LXR linux/drivers/misc/hmc6352.c

   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/slab.h>
  26#include <linux/i2c.h>
  27#include <linux/err.h>
  28#include <linux/delay.h>
  29#include <linux/sysfs.h>
  30
  31static DEFINE_MUTEX(compass_mutex);
  32
  33static int compass_command(struct i2c_client *c, u8 cmd)
  34{
  35        int ret = i2c_master_send(c, &cmd, 1);
  36        if (ret < 0)
  37                dev_warn(&c->dev, "command '%c' failed.\n", cmd);
  38        return ret;
  39}
  40
  41static int compass_store(struct device *dev, const char *buf, size_t count,
  42                        const char *map)
  43{
  44        struct i2c_client *c = to_i2c_client(dev);
  45        int ret;
  46        unsigned long val;
  47
  48        ret = kstrtoul(buf, 10, &val);
  49        if (ret)
  50                return ret;
  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];
  78        int ret;
  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);
  89        if (ret < 0) {
  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 const 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
 151module_i2c_driver(hmc6352_driver);
 152
 153MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
 154MODULE_DESCRIPTION("hmc6352 Compass Driver");
 155MODULE_LICENSE("GPL v2");
 156