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/i2c.h>
  39 #include <linux/i2c-sensor.h>
  40
  41 /* How many retries on register read error */
  42 #define MAX_RETRIES     5
  43
  44 /*
  45  * Address to scan
  46  * Address is fully defined internally and cannot be changed.
  47  */
  48
  49 static unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
  50 static unsigned short normal_i2c_range[] = { I2C_CLIENT_END };
  51 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
  52 static unsigned int normal_isa_range[] = { I2C_CLIENT_ISA_END };
  53
  54 /*
  55  * Insmod parameters
  56  */
  57
  58 SENSORS_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 & 0x80 ? val-0x100 : 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         .owner          = THIS_MODULE,
  97         .name           = "w83l785ts",
  98         .id             = I2C_DRIVERID_W83L785TS,
  99         .flags          = I2C_DF_NOTIFY,
 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 semaphore update_lock;
 111         char valid; /* zero until following fields are valid */
 112         unsigned long last_updated; /* in jiffies */
 113
 114         /* registers values */
 115         u8 temp, temp_over;
 116 };
 117
 118 /*
 119  * Internal variables
 120  */
 121
 122 static int w83l785ts_id = 0;
 123
 124 /*
 125  * Sysfs stuff
 126  */
 127
 128 static ssize_t show_temp(struct device *dev, char *buf)
 129 {
 130         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 131         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp));
 132 }
 133
 134 static ssize_t show_temp_over(struct device *dev, char *buf)
 135 {
 136         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 137         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_over));
 138 }
 139
 140 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
 141 static DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_over, NULL);
 142
 143 /*
 144  * Real code
 145  */
 146
 147 static int w83l785ts_attach_adapter(struct i2c_adapter *adapter)
 148 {
 149         if (!(adapter->class & I2C_CLASS_HWMON))
 150                 return 0;
 151         return i2c_detect(adapter, &addr_data, w83l785ts_detect);
 152 }
 153
 154 /*
 155  * The following function does more than just detection. If detection
 156  * succeeds, it also registers the new chip.
 157  */
 158 static int w83l785ts_detect(struct i2c_adapter *adapter, int address, int kind)
 159 {
 160         struct i2c_client *new_client;
 161         struct w83l785ts_data *data;
 162         int err = 0;
 163
 164
 165         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 166                 goto exit;
 167
 168         if (!(data = kmalloc(sizeof(struct w83l785ts_data), GFP_KERNEL))) {
 169                 err = -ENOMEM;
 170                 goto exit;
 171         }
 172         memset(data, 0, sizeof(struct w83l785ts_data));
 173
 174
 175         /* The common I2C client data is placed right before the
 176          * W83L785TS-specific data. */
 177         new_client = &data->client;
 178         i2c_set_clientdata(new_client, data);
 179         new_client->addr = address;
 180         new_client->adapter = adapter;
 181         new_client->driver = &w83l785ts_driver;
 182         new_client->flags = 0;
 183
 184         /*
 185          * Now we do the remaining detection. A negative kind means that
 186          * the driver was loaded with no force parameter (default), so we
 187          * must both detect and identify the chip (actually there is only
 188          * one possible kind of chip for now, W83L785TS-S). A zero kind means
 189          * that the driver was loaded with the force parameter, the detection
 190          * step shall be skipped. A positive kind means that the driver
 191          * was loaded with the force parameter and a given kind of chip is
 192          * requested, so both the detection and the identification steps
 193          * are skipped.
