drivers/hwmon/w83l785ts.c

   1 /*
   2  * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
   3  *               monitoring
   4  * Copyright (C) 2003-2004  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  * Insmod parameters
  56  */
  57
  58 I2C_CLIENT_INSMOD_1(w83l785ts);
  59
  60 /*
  61  * The W83L785TS-S registers
  62  * Manufacturer ID is 0x5CA3 for Winbond.
  63  */
  64
  65 #define W83L785TS_REG_MAN_ID1           0x4D
  66 #define W83L785TS_REG_MAN_ID2           0x4C
  67 #define W83L785TS_REG_CHIP_ID           0x4E
  68 #define W83L785TS_REG_CONFIG            0x40
  69 #define W83L785TS_REG_TYPE              0x52
  70 #define W83L785TS_REG_TEMP              0x27
  71 #define W83L785TS_REG_TEMP_OVER         0x53 /* not sure about this one */
  72
  73 /*
  74  * Conversions
  75  * The W83L785TS-S uses signed 8-bit values.
  76  */
  77
  78 #define TEMP_FROM_REG(val)      ((val) * 1000)
  79
  80 /*
  81  * Functions declaration
  82  */
  83
  84 static int w83l785ts_probe(struct i2c_client *client,
  85                            const struct i2c_device_id *id);
  86 static int w83l785ts_detect(struct i2c_client *client, int kind,
  87                             struct i2c_board_info *info);
  88 static int w83l785ts_remove(struct i2c_client *client);
  89 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  90 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  91
  92 /*
  93  * Driver data (common to all clients)
  94  */
  95
  96 static const struct i2c_device_id w83l785ts_id[] = {
  97         { "w83l785ts", w83l785ts },
  98         { }
  99 };
 100 MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
 101
 102 static struct i2c_driver w83l785ts_driver = {
 103         .class          = I2C_CLASS_HWMON,
 104         .driver = {
 105                 .name   = "w83l785ts",
 106         },
 107         .probe          = w83l785ts_probe,
 108         .remove         = w83l785ts_remove,
 109         .id_table       = w83l785ts_id,
 110         .detect         = w83l785ts_detect,
 111         .address_data   = &addr_data,
 112 };
 113
 114 /*
 115  * Client data (each client gets its own)
 116  */
 117
 118 struct w83l785ts_data {
 119         struct device *hwmon_dev;
 120         struct mutex update_lock;
 121         char valid; /* zero until following fields are valid */
 122         unsigned long last_updated; /* in jiffies */
 123
 124         /* registers values */
 125         s8 temp[2]; /* 0: input
 126                        1: critical limit */
 127 };
 128
 129 /*
 130  * Sysfs stuff
 131  */
 132
 133 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 134         char *buf)
 135 {
 136         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 137         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 138         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
 139 }
 140
 141 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 142 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
 143
 144 /*
 145  * Real code
 146  */
 147
 148 /* Return 0 if detection is successful, -ENODEV otherwise */
 149 static int w83l785ts_detect(struct i2c_client *new_client, int kind,
 150                             struct i2c_board_info *info)
 151 {
 152         struct i2c_adapter *adapter = new_client->adapter;
 153
 154         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 155                 return -ENODEV;
 156
 157         /*
 158          * Now we do the remaining detection. A negative kind means that
 159          * the driver was loaded with no force parameter (default), so we
 160          * must both detect and identify the chip (actually there is only
 161          * one possible kind of chip for now, W83L785TS-S). A zero kind means
 162          * that the driver was loaded with the force parameter, the detection
 163          * step shall be skipped. A positive kind means that the driver
 164          * was loaded with the force parameter and a given kind of chip is
 165          * requested, so both the detection and the identification steps
 166          * are skipped.
 167          */
 168         if (kind < 0) { /* detection */
 169                 if (((w83l785ts_read_value(new_client,
 170                       W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)
 171                  || ((w83l785ts_read_value(new_client,
 172                       W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {
 173                         dev_dbg(&adapter->dev,
 174                                 "W83L785TS-S detection failed at 0x%02x.\n",
 175                                 new_client->addr);
 176                         return -ENODEV;
 177                 }
 178         }
 179
 180         if (kind <= 0) { /* identification */
 181                 u16 man_id;
 182                 u8 chip_id;
 183
 184                 man_id = (w83l785ts_read_value(new_client,
 185                          W83L785TS_REG_MAN_ID1, 0) << 8) +
 186                          w83l785ts_read_value(new_client,
 187                          W83L785TS_REG_MAN_ID2, 0);
 188                 chip_id = w83l785ts_read_value(new_client,
 189                           W83L785TS_REG_CHIP_ID, 0);
 190
 191                 if (man_id == 0x5CA3) { /* Winbond */
 192                         if (chip_id == 0x70) { /* W83L785TS-S */
 193                                 kind = w83l785ts;
 194                         }
 195                 }
 196
 197                 if (kind <= 0) { /* identification failed */
 198                         dev_info(&adapter->dev,
 199                                  "Unsupported chip (man_id=0x%04X, "
 200                                  "chip_id=0x%02X).\n", man_id, chip_id);
 201                         return -ENODEV;
 202                 }
 203         }
 204
 205         strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
 206
 207         return 0;
 208 }
 209
 210 static int w83l785ts_probe(struct i2c_client *new_client,
 211                            const struct i2c_device_id *id)
 212 {
 213         struct w83l785ts_data *data;
 214         int err = 0;
 215
 216         data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL);
 217         if (!data) {
 218                 err = -ENOMEM;
 219                 goto exit;
 220         }
 221
 222         i2c_set_clientdata(new_client, data);
 223         data->valid = 0;
 224         mutex_init(&data->update_lock);
 225
 226         /* Default values in case the first read fails (unlikely). */
 227         data->temp[1] = data->temp[0] = 0;
 228
 229         /*
 230          * Initialize the W83L785TS chip
 231          * Nothing yet, assume it is already started.
