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/*
* BQ27xxx battery monitor HDQ/1-wire driver
*
* Copyright (C) 2007-2017 Texas Instruments Incorporated - https://www.ti.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/power/bq27xxx_battery.h>
#include <linux/w1.h>
#define W1_FAMILY_BQ27000 0x01
#define HDQ_CMD_READ (0 << 7)
#define HDQ_CMD_WRITE (1 << 7)
static int F_ID;
module_param(F_ID, int, S_IRUSR);
MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
{
u8 val;
mutex_lock(&sl->master->bus_mutex);
w1_write_8(sl->master, HDQ_CMD_READ | reg);
val = w1_read_8(sl->master);
mutex_unlock(&sl->master->bus_mutex);
return val;
}
static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
bool single)
{
struct w1_slave *sl = dev_to_w1_slave(di->dev);
unsigned int timeout = 3;
int upper, lower;
int temp;
if (!single) {
/*
* Make sure the value has not changed in between reading the
* lower and the upper part
*/
upper = w1_bq27000_read(sl, reg + 1);
do {
temp = upper;
if (upper < 0)
return upper;
lower = w1_bq27000_read(sl, reg);
if (lower < 0)
return lower;
upper = w1_bq27000_read(sl, reg + 1);
} while (temp != upper && --timeout);
if (timeout == 0)
return -EIO;
return (upper << 8) | lower;
}
return w1_bq27000_read(sl, reg);
}
static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
{
struct bq27xxx_device_info *di;
di = devm_kzalloc(&sl->dev, sizeof(*di), GFP_KERNEL);
if (!di)
return -ENOMEM;
dev_set_drvdata(&sl->dev, di);
di->dev = &sl->dev;
di->chip = BQ27000;
di->name = "bq27000-battery";
di->bus.read = bq27xxx_battery_hdq_read;
return bq27xxx_battery_setup(di);
}
static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
{
struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);
bq27xxx_battery_teardown(di);
}
static const struct w1_family_ops bq27xxx_battery_hdq_fops = {
.add_slave = bq27xxx_battery_hdq_add_slave,
.remove_slave = bq27xxx_battery_hdq_remove_slave,
};
static struct w1_family bq27xxx_battery_hdq_family = {
.fid = W1_FAMILY_BQ27000,
.fops = &bq27xxx_battery_hdq_fops,
};
static int __init bq27xxx_battery_hdq_init(void)
{
if (F_ID)
bq27xxx_battery_hdq_family.fid = F_ID;
return w1_register_family(&bq27xxx_battery_hdq_family);
}
module_init(bq27xxx_battery_hdq_init);
static void __exit bq27xxx_battery_hdq_exit(void)
{
w1_unregister_family(&bq27xxx_battery_hdq_family);
}
module_exit(bq27xxx_battery_hdq_exit);
MODULE_AUTHOR("Texas Instruments Ltd");
MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));
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