drivers/i2c/chips/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/config.h>
  34 #include <linux/module.h>
  35 #include <linux/delay.h>
  36 #include <linux/init.h>
  37 #include <linux/slab.h>
  38 #include <linux/jiffies.h>
  39 #include <linux/i2c.h>
  40 #include <linux/i2c-sensor.h>
  41
  42 /* How many retries on register read error */
  43 #define MAX_RETRIES     5
  44
  45 /*
  46  * Address to scan
  47  * Address is fully defined internally and cannot be changed.
  48  */
  49
  50 static unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
  51 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  52
  53 /*
  54  * Insmod parameters
  55  */
  56
  57 SENSORS_INSMOD_1(w83l785ts);
  58
  59 /*
  60  * The W83L785TS-S registers
  61  * Manufacturer ID is 0x5CA3 for Winbond.
  62  */
  63
  64 #define W83L785TS_REG_MAN_ID1           0x4D
  65 #define W83L785TS_REG_MAN_ID2           0x4C
  66 #define W83L785TS_REG_CHIP_ID           0x4E
  67 #define W83L785TS_REG_CONFIG            0x40
  68 #define W83L785TS_REG_TYPE              0x52
  69 #define W83L785TS_REG_TEMP              0x27
  70 #define W83L785TS_REG_TEMP_OVER         0x53 /* not sure about this one */
  71
  72 /*
  73  * Conversions
  74  * The W83L785TS-S uses signed 8-bit values.
  75  */
  76
  77 #define TEMP_FROM_REG(val)      ((val & 0x80 ? val-0x100 : val) * 1000)
  78
  79 /*
  80  * Functions declaration
  81  */
  82
  83 static int w83l785ts_attach_adapter(struct i2c_adapter *adapter);
  84 static int w83l785ts_detect(struct i2c_adapter *adapter, int address,
  85         int kind);
  86 static int w83l785ts_detach_client(struct i2c_client *client);
  87 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
  88 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
  89
  90 /*
  91  * Driver data (common to all clients)
  92  */
  93
  94 static struct i2c_driver w83l785ts_driver = {
  95         .owner          = THIS_MODULE,
  96         .name           = "w83l785ts",
  97         .id             = I2C_DRIVERID_W83L785TS,
  98         .flags          = I2C_DF_NOTIFY,
  99         .attach_adapter = w83l785ts_attach_adapter,
 100         .detach_client  = w83l785ts_detach_client,
 101 };
 102
 103 /*
 104  * Client data (each client gets its own)
 105  */
 106
 107 struct w83l785ts_data {
 108         struct i2c_client client;
 109         struct semaphore update_lock;
 110         char valid; /* zero until following fields are valid */
 111         unsigned long last_updated; /* in jiffies */
 112
 113         /* registers values */
 114         u8 temp, temp_over;
 115 };
 116
 117 /*
 118  * Sysfs stuff
 119  */
 120
 121 static ssize_t show_temp(struct device *dev, char *buf)
 122 {
 123         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 124         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp));
 125 }
 126
 127 static ssize_t show_temp_over(struct device *dev, char *buf)
 128 {
 129         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 130         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_over));
 131 }
 132
 133 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
 134 static DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_over, NULL);
 135
 136 /*
 137  * Real code
 138  */
 139
 140 static int w83l785ts_attach_adapter(struct i2c_adapter *adapter)
 141 {
 142         if (!(adapter->class & I2C_CLASS_HWMON))
 143                 return 0;
 144         return i2c_detect(adapter, &addr_data, w83l785ts_detect);
 145 }
 146
 147 /*
 148  * The following function does more than just detection. If detection
 149  * succeeds, it also registers the new chip.
 150  */
 151 static int w83l785ts_detect(struct i2c_adapter *adapter, int address, int kind)
 152 {
 153         struct i2c_client *new_client;
 154         struct w83l785ts_data *data;
 155         int err = 0;
 156
 157
 158         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 159                 goto exit;
 160
 161         if (!(data = kmalloc(sizeof(struct w83l785ts_data), GFP_KERNEL))) {
 162                 err = -ENOMEM;
 163                 goto exit;
 164         }
 165         memset(data, 0, sizeof(struct w83l785ts_data));
 166
 167
 168         /* The common I2C client data is placed right before the
 169          * W83L785TS-specific data. */
 170         new_client = &data->client;
 171         i2c_set_clientdata(new_client, data);
 172         new_client->addr = address;
 173         new_client->adapter = adapter;
 174         new_client->driver = &w83l785ts_driver;
 175         new_client->flags = 0;
 176
 177         /*
 178          * Now we do the remaining detection. A negative kind means that
 179          * the driver was loaded with no force parameter (default), so we
 180          * must both detect and identify the chip (actually there is only
 181          * one possible kind of chip for now, W83L785TS-S). A zero kind means
 182          * that the driver was loaded with the force parameter, the detection
 183          * step shall be skipped. A positive kind means that the driver
 184          * was loaded with the force parameter and a given kind of chip is
 185          * requested, so both the detection and the identification steps
 186          * are skipped.
