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         long val;
 159         int err;
 160
 161         err = kstrtol(buf, 10, &val);
 162         if (err)
 163                 return err;
 164
 165         mutex_lock(&data->update_lock);
 166         data->temp[attr->index] = LM75_TEMP_TO_REG(val);
 167         i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
 168                                      data->temp[attr->index]);
 169         mutex_unlock(&data->update_lock);
 170         return count;
 171 }
 172
 173 static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 174                            char *buf)
 175 {
 176         struct ds1621_data *data = ds1621_update_client(dev);
 177         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 178 }
 179
 180 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 181                           char *buf)
 182 {
 183         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 184         struct ds1621_data *data = ds1621_update_client(dev);
 185         return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 186 }
 187
 188 static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 189 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 190 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 191 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 192 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 193                 DS1621_ALARM_TEMP_LOW);
 194 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 195                 DS1621_ALARM_TEMP_HIGH);
 196
 197 static struct attribute *ds1621_attributes[] = {
 198         &sensor_dev_attr_temp1_input.dev_attr.attr,
 199         &sensor_dev_attr_temp1_min.dev_attr.attr,
 200         &sensor_dev_attr_temp1_max.dev_attr.attr,
 201         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 202         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 203         &dev_attr_alarms.attr,
 204         NULL
 205 };
 206
 207 static const struct attribute_group ds1621_group = {
 208         .attrs = ds1621_attributes,
 209 };
 210
 211
 212 /* Return 0 if detection is successful, -ENODEV otherwise */
 213 static int ds1621_detect(struct i2c_client *client,
 214                          struct i2c_board_info *info)
 215 {
 216         struct i2c_adapter *adapter = client->adapter;
 217         int conf, temp;
 218         int i;
 219
 220         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 221                                      | I2C_FUNC_SMBUS_WORD_DATA
 222                                      | I2C_FUNC_SMBUS_WRITE_BYTE))
 223                 return -ENODEV;
 224
 225         /*
 226          * Now, we do the remaining detection. It is lousy.
 227          *
 228          * The NVB bit should be low if no EEPROM write has been requested
 229          * during the latest 10ms, which is highly improbable in our case.
 230          */
 231         conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 232         if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
 233                 return -ENODEV;
 234         /* The 7 lowest bits of a temperature should always be 0. */
 235         for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
 236                 temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
 237                 if (temp < 0 || (temp & 0x7f00))
 238                         return -ENODEV;
 239         }
 240
 241         strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
 242
 243         return 0;
 244 }
 245
 246 static int ds1621_probe(struct i2c_client *client,
 247                         const struct i2c_device_id *id)
 248 {
 249         struct ds1621_data *data;
 250         int err;
 251
 252         data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 253                             GFP_KERNEL);
 254         if (!data)
 255                 return -ENOMEM;
 256
 257         i2c_set_clientdata(client, data);
 258         mutex_init(&data->update_lock);
 259
 260         /* Initialize the DS1621 chip */
 261         ds1621_init_client(client);
 262
 263         /* Register sysfs hooks */
 264         err = sysfs_create_group(&client->dev.kobj, &ds1621_group);
 265         if (err)
 266                 return err;
 267
 268         data->hwmon_dev = hwmon_device_register(&client->dev);
 269         if (IS_ERR(data->hwmon_dev)) {
 270                 err = PTR_ERR(data->hwmon_dev);
 271                 goto exit_remove_files;
 272         }
 273
 274         return 0;
 275
 276  exit_remove_files:
 277         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 278         return err;
 279 }
 280
 281 static int ds1621_remove(struct i2c_client *client)
 282 {
 283         struct ds1621_data *data = i2c_get_clientdata(client);
 284
 285         hwmon_device_unregister(data->hwmon_dev);
 286         sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 287
 288         return 0;
 289 }
 290
 291 static const struct i2c_device_id ds1621_id[] = {
 292         { "ds1621", 0 },
 293         { "ds1625", 0 },
 294         { }
 295 };
 296 MODULE_DEVICE_TABLE(i2c, ds1621_id);
 297
 298 /* This is the driver that will be inserted */
 299 static struct i2c_driver ds1621_driver = {
 300         .class          = I2C_CLASS_HWMON,
 301         .driver = {
 302                 .name   = "ds1621",
 303         },
 304         .probe          = ds1621_probe,
 305         .remove         = ds1621_remove,
 306         .id_table       = ds1621_id,
 307         .detect         = ds1621_detect,
 308         .address_list   = normal_i2c,
 309 };
 310
 311 module_i2c_driver(ds1621_driver);
 312
 313 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 314 MODULE_DESCRIPTION("DS1621 driver");
 315 MODULE_LICENSE("GPL");