drivers/hwmon/w83l785ts.c

   1 /*
   2  * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
   3  *               monitoring
   4  * Copyright (C) 2003-2009  Jean Delvare <khali@linux-fr.org>
   5  *
   6  * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
   7  * by Winbond. It reports a single external temperature with a 1 deg
   8  * resolution and a 3 deg accuracy. Datasheet can be obtained from
   9  * Winbond's website at:
  10  *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
  11  *
  12  * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
  13  * <khali@linux-fr.org>.
  14  *
  15  * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
  16  * error handling mechanism.
  17  *
  18  * This program is free software; you can redistribute it and/or modify
  19  * it under the terms of the GNU General Public License as published by
  20  * the Free Software Foundation; either version 2 of the License, or
  21  * (at your option) any later version.
  22  *
  23  * This program is distributed in the hope that it will be useful,
  24  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  * GNU General Public License for more details.
  27  *
  28  * You should have received a copy of the GNU General Public License
  29  * along with this program; if not, write to the Free Software
  30  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  31  */
  32
  33 #include <linux/module.h>
  34 #include <linux/delay.h>
  35 #include <linux/init.h>
  36 #include <linux/slab.h>
  37 #include <linux/jiffies.h>
  38 #include <linux/i2c.h>
  39 #include <linux/hwmon.h>
  40 #include <linux/hwmon-sysfs.h>
  41 #include <linux/err.h>
  42 #include <linux/mutex.h>
  43
  44 /* How many retries on register read error */
  45 #define MAX_RETRIES     5
  46
  47 /*
  48  * Address to scan
  49  * Address is fully defined internally and cannot be changed.
  50  */
  51
  52 static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
  53
  54 /*
  55  * The W83L785TS-S registers
  56  * Manufacturer ID is 0x5CA3 for Winbond.
  57  */
  58
  59 #define W83L785TS_REG_MAN_ID1           0x4D
  60 #define W83L785TS_REG_MAN_ID2           0x4C
  61 #define W83L785TS_REG_CHIP_ID           0x4E
  62 #define W83L785TS_REG_CONFIG            0x40
  63 #define W83L785TS_REG_TYPE              0x52
  64 #define W83L785TS_REG_TEMP              0x27
  65 #define W83L785TS_REG_TEMP_OVER         0x53 /* not sure about this one */
  66
  67 /*
  68  * Conversions
  69  * The W83L785TS-S uses signed 8-bit values.
  70  */
  71
  72 #define TEMP_FROM_REG(val)      ((val) * 1000)
  73
  74 /*
  75  * Functions declaration
  76  */
  77
  78 static int w83l785ts_probe(struct i2c_client *client,
  79                            const struct i2c_device_id *id);
  80 static int w83l785ts_detect(struct i2c_client *client,
  81                             struct i2c_board_info *info);
  82 static int w83l785ts_remove(struct i2c_client *client);
  83 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  84 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  85
  86 /*
  87  * Driver data (common to all clients)
  88  */
  89
  90 static const struct i2c_device_id w83l785ts_id[] = {
  91         { "w83l785ts", 0 },
  92         { }
  93 };
  94 MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
  95
  96 static struct i2c_driver w83l785ts_driver = {
  97         .class          = I2C_CLASS_HWMON,
  98         .driver = {
  99                 .name   = "w83l785ts",
 100         },
 101         .probe          = w83l785ts_probe,
 102         .remove         = w83l785ts_remove,
 103         .id_table       = w83l785ts_id,
 104         .detect         = w83l785ts_detect,
 105         .address_list   = normal_i2c,
 106 };
 107
 108 /*
 109  * Client data (each client gets its own)
 110  */
 111
 112 struct w83l785ts_data {
 113         struct device *hwmon_dev;
 114         struct mutex update_lock;
 115         char valid; /* zero until following fields are valid */
 116         unsigned long last_updated; /* in jiffies */
 117
 118         /* registers values */
 119         s8 temp[2]; /* 0: input
 120                        1: critical limit */
 121 };
 122
 123 /*
 124  * Sysfs stuff
 125  */
 126
 127 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 128         char *buf)
 129 {
 130         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 131         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 132         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
 133 }
 134
 135 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 136 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
 137
 138 /*
 139  * Real code
 140  */
 141
 142 /* Return 0 if detection is successful, -ENODEV otherwise */
 143 static int w83l785ts_detect(struct i2c_client *client,
 144                             struct i2c_board_info *info)
 145 {
 146         struct i2c_adapter *adapter = client->adapter;
 147         u16 man_id;
 148         u8 chip_id;
 149
 150         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 151                 return -ENODEV;
 152
 153         /* detection */
 154         if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
 155          || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
 156                 dev_dbg(&adapter->dev,
 157                         "W83L785TS-S detection failed at 0x%02x\n",
 158                         client->addr);
 159                 return -ENODEV;
 160         }
 161
 162         /* Identification */
 163         man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
 164                + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
 165         chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
 166
 167         if (man_id != 0x5CA3            /* Winbond */
 168          || chip_id != 0x70) {          /* W83L785TS-S */
 169                 dev_dbg(&adapter->dev,
 170                         "Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
 171                         man_id, chip_id);
 172                 return -ENODEV;
 173         }
 174
 175         strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
 176
 177         return 0;
 178 }
 179
 180 static int w83l785ts_probe(struct i2c_client *new_client,
 181                            const struct i2c_device_id *id)
 182 {
 183         struct w83l785ts_data *data;
 184         int err = 0;
 185
 186         data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL);
 187         if (!data) {
 188                 err = -ENOMEM;
 189                 goto exit;
 190         }
 191
 192         i2c_set_clientdata(new_client, data);
 193         data->valid = 0;
 194         mutex_init(&data->update_lock);
 195
 196         /* Default values in case the first read fails (unlikely). */
 197         data->temp[1] = data->temp[0] = 0;
 198
 199         /*
 200          * Initialize the W83L785TS chip
 201          * Nothing yet, assume it is already started.
