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                 return i2c_smbus_read_word_swapped(client, reg);
  63         else
  64                 return i2c_smbus_read_byte_data(client, reg);
  65 }
  66
  67 static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
  68 {
  69         return i2c_smbus_write_byte_data(client, reg, value);
  70 }
  71
  72 static struct ad7414_data *ad7414_update_device(struct device *dev)
  73 {
  74         struct i2c_client *client = to_i2c_client(dev);
  75         struct ad7414_data *data = i2c_get_clientdata(client);
  76
  77         mutex_lock(&data->lock);
  78
  79         if (time_after(jiffies, data->next_update) || !data->valid) {
  80                 int value, i;
  81
  82                 dev_dbg(&client->dev, "starting ad7414 update\n");
  83
  84                 value = ad7414_read(client, AD7414_REG_TEMP);
  85                 if (value < 0)
  86                         dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
  87                                 value);
  88                 else
  89                         data->temp_input = value;
  90
  91                 for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
  92                         value = ad7414_read(client, AD7414_REG_LIMIT[i]);
  93                         if (value < 0)
  94                                 dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
  95                                         AD7414_REG_LIMIT[i], value);
  96                         else
  97                                 data->temps[i] = value;
  98                 }
  99
 100                 data->next_update = jiffies + HZ + HZ / 2;
 101                 data->valid = 1;
 102         }
 103
 104         mutex_unlock(&data->lock);
 105
 106         return data;
 107 }
 108
 109 static ssize_t show_temp_input(struct device *dev,
 110                                struct device_attribute *attr, char *buf)
 111 {
 112         struct ad7414_data *data = ad7414_update_device(dev);
 113         return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
 114 }
 115 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
 116
 117 static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
 118                           char *buf)
 119 {
 120         int index = to_sensor_dev_attr(attr)->index;
 121         struct ad7414_data *data = ad7414_update_device(dev);
 122         return sprintf(buf, "%d\n", data->temps[index] * 1000);
 123 }
 124
 125 static ssize_t set_max_min(struct device *dev,
 126                            struct device_attribute *attr,
 127                            const char *buf, size_t count)
 128 {
 129         struct i2c_client *client = to_i2c_client(dev);
 130         struct ad7414_data *data = i2c_get_clientdata(client);
 131         int index = to_sensor_dev_attr(attr)->index;
 132         u8 reg = AD7414_REG_LIMIT[index];
 133         long temp = simple_strtol(buf, NULL, 10);
 134
 135         temp = SENSORS_LIMIT(temp, -40000, 85000);
 136         temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
 137
 138         mutex_lock(&data->lock);
 139         data->temps[index] = temp;
 140         ad7414_write(client, reg, temp);
 141         mutex_unlock(&data->lock);
 142         return count;
 143 }
 144
 145 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 146                           show_max_min, set_max_min, 0);
 147 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 148                           show_max_min, set_max_min, 1);
 149
 150 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 151                           char *buf)
 152 {
 153         int bitnr = to_sensor_dev_attr(attr)->index;
 154         struct ad7414_data *data = ad7414_update_device(dev);
 155         int value = (data->temp_input >> bitnr) & 1;
 156         return sprintf(buf, "%d\n", value);
 157 }
 158
 159 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
 160 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 161
 162 static struct attribute *ad7414_attributes[] = {
 163         &sensor_dev_attr_temp1_input.dev_attr.attr,
 164         &sensor_dev_attr_temp1_max.dev_attr.attr,
 165         &sensor_dev_attr_temp1_min.dev_attr.attr,
 166         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 167         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 168         NULL
 169 };
 170
 171 static const struct attribute_group ad7414_group = {
 172         .attrs = ad7414_attributes,
 173 };
 174
 175 static int ad7414_probe(struct i2c_client *client,
 176                         const struct i2c_device_id *dev_id)
 177 {
 178         struct ad7414_data *data;
 179         int conf;
 180         int err;
 181
 182         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 183                                      I2C_FUNC_SMBUS_READ_WORD_DATA)) {
 184                 err = -EOPNOTSUPP;
 185                 goto exit;
 186         }
 187
 188         data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
 189         if (!data) {
 190                 err = -ENOMEM;
 191                 goto exit;
 192         }
 193
 194         i2c_set_clientdata(client, data);
 195         mutex_init(&data->lock);
 196
 197         dev_info(&client->dev, "chip found\n");
 198
 199         /* Make sure the chip is powered up. */
 200         conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
 201         if (conf < 0)
 202                 dev_warn(&client->dev,
 203                          "ad7414_probe unable to read config register.\n");
 204         else {
 205                 conf &= ~(1 << 7);
 206                 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
 207         }
 208
 209         /* Register sysfs hooks */
 210         err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
 211         if (err)
 212                 goto exit_free;
 213
 214         data->hwmon_dev = hwmon_device_register(&client->dev);
 215         if (IS_ERR(data->hwmon_dev)) {
 216                 err = PTR_ERR(data->hwmon_dev);
 217                 goto exit_remove;
 218         }
 219
 220         return 0;
 221
 222 exit_remove:
 223         sysfs_remove_group(&client->dev.kobj, &ad7414_group);
 224 exit_free:
 225         kfree(data);
 226 exit:
 227         return err;
 228 }
 229
 230 static int __devexit ad7414_remove(struct i2c_client *client)
 231 {
 232         struct ad7414_data *data = i2c_get_clientdata(client);
 233
 234         hwmon_device_unregister(data->hwmon_dev);
 235         sysfs_remove_group(&client->dev.kobj, &ad7414_group);
 236         kfree(data);
 237         return 0;
 238 }
 239
 240 static const struct i2c_device_id ad7414_id[] = {
 241         { "ad7414", 0 },
 242         {}
 243 };
 244 MODULE_DEVICE_TABLE(i2c, ad7414_id);
 245
 246 static struct i2c_driver ad7414_driver = {
 247         .driver = {
 248                 .name   = "ad7414",
 249         },
 250         .probe  = ad7414_probe,
 251         .remove = __devexit_p(ad7414_remove),
 252         .id_table = ad7414_id,
 253 };
 254
 255 static int __init ad7414_init(void)
 256 {
 257         return i2c_add_driver(&ad7414_driver);
 258 }
 259 module_init(ad7414_init);
 260
 261 static void __exit ad7414_exit(void)
 262 {
 263         i2c_del_driver(&ad7414_driver);
 264 }
 265 module_exit(ad7414_exit);
 266
 267 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
 268               "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
 269
 270 MODULE_DESCRIPTION("AD7414 driver");
 271 MODULE_LICENSE("GPL");