linux/drivers/hwmon/ad7414.c
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   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
  39static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };
  40
  41struct 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 */
  51static 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
  60static 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
  68static 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
  73static 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
 110static 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}
 116static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
 117
 118static 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
 126static 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 = SENSORS_LIMIT(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
 150static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 151                          show_max_min, set_max_min, 0);
 152static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 153                          show_max_min, set_max_min, 1);
 154
 155static 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
 164static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
 165static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);
 166
 167static 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
 176static const struct attribute_group ad7414_group = {
 177        .attrs = ad7414_attributes,
 178};
 179
 180static 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
 224exit_remove:
 225        sysfs_remove_group(&client->dev.kobj, &ad7414_group);
 226        return err;
 227}
 228
 229static 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        return 0;
 236}
 237
 238static const struct i2c_device_id ad7414_id[] = {
 239        { "ad7414", 0 },
 240        {}
 241};
 242MODULE_DEVICE_TABLE(i2c, ad7414_id);
 243
 244static 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
 253module_i2c_driver(ad7414_driver);
 254
 255MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
 256              "Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");
 257
 258MODULE_DESCRIPTION("AD7414 driver");
 259MODULE_LICENSE("GPL");
 260
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