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/i2c.h>
  20 #include <linux/hwmon.h>
  21 #include <linux/hwmon-sysfs.h>
  22 #include <linux/err.h>
  23
  24
  25 /* Addresses scanned */
  26 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
  27                                         0x4d, 0x4e, I2C_CLIENT_END };
  28
  29 /* LM73 registers */
  30 #define LM73_REG_INPUT          0x00
  31 #define LM73_REG_CONF           0x01
  32 #define LM73_REG_MAX            0x02
  33 #define LM73_REG_MIN            0x03
  34 #define LM73_REG_CTRL           0x04
  35 #define LM73_REG_ID             0x07
  36
  37 #define LM73_ID                 0x9001  /* 0x0190, byte-swapped */
  38 #define DRVNAME                 "lm73"
  39 #define LM73_TEMP_MIN           (-40)
  40 #define LM73_TEMP_MAX           150
  41
  42 /*-----------------------------------------------------------------------*/
  43
  44
  45 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  46                         const char *buf, size_t count)
  47 {
  48         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  49         struct i2c_client *client = to_i2c_client(dev);
  50         long temp;
  51         short value;
  52         s32 err;
  53
  54         int status = kstrtol(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         err = i2c_smbus_write_word_swapped(client, attr->index, value);
  62         return (err < 0) ? err : 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         int temp;
  71
  72         s32 err = i2c_smbus_read_word_swapped(client, attr->index);
  73         if (err < 0)
  74                 return err;
  75
  76         /* use integer division instead of equivalent right shift to
  77            guarantee arithmetic shift and preserve the sign */
  78         temp = (((s16) err) * 250) / 32;
  79         return scnprintf(buf, PAGE_SIZE, "%d\n", temp);
  80 }
  81
  82
  83 /*-----------------------------------------------------------------------*/
  84
  85 /* sysfs attributes for hwmon */
  86
  87 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  88                         show_temp, set_temp, LM73_REG_MAX);
  89 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  90                         show_temp, set_temp, LM73_REG_MIN);
  91 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  92                         show_temp, NULL, LM73_REG_INPUT);
  93
  94
  95 static struct attribute *lm73_attributes[] = {
  96         &sensor_dev_attr_temp1_input.dev_attr.attr,
  97         &sensor_dev_attr_temp1_max.dev_attr.attr,
  98         &sensor_dev_attr_temp1_min.dev_attr.attr,
  99
 100         NULL
 101 };
 102
 103 static const struct attribute_group lm73_group = {
 104         .attrs = lm73_attributes,
 105 };
 106
 107 /*-----------------------------------------------------------------------*/
 108
 109 /* device probe and removal */
 110
 111 static int
 112 lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
 113 {
 114         struct device *hwmon_dev;
 115         int status;
 116
 117         /* Register sysfs hooks */
 118         status = sysfs_create_group(&client->dev.kobj, &lm73_group);
 119         if (status)
 120                 return status;
 121
 122         hwmon_dev = hwmon_device_register(&client->dev);
 123         if (IS_ERR(hwmon_dev)) {
 124                 status = PTR_ERR(hwmon_dev);
 125                 goto exit_remove;
 126         }
 127         i2c_set_clientdata(client, hwmon_dev);
 128
 129         dev_info(&client->dev, "%s: sensor '%s'\n",
 130                  dev_name(hwmon_dev), client->name);
 131
 132         return 0;
 133
 134 exit_remove:
 135         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 136         return status;
 137 }
 138
 139 static int lm73_remove(struct i2c_client *client)
 140 {
 141         struct device *hwmon_dev = i2c_get_clientdata(client);
 142
 143         hwmon_device_unregister(hwmon_dev);
 144         sysfs_remove_group(&client->dev.kobj, &lm73_group);
 145         return 0;
 146 }
 147
 148 static const struct i2c_device_id lm73_ids[] = {
 149         { "lm73", 0 },
 150         { /* LIST END */ }
 151 };
 152 MODULE_DEVICE_TABLE(i2c, lm73_ids);
 153
 154 /* Return 0 if detection is successful, -ENODEV otherwise */
 155 static int lm73_detect(struct i2c_client *new_client,
 156                         struct i2c_board_info *info)
 157 {
 158         struct i2c_adapter *adapter = new_client->adapter;
 159         int id, ctrl, conf;
 160
 161         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 162                                         I2C_FUNC_SMBUS_WORD_DATA))
 163                 return -ENODEV;
 164
 165         /*
 166          * Do as much detection as possible with byte reads first, as word
 167          * reads can confuse other devices.
 168          */
 169         ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
 170         if (ctrl < 0 || (ctrl & 0x10))
 171                 return -ENODEV;
 172
 173         conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
 174         if (conf < 0 || (conf & 0x0c))
 175                 return -ENODEV;
 176
 177         id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
 178         if (id < 0 || id != (LM73_ID & 0xff))
 179                 return -ENODEV;
 180
 181         /* Check device ID */
 182         id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
 183         if (id < 0 || id != LM73_ID)
 184                 return -ENODEV;
 185
 186         strlcpy(info->type, "lm73", I2C_NAME_SIZE);
 187
 188         return 0;
 189 }
 190
 191 static struct i2c_driver lm73_driver = {
 192         .class          = I2C_CLASS_HWMON,
 193         .driver = {
 194                 .name   = "lm73",
 195         },
 196         .probe          = lm73_probe,
 197         .remove         = lm73_remove,
 198         .id_table       = lm73_ids,
 199         .detect         = lm73_detect,
 200         .address_list   = normal_i2c,
 201 };
 202
 203 module_i2c_driver(lm73_driver);
 204
 205 MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 206 MODULE_DESCRIPTION("LM73 driver");
 207 MODULE_LICENSE("GPL");