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/err.h>
  31 #include "lm75.h"
  32
  33 /* Addresses to scan */
  34 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  35                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  36
  37 /* Insmod parameters */
  38 I2C_CLIENT_INSMOD_1(ds1621);
  39 static int polarity = -1;
  40 module_param(polarity, int, 0);
  41 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  42
  43 /* Many DS1621 constants specified below */
  44 /* Config register used for detection         */
  45 /*  7    6    5    4    3    2    1    0      */
  46 /* |Done|THF |TLF |NVB | X  | X  |POL |1SHOT| */
  47 #define DS1621_REG_CONFIG_NVB           0x10
  48 #define DS1621_REG_CONFIG_POLARITY      0x02
  49 #define DS1621_REG_CONFIG_1SHOT         0x01
  50 #define DS1621_REG_CONFIG_DONE          0x80
  51
  52 /* The DS1621 registers */
  53 #define DS1621_REG_TEMP                 0xAA /* word, RO */
  54 #define DS1621_REG_TEMP_MIN             0xA1 /* word, RW */
  55 #define DS1621_REG_TEMP_MAX             0xA2 /* word, RW */
  56 #define DS1621_REG_CONF                 0xAC /* byte, RW */
  57 #define DS1621_COM_START                0xEE /* no data */
  58 #define DS1621_COM_STOP                 0x22 /* no data */
  59
  60 /* The DS1621 configuration register */
  61 #define DS1621_ALARM_TEMP_HIGH          0x40
  62 #define DS1621_ALARM_TEMP_LOW           0x20
  63
  64 /* Conversions. Rounding and limit checking is only done on the TO_REG
  65    variants. Note that you should be a bit careful with which arguments
  66    these macros are called: arguments may be evaluated more than once.
  67    Fixing this is just not worth it. */
  68 #define ALARMS_FROM_REG(val) ((val) & \
  69                               (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
  70
  71 /* Each client has this additional data */
  72 struct ds1621_data {
  73         struct i2c_client client;
  74         struct class_device *class_dev;
  75         struct semaphore update_lock;
  76         char valid;                     /* !=0 if following fields are valid */
  77         unsigned long last_updated;     /* In jiffies */
  78
  79         u16 temp, temp_min, temp_max;   /* Register values, word */
  80         u8 conf;                        /* Register encoding, combined */
  81 };
  82
  83 static int ds1621_attach_adapter(struct i2c_adapter *adapter);
  84 static int ds1621_detect(struct i2c_adapter *adapter, int address,
  85                          int kind);
  86 static void ds1621_init_client(struct i2c_client *client);
  87 static int ds1621_detach_client(struct i2c_client *client);
  88 static struct ds1621_data *ds1621_update_client(struct device *dev);
  89
  90 /* This is the driver that will be inserted */
  91 static struct i2c_driver ds1621_driver = {
  92         .owner          = THIS_MODULE,
  93         .name           = "ds1621",
  94         .id             = I2C_DRIVERID_DS1621,
  95         .flags          = I2C_DF_NOTIFY,
  96         .attach_adapter = ds1621_attach_adapter,
  97         .detach_client  = ds1621_detach_client,
  98 };
  99
 100 /* All registers are word-sized, except for the configuration register.
 101    DS1621 uses a high-byte first convention, which is exactly opposite to
 102    the usual practice. */
 103 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 104 {
 105         if (reg == DS1621_REG_CONF)
 106                 return i2c_smbus_read_byte_data(client, reg);
 107         else
 108                 return swab16(i2c_smbus_read_word_data(client, reg));
 109 }
 110
 111 /* All registers are word-sized, except for the configuration register.