 194          */
 195         if (kind < 0) { /* detection */
 196                 if (((w83l785ts_read_value(new_client,
 197                       W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)
 198                  || ((w83l785ts_read_value(new_client,
 199                       W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {
 200                         dev_dbg(&adapter->dev,
 201                                 "W83L785TS-S detection failed at 0x%02x.\n",
 202                                 address);
 203                         goto exit_free;
 204                 }
 205         }
 206
 207         if (kind <= 0) { /* identification */
 208                 u16 man_id;
 209                 u8 chip_id;
 210
 211                 man_id = (w83l785ts_read_value(new_client,
 212                          W83L785TS_REG_MAN_ID1, 0) << 8) +
 213                          w83l785ts_read_value(new_client,
 214                          W83L785TS_REG_MAN_ID2, 0);
 215                 chip_id = w83l785ts_read_value(new_client,
 216                           W83L785TS_REG_CHIP_ID, 0);
 217
 218                 if (man_id == 0x5CA3) { /* Winbond */
 219                         if (chip_id == 0x70) { /* W83L785TS-S */
 220                                 kind = w83l785ts;
 221                         }
 222                 }
 223
 224                 if (kind <= 0) { /* identification failed */
 225                         dev_info(&adapter->dev,
 226                                  "Unsupported chip (man_id=0x%04X, "
 227                                  "chip_id=0x%02X).\n", man_id, chip_id);
 228                         goto exit_free;
 229                 }
 230         }
 231
 232         /* We can fill in the remaining client fields. */
 233         strlcpy(new_client->name, "w83l785ts", I2C_NAME_SIZE);
 234         new_client->id = w83l785ts_id++;
 235         data->valid = 0;
 236         init_MUTEX(&data->update_lock);
 237
 238         /* Default values in case the first read fails (unlikely). */
 239         data->temp_over = data->temp = 0;
 240
 241         /* Tell the I2C layer a new client has arrived. */
 242         if ((err = i2c_attach_client(new_client)))
 243                 goto exit_free;
 244
 245         /*
 246          * Initialize the W83L785TS chip
 247          * Nothing yet, assume it is already started.
 248          */
 249
 250         /* Register sysfs hooks */
 251         device_create_file(&new_client->dev, &dev_attr_temp1_input);
 252         device_create_file(&new_client->dev, &dev_attr_temp1_max);
 253
 254         return 0;
 255
 256 exit_free:
 257         kfree(data);
 258 exit:
 259         return err;
 260 }
 261
 262 static int w83l785ts_detach_client(struct i2c_client *client)
 263 {
 264         int err;
 265
 266         if ((err = i2c_detach_client(client))) {
 267                 dev_err(&client->dev, "Client deregistration failed, "
 268                         "client not detached.\n");
 269                 return err;
 270         }
 271
 272         kfree(i2c_get_clientdata(client));
 273         return 0;
 274 }
 275
 276 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 277 {
 278         int value, i;
 279
 280         /* Frequent read errors have been reported on Asus boards, so we
 281          * retry on read errors. If it still fails (unlikely), return the
 282          * default value requested by the caller. */
 283         for (i = 1; i <= MAX_RETRIES; i++) {
 284                 value = i2c_smbus_read_byte_data(client, reg);
 285                 if (value >= 0)
 286                         return value;
 287                 dev_dbg(&client->dev, "Read failed, will retry in %d.\n", i);
 288                 msleep(i);
 289         }
 290
 291         dev_err(&client->dev, "Couldn't read value from register. "
 292                 "Please report.\n");
 293         return defval;
 294 }
 295
 296 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 297 {
 298         struct i2c_client *client = to_i2c_client(dev);
 299         struct w83l785ts_data *data = i2c_get_clientdata(client);
 300
 301         down(&data->update_lock);
 302
 303         if (!data->valid
 304          || (jiffies - data->last_updated > HZ * 2)
 305          || (jiffies < data->last_updated)) {
 306                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 307                 data->temp = w83l785ts_read_value(client,
 308                              W83L785TS_REG_TEMP, data->temp);
 309                 data->temp_over = w83l785ts_read_value(client,
 310                                   W83L785TS_REG_TEMP_OVER, data->temp_over);
 311
 312                 data->last_updated = jiffies;
 313                 data->valid = 1;
 314         }
 315
 316         up(&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);