284 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			284 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| // SPDX-License-Identifier: GPL-2.0-or-later
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| /*
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|  * Nokia RX-51 battery driver
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|  *
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|  * Copyright (C) 2012  Pali Rohár <pali@kernel.org>
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|  */
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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/iio/consumer.h>
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| #include <linux/of.h>
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| 
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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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| 	struct power_supply_desc bat_desc;
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| 	struct iio_channel *channel_temp;
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| 	struct iio_channel *channel_bsi;
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| 	struct iio_channel *channel_vbat;
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| };
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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(struct iio_channel *channel)
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| {
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| 	int val, err;
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| 	err = iio_read_channel_average_raw(channel, &val);
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| 	if (err < 0)
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| 		return err;
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| 	return val;
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| }
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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(di->channel_vbat);
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| 
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| 	if (voltage < 0) {
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| 		dev_err(di->dev, "Could not read ADC: %d\n", voltage);
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| 		return voltage;
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| 	}
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| 
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| 	return 1000 * (10000 * voltage / 1705);
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| }
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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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| /*
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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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| /*
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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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| /*
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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(di->channel_temp);
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| 
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| 	if (raw < 0)
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| 		dev_err(di->dev, "Could not read ADC: %d\n", raw);
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| 	return (rx51_temp_table2_first - min) * 10;
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| }
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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(di->channel_bsi);
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| 
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| 	if (capacity < 0) {
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| 		dev_err(di->dev, "Could not read ADC: %d\n", capacity);
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| 		return capacity;
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| 	}
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| 
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| 	return 1280 * (1200 * capacity)/(1024 - capacity);
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| }
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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 = power_supply_get_drvdata(psy);
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| 
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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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| 
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| 	if (val->intval == INT_MAX || val->intval == INT_MIN)
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| 		return -EINVAL;
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| 
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| 	return 0;
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| }
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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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| 
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| static int rx51_battery_probe(struct platform_device *pdev)
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| {
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| 	struct power_supply_config psy_cfg = {};
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| 	struct rx51_device_info *di;
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| 	int ret;
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| 
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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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| 
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| 	platform_set_drvdata(pdev, di);
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| 
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| 	di->dev = &pdev->dev;
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| 	di->bat_desc.name = "rx51-battery";
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| 	di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
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| 	di->bat_desc.properties = rx51_battery_props;
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| 	di->bat_desc.num_properties = ARRAY_SIZE(rx51_battery_props);
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| 	di->bat_desc.get_property = rx51_battery_get_property;
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| 
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| 	psy_cfg.drv_data = di;
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| 
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| 	di->channel_temp = iio_channel_get(di->dev, "temp");
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| 	if (IS_ERR(di->channel_temp)) {
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| 		ret = PTR_ERR(di->channel_temp);
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| 		goto error;
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| 	}
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| 
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| 	di->channel_bsi  = iio_channel_get(di->dev, "bsi");
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| 	if (IS_ERR(di->channel_bsi)) {
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| 		ret = PTR_ERR(di->channel_bsi);
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| 		goto error_channel_temp;
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| 	}
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| 
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| 	di->channel_vbat = iio_channel_get(di->dev, "vbat");
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| 	if (IS_ERR(di->channel_vbat)) {
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| 		ret = PTR_ERR(di->channel_vbat);
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| 		goto error_channel_bsi;
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| 	}
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| 
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| 	di->bat = power_supply_register(di->dev, &di->bat_desc, &psy_cfg);
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| 	if (IS_ERR(di->bat)) {
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| 		ret = PTR_ERR(di->bat);
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| 		goto error_channel_vbat;
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| 	}
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| 
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| 	return 0;
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| 
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| error_channel_vbat:
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| 	iio_channel_release(di->channel_vbat);
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| error_channel_bsi:
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| 	iio_channel_release(di->channel_bsi);
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| error_channel_temp:
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| 	iio_channel_release(di->channel_temp);
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| error:
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| 
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| 	return ret;
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| }
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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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| 
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| 	power_supply_unregister(di->bat);
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| 
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| 	iio_channel_release(di->channel_vbat);
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| 	iio_channel_release(di->channel_bsi);
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| 	iio_channel_release(di->channel_temp);
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| 
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| 	return 0;
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| }
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| 
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| #ifdef CONFIG_OF
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| static const struct of_device_id n900_battery_of_match[] = {
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| 	{.compatible = "nokia,n900-battery", },
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| 	{ },
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| };
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| MODULE_DEVICE_TABLE(of, n900_battery_of_match);
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| #endif
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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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| 		.of_match_table = of_match_ptr(n900_battery_of_match),
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| 	},
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| };
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| module_platform_driver(rx51_battery_driver);
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| 
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| MODULE_ALIAS("platform:rx51-battery");
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| MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
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| MODULE_DESCRIPTION("Nokia RX-51 battery driver");
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| MODULE_LICENSE("GPL");
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