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         /*
  54          * use integer division instead of equivalent right shift to
  55          * guarantee arithmetic shift and preserve the sign
  56          */
  57         return ((int)reg / 64) * 250;
  58 }
  59
  60 static inline int ad7414_read(struct i2c_client *client, u8 reg)
  61 {
  62         if (reg == AD7414_REG_TEMP)
  63                 return i2c_smbus_read_word_swapped(client, reg);
  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;
 135         int ret = kstrtol(buf, 10, &temp);
 136
 137         if (ret < 0)
 138                 return ret;
 139
 140         temp = clamp_val(temp, -40000, 85000);
 141         temp = (temp + (temp < 0 ? -500 : 500)) / 1000;
 142
 143         mutex_lock(&data->lock);
 144         data->temps[index] = temp;
 145         ad7414_write(client, reg, temp);
 146         mutex_unlock(&data->lock);
 147         return count;
 148 }
 149
 150 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 151                           show_max_min, set_max_min, 0);
 152 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 153                           show_max_min, set_max_min, 1);
 154
 155 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 156                           char *buf)
 157 {
 158         int bitnr = to_sensor_dev_attr(attr)->index;
 159         struct ad7414_data *data = ad7414_update_device(dev);
 160         int value = (data->temp_input >> bitnr) & 1;
 161         return sprintf(buf, "%d\n", value);
 162 }
 163
 164 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
 165 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 166
 167 static struct attribute *ad7414_attributes[] = {
 168         &sensor_dev_attr_temp1_input.dev_attr.attr,
 169         &sensor_dev_attr_temp1_max.dev_attr.attr,
 170         &sensor_dev_attr_temp1_min.dev_attr.attr,
 171         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 172         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 173         NULL
 174 };
 175
 176 static const struct attribute_group ad7414_group = {
 177         .attrs = ad7414_attributes,
 178 };
 179
 180 static int ad7414_probe(struct i2c_client *client,
 181                         const struct i2c_device_id *dev_id)
 182 {
 183         struct ad7414_data *data;
 184         int conf;
 185         int err;
 186
 187         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 188                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 189                 return -EOPNOTSUPP;
 190
 191         data = devm_kzalloc(&client->dev, sizeof(struct ad7414_data),
 192                             GFP_KERNEL);
 193         if (!data)
 194                 return -ENOMEM;
 195
 196         i2c_set_clientdata(client, data);
 197         mutex_init(&data->lock);
 198
 199         dev_info(&client->dev, "chip found\n");
 200
 201         /* Make sure the chip is powered up. */
 202         conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
 203         if (conf < 0)
 204                 dev_warn(&client->dev,
 205                          "ad7414_probe unable to read config register.\n");
 206         else {
 207                 conf &= ~(1 << 7);
 208                 i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
 209         }
 210
 211         /* Register sysfs hooks */
 212         err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
 213         if (err)
 214                 return err;
 215
 216         data->hwmon_dev = hwmon_device_register(&client->dev);
 217         if (IS_ERR(data->hwmon_dev)) {
 218                 err = PTR_ERR(data->hwmon_dev);
 219                 goto exit_remove;
 220         }
 221
 222         return 0;
 223
 224 exit_remove:
 225         sysfs_remove_group(&client->dev.kobj, &ad7414_group);
 226         return err;
 227 }
 228
 229 static int 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         return 0;
 236 }
 237
 238 static const struct i2c_device_id ad7414_id[] = {
 239         { "ad7414", 0 },
 240         {}
 241 };
 242 MODULE_DEVICE_TABLE(i2c, ad7414_id);
 243
 244 static struct i2c_driver ad7414_driver = {
 245         .driver = {
 246                 .name   = "ad7414",
 247         },
 248         .probe  = ad7414_probe,
 249         .remove = ad7414_remove,
 250         .id_table = ad7414_id,
 251 };
 252
 253 module_i2c_driver(ad7414_driver);
 254
 255 MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
 256               "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
 257
 258 MODULE_DESCRIPTION("AD7414 driver");
 259 MODULE_LICENSE("GPL");