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 unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  38                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  39
  40 /* Insmod parameters */
  41 I2C_CLIENT_INSMOD_1(ds1621);
  42 static int polarity = -1;
  43 module_param(polarity, int, 0);
  44 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  45
  46 /* Many DS1621 constants specified below */
  47 /* Config register used for detection         */
  48 /*  7    6    5    4    3    2    1    0      */
  49 /* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
  50 #define DS1621_REG_CONFIG_NVB           0x10
  51 #define DS1621_REG_CONFIG_POLARITY      0x02
  52 #define DS1621_REG_CONFIG_1SHOT         0x01
  53 #define DS1621_REG_CONFIG_DONE          0x80
  54
  55 /* The DS1621 registers */
  56 static const u8 DS1621_REG_TEMP[3] = {
  57         0xAA,           /* input, word, RO */
  58         0xA2,           /* min, word, RW */
  59         0xA1,           /* max, word, RW */
  60 };
  61 #define DS1621_REG_CONF                 0xAC /* byte, RW */
  62 #define DS1621_COM_START                0xEE /* no data */
  63 #define DS1621_COM_STOP                 0x22 /* no data */
  64
  65 /* The DS1621 configuration register */
  66 #define DS1621_ALARM_TEMP_HIGH          0x40
  67 #define DS1621_ALARM_TEMP_LOW           0x20
  68
  69 /* Conversions */
  70 #define ALARMS_FROM_REG(val) ((val) & \
  71                               (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
  72
  73 /* Each client has this additional data */
  74 struct ds1621_data {
  75         struct i2c_client client;
  76         struct class_device *class_dev;
  77         struct mutex update_lock;
  78         char valid;                     /* !=0 if following fields are valid */
  79         unsigned long last_updated;     /* In jiffies */
  80
  81         u16 temp[3];                    /* Register values, word */
  82         u8 conf;                        /* Register encoding, combined */
  83 };
  84
  85 static int ds1621_attach_adapter(struct i2c_adapter *adapter);
  86 static int ds1621_detect(struct i2c_adapter *adapter, int address,
  87                          int kind);
  88 static void ds1621_init_client(struct i2c_client *client);
  89 static int ds1621_detach_client(struct i2c_client *client);
  90 static struct ds1621_data *ds1621_update_client(struct device *dev);
  91
  92 /* This is the driver that will be inserted */
  93 static struct i2c_driver ds1621_driver = {
  94         .driver = {
  95                 .name   = "ds1621",
  96         },
  97         .id             = I2C_DRIVERID_DS1621,
  98         .attach_adapter = ds1621_attach_adapter,
  99         .detach_client  = ds1621_detach_client,
 100 };
 101
 102 /* All registers are word-sized, except for the configuration register.
 103    DS1621 uses a high-byte first convention, which is exactly opposite to
 104    the SMBus standard. */
 105 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 106 {
 107         if (reg == DS1621_REG_CONF)
 108                 return i2c_smbus_read_byte_data(client, reg);
 109         else
 110                 return swab16(i2c_smbus_read_word_data(client, reg));
 111 }
 112
 113 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
 114 {
 115         if (reg == DS1621_REG_CONF)
 116                 return i2c_smbus_write_byte_data(client, reg, value);
 117         else
 118                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 119 }
 120
 121 static void ds1621_init_client(struct i2c_client *client)
 122 {
 123         int reg = ds1621_read_value(client, DS1621_REG_CONF);
 124         /* switch to continuous conversion mode */
 125         reg &= ~ DS1621_REG_CONFIG_1SHOT;
 126
 127         /* setup output polarity */
 128         if (polarity == 0)
 129                 reg &= ~DS1621_REG_CONFIG_POLARITY;
 130         else if (polarity == 1)
 131                 reg |= DS1621_REG_CONFIG_POLARITY;
 132
 133         ds1621_write_value(client, DS1621_REG_CONF, reg);
 134
 135         /* start conversion */
 136         i2c_smbus_write_byte(client, DS1621_COM_START);
 137 }
 138
 139 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 140                          char *buf)
 141 {
 142         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 143         struct ds1621_data *data = ds1621_update_client(dev);
 144         return sprintf(buf, "%d\n",
 145                        LM75_TEMP_FROM_REG(data->temp[attr->index]));
 146 }
 147
 148 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 149                         const char *buf, size_t count)
 150 {
 151         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 152         struct i2c_client *client = to_i2c_client(dev);
 153         struct ds1621_data *data = ds1621_update_client(dev);
 154         u16 val = LM75_TEMP_TO_REG(simple_strtoul(buf, NULL, 10));
 155
 156         mutex_lock(&data->update_lock);
 157         data->temp[attr->index] = val;
 158         ds1621_write_value(client, DS1621_REG_TEMP[attr->index],
 159                            data->temp[attr->index]);
 160         mutex_unlock(&data->update_lock);
 161         return count;
 162 }
 163
 164 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 165                            char *buf)
 166 {
 167         struct ds1621_data *data = ds1621_update_client(dev);
 168         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 169 }
 170
 171 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 172 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 173 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 174 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 175
 176 static struct attribute *ds1621_attributes[] = {
 177         &sensor_dev_attr_temp1_input.dev_attr.attr,
 178         &sensor_dev_attr_temp1_min.dev_attr.attr,
 179         &sensor_dev_attr_temp1_max.dev_attr.attr,
 180         &dev_attr_alarms.attr,
 181         NULL
 182 };
 183
 184 static const struct attribute_group ds1621_group = {
 185         .attrs = ds1621_attributes,
 186 };
 187
 188
 189 static int ds1621_attach_adapter(struct i2c_adapter *adapter)
 190 {
 191         if (!(adapter->class & I2C_CLASS_HWMON))
 192                 return 0;
 193         return i2c_probe(adapter, &addr_data, ds1621_detect);
 194 }
 195
 196 /* This function is called by i2c_probe */
 197 static int ds1621_detect(struct i2c_adapter *adapter, int address,
 198                          int kind)
 199 {
 200         int conf, temp;
 201         struct i2c_client *client;
 202         struct ds1621_data *data;
 203         int i, err = 0;
 204
 205         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 206                                      | I2C_FUNC_SMBUS_WORD_DATA
 207                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 208                 goto exit;
 209
 210         /* OK. For now, we presume we have a valid client. We now create the
 211            client structure, even though we cannot fill it completely yet.
