drivers/hwmon/tmp421.c

   1 /* tmp421.c
   2  *
   3  * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
   4  * Preliminary support by:
   5  * Melvin Rook, Raymond Ng
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 /*
  23  * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
  24  * Supported models: TMP421, TMP422, TMP423
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/slab.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/i2c.h>
  32 #include <linux/hwmon.h>
  33 #include <linux/hwmon-sysfs.h>
  34 #include <linux/err.h>
  35 #include <linux/mutex.h>
  36 #include <linux/sysfs.h>
  37
  38 /* Addresses to scan */
  39 static unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  40                                        I2C_CLIENT_END };
  41
  42 enum chips { tmp421, tmp422, tmp423 };
  43
  44 /* The TMP421 registers */
  45 #define TMP421_CONFIG_REG_1                     0x09
  46 #define TMP421_CONVERSION_RATE_REG              0x0B
  47 #define TMP421_MANUFACTURER_ID_REG              0xFE
  48 #define TMP421_DEVICE_ID_REG                    0xFF
  49
  50 static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  51 static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  52
  53 /* Flags */
  54 #define TMP421_CONFIG_SHUTDOWN                  0x40
  55 #define TMP421_CONFIG_RANGE                     0x04
  56
  57 /* Manufacturer / Device ID's */
  58 #define TMP421_MANUFACTURER_ID                  0x55
  59 #define TMP421_DEVICE_ID                        0x21
  60 #define TMP422_DEVICE_ID                        0x22
  61 #define TMP423_DEVICE_ID                        0x23
  62
  63 static const struct i2c_device_id tmp421_id[] = {
  64         { "tmp421", tmp421 },
  65         { "tmp422", tmp422 },
  66         { "tmp423", tmp423 },
  67         { }
  68 };
  69 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  70
  71 struct tmp421_data {
  72         struct device *hwmon_dev;
  73         struct mutex update_lock;
  74         char valid;
  75         unsigned long last_updated;
  76         int kind;
  77         u8 config;
  78         s16 temp[4];
  79 };
  80
  81 static int temp_from_s16(s16 reg)
  82 {
  83         int temp = reg;
  84
  85         return (temp * 1000 + 128) / 256;
  86 }
  87
  88 static int temp_from_u16(u16 reg)
  89 {
  90         int temp = reg;
  91
  92         /* Add offset for extended temperature range. */
  93         temp -= 64 * 256;
  94
  95         return (temp * 1000 + 128) / 256;
  96 }
  97
  98 static struct tmp421_data *tmp421_update_device(struct device *dev)
  99 {
 100         struct i2c_client *client = to_i2c_client(dev);
 101         struct tmp421_data *data = i2c_get_clientdata(client);
 102         int i;
 103
 104         mutex_lock(&data->update_lock);
 105
 106         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 107                 data->config = i2c_smbus_read_byte_data(client,
 108                         TMP421_CONFIG_REG_1);
 109
 110                 for (i = 0; i <= data->kind; i++) {
 111                         data->temp[i] = i2c_smbus_read_byte_data(client,
 112                                 TMP421_TEMP_MSB[i]) << 8;
 113                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 114                                 TMP421_TEMP_LSB[i]);
 115                 }
 116                 data->last_updated = jiffies;
 117                 data->valid = 1;
 118         }
 119
 120         mutex_unlock(&data->update_lock);
 121
 122         return data;
 123 }
 124
 125 static ssize_t show_temp_value(struct device *dev,
 126                                struct device_attribute *devattr, char *buf)
 127 {
 128         int index = to_sensor_dev_attr(devattr)->index;
 129         struct tmp421_data *data = tmp421_update_device(dev);
 130         int temp;
 131
 132         mutex_lock(&data->update_lock);
 133         if (data->config & TMP421_CONFIG_RANGE)
 134                 temp = temp_from_u16(data->temp[index]);
 135         else
 136                 temp = temp_from_s16(data->temp[index]);
 137         mutex_unlock(&data->update_lock);
 138
 139         return sprintf(buf, "%d\n", temp);
 140 }
 141
 142 static ssize_t show_fault(struct device *dev,
 143                           struct device_attribute *devattr, char *buf)
 144 {
 145         int index = to_sensor_dev_attr(devattr)->index;
 146         struct tmp421_data *data = tmp421_update_device(dev);
 147
 148         /*
 149          * The OPEN bit signals a fault. This is bit 0 of the temperature
 150          * register (low byte).
