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