129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* BQ27xxx battery monitor HDQ/1-wire driver
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*
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* Copyright (C) 2007-2017 Texas Instruments Incorporated - https://www.ti.com/
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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/device.h>
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#include <linux/types.h>
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#include <linux/platform_device.h>
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#include <linux/mutex.h>
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#include <linux/power/bq27xxx_battery.h>
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#include <linux/w1.h>
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#define W1_FAMILY_BQ27000 0x01
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#define HDQ_CMD_READ (0 << 7)
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#define HDQ_CMD_WRITE (1 << 7)
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static int F_ID;
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module_param(F_ID, int, S_IRUSR);
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MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
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static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
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{
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u8 val;
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mutex_lock(&sl->master->bus_mutex);
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w1_write_8(sl->master, HDQ_CMD_READ | reg);
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val = w1_read_8(sl->master);
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mutex_unlock(&sl->master->bus_mutex);
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return val;
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}
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static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
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bool single)
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{
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struct w1_slave *sl = dev_to_w1_slave(di->dev);
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unsigned int timeout = 3;
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int upper, lower;
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int temp;
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if (!single) {
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/*
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* Make sure the value has not changed in between reading the
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* lower and the upper part
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*/
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upper = w1_bq27000_read(sl, reg + 1);
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do {
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temp = upper;
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if (upper < 0)
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return upper;
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lower = w1_bq27000_read(sl, reg);
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if (lower < 0)
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return lower;
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upper = w1_bq27000_read(sl, reg + 1);
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} while (temp != upper && --timeout);
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if (timeout == 0)
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return -EIO;
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return (upper << 8) | lower;
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}
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return w1_bq27000_read(sl, reg);
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}
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static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
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{
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struct bq27xxx_device_info *di;
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di = devm_kzalloc(&sl->dev, sizeof(*di), GFP_KERNEL);
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if (!di)
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return -ENOMEM;
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dev_set_drvdata(&sl->dev, di);
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di->dev = &sl->dev;
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di->chip = BQ27000;
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di->name = "bq27000-battery";
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di->bus.read = bq27xxx_battery_hdq_read;
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return bq27xxx_battery_setup(di);
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}
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static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
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{
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struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);
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bq27xxx_battery_teardown(di);
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}
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static const struct w1_family_ops bq27xxx_battery_hdq_fops = {
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.add_slave = bq27xxx_battery_hdq_add_slave,
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.remove_slave = bq27xxx_battery_hdq_remove_slave,
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};
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static struct w1_family bq27xxx_battery_hdq_family = {
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.fid = W1_FAMILY_BQ27000,
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.fops = &bq27xxx_battery_hdq_fops,
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};
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static int __init bq27xxx_battery_hdq_init(void)
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{
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if (F_ID)
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bq27xxx_battery_hdq_family.fid = F_ID;
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return w1_register_family(&bq27xxx_battery_hdq_family);
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}
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module_init(bq27xxx_battery_hdq_init);
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static void __exit bq27xxx_battery_hdq_exit(void)
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{
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w1_unregister_family(&bq27xxx_battery_hdq_family);
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}
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module_exit(bq27xxx_battery_hdq_exit);
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MODULE_AUTHOR("Texas Instruments Ltd");
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MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));
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