drivers/hwmon/ds1621.c

   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 */
  37 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  38                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  39
  40 /* Insmod parameters */
  41 static int polarity = -1;
  42 module_param(polarity, int, 0);
  43 MODULE_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 */
  55 static 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 */
  73 struct 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
  83 static 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
 104 static 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
 143 static 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
 152 static 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         u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));
 159
 160         mutex_lock(&data->update_lock);
 161         data->temp[attr->index] = val;
 162         i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
 163                                      data->temp[attr->index]);
 164         mutex_unlock(&data->update_lock);
 165         return count;
 166 }
 167
 168 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 169                            char *buf)
 170 {
 171         struct ds1621_data *data = ds1621_update_client(dev);
 172         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 173 }
 174
 175 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 176                           char *buf)
 177 {
 178         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 179         struct ds1621_data *data = ds1621_update_client(dev);
 180         return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 181 }
 182
 183 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 184 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 185 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 186 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 187 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 188                 DS1621_ALARM_TEMP_LOW);
 189 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 190                 DS1621_ALARM_TEMP_HIGH);
 191
 192 static struct attribute *ds1621_attributes[] = {
 193         &sensor_dev_attr_temp1_input.dev_attr.attr,
 194         &sensor_dev_attr_temp1_min.dev_attr.attr,
 195         &sensor_dev_attr_temp1_max.dev_attr.attr,
 196         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 197         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 198         &dev_attr_alarms.attr,
 199         NULL
 200 };
 201
 202 static const struct attribute_group ds1621_group = {
 203         .attrs = ds1621_attributes,
 204 };
 205
 206
 207 /* Return 0 if detection is successful, -ENODEV otherwise */
 208 static int ds1621_detect(struct i2c_client *client,
 209                          struct i2c_board_info *info)
 210 {
 211         struct i2c_adapter *adapter = client->adapter;
 212         int conf, temp;
 213         int i;
 214
 215         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 216                                      | I2C_FUNC_SMBUS_WORD_DATA
 217                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 218                 return -ENODEV;
 219
 220         /* Now, we do the remaining detection. It is lousy. */
 221         /* The NVB bit should be low if no EEPROM write has been  requested
 222            during the latest 10ms, which is highly improbable in our case. */
 223         conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 224         if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
 225                 return -ENODEV;
 226         /* The 7 lowest bits of a temperature should always be 0. */
 227         for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
 228                 temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
 229                 if (temp < 0 || (temp & 0x7f00))
 230                         return -ENODEV;
 231         }
 232
 233         strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
 234
 235         return 0;
 236 }
 237
 238 static int ds1621_probe(struct i2c_client *client,
 239                         const struct i2c_device_id *id)
 240 {
 241         struct ds1621_data *data;
 242         int err;
 243
 244         data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
 245         if (!data) {
 246                 err = -ENOMEM;
 247                 goto exit;
 248         }
 249
 250         i2c_set_clientdata(client, data);
 251         mutex_init(&data->update_lock);
 252
 253         /* Initialize the DS1621 chip */
 254         ds1621_init_client(client);
 255
 256         /* Register sysfs hooks */
 257         if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
 258                 goto exit_free;
 259
 260         data->hwmon_dev = hwmon_device_register(&client->dev);
 261         if (IS_ERR(data->hwmon_dev)) {
 262                 err = PTR_ERR(data->hwmon_dev);
 263                 goto exit_remove_files;
 264         }
 265
 266         return 0;
 267
 268       exit_remove_files:
 269         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 270       exit_free:
 271         kfree(data);
 272       exit:
 273         return err;
 274 }
 275
 276 static int ds1621_remove(struct i2c_client *client)
 277 {
 278         struct ds1621_data *data = i2c_get_clientdata(client);
 279
 280         hwmon_device_unregister(data->hwmon_dev);
 281         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 282
 283         kfree(data);
 284
 285         return 0;
 286 }
 287
 288 static const struct i2c_device_id ds1621_id[] = {
 289         { "ds1621", 0 },
 290         { "ds1625", 0 },
 291         { }
 292 };
 293 MODULE_DEVICE_TABLE(i2c, ds1621_id);
 294
 295 /* This is the driver that will be inserted */
 296 static struct i2c_driver ds1621_driver = {
 297         .class          = I2C_CLASS_HWMON,
 298         .driver = {
 299                 .name   = "ds1621",
 300         },
 301         .probe          = ds1621_probe,
 302         .remove         = ds1621_remove,
 303         .id_table       = ds1621_id,
 304         .detect         = ds1621_detect,
 305         .address_list   = normal_i2c,
 306 };
 307
 308 static int __init ds1621_init(void)
 309 {
 310         return i2c_add_driver(&ds1621_driver);
 311 }
 312
 313 static void __exit ds1621_exit(void)
 314 {
 315         i2c_del_driver(&ds1621_driver);
 316 }
 317
 318
 319 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 320 MODULE_DESCRIPTION("DS1621 driver");
 321 MODULE_LICENSE("GPL");
 322
 323 module_init(ds1621_init);
 324 module_exit(ds1621_exit);