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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
20static DEFINE_MUTEX(compass_mutex);
21
22static int compass_command(struct i2c_client *c, u8 cmd)
23{
24 int ret = i2c_master_send(c, &cmd, 1);
25 if (ret < 0)
26 dev_warn(&c->dev, "command '%c' failed.\n", cmd);
27 return ret;
28}
29
30static 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(buf, 10, &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, map[val]);
45 mutex_unlock(&compass_mutex);
46 if (ret < 0)
47 return ret;
48 return count;
49}
50
51static 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, "EC");
55}
56
57static 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, "SW");
61}
62
63static 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(client, 'A');
72 if (ret != 1) {
73 mutex_unlock(&compass_mutex);
74 return ret;
75 }
76 msleep(10); /* sending 'A' cmd we need to wait for 7-10 millisecs */
77 ret = i2c_master_recv(client, i2c_data, 2);
78 mutex_unlock(&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, "%d.%d\n", ret/10, ret%10);
85}
86
87
88static DEVICE_ATTR(heading0_input, S_IRUGO, compass_heading_data_show, NULL);
89static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store);
90static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store);
91
92static 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
99static const struct attribute_group m_compass_gr = {
100 .name = "hmc6352",
101 .attrs = mid_att_compass
102};
103
104static int hmc6352_probe(struct i2c_client *client)
105{
106 int res;
107
108 res = sysfs_create_group(&client->dev.kobj, &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
118static void hmc6352_remove(struct i2c_client *client)
119{
120 sysfs_remove_group(&client->dev.kobj, &m_compass_gr);
121}
122
123static const struct i2c_device_id hmc6352_id[] = {
124 { .name = "hmc6352" },
125 { }
126};
127
128MODULE_DEVICE_TABLE(i2c, hmc6352_id);
129
130static 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
139module_i2c_driver(hmc6352_driver);
140
141MODULE_AUTHOR("Kalhan Trisal <[email protected]");
142MODULE_DESCRIPTION("hmc6352 Compass Driver");
143MODULE_LICENSE("GPL v2");