158 lines
4.1 KiB
C
158 lines
4.1 KiB
C
/*
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* hmc6352.c - Honeywell Compass Driver
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*
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* Copyright (C) 2009 Intel Corp
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/sysfs.h>
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#include <linux/nospec.h>
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static DEFINE_MUTEX(compass_mutex);
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static int compass_command(struct i2c_client *c, u8 cmd)
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{
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int ret = i2c_master_send(c, &cmd, 1);
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if (ret < 0)
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dev_warn(&c->dev, "command '%c' failed.\n", cmd);
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return ret;
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}
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static int compass_store(struct device *dev, const char *buf, size_t count,
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const char *map)
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{
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struct i2c_client *c = to_i2c_client(dev);
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int ret;
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unsigned long val;
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ret = kstrtoul(buf, 10, &val);
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if (ret)
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return ret;
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if (val >= strlen(map))
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return -EINVAL;
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val = array_index_nospec(val, strlen(map));
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mutex_lock(&compass_mutex);
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ret = compass_command(c, map[val]);
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mutex_unlock(&compass_mutex);
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if (ret < 0)
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return ret;
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return count;
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}
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static ssize_t compass_calibration_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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return compass_store(dev, buf, count, "EC");
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}
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static ssize_t compass_power_mode_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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return compass_store(dev, buf, count, "SW");
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}
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static ssize_t compass_heading_data_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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unsigned char i2c_data[2];
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int ret;
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mutex_lock(&compass_mutex);
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ret = compass_command(client, 'A');
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if (ret != 1) {
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mutex_unlock(&compass_mutex);
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return ret;
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}
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msleep(10); /* sending 'A' cmd we need to wait for 7-10 millisecs */
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ret = i2c_master_recv(client, i2c_data, 2);
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mutex_unlock(&compass_mutex);
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if (ret < 0) {
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dev_warn(dev, "i2c read data cmd failed\n");
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return ret;
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}
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ret = (i2c_data[0] << 8) | i2c_data[1];
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return sprintf(buf, "%d.%d\n", ret/10, ret%10);
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}
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static DEVICE_ATTR(heading0_input, S_IRUGO, compass_heading_data_show, NULL);
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static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store);
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static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store);
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static struct attribute *mid_att_compass[] = {
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&dev_attr_heading0_input.attr,
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&dev_attr_calibration.attr,
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&dev_attr_power_state.attr,
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NULL
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};
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static const struct attribute_group m_compass_gr = {
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.name = "hmc6352",
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.attrs = mid_att_compass
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};
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static int hmc6352_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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int res;
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res = sysfs_create_group(&client->dev.kobj, &m_compass_gr);
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if (res) {
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dev_err(&client->dev, "device_create_file failed\n");
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return res;
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}
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dev_info(&client->dev, "%s HMC6352 compass chip found\n",
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client->name);
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return 0;
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}
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static int hmc6352_remove(struct i2c_client *client)
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{
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sysfs_remove_group(&client->dev.kobj, &m_compass_gr);
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return 0;
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}
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static const struct i2c_device_id hmc6352_id[] = {
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{ "hmc6352", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, hmc6352_id);
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static struct i2c_driver hmc6352_driver = {
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.driver = {
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.name = "hmc6352",
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},
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.probe = hmc6352_probe,
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.remove = hmc6352_remove,
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.id_table = hmc6352_id,
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};
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module_i2c_driver(hmc6352_driver);
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MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
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MODULE_DESCRIPTION("hmc6352 Compass Driver");
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MODULE_LICENSE("GPL v2");
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