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 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_attach_adapter(struct i2c_adapter *adapter);
  85 static int w83l785ts_detect(struct i2c_adapter *adapter, int address,
  86         int kind);
  87 static int w83l785ts_detach_client(struct i2c_client *client);
  88 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  89 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  90
  91 /*
  92  * Driver data (common to all clients)
  93  */
  94
  95 static struct i2c_driver w83l785ts_driver = {
  96         .driver = {
  97                 .name   = "w83l785ts",
  98         },
  99         .id             = I2C_DRIVERID_W83L785TS,
 100         .attach_adapter = w83l785ts_attach_adapter,
 101         .detach_client  = w83l785ts_detach_client,
 102 };
 103
 104 /*
 105  * Client data (each client gets its own)
 106  */
 107
 108 struct w83l785ts_data {
 109         struct i2c_client client;
 110         struct class_device *class_dev;
 111         struct mutex update_lock;
 112         char valid; /* zero until following fields are valid */
 113         unsigned long last_updated; /* in jiffies */
 114
 115         /* registers values */
 116         s8 temp[2]; /* 0: input
 117                        1: critical limit */
 118 };
 119
 120 /*
 121  * Sysfs stuff
 122  */
 123
 124 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 125         char *buf)
 126 {
 127         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 128         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 129         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
 130 }
 131
 132 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 133 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
 134
 135 /*
 136  * Real code
 137  */
 138
 139 static int w83l785ts_attach_adapter(struct i2c_adapter *adapter)
 140 {
 141         if (!(adapter->class & I2C_CLASS_HWMON))
 142                 return 0;
 143         return i2c_probe(adapter, &addr_data, w83l785ts_detect);
 144 }
 145
 146 /*
 147  * The following function does more than just detection. If detection
 148  * succeeds, it also registers the new chip.
 149  */
 150 static int w83l785ts_detect(struct i2c_adapter *adapter, int address, int kind)
 151 {
 152         struct i2c_client *new_client;
 153         struct w83l785ts_data *data;
 154         int err = 0;
 155
 156
 157         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 158                 goto exit;
 159
 160         if (!(data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL))) {
 161                 err = -ENOMEM;
 162                 goto exit;
 163         }
 164
 165         /* The common I2C client data is placed right before the
 166          * W83L785TS-specific data. */
 167         new_client = &data->client;
 168         i2c_set_clientdata(new_client, data);
 169         new_client->addr = address;
 170         new_client->adapter = adapter;
 171         new_client->driver = &w83l785ts_driver;
 172         new_client->flags = 0;
 173
 174         /*
 175          * Now we do the remaining detection. A negative kind means that
 176          * the driver was loaded with no force parameter (default), so we
 177          * must both detect and identify the chip (actually there is only
 178          * one possible kind of chip for now, W83L785TS-S). A zero kind means
 179          * that the driver was loaded with the force parameter, the detection
 180          * step shall be skipped. A positive kind means that the driver
 181          * was loaded with the force parameter and a given kind of chip is
 182          * requested, so both the detection and the identification steps
 183          * are skipped.
 184          */
 185         if (kind < 0) { /* detection */
 186                 if (((w83l785ts_read_value(new_client,
 187                       W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)
 188                  || ((w83l785ts_read_value(new_client,
 189                       W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {
 190                         dev_dbg(&adapter->dev,
 191                                 "W83L785TS-S detection failed at 0x%02x.\n",
 192                                 address);
 193                         goto exit_free;
 194                 }
 195         }
 196
 197         if (kind <= 0) { /* identification */
 198                 u16 man_id;
 199                 u8 chip_id;
 200
 201                 man_id = (w83l785ts_read_value(new_client,
 202                          W83L785TS_REG_MAN_ID1, 0) << 8) +
 203                          w83l785ts_read_value(new_client,
 204                          W83L785TS_REG_MAN_ID2, 0);
 205                 chip_id = w83l785ts_read_value(new_client,
 206                           W83L785TS_REG_CHIP_ID, 0);
 207
 208                 if (man_id == 0x5CA3) { /* Winbond */
 209                         if (chip_id == 0x70) { /* W83L785TS-S */
 210                                 kind = w83l785ts;
 211                         }
 212                 }
 213
 214                 if (kind <= 0) { /* identification failed */
 215                         dev_info(&adapter->dev,
 216                                  "Unsupported chip (man_id=0x%04X, "
 217                                  "chip_id=0x%02X).\n", man_id, chip_id);
 218                         goto exit_free;
 219                 }
 220         }
 221
 222         /* We can fill in the remaining client fields. */
 223         strlcpy(new_client->name, "w83l785ts", I2C_NAME_SIZE);
 224         data->valid = 0;
 225         mutex_init(&data->update_lock);
 226
 227         /* Default values in case the first read fails (unlikely). */
 228         data->temp[1] = data->temp[0] = 0;
 229
 230         /* Tell the I2C layer a new client has arrived. */
 231         if ((err = i2c_attach_client(new_client)))
 232                 goto exit_free;
 233
 234         /*
 235          * Initialize the W83L785TS chip
 236          * Nothing yet, assume it is already started.
