drivers/i2c/chips/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/i2c-sensor.h>
  30 #include "lm75.h"
  31
  32 /* Addresses to scan */
  33 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
  34                                         0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
  35 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  36
  37 /* Insmod parameters */
  38 SENSORS_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 semaphore update_lock;
  75         char valid;                     /* !=0 if following fields are valid */
  76         unsigned long last_updated;     /* In jiffies */
  77
  78         u16 temp, temp_min, temp_max;   /* Register values, word */
  79         u8 conf;                        /* Register encoding, combined */
  80 };
  81
  82 static int ds1621_attach_adapter(struct i2c_adapter *adapter);
  83 static int ds1621_detect(struct i2c_adapter *adapter, int address,
  84                          int kind);
  85 static void ds1621_init_client(struct i2c_client *client);
  86 static int ds1621_detach_client(struct i2c_client *client);
  87 static struct ds1621_data *ds1621_update_client(struct device *dev);
  88
  89 /* This is the driver that will be inserted */
  90 static struct i2c_driver ds1621_driver = {
  91         .owner          = THIS_MODULE,
  92         .name           = "ds1621",
  93         .id             = I2C_DRIVERID_DS1621,
  94         .flags          = I2C_DF_NOTIFY,
  95         .attach_adapter = ds1621_attach_adapter,
  96         .detach_client  = ds1621_detach_client,
  97 };
  98
  99 /* All registers are word-sized, except for the configuration register.
 100    DS1621 uses a high-byte first convention, which is exactly opposite to
 101    the usual practice. */
 102 static int ds1621_read_value(struct i2c_client *client, u8 reg)
 103 {
 104         if (reg == DS1621_REG_CONF)
 105                 return i2c_smbus_read_byte_data(client, reg);
 106         else
 107                 return swab16(i2c_smbus_read_word_data(client, reg));
 108 }
 109
 110 /* All registers are word-sized, except for the configuration register.
 111    DS1621 uses a high-byte first convention, which is exactly opposite to
 112    the usual practice. */
 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 continous 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 #define show(value)                                                     \
 140 static ssize_t show_##value(struct device *dev, char *buf)              \
 141 {                                                                       \
 142         struct ds1621_data *data = ds1621_update_client(dev);           \
 143         return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value));   \
 144 }
 145
 146 show(temp);
 147 show(temp_min);
 148 show(temp_max);
 149
 150 #define set_temp(suffix, value, reg)                                    \
 151 static ssize_t set_temp_##suffix(struct device *dev, const char *buf,   \
 152                                  size_t count)                          \
 153 {                                                                       \
 154         struct i2c_client *client = to_i2c_client(dev);                 \
 155         struct ds1621_data *data = ds1621_update_client(dev);           \
 156         u16 val = LM75_TEMP_TO_REG(simple_strtoul(buf, NULL, 10));      \
 157                                                                         \
 158         down(&data->update_lock);                                       \
 159         data->value = val;                                              \
 160         ds1621_write_value(client, reg, data->value);                   \
 161         up(&data->update_lock);                                         \
 162         return count;                                                   \
 163 }
 164
 165 set_temp(min, temp_min, DS1621_REG_TEMP_MIN);
 166 set_temp(max, temp_max, DS1621_REG_TEMP_MAX);
 167
 168 static ssize_t show_alarms(struct device *dev, char *buf)
 169 {
 170         struct ds1621_data *data = ds1621_update_client(dev);
 171         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 172 }
 173
 174 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 175 static DEVICE_ATTR(temp1_input, S_IRUGO , show_temp, NULL);
 176 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO , show_temp_min, set_temp_min);
 177 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max);
 178
 179
 180 static int ds1621_attach_adapter(struct i2c_adapter *adapter)
 181 {
 182         return i2c_detect(adapter, &addr_data, ds1621_detect);
 183 }
 184
 185 /* This function is called by i2c_detect */
 186 int ds1621_detect(struct i2c_adapter *adapter, int address,
 187                   int kind)
 188 {
 189         int conf, temp;
 190         struct i2c_client *new_client;
 191         struct ds1621_data *data;
 192         int err = 0;
 193
 194         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 195                                      | I2C_FUNC_SMBUS_WORD_DATA
 196                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 197                 goto exit;
 198
 199         /* OK. For now, we presume we have a valid client. We now create the
 200            client structure, even though we cannot fill it completely yet.
