drivers/hwmon/ad7414.c

   1 /*
   2  * An hwmon driver for the Analog Devices AD7414
   3  *
   4  * Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
   5  *
   6  * Copyright (c) 2008 PIKA Technologies
   7  *   Sean MacLennan <smaclennan@pikatech.com>
   8  *
   9  * Copyright (c) 2008 Spansion Inc.
  10  *   Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
  11  *   (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
  12  *
  13  * Based on ad7418.c
  14  * Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 2 of the License, or
  19  * (at your option) any later version.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/jiffies.h>
  24 #include <linux/i2c.h>
  25 #include <linux/hwmon.h>
  26 #include <linux/hwmon-sysfs.h>
  27 #include <linux/err.h>
  28 #include <linux/mutex.h>
  29 #include <linux/sysfs.h>
  30 #include <linux/slab.h>
  31
  32
  33 /* AD7414 registers */
  34 #define AD7414_REG_TEMP         0x00
  35 #define AD7414_REG_CONF         0x01
  36 #define AD7414_REG_T_HIGH       0x02
  37 #define AD7414_REG_T_LOW        0x03
  38
  39 static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };
  40
  41 struct ad7414_data {
  42         struct device           *hwmon_dev;
  43         struct mutex            lock;   /* atomic read data updates */
  44         char                    valid;  /* !=0 if following fields are valid */
  45         unsigned long           next_update;    /* In jiffies */
  46         s16                     temp_input;     /* Register values */
  47         s8                      temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
  48 };
  49
  50 /* REG: (0.25C/bit, two's complement) << 6 */
  51 static inline int ad7414_temp_from_reg(s16 reg)
  52 {
  53         /* use integer division instead of equivalent right shift to
  54          * guarantee arithmetic shift and preserve the sign
  55          */
  56         return ((int)reg / 64) * 250;
  57 }
  58
  59 static inline int ad7414_read(struct i2c_client *client, u8 reg)
  60 {
  61         if (reg == AD7414_REG_TEMP) {
  62                 int value = i2c_smbus_read_word_data(client, reg);
  63                 return (value < 0) ? value : swab16(value);
  64         } else
  65                 return i2c_smbus_read_byte_data(client, reg);
  66 }
  67
  68 static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
  69 {
  70         return i2c_smbus_write_byte_data(client, reg, value);
  71 }
  72
  73 static struct ad7414_data *ad7414_update_device(struct device *dev)
  74 {
  75         struct i2c_client *client = to_i2c_client(dev);
  76         struct ad7414_data *data = i2c_get_clientdata(client);
  77
  78         mutex_lock(&data->lock);
  79
  80         if (time_after(jiffies, data->next_update) || !data->valid) {
  81                 int value, i;
  82
  83                 dev_dbg(&client->dev, "starting ad7414 update\n");
  84
  85                 value = ad7414_read(client, AD7414_REG_TEMP);
  86                 if (value < 0)
  87                         dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
  88                                 value);
  89                 else
  90                         data->temp_input = value;
  91
  92                 for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
  93                         value = ad7414_read(client, AD7414_REG_LIMIT[i]);
  94                         if (value < 0)
  95                                 dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
  96                                         AD7414_REG_LIMIT[i], value);
  97                         else
  98                                 data->temps[i] = value;
  99                 }
 100
 101                 data->next_update = jiffies + HZ + HZ / 2;
 102                 data->valid = 1;
 103         }
 104
 105         mutex_unlock(&data->lock);
 106
 107         return data;
 108 }
 109
 110 static ssize_t show_temp_input(struct device *dev,
 111                                struct device_attribute *attr, char *buf)
 112 {
 113         struct ad7414_data *data = ad7414_update_device(dev);
 114         return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
 115 }
 116 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
 117
 118 static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
 119                           char *buf)
 120 {
 121         int index = to_sensor_dev_attr(attr)->index;
 122         struct ad7414_data *data = ad7414_update_device(dev);
 123         return sprintf(buf, "%d\n", data->temps[index] * 1000);
 124 }
 125
 126 static ssize_t set_max_min(struct device *dev,
 127                            struct device_attribute *attr,
 128                            const char *buf, size_t count)
 129 {
