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