 112    DS1621 uses a high-byte first convention, which is exactly opposite to
 113    the usual practice. */
 114 static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
 115 {
 116         if (reg == DS1621_REG_CONF)
 117                 return i2c_smbus_write_byte_data(client, reg, value);
 118         else
 119                 return i2c_smbus_write_word_data(client, reg, swab16(value));
 120 }
 121
 122 static void ds1621_init_client(struct i2c_client *client)
 123 {
 124         int reg = ds1621_read_value(client, DS1621_REG_CONF);
 125         /* switch to continuous conversion mode */
 126         reg &= ~ DS1621_REG_CONFIG_1SHOT;
 127
 128         /* setup output polarity */
 129         if (polarity == 0)
 130                 reg &= ~DS1621_REG_CONFIG_POLARITY;
 131         else if (polarity == 1)
 132                 reg |= DS1621_REG_CONFIG_POLARITY;
 133
 134         ds1621_write_value(client, DS1621_REG_CONF, reg);
 135
 136         /* start conversion */
 137         i2c_smbus_write_byte(client, DS1621_COM_START);
 138 }
 139
 140 #define show(value)                                                     \
 141 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf)               \
 142 {                                                                       \
 143         struct ds1621_data *data = ds1621_update_client(dev);           \
 144         return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value));   \
 145 }
 146
 147 show(temp);
 148 show(temp_min);
 149 show(temp_max);
 150
 151 #define set_temp(suffix, value, reg)                                    \
 152 static ssize_t set_temp_##suffix(struct device *dev, struct device_attribute *attr, const char *buf,    \
 153                                  size_t count)                          \
 154 {                                                                       \
 155         struct i2c_client *client = to_i2c_client(dev);                 \
 156         struct ds1621_data *data = ds1621_update_client(dev);           \
 157         u16 val = LM75_TEMP_TO_REG(simple_strtoul(buf, NULL, 10));      \
 158                                                                         \
 159         down(&data->update_lock);                                       \
 160         data->value = val;                                              \
 161         ds1621_write_value(client, reg, data->value);                   \
 162         up(&data->update_lock);                                         \
 163         return count;                                                   \
 164 }
 165
 166 set_temp(min, temp_min, DS1621_REG_TEMP_MIN);
 167 set_temp(max, temp_max, DS1621_REG_TEMP_MAX);
 168
 169 static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, 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 DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 176 static DEVICE_ATTR(temp1_input, S_IRUGO , show_temp, NULL);
 177 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO , show_temp_min, set_temp_min);
 178 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
 179
 180
 181 static int ds1621_attach_adapter(struct i2c_adapter *adapter)
 182 {
 183         return i2c_probe(adapter, &addr_data, ds1621_detect);
 184 }
 185
 186 /* This function is called by i2c_probe */
 187 int ds1621_detect(struct i2c_adapter *adapter, int address,
 188                   int kind)
 189 {
 190         int conf, temp;
 191         struct i2c_client *new_client;
 192         struct ds1621_data *data;
 193         int err = 0;
 194
 195         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 196                                      | I2C_FUNC_SMBUS_WORD_DATA
 197                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 198                 goto exit;
 199
 200         /* OK. For now, we presume we have a valid client. We now create the
 201            client structure, even though we cannot fill it completely yet.
