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 /* Temperature registers are word-sized.
  84    DS1621 uses a high-byte first convention, which is exactly opposite to
  85    the SMBus standard. */
  86 static int ds1621_read_temp(struct i2c_client *client, u8 reg)
  87 {
  88         int ret;
  89
  90         ret = i2c_smbus_read_word_data(client, reg);
  91         if (ret < 0)
  92                 return ret;
  93         return swab16(ret);
  94 }
  95
  96 static int ds1621_write_temp(struct i2c_client *client, u8 reg, u16 value)
  97 {
  98         return i2c_smbus_write_word_data(client, reg, swab16(value));
  99 }
 100
 101 static void ds1621_init_client(struct i2c_client *client)
 102 {
 103         u8 conf, new_conf;
 104
 105         new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 106         /* switch to continuous conversion mode */
 107         new_conf &= ~DS1621_REG_CONFIG_1SHOT;
 108
 109         /* setup output polarity */
 110         if (polarity == 0)
 111                 new_conf &= ~DS1621_REG_CONFIG_POLARITY;
 112         else if (polarity == 1)
 113                 new_conf |= DS1621_REG_CONFIG_POLARITY;
 114
 115         if (conf != new_conf)
 116                 i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
 117
 118         /* start conversion */
 119         i2c_smbus_write_byte(client, DS1621_COM_START);
 120 }
 121
 122 static struct ds1621_data *ds1621_update_client(struct device *dev)
 123 {
 124         struct i2c_client *client = to_i2c_client(dev);
 125         struct ds1621_data *data = i2c_get_clientdata(client);
 126         u8 new_conf;
 127
 128         mutex_lock(&data->update_lock);
 129
 130         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 131             || !data->valid) {
 132                 int i;
 133
 134                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 135
 136                 data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 137
 138                 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 139                         data->temp[i] = ds1621_read_temp(client,
 140                                                          DS1621_REG_TEMP[i]);
 141
 142                 /* reset alarms if necessary */
 143                 new_conf = data->conf;
 144                 if (data->temp[0] > data->temp[1])      /* input > min */
 145                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 146                 if (data->temp[0] < data->temp[2])      /* input < max */
 147                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 148                 if (data->conf != new_conf)
 149                         i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
 150                                                   new_conf);
 151
 152                 data->last_updated = jiffies;
 153                 data->valid = 1;
 154         }
 155
 156         mutex_unlock(&data->update_lock);
 157
 158         return data;
 159 }
 160
 161 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 162                          char *buf)
 163 {
 164         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 165         struct ds1621_data *data = ds1621_update_client(dev);
 166         return sprintf(buf, "%d\n",
 167                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
 168 }
 169
 170 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 171                         const char *buf, size_t count)
 172 {
 173         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 174         struct i2c_client *client = to_i2c_client(dev);
 175         struct ds1621_data *data = i2c_get_clientdata(client);
 176         u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));
 177
 178         mutex_lock(&data->update_lock);
 179         data->temp[attr->index] = val;
 180         ds1621_write_temp(client, DS1621_REG_TEMP[attr->index],
 181                           data->temp[attr->index]);
 182         mutex_unlock(&data->update_lock);
 183         return count;
 184 }
 185
 186 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 187                            char *buf)
 188 {
 189         struct ds1621_data *data = ds1621_update_client(dev);
 190         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 191 }
 192
 193 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 194                           char *buf)
 195 {
 196         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 197         struct ds1621_data *data = ds1621_update_client(dev);
 198         return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 199 }
 200
 201 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 202 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 203 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 204 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 205 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 206                 DS1621_ALARM_TEMP_LOW);
 207 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 208                 DS1621_ALARM_TEMP_HIGH);
 209
 210 static struct attribute *ds1621_attributes[] = {
 211         &sensor_dev_attr_temp1_input.dev_attr.attr,
 212         &sensor_dev_attr_temp1_min.dev_attr.attr,
 213         &sensor_dev_attr_temp1_max.dev_attr.attr,
 214         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 215         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 216         &dev_attr_alarms.attr,
 217         NULL
 218 };
 219
 220 static const struct attribute_group ds1621_group = {
 221         .attrs = ds1621_attributes,
 222 };
 223
 224
 225 /* Return 0 if detection is successful, -ENODEV otherwise */
 226 static int ds1621_detect(struct i2c_client *client,
 227                          struct i2c_board_info *info)
 228 {
 229         struct i2c_adapter *adapter = client->adapter;
 230         int conf, temp;
 231         int i;
 232
 233         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 234                                      | I2C_FUNC_SMBUS_WORD_DATA
 235                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 236                 return -ENODEV;
 237
 238         /* Now, we do the remaining detection. It is lousy. */
 239         /* The NVB bit should be low if no EEPROM write has been  requested
 240            during the latest 10ms, which is highly improbable in our case. */
 241         conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 242         if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
 243                 return -ENODEV;
 244         /* The 7 lowest bits of a temperature should always be 0. */
 245         for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
 246                 temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
 247                 if (temp < 0 || (temp & 0x7f00))
 248                         return -ENODEV;
 249         }
 250
 251         strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
 252
 253         return 0;
 254 }
 255
 256 static int ds1621_probe(struct i2c_client *client,
 257                         const struct i2c_device_id *id)
 258 {
 259         struct ds1621_data *data;
 260         int err;
 261
 262         data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
 263         if (!data) {
 264                 err = -ENOMEM;
 265                 goto exit;
 266         }
 267
 268         i2c_set_clientdata(client, data);
 269         mutex_init(&data->update_lock);
 270
 271         /* Initialize the DS1621 chip */
 272         ds1621_init_client(client);
 273
 274         /* Register sysfs hooks */
 275         if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
 276                 goto exit_free;
 277
 278         data->hwmon_dev = hwmon_device_register(&client->dev);
 279         if (IS_ERR(data->hwmon_dev)) {
 280                 err = PTR_ERR(data->hwmon_dev);
 281                 goto exit_remove_files;
 282         }
 283
 284         return 0;
 285
 286       exit_remove_files:
 287         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 288       exit_free:
 289         kfree(data);
 290       exit:
 291         return err;
 292 }
 293
 294 static int ds1621_remove(struct i2c_client *client)
 295 {
 296         struct ds1621_data *data = i2c_get_clientdata(client);
 297
 298         hwmon_device_unregister(data->hwmon_dev);
 299         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 300
 301         kfree(data);
 302
 303         return 0;
 304 }
 305
 306 static const struct i2c_device_id ds1621_id[] = {
 307         { "ds1621", 0 },
 308         { "ds1625", 0 },
 309         { }
 310 };
 311 MODULE_DEVICE_TABLE(i2c, ds1621_id);
 312
 313 /* This is the driver that will be inserted */
 314 static struct i2c_driver ds1621_driver = {
 315         .class          = I2C_CLASS_HWMON,
 316         .driver = {
 317                 .name   = "ds1621",
 318         },
 319         .probe          = ds1621_probe,
 320         .remove         = ds1621_remove,
 321         .id_table       = ds1621_id,
 322         .detect         = ds1621_detect,
 323         .address_list   = normal_i2c,
 324 };
 325
 326 static int __init ds1621_init(void)
 327 {
 328         return i2c_add_driver(&ds1621_driver);
 329 }
 330
 331 static void __exit ds1621_exit(void)
 332 {
 333         i2c_del_driver(&ds1621_driver);
 334 }
 335
 336
 337 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 338 MODULE_DESCRIPTION("DS1621 driver");
 339 MODULE_LICENSE("GPL");
 340
 341 module_init(ds1621_init);
 342 module_exit(ds1621_exit);