linux/drivers/hwmon/lm73.c
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   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 */
  26static 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
  45static 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
  53        int status = kstrtol(buf, 10, &temp);
  54        if (status < 0)
  55                return status;
  56
  57        /* Write value */
  58        value = (short) SENSORS_LIMIT(temp/250, (LM73_TEMP_MIN*4),
  59                (LM73_TEMP_MAX*4)) << 5;
  60        i2c_smbus_write_word_swapped(client, attr->index, value);
  61        return count;
  62}
  63
  64static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  65                         char *buf)
  66{
  67        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  68        struct i2c_client *client = to_i2c_client(dev);
  69        /* use integer division instead of equivalent right shift to
  70           guarantee arithmetic shift and preserve the sign */
  71        int temp = ((s16) (i2c_smbus_read_word_swapped(client,
  72                    attr->index))*250) / 32;
  73        return sprintf(buf, "%d\n", temp);
  74}
  75
  76
  77/*-----------------------------------------------------------------------*/
  78
  79/* sysfs attributes for hwmon */
  80
  81static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  82                        show_temp, set_temp, LM73_REG_MAX);
  83static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  84                        show_temp, set_temp, LM73_REG_MIN);
  85static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  86                        show_temp, NULL, LM73_REG_INPUT);
  87
  88
  89static struct attribute *lm73_attributes[] = {
  90        &sensor_dev_attr_temp1_input.dev_attr.attr,
  91        &sensor_dev_attr_temp1_max.dev_attr.attr,
  92        &sensor_dev_attr_temp1_min.dev_attr.attr,
  93
  94        NULL
  95};
  96
  97static const struct attribute_group lm73_group = {
  98        .attrs = lm73_attributes,
  99};
 100
 101/*-----------------------------------------------------------------------*/
 102
 103/* device probe and removal */
 104
 105static int
 106lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
 107{
 108        struct device *hwmon_dev;
 109        int status;
 110
 111        /* Register sysfs hooks */
 112        status = sysfs_create_group(&client->dev.kobj, &lm73_group);
 113        if (status)
 114                return status;
 115
 116        hwmon_dev = hwmon_device_register(&client->dev);
 117        if (IS_ERR(hwmon_dev)) {
 118                status = PTR_ERR(hwmon_dev);
 119                goto exit_remove;
 120        }
 121        i2c_set_clientdata(client, hwmon_dev);
 122
 123        dev_info(&client->dev, "%s: sensor '%s'\n",
 124                 dev_name(hwmon_dev), client->name);
 125
 126        return 0;
 127
 128exit_remove:
 129        sysfs_remove_group(&client->dev.kobj, &lm73_group);
 130        return status;
 131}
 132
 133static int lm73_remove(struct i2c_client *client)
 134{
 135        struct device *hwmon_dev = i2c_get_clientdata(client);
 136
 137        hwmon_device_unregister(hwmon_dev);
 138        sysfs_remove_group(&client->dev.kobj, &lm73_group);
 139        return 0;
 140}
 141
 142static const struct i2c_device_id lm73_ids[] = {
 143        { "lm73", 0 },
 144        { /* LIST END */ }
 145};
 146MODULE_DEVICE_TABLE(i2c, lm73_ids);
 147
 148/* Return 0 if detection is successful, -ENODEV otherwise */
 149static int lm73_detect(struct i2c_client *new_client,
 150                        struct i2c_board_info *info)
 151{
 152        struct i2c_adapter *adapter = new_client->adapter;
 153        int id, ctrl, conf;
 154
 155        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 156                                        I2C_FUNC_SMBUS_WORD_DATA))
 157                return -ENODEV;
 158
 159        /*
 160         * Do as much detection as possible with byte reads first, as word
 161         * reads can confuse other devices.
 162         */
 163        ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
 164        if (ctrl < 0 || (ctrl & 0x10))
 165                return -ENODEV;
 166
 167        conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
 168        if (conf < 0 || (conf & 0x0c))
 169                return -ENODEV;
 170
 171        id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
 172        if (id < 0 || id != (LM73_ID & 0xff))
 173                return -ENODEV;
 174
 175        /* Check device ID */
 176        id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
 177        if (id < 0 || id != LM73_ID)
 178                return -ENODEV;
 179
 180        strlcpy(info->type, "lm73", I2C_NAME_SIZE);
 181
 182        return 0;
 183}
 184
 185static struct i2c_driver lm73_driver = {
 186        .class          = I2C_CLASS_HWMON,
 187        .driver = {
 188                .name   = "lm73",
 189        },
 190        .probe          = lm73_probe,
 191        .remove         = lm73_remove,
 192        .id_table       = lm73_ids,
 193        .detect         = lm73_detect,
 194        .address_list   = normal_i2c,
 195};
 196
 197module_i2c_driver(lm73_driver);
 198
 199MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 200MODULE_DESCRIPTION("LM73 driver");
 201MODULE_LICENSE("GPL");
 202
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