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
compass_command(struct i2c_client * c,u8 cmd)22 static 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
compass_store(struct device * dev,const char * buf,size_t count,const char * map)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(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
compass_calibration_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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, "EC");
55 }
56
compass_power_mode_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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, "SW");
61 }
62
compass_heading_data_show(struct device * dev,struct device_attribute * attr,char * buf)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(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
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
hmc6352_probe(struct i2c_client * client,const struct i2c_device_id * id)104 static int hmc6352_probe(struct i2c_client *client,
105 const struct i2c_device_id *id)
106 {
107 int res;
108
109 res = sysfs_create_group(&client->dev.kobj, &m_compass_gr);
110 if (res) {
111 dev_err(&client->dev, "device_create_file failed\n");
112 return res;
113 }
114 dev_info(&client->dev, "%s HMC6352 compass chip found\n",
115 client->name);
116 return 0;
117 }
118
hmc6352_remove(struct i2c_client * client)119 static int hmc6352_remove(struct i2c_client *client)
120 {
121 sysfs_remove_group(&client->dev.kobj, &m_compass_gr);
122 return 0;
123 }
124
125 static const struct i2c_device_id hmc6352_id[] = {
126 { "hmc6352", 0 },
127 { }
128 };
129
130 MODULE_DEVICE_TABLE(i2c, hmc6352_id);
131
132 static struct i2c_driver hmc6352_driver = {
133 .driver = {
134 .name = "hmc6352",
135 },
136 .probe = hmc6352_probe,
137 .remove = hmc6352_remove,
138 .id_table = hmc6352_id,
139 };
140
141 module_i2c_driver(hmc6352_driver);
142
143 MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
144 MODULE_DESCRIPTION("hmc6352 Compass Driver");
145 MODULE_LICENSE("GPL v2");
146