 202          */
 203
 204         err = device_create_file(&new_client->dev,
 205                                  &sensor_dev_attr_temp1_input.dev_attr);
 206         if (err)
 207                 goto exit_remove;
 208
 209         err = device_create_file(&new_client->dev,
 210                                  &sensor_dev_attr_temp1_max.dev_attr);
 211         if (err)
 212                 goto exit_remove;
 213
 214         /* Register sysfs hooks */
 215         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 216         if (IS_ERR(data->hwmon_dev)) {
 217                 err = PTR_ERR(data->hwmon_dev);
 218                 goto exit_remove;
 219         }
 220
 221         return 0;
 222
 223 exit_remove:
 224         device_remove_file(&new_client->dev,
 225                            &sensor_dev_attr_temp1_input.dev_attr);
 226         device_remove_file(&new_client->dev,
 227                            &sensor_dev_attr_temp1_max.dev_attr);
 228         kfree(data);
 229 exit:
 230         return err;
 231 }
 232
 233 static int w83l785ts_remove(struct i2c_client *client)
 234 {
 235         struct w83l785ts_data *data = i2c_get_clientdata(client);
 236
 237         hwmon_device_unregister(data->hwmon_dev);
 238         device_remove_file(&client->dev,
 239                            &sensor_dev_attr_temp1_input.dev_attr);
 240         device_remove_file(&client->dev,
 241                            &sensor_dev_attr_temp1_max.dev_attr);
 242
 243         kfree(data);
 244         return 0;
 245 }
 246
 247 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 248 {
 249         int value, i;
 250         struct device *dev;
 251         const char *prefix;
 252
 253         /* We might be called during detection, at which point the client
 254            isn't yet fully initialized, so we can't use dev_dbg on it */
 255         if (i2c_get_clientdata(client)) {
 256                 dev = &client->dev;
 257                 prefix = "";
 258         } else {
 259                 dev = &client->adapter->dev;
 260                 prefix = "w83l785ts: ";
 261         }
 262
 263         /* Frequent read errors have been reported on Asus boards, so we
 264          * retry on read errors. If it still fails (unlikely), return the
 265          * default value requested by the caller. */
 266         for (i = 1; i <= MAX_RETRIES; i++) {
 267                 value = i2c_smbus_read_byte_data(client, reg);
 268                 if (value >= 0) {
 269                         dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
 270                                 prefix, value, reg);
 271                         return value;
 272                 }
 273                 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
 274                 msleep(i);
 275         }
 276
 277         dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
 278                 reg);
 279         return defval;
 280 }
 281
 282 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 283 {
 284         struct i2c_client *client = to_i2c_client(dev);
 285         struct w83l785ts_data *data = i2c_get_clientdata(client);
 286
 287         mutex_lock(&data->update_lock);
 288
 289         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 290                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 291                 data->temp[0] = w83l785ts_read_value(client,
 292                                 W83L785TS_REG_TEMP, data->temp[0]);
 293                 data->temp[1] = w83l785ts_read_value(client,
 294                                 W83L785TS_REG_TEMP_OVER, data->temp[1]);
 295
 296                 data->last_updated = jiffies;
 297                 data->valid = 1;
 298         }
 299
 300         mutex_unlock(&data->update_lock);
 301
 302         return data;
 303 }
 304
 305 static int __init sensors_w83l785ts_init(void)
 306 {
 307         return i2c_add_driver(&w83l785ts_driver);
 308 }
 309
 310 static void __exit sensors_w83l785ts_exit(void)
 311 {
 312         i2c_del_driver(&w83l785ts_driver);
 313 }
 314
 315 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 316 MODULE_DESCRIPTION("W83L785TS-S driver");
 317 MODULE_LICENSE("GPL");
 318
 319 module_init(sensors_w83l785ts_init);
 320 module_exit(sensors_w83l785ts_exit);