 232          */
 233
 234         err = device_create_file(&new_client->dev,
 235                                  &sensor_dev_attr_temp1_input.dev_attr);
 236         if (err)
 237                 goto exit_remove;
 238
 239         err = device_create_file(&new_client->dev,
 240                                  &sensor_dev_attr_temp1_max.dev_attr);
 241         if (err)
 242                 goto exit_remove;
 243
 244         /* Register sysfs hooks */
 245         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 246         if (IS_ERR(data->hwmon_dev)) {
 247                 err = PTR_ERR(data->hwmon_dev);
 248                 goto exit_remove;
 249         }
 250
 251         return 0;
 252
 253 exit_remove:
 254         device_remove_file(&new_client->dev,
 255                            &sensor_dev_attr_temp1_input.dev_attr);
 256         device_remove_file(&new_client->dev,
 257                            &sensor_dev_attr_temp1_max.dev_attr);
 258         kfree(data);
 259 exit:
 260         return err;
 261 }
 262
 263 static int w83l785ts_remove(struct i2c_client *client)
 264 {
 265         struct w83l785ts_data *data = i2c_get_clientdata(client);
 266
 267         hwmon_device_unregister(data->hwmon_dev);
 268         device_remove_file(&client->dev,
 269                            &sensor_dev_attr_temp1_input.dev_attr);
 270         device_remove_file(&client->dev,
 271                            &sensor_dev_attr_temp1_max.dev_attr);
 272
 273         kfree(data);
 274         return 0;
 275 }
 276
 277 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 278 {
 279         int value, i;
 280         struct device *dev;
 281         const char *prefix;
 282
 283         /* We might be called during detection, at which point the client
 284            isn't yet fully initialized, so we can't use dev_dbg on it */
 285         if (i2c_get_clientdata(client)) {
 286                 dev = &client->dev;
 287                 prefix = "";
 288         } else {
 289                 dev = &client->adapter->dev;
 290                 prefix = "w83l785ts: ";
 291         }
 292
 293         /* Frequent read errors have been reported on Asus boards, so we
 294          * retry on read errors. If it still fails (unlikely), return the
 295          * default value requested by the caller. */
 296         for (i = 1; i <= MAX_RETRIES; i++) {
 297                 value = i2c_smbus_read_byte_data(client, reg);
 298                 if (value >= 0) {
 299                         dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
 300                                 prefix, value, reg);
 301                         return value;
 302                 }
 303                 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
 304                 msleep(i);
 305         }
 306
 307         dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
 308                 reg);
 309         return defval;
 310 }
 311
 312 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 313 {
 314         struct i2c_client *client = to_i2c_client(dev);
 315         struct w83l785ts_data *data = i2c_get_clientdata(client);
 316
 317         mutex_lock(&data->update_lock);
 318
 319         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 320                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 321                 data->temp[0] = w83l785ts_read_value(client,
 322                                 W83L785TS_REG_TEMP, data->temp[0]);
 323                 data->temp[1] = w83l785ts_read_value(client,
 324                                 W83L785TS_REG_TEMP_OVER, data->temp[1]);
 325
 326                 data->last_updated = jiffies;
 327                 data->valid = 1;
 328         }
 329
 330         mutex_unlock(&data->update_lock);
 331
 332         return data;
 333 }
 334
 335 static int __init sensors_w83l785ts_init(void)
 336 {
 337         return i2c_add_driver(&w83l785ts_driver);
 338 }
 339
 340 static void __exit sensors_w83l785ts_exit(void)
 341 {
 342         i2c_del_driver(&w83l785ts_driver);
 343 }
 344
 345 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 346 MODULE_DESCRIPTION("W83L785TS-S driver");
 347 MODULE_LICENSE("GPL");
 348
 349 module_init(sensors_w83l785ts_init);
 350 module_exit(sensors_w83l785ts_exit);