
 271        iio_channel_release(di->channel_temp);
 272
 273        return 0;
 274}
 275
 276#ifdef CONFIG_OF
 277static const struct of_device_id n900_battery_of_match[] = {
 278        {.compatible = "nokia,n900-battery", },
 279        { },
 280};
 281MODULE_DEVICE_TABLE(of, n900_battery_of_match);
 282#endif
 283
 284static struct platform_driver rx51_battery_driver = {
 285        .probe = rx51_battery_probe,
 286        .remove = rx51_battery_remove,
 287        .driver = {
 288                .name = "rx51-battery",
 289                .of_match_table = of_match_ptr(n900_battery_of_match),
 290        },
 291};
 292module_platform_driver(rx51_battery_driver);
 293
 294MODULE_ALIAS("platform:rx51-battery");
 295MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 296MODULE_DESCRIPTION("Nokia RX-51 battery driver");
 297MODULE_LICENSE("GPL");
 298