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 /* Insmod parameters */
  43 I2C_CLIENT_INSMOD_3(tmp421, tmp422, tmp423);
  44
  45 /* The TMP421 registers */
  46 #define TMP421_CONFIG_REG_1                     0x09
  47 #define TMP421_CONVERSION_RATE_REG              0x0B
  48 #define TMP421_MANUFACTURER_ID_REG              0xFE
  49 #define TMP421_DEVICE_ID_REG                    0xFF
  50
  51 static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  52 static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  53
  54 /* Flags */
  55 #define TMP421_CONFIG_SHUTDOWN                  0x40
  56 #define TMP421_CONFIG_RANGE                     0x04
  57
  58 /* Manufacturer / Device ID's */
  59 #define TMP421_MANUFACTURER_ID                  0x55
  60 #define TMP421_DEVICE_ID                        0x21
  61 #define TMP422_DEVICE_ID                        0x22
  62 #define TMP423_DEVICE_ID                        0x23
  63
  64 static const struct i2c_device_id tmp421_id[] = {
  65         { "tmp421", tmp421 },
  66         { "tmp422", tmp422 },
  67         { "tmp423", tmp423 },
  68         { }
  69 };
  70 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  71
  72 struct tmp421_data {
  73         struct device *hwmon_dev;
  74         struct mutex update_lock;
  75         char valid;
  76         unsigned long last_updated;
  77         int kind;
  78         u8 config;
  79         s16 temp[4];
  80 };
  81
  82 static int temp_from_s16(s16 reg)
  83 {
  84         int temp = reg;
  85
  86         return (temp * 1000 + 128) / 256;
  87 }
  88
  89 static int temp_from_u16(u16 reg)
  90 {
  91         int temp = reg;
  92
  93         /* Add offset for extended temperature range. */
  94         temp -= 64 * 256;
  95
  96         return (temp * 1000 + 128) / 256;
  97 }
  98
  99 static struct tmp421_data *tmp421_update_device(struct device *dev)
 100 {
 101         struct i2c_client *client = to_i2c_client(dev);
 102         struct tmp421_data *data = i2c_get_clientdata(client);
 103         int i;
 104
 105         mutex_lock(&data->update_lock);
 106
 107         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 108                 data->config = i2c_smbus_read_byte_data(client,
 109                         TMP421_CONFIG_REG_1);
 110
 111                 for (i = 0; i <= data->kind; i++) {
 112                         data->temp[i] = i2c_smbus_read_byte_data(client,
 113                                 TMP421_TEMP_MSB[i]) << 8;
 114                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 115                                 TMP421_TEMP_LSB[i]);
 116                 }
 117                 data->last_updated = jiffies;
 118                 data->valid = 1;
 119         }
 120
 121         mutex_unlock(&data->update_lock);
 122
 123         return data;
 124 }
 125
 126 static ssize_t show_temp_value(struct device *dev,
 127                                struct device_attribute *devattr, char *buf)
 128 {
 129         int index = to_sensor_dev_attr(devattr)->index;
 130         struct tmp421_data *data = tmp421_update_device(dev);
 131         int temp;
 132
 133         mutex_lock(&data->update_lock);
 134         if (data->config & TMP421_CONFIG_RANGE)
 135                 temp = temp_from_u16(data->temp[index]);
 136         else
 137                 temp = temp_from_s16(data->temp[index]);
 138         mutex_unlock(&data->update_lock);
 139
 140         return sprintf(buf, "%d\n", temp);
 141 }
 142
 143 static ssize_t show_fault(struct device *dev,
 144                           struct device_attribute *devattr, char *buf)
 145 {
 146         int index = to_sensor_dev_attr(devattr)->index;
 147         struct tmp421_data *data = tmp421_update_device(dev);
 148
 149         /*
 150          * The OPEN bit signals a fault. This is bit 0 of the temperature
 151          * register (low byte).
