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1/*
2 * hmc6352.c - Honeywell Compass Driver
3 *
4 * Copyright (C) 2009 Intel Corp
5 *
6 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; version 2 of the License.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
21 *
22 */
23
24#include <linux/module.h>
25#include <linux/init.h>
26#include <linux/slab.h>
27#include <linux/i2c.h>
28#include <linux/err.h>
29#include <linux/delay.h>
30#include <linux/sysfs.h>
31
32static DEFINE_MUTEX(compass_mutex);
33
34static int compass_command(struct i2c_client *c, u8 cmd)
35{
36 int ret = i2c_master_send(c, &cmd, 1);
37 if (ret < 0)
38 dev_warn(&c->dev, "command '%c' failed.\n", cmd);
39 return ret;
40}
41
42static int compass_store(struct device *dev, const char *buf, size_t count,
43 const char *map)
44{
45 struct i2c_client *c = to_i2c_client(dev);
46 int ret;
47 unsigned long val;
48
49 if (strict_strtoul(buf, 10, &val))
50 return -EINVAL;
51 if (val >= strlen(map))
52 return -EINVAL;
53 mutex_lock(&compass_mutex);
54 ret = compass_command(c, map[val]);
55 mutex_unlock(&compass_mutex);
56 if (ret < 0)
57 return ret;
58 return count;
59}
60
61static ssize_t compass_calibration_store(struct device *dev,
62 struct device_attribute *attr, const char *buf, size_t count)
63{
64 return compass_store(dev, buf, count, "EC");
65}
66
67static ssize_t compass_power_mode_store(struct device *dev,
68 struct device_attribute *attr, const char *buf, size_t count)
69{
70 return compass_store(dev, buf, count, "SW");
71}
72
73static ssize_t compass_heading_data_show(struct device *dev,
74 struct device_attribute *attr, char *buf)
75{
76 struct i2c_client *client = to_i2c_client(dev);
77 unsigned char i2c_data[2];
6f7d485e 78 int ret;
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79
80 mutex_lock(&compass_mutex);
81 ret = compass_command(client, 'A');
82 if (ret != 1) {
83 mutex_unlock(&compass_mutex);
84 return ret;
85 }
86 msleep(10); /* sending 'A' cmd we need to wait for 7-10 millisecs */
87 ret = i2c_master_recv(client, i2c_data, 2);
88 mutex_unlock(&compass_mutex);
6f7d485e 89 if (ret < 0) {
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90 dev_warn(dev, "i2c read data cmd failed\n");
91 return ret;
92 }
93 ret = (i2c_data[0] << 8) | i2c_data[1];
94 return sprintf(buf, "%d.%d\n", ret/10, ret%10);
95}
96
97
98static DEVICE_ATTR(heading0_input, S_IRUGO, compass_heading_data_show, NULL);
99static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store);
100static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store);
101
102static struct attribute *mid_att_compass[] = {
103 &dev_attr_heading0_input.attr,
104 &dev_attr_calibration.attr,
105 &dev_attr_power_state.attr,
106 NULL
107};
108
109static const struct attribute_group m_compass_gr = {
110 .name = "hmc6352",
111 .attrs = mid_att_compass
112};
113
114static int hmc6352_probe(struct i2c_client *client,
115 const struct i2c_device_id *id)
116{
117 int res;
118
119 res = sysfs_create_group(&client->dev.kobj, &m_compass_gr);
120 if (res) {
121 dev_err(&client->dev, "device_create_file failed\n");
122 return res;
123 }
124 dev_info(&client->dev, "%s HMC6352 compass chip found\n",
125 client->name);
126 return 0;
127}
128
129static int hmc6352_remove(struct i2c_client *client)
130{
131 sysfs_remove_group(&client->dev.kobj, &m_compass_gr);
132 return 0;
133}
134
135static struct i2c_device_id hmc6352_id[] = {
136 { "hmc6352", 0 },
137 { }
138};
139
140MODULE_DEVICE_TABLE(i2c, hmc6352_id);
141
142static struct i2c_driver hmc6352_driver = {
143 .driver = {
144 .name = "hmc6352",
145 },
146 .probe = hmc6352_probe,
147 .remove = hmc6352_remove,
148 .id_table = hmc6352_id,
149};
150
151static int __init sensor_hmc6352_init(void)
152{
153 return i2c_add_driver(&hmc6352_driver);
154}
155
156static void __exit sensor_hmc6352_exit(void)
157{
158 i2c_del_driver(&hmc6352_driver);
159}
160
161module_init(sensor_hmc6352_init);
162module_exit(sensor_hmc6352_exit);
163
164MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
165MODULE_DESCRIPTION("hmc6352 Compass Driver");
166MODULE_LICENSE("GPL v2");