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hmc6352: add driver for the HMC6352 compass
This driver will report the heading values in degrees to the sysfs interface. The values returned are headings . e.g. 245.6 Alan: Cleanups requested now all folded in and a sysfs description to keep Andrew happy. The sysfs description now resembles hwmon. Signed-off-by: Kalhan Trisal <[email protected]> Reviewed-by: Jean Delvare <[email protected]> Signed-off-by: Alan Cox <[email protected]> Cc: Jonathan Cameron <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
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Where: /sys/bus/i2c/devices/.../heading0_input | ||
Date: April 2010 | ||
Kernel Version: 2.6.36? | ||
Contact: [email protected] | ||
Description: Reports the current heading from the compass as a floating | ||
point value in degrees. | ||
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Where: /sys/bus/i2c/devices/.../power_state | ||
Date: April 2010 | ||
Kernel Version: 2.6.36? | ||
Contact: [email protected] | ||
Description: Sets the power state of the device. 0 sets the device into | ||
sleep mode, 1 wakes it up. | ||
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Where: /sys/bus/i2c/devices/.../calibration | ||
Date: April 2010 | ||
Kernel Version: 2.6.36? | ||
Contact: [email protected] | ||
Description: Sets the calibration on or off (1 = on, 0 = off). See the | ||
chip data sheet. | ||
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/* | ||
* hmc6352.c - Honeywell Compass Driver | ||
* | ||
* Copyright (C) 2009 Intel Corp | ||
* | ||
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
* | ||
* This program is free software; you can redistribute it and/or modify | ||
* it under the terms of the GNU General Public License as published by | ||
* the Free Software Foundation; version 2 of the License. | ||
* | ||
* This program is distributed in the hope that it will be useful, but | ||
* WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
* General Public License for more details. | ||
* | ||
* You should have received a copy of the GNU General Public License along | ||
* with this program; if not, write to the Free Software Foundation, Inc., | ||
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. | ||
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ||
* | ||
*/ | ||
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#include <linux/module.h> | ||
#include <linux/init.h> | ||
#include <linux/slab.h> | ||
#include <linux/i2c.h> | ||
#include <linux/err.h> | ||
#include <linux/delay.h> | ||
#include <linux/sysfs.h> | ||
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static DEFINE_MUTEX(compass_mutex); | ||
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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; | ||
} | ||
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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; | ||
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if (strict_strtoul(buf, 10, &val)) | ||
return -EINVAL; | ||
if (val >= strlen(map)) | ||
return -EINVAL; | ||
mutex_lock(&compass_mutex); | ||
ret = compass_command(c, map[val]); | ||
mutex_unlock(&compass_mutex); | ||
if (ret < 0) | ||
return ret; | ||
return count; | ||
} | ||
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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"); | ||
} | ||
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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"); | ||
} | ||
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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]; | ||
unsigned int ret; | ||
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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 != 1) { | ||
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); | ||
} | ||
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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); | ||
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static struct attribute *mid_att_compass[] = { | ||
&dev_attr_heading0_input.attr, | ||
&dev_attr_calibration.attr, | ||
&dev_attr_power_state.attr, | ||
NULL | ||
}; | ||
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static const struct attribute_group m_compass_gr = { | ||
.name = "hmc6352", | ||
.attrs = mid_att_compass | ||
}; | ||
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static int hmc6352_probe(struct i2c_client *client, | ||
const struct i2c_device_id *id) | ||
{ | ||
int res; | ||
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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; | ||
} | ||
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static int hmc6352_remove(struct i2c_client *client) | ||
{ | ||
sysfs_remove_group(&client->dev.kobj, &m_compass_gr); | ||
return 0; | ||
} | ||
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static struct i2c_device_id hmc6352_id[] = { | ||
{ "hmc6352", 0 }, | ||
{ } | ||
}; | ||
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MODULE_DEVICE_TABLE(i2c, hmc6352_id); | ||
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static struct i2c_driver hmc6352_driver = { | ||
.driver = { | ||
.name = "hmc6352", | ||
}, | ||
.probe = hmc6352_probe, | ||
.remove = hmc6352_remove, | ||
.id_table = hmc6352_id, | ||
}; | ||
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static int __init sensor_hmc6352_init(void) | ||
{ | ||
return i2c_add_driver(&hmc6352_driver); | ||
} | ||
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static void __exit sensor_hmc6352_exit(void) | ||
{ | ||
i2c_del_driver(&hmc6352_driver); | ||
} | ||
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module_init(sensor_hmc6352_init); | ||
module_exit(sensor_hmc6352_exit); | ||
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MODULE_AUTHOR("Kalhan Trisal <[email protected]"); | ||
MODULE_DESCRIPTION("hmc6352 Compass Driver"); | ||
MODULE_LICENSE("GPL v2"); |