linux/drivers/hwmon/ds1621.c
<<
>>
Prefs
   1/*
   2 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
   3 *            monitoring
   4 * Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
   5 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
   6 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
   7 * the help of Jean Delvare <khali@linux-fr.org>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2 of the License, or
  12 * (at your option) any later version.
  13 *
  14 * This program is distributed in the hope that it will be useful,
  15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 * GNU General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24#include <linux/module.h>
  25#include <linux/init.h>
  26#include <linux/slab.h>
  27#include <linux/jiffies.h>
  28#include <linux/i2c.h>
  29#include <linux/hwmon.h>
  30#include <linux/hwmon-sysfs.h>
  31#include <linux/err.h>
  32#include <linux/mutex.h>
  33#include <linux/sysfs.h>
  34#include "lm75.h"
  35
  36/* Addresses to scan */
  37static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  38                                        0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  39
  40/* Insmod parameters */
  41static int polarity = -1;
  42module_param(polarity, int, 0);
  43MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  44
  45/* Many DS1621 constants specified below */
  46/* Config register used for detection         */
  47/*  7    6    5    4    3    2    1    0      */
  48/* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
  49#define DS1621_REG_CONFIG_NVB           0x10
  50#define DS1621_REG_CONFIG_POLARITY      0x02
  51#define DS1621_REG_CONFIG_1SHOT         0x01
  52#define DS1621_REG_CONFIG_DONE          0x80
  53
  54/* The DS1621 registers */
  55static const u8 DS1621_REG_TEMP[3] = {
  56        0xAA,           /* input, word, RO */
  57        0xA2,           /* min, word, RW */
  58        0xA1,           /* max, word, RW */
  59};
  60#define DS1621_REG_CONF                 0xAC /* byte, RW */
  61#define DS1621_COM_START                0xEE /* no data */
  62#define DS1621_COM_STOP                 0x22 /* no data */
  63
  64/* The DS1621 configuration register */
  65#define DS1621_ALARM_TEMP_HIGH          0x40
  66#define DS1621_ALARM_TEMP_LOW           0x20
  67
  68/* Conversions */
  69#define ALARMS_FROM_REG(val) ((val) & \
  70                        (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
  71
  72/* Each client has this additional data */
  73struct ds1621_data {
  74        struct device *hwmon_dev;
  75        struct mutex update_lock;
  76        char valid;                     /* !=0 if following fields are valid */
  77        unsigned long last_updated;     /* In jiffies */
  78
  79        u16 temp[3];                    /* Register values, word */
  80        u8 conf;                        /* Register encoding, combined */
  81};
  82
  83static void ds1621_init_client(struct i2c_client *client)
  84{
  85        u8 conf, new_conf;
  86
  87        new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
  88        /* switch to continuous conversion mode */
  89        new_conf &= ~DS1621_REG_CONFIG_1SHOT;
  90
  91        /* setup output polarity */
  92        if (polarity == 0)
  93                new_conf &= ~DS1621_REG_CONFIG_POLARITY;
  94        else if (polarity == 1)
  95                new_conf |= DS1621_REG_CONFIG_POLARITY;
  96
  97        if (conf != new_conf)
  98                i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
  99
 100        /* start conversion */
 101        i2c_smbus_write_byte(client, DS1621_COM_START);
 102}
 103
 104static struct ds1621_data *ds1621_update_client(struct device *dev)
 105{
 106        struct i2c_client *client = to_i2c_client(dev);
 107        struct ds1621_data *data = i2c_get_clientdata(client);
 108        u8 new_conf;
 109
 110        mutex_lock(&data->update_lock);
 111
 112        if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 113            || !data->valid) {
 114                int i;
 115
 116                dev_dbg(&client->dev, "Starting ds1621 update\n");
 117
 118                data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 119
 120                for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 121                        data->temp[i] = i2c_smbus_read_word_swapped(client,
 122                                                         DS1621_REG_TEMP[i]);
 123
 124                /* reset alarms if necessary */
 125                new_conf = data->conf;
 126                if (data->temp[0] > data->temp[1])      /* input > min */
 127                        new_conf &= ~DS1621_ALARM_TEMP_LOW;
 128                if (data->temp[0] < data->temp[2])      /* input < max */
 129                        new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 130                if (data->conf != new_conf)
 131                        i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
 132                                                  new_conf);
 133
 134                data->last_updated = jiffies;
 135                data->valid = 1;
 136        }
 137
 138        mutex_unlock(&data->update_lock);
 139
 140        return data;
 141}
 142
 143static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 144                         char *buf)
 145{
 146        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 147        struct ds1621_data *data = ds1621_update_client(dev);
 148        return sprintf(buf, "%d\n",
 149                       LM75_TEMP_FROM_REG(data->temp[attr->index]));
 150}
 151
 152static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 153                        const char *buf, size_t count)
 154{
