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 
24 static int F_ID;
25 module_param(F_ID, int, S_IRUSR);
26 MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");
27 
28 static 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 
40 static 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 
75 static 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 
93 static 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 
100 static 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 
105 static struct w1_family bq27xxx_battery_hdq_family = {
106 	.fid = W1_FAMILY_BQ27000,
107 	.fops = &bq27xxx_battery_hdq_fops,
108 };
109 
110 static 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 }
117 module_init(bq27xxx_battery_hdq_init);
118 
119 static void __exit bq27xxx_battery_hdq_exit(void)
120 {
121 	w1_unregister_family(&bq27xxx_battery_hdq_family);
122 }
123 module_exit(bq27xxx_battery_hdq_exit);
124 
125 MODULE_AUTHOR("Texas Instruments Ltd");
126 MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
127 MODULE_LICENSE("GPL");
128 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));
129