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(lock: &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(dev: 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: 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: 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(dev: &sl->dev, size: sizeof(*di), GFP_KERNEL); |
80 | if (!di) |
81 | return -ENOMEM; |
82 | |
83 | dev_set_drvdata(dev: &sl->dev, data: 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(dev: &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(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(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 | |