1 // SPDX-License-Identifier: GPL-2.0-only
3 * hmc6352.c - Honeywell Compass Driver
5 * Copyright (C) 2009 Intel Corp
7 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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>
20 static DEFINE_MUTEX(compass_mutex
);
22 static int compass_command(struct i2c_client
*c
, u8 cmd
)
24 int ret
= i2c_master_send(c
, &cmd
, 1);
26 dev_warn(&c
->dev
, "command '%c' failed.\n", cmd
);
30 static int compass_store(struct device
*dev
, const char *buf
, size_t count
,
33 struct i2c_client
*c
= to_i2c_client(dev
);
37 ret
= kstrtoul(buf
, 10, &val
);
40 if (val
>= strlen(map
))
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
);
51 static ssize_t
compass_calibration_store(struct device
*dev
,
52 struct device_attribute
*attr
, const char *buf
, size_t count
)
54 return compass_store(dev
, buf
, count
, "EC");
57 static ssize_t
compass_power_mode_store(struct device
*dev
,
58 struct device_attribute
*attr
, const char *buf
, size_t count
)
60 return compass_store(dev
, buf
, count
, "SW");
63 static ssize_t
compass_heading_data_show(struct device
*dev
,
64 struct device_attribute
*attr
, char *buf
)
66 struct i2c_client
*client
= to_i2c_client(dev
);
67 unsigned char i2c_data
[2];
70 mutex_lock(&compass_mutex
);
71 ret
= compass_command(client
, 'A');
73 mutex_unlock(&compass_mutex
);
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
);
80 dev_warn(dev
, "i2c read data cmd failed\n");
83 ret
= (i2c_data
[0] << 8) | i2c_data
[1];
84 return sprintf(buf
, "%d.%d\n", ret
/10, ret
%10);
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
);
92 static struct attribute
*mid_att_compass
[] = {
93 &dev_attr_heading0_input
.attr
,
94 &dev_attr_calibration
.attr
,
95 &dev_attr_power_state
.attr
,
99 static const struct attribute_group m_compass_gr
= {
101 .attrs
= mid_att_compass
104 static int hmc6352_probe(struct i2c_client
*client
,
105 const struct i2c_device_id
*id
)
109 res
= sysfs_create_group(&client
->dev
.kobj
, &m_compass_gr
);
111 dev_err(&client
->dev
, "device_create_file failed\n");
114 dev_info(&client
->dev
, "%s HMC6352 compass chip found\n",
119 static int hmc6352_remove(struct i2c_client
*client
)
121 sysfs_remove_group(&client
->dev
.kobj
, &m_compass_gr
);
125 static const struct i2c_device_id hmc6352_id
[] = {
130 MODULE_DEVICE_TABLE(i2c
, hmc6352_id
);
132 static struct i2c_driver hmc6352_driver
= {
136 .probe
= hmc6352_probe
,
137 .remove
= hmc6352_remove
,
138 .id_table
= hmc6352_id
,
141 module_i2c_driver(hmc6352_driver
);
143 MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
144 MODULE_DESCRIPTION("hmc6352 Compass Driver");
145 MODULE_LICENSE("GPL v2");