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