drivers/hwmon/lm73.c

   1 /*
   2  * LM73 Sensor driver
   3  * Based on LM75
   4  *
   5  * Copyright (C) 2007, CenoSYS (www.cenosys.com).
   6  * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
   7  *
   8  * Guillaume Ligneul <guillaume.ligneul@gmail.com>
   9  * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
  10  * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
  11  *
  12  * This software program is licensed subject to the GNU General Public License
  13  * (GPL).Version 2,June 1991, available at
  14  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/i2c.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/hwmon-sysfs.h>
  23 #include <linux/err.h>
  24
  25
  26 /* Addresses scanned */
  27 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
  28                                         0x4d, 0x4e, I2C_CLIENT_END };
  29
  30 /* LM73 registers */
  31 #define LM73_REG_INPUT          0x00
  32 #define LM73_REG_CONF           0x01
  33 #define LM73_REG_MAX            0x02
  34 #define LM73_REG_MIN            0x03
  35 #define LM73_REG_CTRL           0x04
  36 #define LM73_REG_ID             0x07
  37
  38 #define LM73_ID                 0x9001 /* or 0x190 after a swab16() */
  39 #define DRVNAME                 "lm73"
  40 #define LM73_TEMP_MIN           (-40)
  41 #define LM73_TEMP_MAX           150
  42
  43 /*-----------------------------------------------------------------------*/
  44
  45
  46 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  47                         const char *buf, size_t count)
  48 {
  49         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  50         struct i2c_client *client = to_i2c_client(dev);
  51         long temp;
  52         short value;
  53
  54         int status = strict_strtol(buf, 10, &temp);
  55         if (status < 0)
  56                 return status;
  57
  58         /* Write value */
  59         value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
  60                 (LM73_TEMP_MAX*4)) << 5;
  61         i2c_smbus_write_word_data(client, attr->index, swab16(value));
  62         return count;
  63 }
  64
  65 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  66                          char *buf)
  67 {
  68         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  69         struct i2c_client *client = to_i2c_client(dev);
  70         /* use integer division instead of equivalent right shift to
  71            guarantee arithmetic shift and preserve the sign */
  72         int temp = ((s16) (swab16(i2c_smbus_read_word_data(client,
  73                 attr->index)))*250) / 32;
  74         return sprintf(buf, "%d\n", temp);
  75 }
  76
  77
  78 /*-----------------------------------------------------------------------*/
  79
  80 /* sysfs attributes for hwmon */
  81
  82 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  83                         show_temp, set_temp, LM73_REG_MAX);
  84 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  85                         show_temp, set_temp, LM73_REG_MIN);
  86 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  87                         show_temp, NULL, LM73_REG_INPUT);
  88
  89
  90 static struct attribute *lm73_attributes[] = {
  91         &sensor_dev_attr_temp1_input.dev_attr.attr,
  92         &sensor_dev_attr_temp1_max.dev_attr.attr,
  93         &sensor_dev_attr_temp1_min.dev_attr.attr,
  94
  95         NULL
  96 };
  97
  98 static const struct attribute_group lm73_group = {
  99         .attrs = lm73_attributes,
 100 };
 101
 102 /*-----------------------------------------------------------------------*/
 103
 104 /* device probe and removal */
 105
 106 static int
 107 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
 108 {
 109         struct device *hwmon_dev;
 110         int status;
 111
 112         /* Register sysfs hooks */
 113         status = sysfs_create_group(&client->dev.kobj, &lm73_group);
 114         if (status)
 115                 return status;
 116
 117         hwmon_dev = hwmon_device_register(&client->dev);
 118         if (IS_ERR(hwmon_dev)) {
 119                 status = PTR_ERR(hwmon_dev);
 120                 goto exit_remove;
 121         }
 122         i2c_set_clientdata(client, hwmon_dev);
 123
 124         dev_info(&client->dev, "%s: sensor '%s'\n",
 125                  dev_name(hwmon_dev), client->name);
 126
 127         return 0;
 128
 129 exit_remove:
 130         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 131         return status;
 132 }
 133
 134 static int lm73_remove(struct i2c_client *client)
 135 {
 136         struct device *hwmon_dev = i2c_get_clientdata(client);
 137
 138         hwmon_device_unregister(hwmon_dev);
 139         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 140         i2c_set_clientdata(client, NULL);
 141         return 0;
 142 }
 143
 144 static const struct i2c_device_id lm73_ids[] = {
 145         { "lm73", 0 },
 146         { /* LIST END */ }
 147 };
 148 MODULE_DEVICE_TABLE(i2c, lm73_ids);
 149
 150 /* Return 0 if detection is successful, -ENODEV otherwise */
 151 static int lm73_detect(struct i2c_client *new_client,
 152                         struct i2c_board_info *info)
 153 {
 154         struct i2c_adapter *adapter = new_client->adapter;
 155         u16 id;
 156         u8 ctrl;
 157
 158         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 159                                         I2C_FUNC_SMBUS_WORD_DATA))
 160                 return -ENODEV;
 161
 162         /* Check device ID */
 163         id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
 164         ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
 165         if ((id != LM73_ID) || (ctrl & 0x10))
 166                 return -ENODEV;
 167
 168         strlcpy(info->type, "lm73", I2C_NAME_SIZE);
 169
 170         return 0;
 171 }
 172
 173 static struct i2c_driver lm73_driver = {
 174         .class          = I2C_CLASS_HWMON,
 175         .driver = {
 176                 .name   = "lm73",
 177         },
 178         .probe          = lm73_probe,
 179         .remove         = lm73_remove,
 180         .id_table       = lm73_ids,
 181         .detect         = lm73_detect,
 182         .address_list   = normal_i2c,
 183 };
 184
 185 /* module glue */
 186
 187 static int __init sensors_lm73_init(void)
 188 {
 189         return i2c_add_driver(&lm73_driver);
 190 }
 191
 192 static void __exit sensors_lm73_exit(void)
 193 {
 194         i2c_del_driver(&lm73_driver);
 195 }
 196
 197 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 198 MODULE_DESCRIPTION("LM73 driver");
 199 MODULE_LICENSE("GPL");
 200
 201 module_init(sensors_lm73_init);
 202 module_exit(sensors_lm73_exit);