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
w1_bq27000_read(struct w1_slave * sl,unsigned int reg)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
bq27xxx_battery_hdq_read(struct bq27xxx_device_info * di,u8 reg,bool single)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
bq27xxx_battery_hdq_add_slave(struct w1_slave * sl)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
bq27xxx_battery_hdq_remove_slave(struct w1_slave * sl)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
bq27xxx_battery_hdq_init(void)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
bq27xxx_battery_hdq_exit(void)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