 151          */
 152         if (data->temp[index] & 0x01)
 153                 return sprintf(buf, "1\n");
 154         else
 155                 return sprintf(buf, "0\n");
 156 }
 157
 158 static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
 159                                 int n)
 160 {
 161         struct device *dev = container_of(kobj, struct device, kobj);
 162         struct tmp421_data *data = dev_get_drvdata(dev);
 163         struct device_attribute *devattr;
 164         unsigned int index;
 165
 166         devattr = container_of(a, struct device_attribute, attr);
 167         index = to_sensor_dev_attr(devattr)->index;
 168
 169         if (data->kind > index)
 170                 return a->mode;
 171
 172         return 0;
 173 }
 174
 175 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
 176 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
 177 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
 178 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
 179 static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
 180 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
 181 static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
 182
 183 static struct attribute *tmp421_attr[] = {
 184         &sensor_dev_attr_temp1_input.dev_attr.attr,
 185         &sensor_dev_attr_temp2_input.dev_attr.attr,
 186         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 187         &sensor_dev_attr_temp3_input.dev_attr.attr,
 188         &sensor_dev_attr_temp3_fault.dev_attr.attr,
 189         &sensor_dev_attr_temp4_input.dev_attr.attr,
 190         &sensor_dev_attr_temp4_fault.dev_attr.attr,
 191         NULL
 192 };
 193
 194 static const struct attribute_group tmp421_group = {
 195         .attrs = tmp421_attr,
 196         .is_visible = tmp421_is_visible,
 197 };
 198
 199 static int tmp421_init_client(struct i2c_client *client)
 200 {
 201         int config, config_orig;
 202
 203         /* Set the conversion rate to 2 Hz */
 204         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 205
 206         /* Start conversions (disable shutdown if necessary) */
 207         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 208         if (config < 0) {
 209                 dev_err(&client->dev, "Could not read configuration"
 210                          " register (%d)\n", config);
 211                 return -ENODEV;
 212         }
 213
 214         config_orig = config;
 215         config &= ~TMP421_CONFIG_SHUTDOWN;
 216
 217         if (config != config_orig) {
 218                 dev_info(&client->dev, "Enable monitoring chip\n");
 219                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 220         }
 221
 222         return 0;
 223 }
 224
 225 static int tmp421_detect(struct i2c_client *client,
 226                          struct i2c_board_info *info)
 227 {
 228         enum chips kind;
 229         struct i2c_adapter *adapter = client->adapter;
 230         const char *names[] = { "TMP421", "TMP422", "TMP423" };
 231         u8 reg;
 232
 233         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 234                 return -ENODEV;
 235
 236         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 237         if (reg != TMP421_MANUFACTURER_ID)
 238                 return -ENODEV;
 239
 240         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 241         switch (reg) {
 242         case TMP421_DEVICE_ID:
 243                 kind = tmp421;
 244                 break;
 245         case TMP422_DEVICE_ID:
 246                 kind = tmp422;
 247                 break;
 248         case TMP423_DEVICE_ID:
 249                 kind = tmp423;
 250                 break;
 251         default:
 252                 return -ENODEV;
 253         }
 254
 255         strlcpy(info->type, tmp421_id[kind - 1].name, I2C_NAME_SIZE);
 256         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 257                  names[kind - 1], client->addr);
 258
 259         return 0;
 260 }
 261
 262 static int tmp421_probe(struct i2c_client *client,
 263                         const struct i2c_device_id *id)
 264 {
 265         struct tmp421_data *data;
 266         int err;
 267
 268         data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
 269         if (!data)
 270                 return -ENOMEM;
 271
 272         i2c_set_clientdata(client, data);
 273         mutex_init(&data->update_lock);
 274         data->kind = id->driver_data;
 275
 276         err = tmp421_init_client(client);
 277         if (err)
 278                 goto exit_free;
 279
 280         err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
 281         if (err)
 282                 goto exit_free;
 283
 284         data->hwmon_dev = hwmon_device_register(&client->dev);
 285         if (IS_ERR(data->hwmon_dev)) {
 286                 err = PTR_ERR(data->hwmon_dev);
 287                 data->hwmon_dev = NULL;
 288                 goto exit_remove;
 289         }
 290         return 0;
 291
 292 exit_remove:
 293         sysfs_remove_group(&client->dev.kobj, &tmp421_group);
 294
 295 exit_free:
 296         i2c_set_clientdata(client, NULL);
 297         kfree(data);
 298
 299         return err;
 300 }
 301
 302 static int tmp421_remove(struct i2c_client *client)
 303 {
 304         struct tmp421_data *data = i2c_get_clientdata(client);
 305
 306         hwmon_device_unregister(data->hwmon_dev);
 307         sysfs_remove_group(&client->dev.kobj, &tmp421_group);
 308
 309         i2c_set_clientdata(client, NULL);
 310         kfree(data);
 311
 312         return 0;
 313 }
 314
 315 static struct i2c_driver tmp421_driver = {
 316         .class = I2C_CLASS_HWMON,
 317         .driver = {
 318                 .name   = "tmp421",
 319         },
 320         .probe = tmp421_probe,
 321         .remove = tmp421_remove,
 322         .id_table = tmp421_id,
 323         .detect = tmp421_detect,
 324         .address_list = normal_i2c,
 325 };
 326
 327 static int __init tmp421_init(void)
 328 {
 329         return i2c_add_driver(&tmp421_driver);
 330 }
 331
 332 static void __exit tmp421_exit(void)
 333 {
 334         i2c_del_driver(&tmp421_driver);
 335 }
 336
 337 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 338 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
 339                    " driver");
 340 MODULE_LICENSE("GPL");
 341
 342 module_init(tmp421_init);
 343 module_exit(tmp421_exit);