 202            But it allows us to access ds1621_{read,write}_value. */
 203         if (!(data = kmalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {
 204                 err = -ENOMEM;
 205                 goto exit;
 206         }
 207         memset(data, 0, sizeof(struct ds1621_data));
 208
 209         new_client = &data->client;
 210         i2c_set_clientdata(new_client, data);
 211         new_client->addr = address;
 212         new_client->adapter = adapter;
 213         new_client->driver = &ds1621_driver;
 214         new_client->flags = 0;
 215
 216
 217         /* Now, we do the remaining detection. It is lousy. */
 218         if (kind < 0) {
 219                 /* The NVB bit should be low if no EEPROM write has been
 220                    requested during the latest 10ms, which is highly
 221                    improbable in our case. */
 222                 conf = ds1621_read_value(new_client, DS1621_REG_CONF);
 223                 if (conf & DS1621_REG_CONFIG_NVB)
 224                         goto exit_free;
 225                 /* The 7 lowest bits of a temperature should always be 0. */
 226                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP);
 227                 if (temp & 0x007f)
 228                         goto exit_free;
 229                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP_MIN);
 230                 if (temp & 0x007f)
 231                         goto exit_free;
 232                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP_MAX);
 233                 if (temp & 0x007f)
 234                         goto exit_free;
 235         }
 236
 237         /* Determine the chip type - only one kind supported! */
 238         if (kind <= 0)
 239                 kind = ds1621;
 240
 241         /* Fill in remaining client fields and put it into the global list */
 242         strlcpy(new_client->name, "ds1621", I2C_NAME_SIZE);
 243         data->valid = 0;
 244         init_MUTEX(&data->update_lock);
 245
 246         /* Tell the I2C layer a new client has arrived */
 247         if ((err = i2c_attach_client(new_client)))
 248                 goto exit_free;
 249
 250         /* Initialize the DS1621 chip */
 251         ds1621_init_client(new_client);
 252
 253         /* Register sysfs hooks */
 254         data->class_dev = hwmon_device_register(&new_client->dev);
 255         if (IS_ERR(data->class_dev)) {
 256                 err = PTR_ERR(data->class_dev);
 257                 goto exit_detach;
 258         }
 259
 260         device_create_file(&new_client->dev, &dev_attr_alarms);
 261         device_create_file(&new_client->dev, &dev_attr_temp1_input);
 262         device_create_file(&new_client->dev, &dev_attr_temp1_min);
 263         device_create_file(&new_client->dev, &dev_attr_temp1_max);
 264
 265         return 0;
 266
 267 /* OK, this is not exactly good programming practice, usually. But it is
 268    very code-efficient in this case. */
 269       exit_detach:
 270         i2c_detach_client(new_client);
 271       exit_free:
 272         kfree(data);
 273       exit:
 274         return err;
 275 }
 276
 277 static int ds1621_detach_client(struct i2c_client *client)
 278 {
 279         struct ds1621_data *data = i2c_get_clientdata(client);
 280         int err;
 281
 282         hwmon_device_unregister(data->class_dev);
 283
 284         if ((err = i2c_detach_client(client)))
 285                 return err;
 286
 287         kfree(data);
 288
 289         return 0;
 290 }
 291
 292
 293 static struct ds1621_data *ds1621_update_client(struct device *dev)
 294 {
 295         struct i2c_client *client = to_i2c_client(dev);
 296         struct ds1621_data *data = i2c_get_clientdata(client);
 297         u8 new_conf;
 298
 299         down(&data->update_lock);
 300
 301         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 302             || !data->valid) {
 303
 304                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 305
 306                 data->conf = ds1621_read_value(client, DS1621_REG_CONF);
 307
 308                 data->temp = ds1621_read_value(client, DS1621_REG_TEMP);
 309
 310                 data->temp_min = ds1621_read_value(client,
 311                                                     DS1621_REG_TEMP_MIN);
 312                 data->temp_max = ds1621_read_value(client,
 313                                                     DS1621_REG_TEMP_MAX);
 314
 315                 /* reset alarms if necessary */
 316                 new_conf = data->conf;
 317                 if (data->temp < data->temp_min)
 318                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 319                 if (data->temp > data->temp_max)
 320                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 321                 if (data->conf != new_conf)
 322                         ds1621_write_value(client, DS1621_REG_CONF,
 323                                            new_conf);
 324
 325                 data->last_updated = jiffies;
 326                 data->valid = 1;
 327         }
 328
 329         up(&data->update_lock);
 330
 331         return data;
 332 }
 333
 334 static int __init ds1621_init(void)
 335 {
 336         return i2c_add_driver(&ds1621_driver);
 337 }
 338
 339 static void __exit ds1621_exit(void)
 340 {
 341         i2c_del_driver(&ds1621_driver);
 342 }
 343
 344
 345 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 346 MODULE_DESCRIPTION("DS1621 driver");
 347 MODULE_LICENSE("GPL");
 348
 349 module_init(ds1621_init);
 350 module_exit(ds1621_exit);