 155        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 156        struct i2c_client *client = to_i2c_client(dev);
 157        struct ds1621_data *data = i2c_get_clientdata(client);
 158        long val;
 159        int err;
 160
 161        err = kstrtol(buf, 10, &val);
 162        if (err)
 163                return err;
 164
 165        mutex_lock(&data->update_lock);
 166        data->temp[attr->index] = LM75_TEMP_TO_REG(val);
 167        i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
 168                                     data->temp[attr->index]);
 169        mutex_unlock(&data->update_lock);
 170        return count;
 171}
 172
 173static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 174                           char *buf)
 175{
 176        struct ds1621_data *data = ds1621_update_client(dev);
 177        return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 178}
 179
 180static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 181                          char *buf)
 182{
 183        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 184        struct ds1621_data *data = ds1621_update_client(dev);
 185        return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 186}
 187
 188static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 189static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 190static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 191static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 192static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 193                DS1621_ALARM_TEMP_LOW);
 194static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 195                DS1621_ALARM_TEMP_HIGH);
 196
 197static struct attribute *ds1621_attributes[] = {
 198        &sensor_dev_attr_temp1_input.dev_attr.attr,
 199        &sensor_dev_attr_temp1_min.dev_attr.attr,
 200        &sensor_dev_attr_temp1_max.dev_attr.attr,
 201        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 202        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 203        &dev_attr_alarms.attr,
 204        NULL
 205};
 206
 207static const struct attribute_group ds1621_group = {
 208        .attrs = ds1621_attributes,
 209};
 210
 211
 212/* Return 0 if detection is successful, -ENODEV otherwise */
 213static int ds1621_detect(struct i2c_client *client,
 214                         struct i2c_board_info *info)
 215{
 216        struct i2c_adapter *adapter = client->adapter;
 217        int conf, temp;
 218        int i;
 219
 220        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 221                                     | I2C_FUNC_SMBUS_WORD_DATA
 222                                     | I2C_FUNC_SMBUS_WRITE_BYTE))
 223                return -ENODEV;
 224
 225        /*
 226         * Now, we do the remaining detection. It is lousy.
 227         *
 228         * The NVB bit should be low if no EEPROM write has been requested
 229         * during the latest 10ms, which is highly improbable in our case.
 230         */
 231        conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 232        if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
 233                return -ENODEV;
 234        /* The 7 lowest bits of a temperature should always be 0. */
 235        for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
 236                temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
 237                if (temp < 0 || (temp & 0x7f00))
 238                        return -ENODEV;
 239        }
 240
 241        strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
 242
 243        return 0;
 244}
 245
 246static int ds1621_probe(struct i2c_client *client,
 247                        const struct i2c_device_id *id)
 248{
 249        struct ds1621_data *data;
 250        int err;
 251
 252        data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 253                            GFP_KERNEL);
 254        if (!data)
 255                return -ENOMEM;
 256
 257        i2c_set_clientdata(client, data);
 258        mutex_init(&data->update_lock);
 259
 260        /* Initialize the DS1621 chip */
 261        ds1621_init_client(client);
 262
 263        /* Register sysfs hooks */
 264        err = sysfs_create_group(&client->dev.kobj, &ds1621_group);
 265        if (err)
 266                return err;
 267
 268        data->hwmon_dev = hwmon_device_register(&client->dev);
 269        if (IS_ERR(data->hwmon_dev)) {
 270                err = PTR_ERR(data->hwmon_dev);
 271                goto exit_remove_files;
 272        }
 273
 274        return 0;
 275
 276 exit_remove_files:
 277        sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 278        return err;
 279}
 280
 281static int ds1621_remove(struct i2c_client *client)
 282{
 283        struct ds1621_data *data = i2c_get_clientdata(client);
 284
 285        hwmon_device_unregister(data->hwmon_dev);
 286        sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 287
 288        return 0;
 289}
 290
 291static const struct i2c_device_id ds1621_id[] = {
 292        { "ds1621", 0 },
 293        { "ds1625", 0 },
 294        { }
 295};
 296MODULE_DEVICE_TABLE(i2c, ds1621_id);
 297
 298/* This is the driver that will be inserted */
 299static struct i2c_driver ds1621_driver = {
 300        .class          = I2C_CLASS_HWMON,
 301        .driver = {
 302                .name   = "ds1621",
 303        },
 304        .probe          = ds1621_probe,
 305        .remove         = ds1621_remove,
 306        .id_table       = ds1621_id,
 307        .detect         = ds1621_detect,
 308        .address_list   = normal_i2c,
 309};
 310
 311module_i2c_driver(ds1621_driver);
 312
 313MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 314MODULE_DESCRIPTION("DS1621 driver");
 315MODULE_LICENSE("GPL");
 316
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.