 130         struct i2c_client *client = to_i2c_client(dev);
 131         struct ad7414_data *data = i2c_get_clientdata(client);
 132         int index = to_sensor_dev_attr(attr)->index;
 133         u8 reg = AD7414_REG_LIMIT[index];
 134         long temp = simple_strtol(buf, NULL, 10);
 135
 136         temp = SENSORS_LIMIT(temp, -40000, 85000);
 137         temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
 138
 139         mutex_lock(&data->lock);
 140         data->temps[index] = temp;
 141         ad7414_write(client, reg, temp);
 142         mutex_unlock(&data->lock);
 143         return count;
 144 }
 145
 146 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 147                           show_max_min, set_max_min, 0);
 148 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 149                           show_max_min, set_max_min, 1);
 150
 151 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 152                           char *buf)
 153 {
 154         int bitnr = to_sensor_dev_attr(attr)->index;
 155         struct ad7414_data *data = ad7414_update_device(dev);
 156         int value = (data->temp_input >> bitnr) & 1;
 157         return sprintf(buf, "%d\n", value);
 158 }
 159
 160 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
 161 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 162
 163 static struct attribute *ad7414_attributes[] = {
 164         &sensor_dev_attr_temp1_input.dev_attr.attr,
 165         &sensor_dev_attr_temp1_max.dev_attr.attr,
 166         &sensor_dev_attr_temp1_min.dev_attr.attr,
 167         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 168         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 169         NULL
 170 };
 171
 172 static const struct attribute_group ad7414_group = {
 173         .attrs = ad7414_attributes,
 174 };
 175
 176 static int ad7414_probe(struct i2c_client *client,
 177                         const struct i2c_device_id *dev_id)
 178 {
 179         struct ad7414_data *data;
 180         int conf;
 181         int err = 0;
 182
 183         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 184                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 185                 goto exit;
 186
 187         data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
 188         if (!data) {
 189                 err = -ENOMEM;
 190                 goto exit;
 191         }
 192
 193         i2c_set_clientdata(client, data);
 194         mutex_init(&data->lock);
 195
 196         dev_info(&client->dev, "chip found\n");
 197
 198         /* Make sure the chip is powered up. */
 199         conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
 200         if (conf < 0)
 201                 dev_warn(&client->dev,
 202                          "ad7414_probe unable to read config register.\n");
 203         else {
 204                 conf &= ~(1 << 7);
 205                 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
 206         }
 207
 208         /* Register sysfs hooks */
 209         err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
 210         if (err)
 211                 goto exit_free;
 212
 213         data->hwmon_dev = hwmon_device_register(&client->dev);
 214         if (IS_ERR(data->hwmon_dev)) {
 215                 err = PTR_ERR(data->hwmon_dev);
 216                 goto exit_remove;
 217         }
 218
 219         return 0;
 220
 221 exit_remove:
 222         sysfs_remove_group(&client->dev.kobj, &ad7414_group);
 223 exit_free:
 224         kfree(data);
 225 exit:
 226         return err;
 227 }
 228
 229 static int __devexit ad7414_remove(struct i2c_client *client)
 230 {
 231         struct ad7414_data *data = i2c_get_clientdata(client);
 232
 233         hwmon_device_unregister(data->hwmon_dev);
 234         sysfs_remove_group(&client->dev.kobj, &ad7414_group);
 235         kfree(data);
 236         return 0;
 237 }
 238
 239 static const struct i2c_device_id ad7414_id[] = {
 240         { "ad7414", 0 },
 241         {}
 242 };
 243
 244 static struct i2c_driver ad7414_driver = {
 245         .driver = {
 246                 .name   = "ad7414",
 247         },
 248         .probe  = ad7414_probe,
 249         .remove = __devexit_p(ad7414_remove),
 250         .id_table = ad7414_id,
 251 };
 252
 253 static int __init ad7414_init(void)
 254 {
 255         return i2c_add_driver(&ad7414_driver);
 256 }
 257 module_init(ad7414_init);
 258
 259 static void __exit ad7414_exit(void)
 260 {
 261         i2c_del_driver(&ad7414_driver);
 262 }
 263 module_exit(ad7414_exit);
 264
 265 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
 266               "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
 267
 268 MODULE_DESCRIPTION("AD7414 driver");
 269 MODULE_LICENSE("GPL");