382 lines
8.1 KiB
C
382 lines
8.1 KiB
C
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/*
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* BQ27x00 battery driver
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*
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* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
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* Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
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*
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* Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
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*
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* This package 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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* THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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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/jiffies.h>
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#include <linux/workqueue.h>
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#include <linux/delay.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/idr.h>
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#include <linux/i2c.h>
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#include <asm/unaligned.h>
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#define DRIVER_VERSION "1.0.0"
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#define BQ27x00_REG_TEMP 0x06
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#define BQ27x00_REG_VOLT 0x08
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#define BQ27x00_REG_RSOC 0x0B /* Relative State-of-Charge */
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#define BQ27x00_REG_AI 0x14
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#define BQ27x00_REG_FLAGS 0x0A
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/* If the system has several batteries we need a different name for each
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* of them...
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*/
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static DEFINE_IDR(battery_id);
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static DEFINE_MUTEX(battery_mutex);
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struct bq27x00_device_info;
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struct bq27x00_access_methods {
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int (*read)(u8 reg, int *rt_value, int b_single,
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struct bq27x00_device_info *di);
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};
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struct bq27x00_device_info {
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struct device *dev;
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int id;
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int voltage_uV;
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int current_uA;
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int temp_C;
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int charge_rsoc;
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struct bq27x00_access_methods *bus;
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struct power_supply bat;
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struct i2c_client *client;
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};
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static enum power_supply_property bq27x00_battery_props[] = {
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POWER_SUPPLY_PROP_PRESENT,
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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_CAPACITY,
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POWER_SUPPLY_PROP_TEMP,
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};
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/*
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* Common code for BQ27x00 devices
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*/
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static int bq27x00_read(u8 reg, int *rt_value, int b_single,
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struct bq27x00_device_info *di)
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{
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int ret;
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ret = di->bus->read(reg, rt_value, b_single, di);
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*rt_value = be16_to_cpu(*rt_value);
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return ret;
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}
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/*
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* Return the battery temperature in Celsius degrees
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* Or < 0 if something fails.
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*/
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static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
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{
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int ret;
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int temp = 0;
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ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
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if (ret) {
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dev_err(di->dev, "error reading temperature\n");
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return ret;
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}
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return (temp >> 2) - 273;
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}
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/*
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* Return the battery Voltage in milivolts
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* Or < 0 if something fails.
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*/
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static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
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{
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int ret;
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int volt = 0;
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ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
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if (ret) {
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dev_err(di->dev, "error reading voltage\n");
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return ret;
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}
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return volt;
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}
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/*
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* Return the battery average current
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* Note that current can be negative signed as well
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* Or 0 if something fails.
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*/
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static int bq27x00_battery_current(struct bq27x00_device_info *di)
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{
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int ret;
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int curr = 0;
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int flags = 0;
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ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
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if (ret) {
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dev_err(di->dev, "error reading current\n");
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return 0;
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}
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ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
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if (ret < 0) {
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dev_err(di->dev, "error reading flags\n");
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return 0;
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}
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if ((flags & (1 << 7)) != 0) {
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dev_dbg(di->dev, "negative current!\n");
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return -curr;
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}
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return curr;
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}
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/*
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* Return the battery Relative State-of-Charge
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* Or < 0 if something fails.