 201            But it allows us to access ds1621_{read,write}_value. */
 202         if (!(data = kmalloc(sizeof(struct ds1621_data), GFP_KERNEL))) {
 203                 err = -ENOMEM;
 204                 goto exit;
 205         }
 206         memset(data, 0, sizeof(struct ds1621_data));
 207
 208         new_client = &data->client;
 209         i2c_set_clientdata(new_client, data);
 210         new_client->addr = address;
 211         new_client->adapter = adapter;
 212         new_client->driver = &ds1621_driver;
 213         new_client->flags = 0;
 214
 215
 216         /* Now, we do the remaining detection. It is lousy. */
 217         if (kind < 0) {
 218                 /* The NVB bit should be low if no EEPROM write has been
 219                    requested during the latest 10ms, which is highly
 220                    improbable in our case. */
 221                 conf = ds1621_read_value(new_client, DS1621_REG_CONF);
 222                 if (conf & DS1621_REG_CONFIG_NVB)
 223                         goto exit_free;
 224                 /* The 7 lowest bits of a temperature should always be 0. */
 225                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP);
 226                 if (temp & 0x007f)
 227                         goto exit_free;
 228                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP_MIN);
 229                 if (temp & 0x007f)
 230                         goto exit_free;
 231                 temp = ds1621_read_value(new_client, DS1621_REG_TEMP_MAX);
 232                 if (temp & 0x007f)
 233                         goto exit_free;
 234         }
 235
 236         /* Determine the chip type - only one kind supported! */
 237         if (kind <= 0)
 238                 kind = ds1621;
 239
 240         /* Fill in remaining client fields and put it into the global list */
 241         strlcpy(new_client->name, "ds1621", I2C_NAME_SIZE);
 242         data->valid = 0;
 243         init_MUTEX(&data->update_lock);
 244
 245         /* Tell the I2C layer a new client has arrived */
 246         if ((err = i2c_attach_client(new_client)))
 247                 goto exit_free;
 248
 249         /* Initialize the DS1621 chip */
 250         ds1621_init_client(new_client);
 251
 252         /* Register sysfs hooks */
 253         device_create_file(&new_client->dev, &dev_attr_alarms);
 254         device_create_file(&new_client->dev, &dev_attr_temp1_input);
 255         device_create_file(&new_client->dev, &dev_attr_temp1_min);
 256         device_create_file(&new_client->dev, &dev_attr_temp1_max);
 257
 258         return 0;
 259
 260 /* OK, this is not exactly good programming practice, usually. But it is
 261    very code-efficient in this case. */
 262       exit_free:
 263         kfree(data);
 264       exit:
 265         return err;
 266 }
 267
 268 static int ds1621_detach_client(struct i2c_client *client)
 269 {
 270         int err;
 271
 272         if ((err = i2c_detach_client(client))) {
 273                 dev_err(&client->dev, "Client deregistration failed, "
 274                         "client not detached.\n");
 275                 return err;
 276         }
 277
 278         kfree(i2c_get_clientdata(client));
 279
 280         return 0;
 281 }
 282
 283
 284 static struct ds1621_data *ds1621_update_client(struct device *dev)
 285 {
 286         struct i2c_client *client = to_i2c_client(dev);
 287         struct ds1621_data *data = i2c_get_clientdata(client);
 288         u8 new_conf;
 289
 290         down(&data->update_lock);
 291
 292         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 293             || !data->valid) {
 294
 295                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 296
 297                 data->conf = ds1621_read_value(client, DS1621_REG_CONF);
 298
 299                 data->temp = ds1621_read_value(client, DS1621_REG_TEMP);
 300
 301                 data->temp_min = ds1621_read_value(client,
 302                                                     DS1621_REG_TEMP_MIN);
 303                 data->temp_max = ds1621_read_value(client,
 304                                                     DS1621_REG_TEMP_MAX);
 305
 306                 /* reset alarms if neccessary */
 307                 new_conf = data->conf;
 308                 if (data->temp < data->temp_min)
 309                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 310                 if (data->temp > data->temp_max)
 311                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 312                 if (data->conf != new_conf)
 313                         ds1621_write_value(client, DS1621_REG_CONF,
 314                                            new_conf);
 315
 316                 data->last_updated = jiffies;
 317                 data->valid = 1;
 318         }
 319
 320         up(&data->update_lock);
 321
 322         return data;
 323 }
 324
 325 static int __init ds1621_init(void)
 326 {
 327         return i2c_add_driver(&ds1621_driver);
 328 }
 329
 330 static void __exit ds1621_exit(void)
 331 {
 332         i2c_del_driver(&ds1621_driver);
 333 }
 334
 335
 336 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 337 MODULE_DESCRIPTION("DS1621 driver");
 338 MODULE_LICENSE("GPL");
 339
 340 module_init(ds1621_init);
 341 module_exit(ds1621_exit);