 212            But it allows us to access ds1621_{read,write}_value. */
 213         if (!(data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {
 214                 err = -ENOMEM;
 215                 goto exit;
 216         }
 217
 218         client = &data->client;
 219         i2c_set_clientdata(client, data);
 220         client->addr = address;
 221         client->adapter = adapter;
 222         client->driver = &ds1621_driver;
 223
 224         /* Now, we do the remaining detection. It is lousy. */
 225         if (kind < 0) {
 226                 /* The NVB bit should be low if no EEPROM write has been
 227                    requested during the latest 10ms, which is highly
 228                    improbable in our case. */
 229                 conf = ds1621_read_value(client, DS1621_REG_CONF);
 230                 if (conf & DS1621_REG_CONFIG_NVB)
 231                         goto exit_free;
 232                 /* The 7 lowest bits of a temperature should always be 0. */
 233                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 234                         temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);
 235                         if (temp & 0x007f)
 236                                 goto exit_free;
 237                 }
 238         }
 239
 240         /* Fill in remaining client fields and put it into the global list */
 241         strlcpy(client->name, "ds1621", I2C_NAME_SIZE);
 242         mutex_init(&data->update_lock);
 243
 244         /* Tell the I2C layer a new client has arrived */
 245         if ((err = i2c_attach_client(client)))
 246                 goto exit_free;
 247
 248         /* Initialize the DS1621 chip */
 249         ds1621_init_client(client);
 250
 251         /* Register sysfs hooks */
 252         if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
 253                 goto exit_detach;
 254
 255         data->class_dev = hwmon_device_register(&client->dev);
 256         if (IS_ERR(data->class_dev)) {
 257                 err = PTR_ERR(data->class_dev);
 258                 goto exit_remove_files;
 259         }
 260
 261         return 0;
 262
 263       exit_remove_files:
 264         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 265       exit_detach:
 266         i2c_detach_client(client);
 267       exit_free:
 268         kfree(data);
 269       exit:
 270         return err;
 271 }
 272
 273 static int ds1621_detach_client(struct i2c_client *client)
 274 {
 275         struct ds1621_data *data = i2c_get_clientdata(client);
 276         int err;
 277
 278         hwmon_device_unregister(data->class_dev);
 279         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 280
 281         if ((err = i2c_detach_client(client)))
 282                 return err;
 283
 284         kfree(data);
 285
 286         return 0;
 287 }
 288
 289
 290 static struct ds1621_data *ds1621_update_client(struct device *dev)
 291 {
 292         struct i2c_client *client = to_i2c_client(dev);
 293         struct ds1621_data *data = i2c_get_clientdata(client);
 294         u8 new_conf;
 295
 296         mutex_lock(&data->update_lock);
 297
 298         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 299             || !data->valid) {
 300                 int i;
 301
 302                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 303
 304                 data->conf = ds1621_read_value(client, DS1621_REG_CONF);
 305
 306                 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 307                         data->temp[i] = ds1621_read_value(client,
 308                                                           DS1621_REG_TEMP[i]);
 309
 310                 /* reset alarms if necessary */
 311                 new_conf = data->conf;
 312                 if (data->temp[0] > data->temp[1])      /* input > min */
 313                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 314                 if (data->temp[0] < data->temp[2])      /* input < max */
 315                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 316                 if (data->conf != new_conf)
 317                         ds1621_write_value(client, DS1621_REG_CONF,
 318                                            new_conf);
 319
 320                 data->last_updated = jiffies;
 321                 data->valid = 1;
 322         }
 323
 324         mutex_unlock(&data->update_lock);
 325
 326         return data;
 327 }
 328
 329 static int __init ds1621_init(void)
 330 {
 331         return i2c_add_driver(&ds1621_driver);
 332 }
 333
 334 static void __exit ds1621_exit(void)
 335 {
 336         i2c_del_driver(&ds1621_driver);
 337 }
 338
 339
 340 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 341 MODULE_DESCRIPTION("DS1621 driver");
 342 MODULE_LICENSE("GPL");
 343
 344 module_init(ds1621_init);
 345 module_exit(ds1621_exit);