 237          */
 238
 239         /* Register sysfs hooks */
 240         data->class_dev = hwmon_device_register(&new_client->dev);
 241         if (IS_ERR(data->class_dev)) {
 242                 err = PTR_ERR(data->class_dev);
 243                 goto exit_detach;
 244         }
 245
 246         device_create_file(&new_client->dev,
 247                            &sensor_dev_attr_temp1_input.dev_attr);
 248         device_create_file(&new_client->dev,
 249                            &sensor_dev_attr_temp1_max.dev_attr);
 250
 251         return 0;
 252
 253 exit_detach:
 254         i2c_detach_client(new_client);
 255 exit_free:
 256         kfree(data);
 257 exit:
 258         return err;
 259 }
 260
 261 static int w83l785ts_detach_client(struct i2c_client *client)
 262 {
 263         struct w83l785ts_data *data = i2c_get_clientdata(client);
 264         int err;
 265
 266         hwmon_device_unregister(data->class_dev);
 267
 268         if ((err = i2c_detach_client(client)))
 269                 return err;
 270
 271         kfree(data);
 272         return 0;
 273 }
 274
 275 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 276 {
 277         int value, i;
 278
 279         /* Frequent read errors have been reported on Asus boards, so we
 280          * retry on read errors. If it still fails (unlikely), return the
 281          * default value requested by the caller. */
 282         for (i = 1; i <= MAX_RETRIES; i++) {
 283                 value = i2c_smbus_read_byte_data(client, reg);
 284                 if (value >= 0) {
 285                         dev_dbg(&client->dev, "Read 0x%02x from register "
 286                                 "0x%02x.\n", value, reg);
 287                         return value;
 288                 }
 289                 dev_dbg(&client->dev, "Read failed, will retry in %d.\n", i);
 290                 msleep(i);
 291         }
 292
 293         dev_err(&client->dev, "Couldn't read value from register 0x%02x. "
 294                 "Please report.\n", reg);
 295         return defval;
 296 }
 297
 298 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 299 {
 300         struct i2c_client *client = to_i2c_client(dev);
 301         struct w83l785ts_data *data = i2c_get_clientdata(client);
 302
 303         mutex_lock(&data->update_lock);
 304
 305         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 306                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 307                 data->temp[0] = w83l785ts_read_value(client,
 308                                 W83L785TS_REG_TEMP, data->temp[0]);
 309                 data->temp[1] = w83l785ts_read_value(client,
 310                                 W83L785TS_REG_TEMP_OVER, data->temp[1]);
 311
 312                 data->last_updated = jiffies;
 313                 data->valid = 1;
 314         }
 315
 316         mutex_unlock(&data->update_lock);
 317
 318         return data;
 319 }
 320
 321 static int __init sensors_w83l785ts_init(void)
 322 {
 323         return i2c_add_driver(&w83l785ts_driver);
 324 }
 325
 326 static void __exit sensors_w83l785ts_exit(void)
 327 {
 328         i2c_del_driver(&w83l785ts_driver);
 329 }
 330
 331 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 332 MODULE_DESCRIPTION("W83L785TS-S driver");
 333 MODULE_LICENSE("GPL");
 334
 335 module_init(sensors_w83l785ts_init);
 336 module_exit(sensors_w83l785ts_exit);