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
  18 /*
  19  * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
  20  * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/i2c.h>
  28 #include <linux/hwmon.h>
  29 #include <linux/hwmon-sysfs.h>
  30 #include <linux/err.h>
  31 #include <linux/mutex.h>
  32 #include <linux/sysfs.h>
  33
  34 /* Addresses to scan */
  35 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  36                                              I2C_CLIENT_END };
  37
  38 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
  39
  40 /* The TMP421 registers */
  41 #define TMP421_STATUS_REG                       0x08
  42 #define TMP421_CONFIG_REG_1                     0x09
  43 #define TMP421_CONVERSION_RATE_REG              0x0B
  44 #define TMP421_MANUFACTURER_ID_REG              0xFE
  45 #define TMP421_DEVICE_ID_REG                    0xFF
  46
  47 static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  48 static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  49
  50 /* Flags */
  51 #define TMP421_CONFIG_SHUTDOWN                  0x40
  52 #define TMP421_CONFIG_RANGE                     0x04
  53
  54 /* Manufacturer / Device ID's */
  55 #define TMP421_MANUFACTURER_ID                  0x55
  56 #define TMP421_DEVICE_ID                        0x21
  57 #define TMP422_DEVICE_ID                        0x22
  58 #define TMP423_DEVICE_ID                        0x23
  59 #define TMP441_DEVICE_ID                        0x41
  60 #define TMP442_DEVICE_ID                        0x42
  61
  62 static const struct i2c_device_id tmp421_id[] = {
  63         { "tmp421", 2 },
  64         { "tmp422", 3 },
  65         { "tmp423", 4 },
  66         { "tmp441", 2 },
  67         { "tmp442", 3 },
  68         { }
  69 };
  70 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  71
  72 struct tmp421_data {
  73         struct i2c_client *client;
  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 tmp421_data *data = dev_get_drvdata(dev);
 104         struct i2c_client *client = data->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 umode_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 const struct attribute_group *tmp421_groups[] = {
 203         &tmp421_group,
 204         NULL
 205 };
 206
 207 static int tmp421_init_client(struct i2c_client *client)
 208 {
 209         int config, config_orig;
 210
 211         /* Set the conversion rate to 2 Hz */
 212         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 213
 214         /* Start conversions (disable shutdown if necessary) */
 215         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 216         if (config < 0) {
 217                 dev_err(&client->dev,
 218                         "Could not read configuration register (%d)\n", config);
 219                 return config;
 220         }
 221
 222         config_orig = config;
 223         config &= ~TMP421_CONFIG_SHUTDOWN;
 224
 225         if (config != config_orig) {
 226                 dev_info(&client->dev, "Enable monitoring chip\n");
 227                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 228         }
 229
 230         return 0;
 231 }
 232
 233 static int tmp421_detect(struct i2c_client *client,
 234                          struct i2c_board_info *info)
 235 {
 236         enum chips kind;
 237         struct i2c_adapter *adapter = client->adapter;
 238         const char * const names[] = { "TMP421", "TMP422", "TMP423",
 239                                        "TMP441", "TMP442" };
 240         int addr = client->addr;
 241         u8 reg;
 242
 243         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 244                 return -ENODEV;
 245
 246         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 247         if (reg != TMP421_MANUFACTURER_ID)
 248                 return -ENODEV;
 249
 250         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 251         if (reg & 0xf8)
 252                 return -ENODEV;
 253
 254         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 255         if (reg & 0x7f)
 256                 return -ENODEV;
 257
 258         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 259         switch (reg) {
 260         case TMP421_DEVICE_ID:
 261                 kind = tmp421;
 262                 break;
 263         case TMP422_DEVICE_ID:
 264                 if (addr == 0x2a)
 265                         return -ENODEV;
 266                 kind = tmp422;
 267                 break;
 268         case TMP423_DEVICE_ID:
 269                 if (addr != 0x4c && addr != 0x4d)
 270                         return -ENODEV;
 271                 kind = tmp423;
 272                 break;
 273         case TMP441_DEVICE_ID:
 274                 kind = tmp441;
 275                 break;
 276         case TMP442_DEVICE_ID:
 277                 if (addr != 0x4c && addr != 0x4d)
 278                         return -ENODEV;
 279                 kind = tmp442;
 280                 break;
 281         default:
 282                 return -ENODEV;
 283         }
 284
 285         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 286         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 287                  names[kind], client->addr);
 288
 289         return 0;
 290 }
 291
 292 static int tmp421_probe(struct i2c_client *client,
 293                         const struct i2c_device_id *id)
 294 {
 295         struct device *dev = &client->dev;
 296         struct device *hwmon_dev;
 297         struct tmp421_data *data;
 298         int err;
 299
 300         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 301         if (!data)
 302                 return -ENOMEM;
 303
 304         mutex_init(&data->update_lock);
 305         data->channels = id->driver_data;
 306         data->client = client;
 307
 308         err = tmp421_init_client(client);
 309         if (err)
 310                 return err;
 311
 312         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 313                                                            data, tmp421_groups);
 314         return PTR_ERR_OR_ZERO(hwmon_dev);
 315 }
 316
 317 static struct i2c_driver tmp421_driver = {
 318         .class = I2C_CLASS_HWMON,
 319         .driver = {
 320                 .name   = "tmp421",
 321         },
 322         .probe = tmp421_probe,
 323         .id_table = tmp421_id,
 324         .detect = tmp421_detect,
 325         .address_list = normal_i2c,
 326 };
 327
 328 module_i2c_driver(tmp421_driver);
 329
 330 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 331 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 332 MODULE_LICENSE("GPL");