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, 1: critical limit */
 120 };
 121
 122 /*
 123  * Sysfs stuff
 124  */
 125
 126 static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
 127         char *buf)
 128 {
 129         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 130         struct w83l785ts_data *data = w83l785ts_update_device(dev);
 131         return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
 132 }
 133
 134 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 135 static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
 136
 137 /*
 138  * Real code
 139  */
 140
 141 /* Return 0 if detection is successful, -ENODEV otherwise */
 142 static int w83l785ts_detect(struct i2c_client *client,
 143                             struct i2c_board_info *info)
 144 {
 145         struct i2c_adapter *adapter = client->adapter;
 146         u16 man_id;
 147         u8 chip_id;
 148
 149         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 150                 return -ENODEV;
 151
 152         /* detection */
 153         if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
 154          || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
 155                 dev_dbg(&adapter->dev,
 156                         "W83L785TS-S detection failed at 0x%02x\n",
 157                         client->addr);
 158                 return -ENODEV;
 159         }
 160
 161         /* Identification */
 162         man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
 163                + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
 164         chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
 165
 166         if (man_id != 0x5CA3            /* Winbond */
 167          || chip_id != 0x70) {          /* W83L785TS-S */
 168                 dev_dbg(&adapter->dev,
 169                         "Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
 170                         man_id, chip_id);
 171                 return -ENODEV;
 172         }
 173
 174         strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
 175
 176         return 0;
 177 }
 178
 179 static int w83l785ts_probe(struct i2c_client *client,
 180                            const struct i2c_device_id *id)
 181 {
 182         struct w83l785ts_data *data;
 183         struct device *dev = &client->dev;
 184         int err;
 185
 186         data = devm_kzalloc(dev, sizeof(struct w83l785ts_data), GFP_KERNEL);
 187         if (!data)
 188                 return -ENOMEM;
 189
 190         i2c_set_clientdata(client, data);
 191         data->valid = 0;
 192         mutex_init(&data->update_lock);
 193
 194         /* Default values in case the first read fails (unlikely). */
 195         data->temp[1] = data->temp[0] = 0;
 196
 197         /*
 198          * Initialize the W83L785TS chip
 199          * Nothing yet, assume it is already started.
 200          */
 201
 202         err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
 203         if (err)
 204                 return err;
 205
 206         err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
 207         if (err)
 208                 goto exit_remove;
 209
 210         /* Register sysfs hooks */
 211         data->hwmon_dev = hwmon_device_register(dev);
 212         if (IS_ERR(data->hwmon_dev)) {
 213                 err = PTR_ERR(data->hwmon_dev);
 214                 goto exit_remove;
 215         }
 216
 217         return 0;
 218
 219 exit_remove:
 220         device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
 221         device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
 222         return err;
 223 }
 224
 225 static int w83l785ts_remove(struct i2c_client *client)
 226 {
 227         struct w83l785ts_data *data = i2c_get_clientdata(client);
 228
 229         hwmon_device_unregister(data->hwmon_dev);
 230         device_remove_file(&client->dev,
 231                            &sensor_dev_attr_temp1_input.dev_attr);
 232         device_remove_file(&client->dev,
 233                            &sensor_dev_attr_temp1_max.dev_attr);
 234
 235         return 0;
 236 }
 237
 238 static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
 239 {
 240         int value, i;
 241         struct device *dev;
 242         const char *prefix;
 243
 244         /*
 245          * We might be called during detection, at which point the client
 246          * isn't yet fully initialized, so we can't use dev_dbg on it
 247          */
 248         if (i2c_get_clientdata(client)) {
 249                 dev = &client->dev;
 250                 prefix = "";
 251         } else {
 252                 dev = &client->adapter->dev;
 253                 prefix = "w83l785ts: ";
 254         }
 255
 256         /*
 257          * Frequent read errors have been reported on Asus boards, so we
 258          * retry on read errors. If it still fails (unlikely), return the
 259          * default value requested by the caller.
 260          */
 261         for (i = 1; i <= MAX_RETRIES; i++) {
 262                 value = i2c_smbus_read_byte_data(client, reg);
 263                 if (value >= 0) {
 264                         dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
 265                                 prefix, value, reg);
 266                         return value;
 267                 }
 268                 dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
 269                 msleep(i);
 270         }
 271
 272         dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
 273                 reg);
 274         return defval;
 275 }
 276
 277 static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
 278 {
 279         struct i2c_client *client = to_i2c_client(dev);
 280         struct w83l785ts_data *data = i2c_get_clientdata(client);
 281
 282         mutex_lock(&data->update_lock);
 283
 284         if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
 285                 dev_dbg(&client->dev, "Updating w83l785ts data.\n");
 286                 data->temp[0] = w83l785ts_read_value(client,
 287                                 W83L785TS_REG_TEMP, data->temp[0]);
 288                 data->temp[1] = w83l785ts_read_value(client,
 289                                 W83L785TS_REG_TEMP_OVER, data->temp[1]);
 290
 291                 data->last_updated = jiffies;
 292                 data->valid = 1;
 293         }
 294
 295         mutex_unlock(&data->update_lock);
 296
 297         return data;
 298 }
 299
 300 module_i2c_driver(w83l785ts_driver);
 301
 302 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 303 MODULE_DESCRIPTION("W83L785TS-S driver");
 304 MODULE_LICENSE("GPL");