 187          */
 188         if (kind < 0) { /* detection */
 189                 if (((w83l785ts_read_value(new_client,
 190                       W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)
 191                  || ((w83l785ts_read_value(new_client,
 192                       W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {
 193                         dev_dbg(&adapter->dev,
 194                                 "W83L785TS-S detection failed at 0x%02x.\n",
 195                                 address);
 196                         goto exit_free;
 197                 }
 198         }
 199
 200         if (kind <= 0) { /* identification */
 201                 u16 man_id;
 202                 u8 chip_id;
 203
 204                 man_id = (w83l785ts_read_value(new_client,
 205                          W83L785TS_REG_MAN_ID1, 0) << 8) +
 206                          w83l785ts_read_value(new_client,
 207                          W83L785TS_REG_MAN_ID2, 0);
 208                 chip_id = w83l785ts_read_value(new_client,
 209                           W83L785TS_REG_CHIP_ID, 0);
 210
 211                 if (man_id == 0x5CA3) { /* Winbond */
 212                         if (chip_id == 0x70) { /* W83L785TS-S */
 213                                 kind = w83l785ts;
 214                         }
 215                 }
 216
 217                 if (kind <= 0) { /* identification failed */
 218                         dev_info(&adapter->dev,
 219                                  "Unsupported chip (man_id=0x%04X, "
 220                                  "chip_id=0x%02X).\n", man_id, chip_id);
 221                         goto exit_free;
 222                 }
 223         }
 224
 225         /* We can fill in the remaining client fields. */
 226         strlcpy(new_client->name, "w83l785ts", I2C_NAME_SIZE);
 227         data->valid = 0;
 228         init_MUTEX(&data->update_lock);
 229
 230         /* Default values in case the first read fails (unlikely). */
 231         data->temp_over = data->temp = 0;
 232
 233         /* Tell the I2C layer a new client has arrived. */
 234         if ((err = i2c_attach_client(new_client)))
 235                 goto exit_free;
 236
 237         /*
 238          * Initialize the W83L785TS chip
 239          * Nothing yet, assume it is already started.
 240          */
 241
 242         /* Register sysfs hooks */
 243         device_create_file(&new_client->dev, &dev_attr_temp1_input);
 244         device_create_file(&new_client->dev, &dev_attr_temp1_max);
 245
 246         return 0;
 247
 248 exit_free:
 249         kfree(data);
 250 exit:
 251         return err;
 252 }
 253
 254 static int w83l785ts_detach_client(struct i2c_client *client)
 255 {
 256         int err;
 257
 258         if ((err = i2c_detach_client(client))) {
 259                 dev_err(&client->dev, "Client deregistration failed, "
 260                         "client not detached.\n");
 261                 return err;
 262         }
 263
 264         kfree(i2c_get_clientdata(client));
 265         return 0;
 266 }
 267
 268 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 269 {
 270         int value, i;
 271
 272         /* Frequent read errors have been reported on Asus boards, so we
 273          * retry on read errors. If it still fails (unlikely), return the
 274          * default value requested by the caller. */
 275         for (i = 1; i <= MAX_RETRIES; i++) {
 276                 value = i2c_smbus_read_byte_data(client, reg);
 277                 if (value >= 0) {
 278                         dev_dbg(&client->dev, "Read 0x%02x from register "
 279                                 "0x%02x.\n", value, reg);
 280                         return value;
 281                 }
 282                 dev_dbg(&client->dev, "Read failed, will retry in %d.\n", i);
 283                 msleep(i);
 284         }
 285
 286         dev_err(&client->dev, "Couldn't read value from register 0x%02x. "
 287                 "Please report.\n", reg);
 288         return defval;
 289 }
 290
 291 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 292 {
 293         struct i2c_client *client = to_i2c_client(dev);
 294         struct w83l785ts_data *data = i2c_get_clientdata(client);
 295
 296         down(&data->update_lock);
 297
 298         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 299                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 300                 data->temp = w83l785ts_read_value(client,
 301                              W83L785TS_REG_TEMP, data->temp);
 302                 data->temp_over = w83l785ts_read_value(client,
 303                                   W83L785TS_REG_TEMP_OVER, data->temp_over);
 304
 305                 data->last_updated = jiffies;
 306                 data->valid = 1;
 307         }
 308
 309         up(&data->update_lock);
 310
 311         return data;
 312 }
 313
 314 static int __init sensors_w83l785ts_init(void)
 315 {
 316         return i2c_add_driver(&w83l785ts_driver);
 317 }
 318
 319 static void __exit sensors_w83l785ts_exit(void)
 320 {
 321         i2c_del_driver(&w83l785ts_driver);
 322 }
 323
 324 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 325 MODULE_DESCRIPTION("W83L785TS-S driver");
 326 MODULE_LICENSE("GPL");
 327
 328 module_init(sensors_w83l785ts_init);
 329 module_exit(sensors_w83l785ts_exit);