cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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bq27xxx_battery_hdq.c (2905B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * BQ27xxx battery monitor HDQ/1-wire driver
      4 *
      5 * Copyright (C) 2007-2017 Texas Instruments Incorporated - https://www.ti.com/
      6 *
      7 */
      8
      9#include <linux/kernel.h>
     10#include <linux/module.h>
     11#include <linux/device.h>
     12#include <linux/types.h>
     13#include <linux/platform_device.h>
     14#include <linux/mutex.h>
     15#include <linux/power/bq27xxx_battery.h>
     16
     17#include <linux/w1.h>
     18
     19#define W1_FAMILY_BQ27000	0x01
     20
     21#define HDQ_CMD_READ	(0 << 7)
     22#define HDQ_CMD_WRITE	(1 << 7)
     23
     24static int F_ID;
     25module_param(F_ID, int, S_IRUSR);
     26MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
     27
     28static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
     29{
     30	u8 val;
     31
     32	mutex_lock(&sl->master->bus_mutex);
     33	w1_write_8(sl->master, HDQ_CMD_READ | reg);
     34	val = w1_read_8(sl->master);
     35	mutex_unlock(&sl->master->bus_mutex);
     36
     37	return val;
     38}
     39
     40static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
     41				    bool single)
     42{
     43	struct w1_slave *sl = dev_to_w1_slave(di->dev);
     44	unsigned int timeout = 3;
     45	int upper, lower;
     46	int temp;
     47
     48	if (!single) {
     49		/*
     50		 * Make sure the value has not changed in between reading the
     51		 * lower and the upper part
     52		 */
     53		upper = w1_bq27000_read(sl, reg + 1);
     54		do {
     55			temp = upper;
     56			if (upper < 0)
     57				return upper;
     58
     59			lower = w1_bq27000_read(sl, reg);
     60			if (lower < 0)
     61				return lower;
     62
     63			upper = w1_bq27000_read(sl, reg + 1);
     64		} while (temp != upper && --timeout);
     65
     66		if (timeout == 0)
     67			return -EIO;
     68
     69		return (upper << 8) | lower;
     70	}
     71
     72	return w1_bq27000_read(sl, reg);
     73}
     74
     75static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
     76{
     77	struct bq27xxx_device_info *di;
     78
     79	di = devm_kzalloc(&sl->dev, sizeof(*di), GFP_KERNEL);
     80	if (!di)
     81		return -ENOMEM;
     82
     83	dev_set_drvdata(&sl->dev, di);
     84
     85	di->dev = &sl->dev;
     86	di->chip = BQ27000;
     87	di->name = "bq27000-battery";
     88	di->bus.read = bq27xxx_battery_hdq_read;
     89
     90	return bq27xxx_battery_setup(di);
     91}
     92
     93static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
     94{
     95	struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);
     96
     97	bq27xxx_battery_teardown(di);
     98}
     99
    100static const struct w1_family_ops bq27xxx_battery_hdq_fops = {
    101	.add_slave	= bq27xxx_battery_hdq_add_slave,
    102	.remove_slave	= bq27xxx_battery_hdq_remove_slave,
    103};
    104
    105static struct w1_family bq27xxx_battery_hdq_family = {
    106	.fid = W1_FAMILY_BQ27000,
    107	.fops = &bq27xxx_battery_hdq_fops,
    108};
    109
    110static int __init bq27xxx_battery_hdq_init(void)
    111{
    112	if (F_ID)
    113		bq27xxx_battery_hdq_family.fid = F_ID;
    114
    115	return w1_register_family(&bq27xxx_battery_hdq_family);
    116}
    117module_init(bq27xxx_battery_hdq_init);
    118
    119static void __exit bq27xxx_battery_hdq_exit(void)
    120{
    121	w1_unregister_family(&bq27xxx_battery_hdq_family);
    122}
    123module_exit(bq27xxx_battery_hdq_exit);
    124
    125MODULE_AUTHOR("Texas Instruments Ltd");
    126MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
    127MODULE_LICENSE("GPL");
    128MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));