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        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
  65static 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
  87static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  88                        show_temp, set_temp, LM73_REG_MAX);
  89static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  90                        show_temp, set_temp, LM73_REG_MIN);
  91static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  92                        show_temp, NULL, LM73_REG_INPUT);
  93
  94
  95static 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
 103static const struct attribute_group lm73_group = {
 104        .attrs = lm73_attributes,
 105};
 106
 107/*-----------------------------------------------------------------------*/
 108
 109/* device probe and removal */
 110
 111static int
 112lm73_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
 134exit_remove:
 135        sysfs_remove_group(&client->dev.kobj, &lm73_group);
 136        return status;
 137}
 138
 139static 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
 148static const struct i2c_device_id lm73_ids[] = {
 149        { "lm73", 0 },
 150        { /* LIST END */ }
 151};
 152MODULE_DEVICE_TABLE(i2c, lm73_ids);
 153
 154/* Return 0 if detection is successful, -ENODEV otherwise */
 155static 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
 191static 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
 203module_i2c_driver(lm73_driver);
 204
 205MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
 206MODULE_DESCRIPTION("LM73 driver");
 207MODULE_LICENSE("GPL");
 208
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