1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * hmc6352.c - Honeywell Compass Driver |
4 | * |
5 | * Copyright (C) 2009 Intel Corp |
6 | * |
7 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
8 | * |
9 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
10 | */ |
11 | |
12 | #include <linux/module.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/i2c.h> |
15 | #include <linux/err.h> |
16 | #include <linux/delay.h> |
17 | #include <linux/sysfs.h> |
18 | #include <linux/nospec.h> |
19 | |
20 | static DEFINE_MUTEX(compass_mutex); |
21 | |
22 | static int compass_command(struct i2c_client *c, u8 cmd) |
23 | { |
24 | int ret = i2c_master_send(client: c, buf: &cmd, count: 1); |
25 | if (ret < 0) |
26 | dev_warn(&c->dev, "command '%c' failed.\n" , cmd); |
27 | return ret; |
28 | } |
29 | |
30 | static int compass_store(struct device *dev, const char *buf, size_t count, |
31 | const char *map) |
32 | { |
33 | struct i2c_client *c = to_i2c_client(dev); |
34 | int ret; |
35 | unsigned long val; |
36 | |
37 | ret = kstrtoul(s: buf, base: 10, res: &val); |
38 | if (ret) |
39 | return ret; |
40 | if (val >= strlen(map)) |
41 | return -EINVAL; |
42 | val = array_index_nospec(val, strlen(map)); |
43 | mutex_lock(&compass_mutex); |
44 | ret = compass_command(c, cmd: map[val]); |
45 | mutex_unlock(lock: &compass_mutex); |
46 | if (ret < 0) |
47 | return ret; |
48 | return count; |
49 | } |
50 | |
51 | static ssize_t compass_calibration_store(struct device *dev, |
52 | struct device_attribute *attr, const char *buf, size_t count) |
53 | { |
54 | return compass_store(dev, buf, count, map: "EC" ); |
55 | } |
56 | |
57 | static ssize_t compass_power_mode_store(struct device *dev, |
58 | struct device_attribute *attr, const char *buf, size_t count) |
59 | { |
60 | return compass_store(dev, buf, count, map: "SW" ); |
61 | } |
62 | |
63 | static ssize_t compass_heading_data_show(struct device *dev, |
64 | struct device_attribute *attr, char *buf) |
65 | { |
66 | struct i2c_client *client = to_i2c_client(dev); |
67 | unsigned char i2c_data[2]; |
68 | int ret; |
69 | |
70 | mutex_lock(&compass_mutex); |
71 | ret = compass_command(c: client, cmd: 'A'); |
72 | if (ret != 1) { |
73 | mutex_unlock(lock: &compass_mutex); |
74 | return ret; |
75 | } |
76 | msleep(msecs: 10); /* sending 'A' cmd we need to wait for 7-10 millisecs */ |
77 | ret = i2c_master_recv(client, buf: i2c_data, count: 2); |
78 | mutex_unlock(lock: &compass_mutex); |
79 | if (ret < 0) { |
80 | dev_warn(dev, "i2c read data cmd failed\n" ); |
81 | return ret; |
82 | } |
83 | ret = (i2c_data[0] << 8) | i2c_data[1]; |
84 | return sprintf(buf, fmt: "%d.%d\n" , ret/10, ret%10); |
85 | } |
86 | |
87 | |
88 | static DEVICE_ATTR(heading0_input, S_IRUGO, compass_heading_data_show, NULL); |
89 | static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store); |
90 | static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store); |
91 | |
92 | static struct attribute *mid_att_compass[] = { |
93 | &dev_attr_heading0_input.attr, |
94 | &dev_attr_calibration.attr, |
95 | &dev_attr_power_state.attr, |
96 | NULL |
97 | }; |
98 | |
99 | static const struct attribute_group m_compass_gr = { |
100 | .name = "hmc6352" , |
101 | .attrs = mid_att_compass |
102 | }; |
103 | |
104 | static int hmc6352_probe(struct i2c_client *client) |
105 | { |
106 | int res; |
107 | |
108 | res = sysfs_create_group(kobj: &client->dev.kobj, grp: &m_compass_gr); |
109 | if (res) { |
110 | dev_err(&client->dev, "device_create_file failed\n" ); |
111 | return res; |
112 | } |
113 | dev_info(&client->dev, "%s HMC6352 compass chip found\n" , |
114 | client->name); |
115 | return 0; |
116 | } |
117 | |
118 | static void hmc6352_remove(struct i2c_client *client) |
119 | { |
120 | sysfs_remove_group(kobj: &client->dev.kobj, grp: &m_compass_gr); |
121 | } |
122 | |
123 | static const struct i2c_device_id hmc6352_id[] = { |
124 | { "hmc6352" , 0 }, |
125 | { } |
126 | }; |
127 | |
128 | MODULE_DEVICE_TABLE(i2c, hmc6352_id); |
129 | |
130 | static struct i2c_driver hmc6352_driver = { |
131 | .driver = { |
132 | .name = "hmc6352" , |
133 | }, |
134 | .probe = hmc6352_probe, |
135 | .remove = hmc6352_remove, |
136 | .id_table = hmc6352_id, |
137 | }; |
138 | |
139 | module_i2c_driver(hmc6352_driver); |
140 | |
141 | MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com" ); |
142 | MODULE_DESCRIPTION("hmc6352 Compass Driver" ); |
143 | MODULE_LICENSE("GPL v2" ); |
144 | |