 152          */
 153         if (data->temp[index] & 0x01)
 154                 return sprintf(buf, "1\n");
 155         else
 156                 return sprintf(buf, "0\n");
 157 }
 158
 159 static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
 160                                 int n)
 161 {
 162         struct device *dev = container_of(kobj, struct device, kobj);
 163         struct tmp421_data *data = dev_get_drvdata(dev);
 164         struct device_attribute *devattr;
 165         unsigned int index;
 166
 167         devattr = container_of(a, struct device_attribute, attr);
 168         index = to_sensor_dev_attr(devattr)->index;
 169
 170         if (data->kind > index)
 171                 return a->mode;
 172
 173         return 0;
 174 }
 175
 176 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
 177 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
 178 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
 179 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
 180 static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
 181 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
 182 static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
 183
 184 static struct attribute *tmp421_attr[] = {
 185         &sensor_dev_attr_temp1_input.dev_attr.attr,
 186         &sensor_dev_attr_temp2_input.dev_attr.attr,
 187         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 188         &sensor_dev_attr_temp3_input.dev_attr.attr,
 189         &sensor_dev_attr_temp3_fault.dev_attr.attr,
 190         &sensor_dev_attr_temp4_input.dev_attr.attr,
 191         &sensor_dev_attr_temp4_fault.dev_attr.attr,
 192         NULL
 193 };
 194
 195 static const struct attribute_group tmp421_group = {
 196         .attrs = tmp421_attr,
 197         .is_visible = tmp421_is_visible,
 198 };
 199
 200 static int tmp421_init_client(struct i2c_client *client)
 201 {
 202         int config, config_orig;
 203
 204         /* Set the conversion rate to 2 Hz */
 205         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 206
 207         /* Start conversions (disable shutdown if necessary) */
 208         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 209         if (config < 0) {
 210                 dev_err(&client->dev, "Could not read configuration"
 211                          " register (%d)\n", config);
 212                 return -ENODEV;
 213         }
 214
 215         config_orig = config;
 216         config &= ~TMP421_CONFIG_SHUTDOWN;
 217
 218         if (config != config_orig) {
 219                 dev_info(&client->dev, "Enable monitoring chip\n");
 220                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 221         }
 222
 223         return 0;
 224 }
 225
 226 static int tmp421_detect(struct i2c_client *client, int kind,
 227                          struct i2c_board_info *info)
 228 {
 229         struct i2c_adapter *adapter = client->adapter;
 230         const char *names[] = { "TMP421", "TMP422", "TMP423" };
 231
 232         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 233                 return -ENODEV;
 234
 235         if (kind <= 0) {
 236                 u8 reg;
 237
 238                 reg = i2c_smbus_read_byte_data(client,
 239                                                TMP421_MANUFACTURER_ID_REG);
 240                 if (reg != TMP421_MANUFACTURER_ID)
 241                         return -ENODEV;
 242
 243                 reg = i2c_smbus_read_byte_data(client,
 244                                                TMP421_DEVICE_ID_REG);
 245                 switch (reg) {
 246                 case TMP421_DEVICE_ID:
 247                         kind = tmp421;
 248                         break;
 249                 case TMP422_DEVICE_ID:
 250                         kind = tmp422;
 251                         break;
 252                 case TMP423_DEVICE_ID:
 253                         kind = tmp423;
 254                         break;
 255                 default:
 256                         return -ENODEV;
 257                 }
 258         }
 259         strlcpy(info->type, tmp421_id[kind - 1].name, I2C_NAME_SIZE);
 260         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 261                  names[kind - 1], client->addr);
 262
 263         return 0;
 264 }
 265
 266 static int tmp421_probe(struct i2c_client *client,
 267                         const struct i2c_device_id *id)
 268 {
 269         struct tmp421_data *data;
 270         int err;
 271
 272         data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
 273         if (!data)
 274                 return -ENOMEM;
 275
 276         i2c_set_clientdata(client, data);
 277         mutex_init(&data->update_lock);
 278         data->kind = id->driver_data;
 279
 280         err = tmp421_init_client(client);
 281         if (err)
 282                 goto exit_free;
 283
 284         err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
 285         if (err)
 286                 goto exit_free;
 287
 288         data->hwmon_dev = hwmon_device_register(&client->dev);
 289         if (IS_ERR(data->hwmon_dev)) {
 290                 err = PTR_ERR(data->hwmon_dev);
 291                 data->hwmon_dev = NULL;
 292                 goto exit_remove;
 293         }
 294         return 0;
 295
 296 exit_remove:
 297         sysfs_remove_group(&client->dev.kobj, &tmp421_group);
 298
 299 exit_free:
 300         i2c_set_clientdata(client, NULL);
 301         kfree(data);
 302
 303         return err;
 304 }
 305
 306 static int tmp421_remove(struct i2c_client *client)
 307 {
 308         struct tmp421_data *data = i2c_get_clientdata(client);
 309
 310         hwmon_device_unregister(data->hwmon_dev);
 311         sysfs_remove_group(&client->dev.kobj, &tmp421_group);
 312
 313         i2c_set_clientdata(client, NULL);
 314         kfree(data);
 315
 316         return 0;
 317 }
 318
 319 static struct i2c_driver tmp421_driver = {
 320         .class = I2C_CLASS_HWMON,
 321         .driver = {
 322                 .name   = "tmp421",
 323         },
 324         .probe = tmp421_probe,
 325         .remove = tmp421_remove,
 326         .id_table = tmp421_id,
 327         .detect = tmp421_detect,
 328         .address_data = &addr_data,
 329 };
 330
 331 static int __init tmp421_init(void)
 332 {
 333         return i2c_add_driver(&tmp421_driver);
 334 }
 335
 336 static void __exit tmp421_exit(void)
 337 {
 338         i2c_del_driver(&tmp421_driver);
 339 }
 340
 341 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 342 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
 343                    " driver");
 344 MODULE_LICENSE("GPL");
 345
 346 module_init(tmp421_init);
 347 module_exit(tmp421_exit);