diff options
Diffstat (limited to 'drivers/power/rx51_battery.c')
| -rw-r--r-- | drivers/power/rx51_battery.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/power/rx51_battery.c b/drivers/power/rx51_battery.c new file mode 100644 index 00000000000..ca49d6c0ee9 --- /dev/null +++ b/drivers/power/rx51_battery.c @@ -0,0 +1,251 @@ +/* + * Nokia RX-51 battery driver + * + * Copyright (C) 2012 Pali Rohár <pali.rohar@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <linux/module.h> +#include <linux/param.h> +#include <linux/platform_device.h> +#include <linux/power_supply.h> +#include <linux/slab.h> +#include <linux/i2c/twl4030-madc.h> + +struct rx51_device_info { + struct device *dev; + struct power_supply bat; +}; + +/* + * Read ADCIN channel value, code copied from maemo kernel + */ +static int rx51_battery_read_adc(int channel) +{ + struct twl4030_madc_request req; + + req.channels = 1 << channel; + req.do_avg = 1; + req.method = TWL4030_MADC_SW1; + req.func_cb = NULL; + req.type = TWL4030_MADC_WAIT; + + if (twl4030_madc_conversion(&req) <= 0) + return -ENODATA; + + return req.rbuf[channel]; +} + +/* + * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage + * This conversion formula was extracted from maemo program bsi-read + */ +static int rx51_battery_read_voltage(struct rx51_device_info *di) +{ + int voltage = rx51_battery_read_adc(12); + + if (voltage < 0) + return voltage; + + return 1000 * (10000 * voltage / 1705); +} + +/* + * Temperature look-up tables + * TEMP = (1/(t1 + 1/298) - 273.15) + * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255)) + * Formula is based on experimental data, RX-51 CAL data, maemo program bme + * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671 + */ + +/* + * Table1 (temperature for first 25 RAW values) + * Usage: TEMP = rx51_temp_table1[RAW] + * RAW is between 1 and 24 + * TEMP is between 201 C and 55 C + */ +static u8 rx51_temp_table1[] = { + 255, 201, 159, 138, 124, 114, 106, 99, 94, 89, 85, 82, 78, 75, + 73, 70, 68, 66, 64, 62, 61, 59, 57, 56, 55 +}; + +/* + * Table2 (lowest RAW value for temperature) + * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first] + * TEMP is between 53 C and -32 C + * RAW is between 25 and 993 + */ +#define rx51_temp_table2_first 53 +static u16 rx51_temp_table2[] = { + 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, + 40, 41, 43, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 64, + 66, 69, 71, 74, 77, 80, 83, 86, 90, 94, 97, 101, 106, 110, + 115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211, + 221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415, + 437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885, + 937, 993, 1024 +}; + +/* + * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius + * Use Temperature look-up tables for conversation + */ +static int rx51_battery_read_temperature(struct rx51_device_info *di) +{ + int min = 0; + int max = ARRAY_SIZE(rx51_temp_table2) - 1; + int raw = rx51_battery_read_adc(0); + + /* Zero and negative values are undefined */ + if (raw <= 0) + return INT_MAX; + + /* ADC channels are 10 bit, higher value are undefined */ + if (raw >= (1 << 10)) + return INT_MIN; + + /* First check for temperature in first direct table */ + if (raw < ARRAY_SIZE(rx51_temp_table1)) + return rx51_temp_table1[raw] * 100; + + /* Binary search RAW value in second inverse table */ + while (max - min > 1) { + int mid = (max + min) / 2; + if (rx51_temp_table2[mid] <= raw) + min = mid; + else if (rx51_temp_table2[mid] > raw) + max = mid; + if (rx51_temp_table2[mid] == raw) + break; + } + + return (rx51_temp_table2_first - min) * 100; +} + +/* + * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah + * This conversion formula was extracted from maemo program bsi-read + */ +static int rx51_battery_read_capacity(struct rx51_device_info *di) +{ + int capacity = rx51_battery_read_adc(4); + + if (capacity < 0) + return capacity; + + return 1280 * (1200 * capacity)/(1024 - capacity); +} + +/* + * Return power_supply property + */ +static int rx51_battery_get_property(struct power_supply *psy, + enum power_supply_property psp, + union power_supply_propval *val) +{ + struct rx51_device_info *di = container_of((psy), + struct rx51_device_info, bat); + + switch (psp) { + case POWER_SUPPLY_PROP_TECHNOLOGY: + val->intval = POWER_SUPPLY_TECHNOLOGY_LION; + break; + case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN: + val->intval = 4200000; + break; + case POWER_SUPPLY_PROP_PRESENT: + val->intval = rx51_battery_read_voltage(di) ? 1 : 0; + break; + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + val->intval = rx51_battery_read_voltage(di); + break; + case POWER_SUPPLY_PROP_TEMP: + val->intval = rx51_battery_read_temperature(di); + break; + case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: + val->intval = rx51_battery_read_capacity(di); + break; + default: + return -EINVAL; + } + + if (val->intval == INT_MAX || val->intval == INT_MIN) + return -EINVAL; + + return 0; +} + +static enum power_supply_property rx51_battery_props[] = { + POWER_SUPPLY_PROP_TECHNOLOGY, + POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, + POWER_SUPPLY_PROP_PRESENT, + POWER_SUPPLY_PROP_VOLTAGE_NOW, + POWER_SUPPLY_PROP_TEMP, + POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, +}; + +static int __devinit rx51_battery_probe(struct platform_device *pdev) +{ + struct rx51_device_info *di; + int ret; + + di = kzalloc(sizeof(*di), GFP_KERNEL); + if (!di) + return -ENOMEM; + + platform_set_drvdata(pdev, di); + + di->bat.name = dev_name(&pdev->dev); + di->bat.type = POWER_SUPPLY_TYPE_BATTERY; + di->bat.properties = rx51_battery_props; + di->bat.num_properties = ARRAY_SIZE(rx51_battery_props); + di->bat.get_property = rx51_battery_get_property; + + ret = power_supply_register(di->dev, &di->bat); + if (ret) { + platform_set_drvdata(pdev, NULL); + kfree(di); + return ret; + } + + return 0; +} + +static int __devexit rx51_battery_remove(struct platform_device *pdev) +{ + struct rx51_device_info *di = platform_get_drvdata(pdev); + + power_supply_unregister(&di->bat); + platform_set_drvdata(pdev, NULL); + kfree(di); + + return 0; +} + +static struct platform_driver rx51_battery_driver = { + .probe = rx51_battery_probe, + .remove = __devexit_p(rx51_battery_remove), + .driver = { + .name = "rx51-battery", + .owner = THIS_MODULE, + }, +}; +module_platform_driver(rx51_battery_driver); + +MODULE_ALIAS("platform:rx51-battery"); +MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>"); +MODULE_DESCRIPTION("Nokia RX-51 battery driver"); +MODULE_LICENSE("GPL"); |