/* * 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. * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * */ #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> static DEFINE_MUTEX(compass_mutex); 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; } 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; ret = kstrtoul(buf, 10, &val); if (ret) return ret; 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; } 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"); } 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"); } 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]; int ret; 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 < 0) { 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); } 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); static struct attribute *mid_att_compass[] = { &dev_attr_heading0_input.attr, &dev_attr_calibration.attr, &dev_attr_power_state.attr, NULL }; static const struct attribute_group m_compass_gr = { .name = "hmc6352", .attrs = mid_att_compass }; static int hmc6352_probe(struct i2c_client *client, const struct i2c_device_id *id) { int res; 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; } static int hmc6352_remove(struct i2c_client *client) { sysfs_remove_group(&client->dev.kobj, &m_compass_gr); return 0; } static struct i2c_device_id hmc6352_id[] = { { "hmc6352", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, hmc6352_id); static struct i2c_driver hmc6352_driver = { .driver = { .name = "hmc6352", }, .probe = hmc6352_probe, .remove = hmc6352_remove, .id_table = hmc6352_id, }; module_i2c_driver(hmc6352_driver); MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com"); MODULE_DESCRIPTION("hmc6352 Compass Driver"); MODULE_LICENSE("GPL v2");