421 lines
9.5 KiB
C
421 lines
9.5 KiB
C
/*
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* I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
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*
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* Copyright (C) 2009 Bluewater Systems Ltd
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*
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* Author: Ryan Mallon <ryan@bluewatersys.com>
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*
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* DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
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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 version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/swab.h>
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#include <linux/i2c.h>
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#include <linux/idr.h>
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#include <linux/power_supply.h>
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#include <linux/slab.h>
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#include <linux/ds2782_battery.h>
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#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */
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#define DS278x_REG_VOLT_MSB 0x0c
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#define DS278x_REG_TEMP_MSB 0x0a
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#define DS278x_REG_CURRENT_MSB 0x0e
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/* EEPROM Block */
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#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
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/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
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#define DS2782_CURRENT_UNITS 1563
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#define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */
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#define DS2786_CURRENT_UNITS 25
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struct ds278x_info;
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struct ds278x_battery_ops {
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int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
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int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
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int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
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};
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#define to_ds278x_info(x) container_of(x, struct ds278x_info, battery)
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struct ds278x_info {
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struct i2c_client *client;
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struct power_supply battery;
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struct ds278x_battery_ops *ops;
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int id;
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int rsns;
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};
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static DEFINE_IDR(battery_id);
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static DEFINE_MUTEX(battery_lock);
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static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
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{
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int ret;
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ret = i2c_smbus_read_byte_data(info->client, reg);
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if (ret < 0) {
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dev_err(&info->client->dev, "register read failed\n");
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return ret;
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}
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*val = ret;
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return 0;
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}
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static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
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s16 *val)
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{
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int ret;
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ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb));
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if (ret < 0) {
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dev_err(&info->client->dev, "register read failed\n");
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return ret;
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}
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*val = ret;
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return 0;
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}
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static int ds278x_get_temp(struct ds278x_info *info, int *temp)
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{
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s16 raw;
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int err;
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/*
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* Temperature is measured in units of 0.125 degrees celcius, the
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* power_supply class measures temperature in tenths of degrees
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* celsius. The temperature value is stored as a 10 bit number, plus
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* sign in the upper bits of a 16 bit register.
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*/
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err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
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if (err)
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return err;
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*temp = ((raw / 32) * 125) / 100;
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return 0;
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}
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static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
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{
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int sense_res;
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int err;
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u8 sense_res_raw;
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s16 raw;
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/*
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* The units of measurement for current are dependent on the value of
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* the sense resistor.
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*/
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err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
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if (err)
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return err;
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if (sense_res_raw == 0) {
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dev_err(&info->client->dev, "sense resistor value is 0\n");
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return -ENXIO;
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}
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sense_res = 1000 / sense_res_raw;
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dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
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sense_res);
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err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
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if (err)
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return err;
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*current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
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return 0;
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}
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static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
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{
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s16 raw;
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int err;
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/*
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* Voltage is measured in units of 4.88mV. The voltage is stored as
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* a 10-bit number plus sign, in the upper bits of a 16-bit register
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*/
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err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
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if (err)
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return err;
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*voltage_uV = (raw / 32) * 4800;
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return 0;
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}
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static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
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{
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int err;
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u8 raw;
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err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
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if (err)
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return err;
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*capacity = raw;
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return 0;
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}
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static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
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{
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int err;
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s16 raw;
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err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
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if (err)
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return err;
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*current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
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return 0;
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}
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static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
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{
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s16 raw;
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int err;
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/*
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* Voltage is measured in units of 1.22mV. The voltage is stored as
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* a 10-bit number plus sign, in the upper bits of a 16-bit register
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*/
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err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
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if (err)
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return err;
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*voltage_uV = (raw / 8) * 1220;
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return 0;
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}
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static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
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{
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int err;
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u8 raw;
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err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
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if (err)
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return err;
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/* Relative capacity is displayed with resolution 0.5 % */
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*capacity = raw/2 ;
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return 0;
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}
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static int ds278x_get_status(struct ds278x_info *info, int *status)
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{
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int err;
