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));
129