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*/
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static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
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{
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int ret;
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int rsoc = 0;
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ret = bq27x00_read(BQ27x00_REG_RSOC, &rsoc, 1, di);
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if (ret) {
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dev_err(di->dev, "error reading relative State-of-Charge\n");
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return ret;
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}
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return rsoc >> 8;
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}
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#define to_bq27x00_device_info(x) container_of((x), \
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struct bq27x00_device_info, bat);
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static int bq27x00_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 bq27x00_device_info *di = to_bq27x00_device_info(psy);
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switch (psp) {
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case POWER_SUPPLY_PROP_VOLTAGE_NOW:
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case POWER_SUPPLY_PROP_PRESENT:
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val->intval = bq27x00_battery_voltage(di);
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if (psp == POWER_SUPPLY_PROP_PRESENT)
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val->intval = val->intval <= 0 ? 0 : 1;
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break;
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case POWER_SUPPLY_PROP_CURRENT_NOW:
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val->intval = bq27x00_battery_current(di);
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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val->intval = bq27x00_battery_rsoc(di);
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break;
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case POWER_SUPPLY_PROP_TEMP:
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val->intval = bq27x00_battery_temperature(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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return 0;
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}
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static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
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{
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di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
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di->bat.properties = bq27x00_battery_props;
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di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
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di->bat.get_property = bq27x00_battery_get_property;
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di->bat.external_power_changed = NULL;
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}
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/*
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* BQ27200 specific code
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*/
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static int bq27200_read(u8 reg, int *rt_value, int b_single,
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struct bq27x00_device_info *di)
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{
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struct i2c_client *client = di->client;
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struct i2c_msg msg[1];
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unsigned char data[2];
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int err;
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if (!client->adapter)
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return -ENODEV;
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msg->addr = client->addr;
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msg->flags = 0;
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msg->len = 1;
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msg->buf = data;
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data[0] = reg;
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err = i2c_transfer(client->adapter, msg, 1);
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if (err >= 0) {
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if (!b_single)
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msg->len = 2;
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else
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msg->len = 1;
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msg->flags = I2C_M_RD;
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err = i2c_transfer(client->adapter, msg, 1);
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if (err >= 0) {
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if (!b_single)
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*rt_value = get_unaligned_be16(data);
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else
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*rt_value = data[0];
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return 0;
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}
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}
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return err;
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}
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static int bq27200_battery_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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char *name;
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struct bq27x00_device_info *di;
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struct bq27x00_access_methods *bus;
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int num;
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int retval = 0;
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/* Get new ID for the new battery device */
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retval = idr_pre_get(&battery_id, GFP_KERNEL);
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if (retval == 0)
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return -ENOMEM;
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mutex_lock(&battery_mutex);
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retval = idr_get_new(&battery_id, client, &num);
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mutex_unlock(&battery_mutex);
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if (retval < 0)
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return retval;
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name = kasprintf(GFP_KERNEL, "bq27200-%d", num);
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if (!name) {
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dev_err(&client->dev, "failed to allocate device name\n");
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retval = -ENOMEM;
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goto batt_failed_1;
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}
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di = kzalloc(sizeof(*di), GFP_KERNEL);
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if (!di) {
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dev_err(&client->dev, "failed to allocate device info data\n");
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retval = -ENOMEM;
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goto batt_failed_2;
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}
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di->id = num;
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bus = kzalloc(sizeof(*bus), GFP_KERNEL);
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if (!bus) {
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dev_err(&client->dev, "failed to allocate access method "
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"data\n");
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retval = -ENOMEM;
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goto batt_failed_3;
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}
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i2c_set_clientdata(client, di);
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di->dev = &client->dev;
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di->bat.name = name;
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bus->read = &bq27200_read;
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di->bus = bus;
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di->client = client;
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bq27x00_powersupply_init(di);
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retval = power_supply_register(&client->dev, &di->bat);
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if (retval) {
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dev_err(&client->dev, "failed to register battery\n");
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goto batt_failed_4;
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}
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dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
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return 0;
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batt_failed_4:
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kfree(bus);
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batt_failed_3:
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kfree(di);
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batt_failed_2:
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kfree(name);
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batt_failed_1:
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mutex_lock(&battery_mutex);
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idr_remove(&battery_id, num);
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mutex_unlock(&battery_mutex);
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return retval;
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}
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static int bq27200_battery_remove(struct i2c_client *client)
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{
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struct bq27x00_device_info *di = i2c_get_clientdata(client);
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power_supply_unregister(&di->bat);
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kfree(di->bat.name);
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mutex_lock(&battery_mutex);
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idr_remove(&battery_id, di->id);
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mutex_unlock(&battery_mutex);
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kfree(di);
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return 0;
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}
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/*
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* Module stuff
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*/
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static const struct i2c_device_id bq27200_id[] = {
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{ "bq27200", 0 },
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{},
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};
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static struct i2c_driver bq27200_battery_driver = {
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.driver = {
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.name = "bq27200-battery",
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},
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.probe = bq27200_battery_probe,
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.remove = bq27200_battery_remove,
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.id_table = bq27200_id,
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};
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static int __init bq27x00_battery_init(void)
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{
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int ret;
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ret = i2c_add_driver(&bq27200_battery_driver);
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if (ret)
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printk(KERN_ERR "Unable to register BQ27200 driver\n");
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return ret;
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}
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module_init(bq27x00_battery_init);
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static void __exit bq27x00_battery_exit(void)
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{
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i2c_del_driver(&bq27200_battery_driver);
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}
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module_exit(bq27x00_battery_exit);
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MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
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MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
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MODULE_LICENSE("GPL");
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