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int current_uA;
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int capacity;
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err = info->ops->get_battery_current(info, ¤t_uA);
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if (err)
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return err;
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err = info->ops->get_battery_capacity(info, &capacity);
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if (err)
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return err;
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if (capacity == 100)
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*status = POWER_SUPPLY_STATUS_FULL;
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else if (current_uA == 0)
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*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
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else if (current_uA < 0)
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*status = POWER_SUPPLY_STATUS_DISCHARGING;
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else
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*status = POWER_SUPPLY_STATUS_CHARGING;
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return 0;
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}
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static int ds278x_battery_get_property(struct power_supply *psy,
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enum power_supply_property prop,
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union power_supply_propval *val)
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{
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struct ds278x_info *info = to_ds278x_info(psy);
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int ret;
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switch (prop) {
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case POWER_SUPPLY_PROP_STATUS:
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ret = ds278x_get_status(info, &val->intval);
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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ret = info->ops->get_battery_capacity(info, &val->intval);
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_NOW:
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ret = info->ops->get_battery_voltage(info, &val->intval);
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break;
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case POWER_SUPPLY_PROP_CURRENT_NOW:
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ret = info->ops->get_battery_current(info, &val->intval);
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break;
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case POWER_SUPPLY_PROP_TEMP:
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ret = ds278x_get_temp(info, &val->intval);
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break;
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default:
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ret = -EINVAL;
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}
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return ret;
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}
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static enum power_supply_property ds278x_battery_props[] = {
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POWER_SUPPLY_PROP_STATUS,
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POWER_SUPPLY_PROP_CAPACITY,
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POWER_SUPPLY_PROP_VOLTAGE_NOW,
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POWER_SUPPLY_PROP_CURRENT_NOW,
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POWER_SUPPLY_PROP_TEMP,
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};
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static void ds278x_power_supply_init(struct power_supply *battery)
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{
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battery->type = POWER_SUPPLY_TYPE_BATTERY;
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battery->properties = ds278x_battery_props;
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battery->num_properties = ARRAY_SIZE(ds278x_battery_props);
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battery->get_property = ds278x_battery_get_property;
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battery->external_power_changed = NULL;
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}
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static int ds278x_battery_remove(struct i2c_client *client)
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{
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struct ds278x_info *info = i2c_get_clientdata(client);
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power_supply_unregister(&info->battery);
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kfree(info->battery.name);
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mutex_lock(&battery_lock);
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idr_remove(&battery_id, info->id);
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mutex_unlock(&battery_lock);
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kfree(info);
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return 0;
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}
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enum ds278x_num_id {
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DS2782 = 0,
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DS2786,
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};
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static struct ds278x_battery_ops ds278x_ops[] = {
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[DS2782] = {
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.get_battery_current = ds2782_get_current,
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.get_battery_voltage = ds2782_get_voltage,
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.get_battery_capacity = ds2782_get_capacity,
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},
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[DS2786] = {
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.get_battery_current = ds2786_get_current,
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.get_battery_voltage = ds2786_get_voltage,
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.get_battery_capacity = ds2786_get_capacity,
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}
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};
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static int ds278x_battery_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct ds278x_platform_data *pdata = client->dev.platform_data;
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struct ds278x_info *info;
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int ret;
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int num;
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/*
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* ds2786 should have the sense resistor value set
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* in the platform data
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*/
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if (id->driver_data == DS2786 && !pdata) {
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dev_err(&client->dev, "missing platform data for ds2786\n");
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return -EINVAL;
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}
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/* Get an ID for this battery */
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ret = idr_pre_get(&battery_id, GFP_KERNEL);
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if (ret == 0) {
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ret = -ENOMEM;
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goto fail_id;
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}
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mutex_lock(&battery_lock);
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ret = idr_get_new(&battery_id, client, &num);
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mutex_unlock(&battery_lock);
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if (ret < 0)
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goto fail_id;
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info = kzalloc(sizeof(*info), GFP_KERNEL);
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if (!info) {
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ret = -ENOMEM;
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goto fail_info;
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}
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info->battery.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num);
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if (!info->battery.name) {
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ret = -ENOMEM;
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goto fail_name;
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}
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if (id->driver_data == DS2786)
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info->rsns = pdata->rsns;
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i2c_set_clientdata(client, info);
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info->client = client;
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info->id = num;
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info->ops = &ds278x_ops[id->driver_data];
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ds278x_power_supply_init(&info->battery);
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ret = power_supply_register(&client->dev, &info->battery);
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if (ret) {
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dev_err(&client->dev, "failed to register battery\n");
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goto fail_register;
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}
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return 0;
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fail_register:
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kfree(info->battery.name);
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fail_name:
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kfree(info);
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fail_info:
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mutex_lock(&battery_lock);
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idr_remove(&battery_id, num);
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mutex_unlock(&battery_lock);
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fail_id:
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return ret;
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}
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static const struct i2c_device_id ds278x_id[] = {
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{"ds2782", DS2782},
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{"ds2786", DS2786},
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{},
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};
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static struct i2c_driver ds278x_battery_driver = {
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.driver = {
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.name = "ds2782-battery",
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},
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.probe = ds278x_battery_probe,
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.remove = ds278x_battery_remove,
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.id_table = ds278x_id,
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};
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static int __init ds278x_init(void)
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{
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return i2c_add_driver(&ds278x_battery_driver);
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}
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module_init(ds278x_init);
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static void __exit ds278x_exit(void)
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{
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i2c_del_driver(&ds278x_battery_driver);
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}
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module_exit(ds278x_exit);
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MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>");
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MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
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MODULE_LICENSE("GPL");
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