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         u32 temp_config[5];
  76         struct hwmon_channel_info temp_info;
  77         const struct hwmon_channel_info *info[2];
  78         struct hwmon_chip_info chip;
  79         char valid;
  80         unsigned long last_updated;
  81         int channels;
  82         u8 config;
  83         s16 temp[4];
  84 };
  85
  86 static int temp_from_s16(s16 reg)
  87 {
  88         /* Mask out status bits */
  89         int temp = reg & ~0xf;
  90
  91         return (temp * 1000 + 128) / 256;
  92 }
  93
  94 static int temp_from_u16(u16 reg)
  95 {
  96         /* Mask out status bits */
  97         int temp = reg & ~0xf;
  98
  99         /* Add offset for extended temperature range. */
 100         temp -= 64 * 256;
 101
 102         return (temp * 1000 + 128) / 256;
 103 }
 104
 105 static struct tmp421_data *tmp421_update_device(struct device *dev)
 106 {
 107         struct tmp421_data *data = dev_get_drvdata(dev);
 108         struct i2c_client *client = data->client;
 109         int i;
 110
 111         mutex_lock(&data->update_lock);
 112
 113         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 114                 data->config = i2c_smbus_read_byte_data(client,
 115                         TMP421_CONFIG_REG_1);
 116
 117                 for (i = 0; i < data->channels; i++) {
 118                         data->temp[i] = i2c_smbus_read_byte_data(client,
 119                                 TMP421_TEMP_MSB[i]) << 8;
 120                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 121                                 TMP421_TEMP_LSB[i]);
 122                 }
 123                 data->last_updated = jiffies;
 124                 data->valid = 1;
 125         }
 126
 127         mutex_unlock(&data->update_lock);
 128
 129         return data;
 130 }
 131
 132 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 133                        u32 attr, int channel, long *val)
 134 {
 135         struct tmp421_data *tmp421 = tmp421_update_device(dev);
 136
 137         switch (attr) {
 138         case hwmon_temp_input:
 139                 if (tmp421->config & TMP421_CONFIG_RANGE)
 140                         *val = temp_from_u16(tmp421->temp[channel]);
 141                 else
 142                         *val = temp_from_s16(tmp421->temp[channel]);
 143                 return 0;
 144         case hwmon_temp_fault:
 145                 /*
 146                  * The OPEN bit signals a fault. This is bit 0 of the temperature
 147                  * register (low byte).
 148                  */
 149                 *val = tmp421->temp[channel] & 0x01;
 150                 return 0;
 151         default:
 152                 return -EOPNOTSUPP;
 153         }
 154
 155 }
 156
 157 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 158                                  u32 attr, int channel)
 159 {
 160         switch (attr) {
 161         case hwmon_temp_fault:
 162                 if (channel == 0)
 163                         return 0;
 164                 return S_IRUGO;
 165         case hwmon_temp_input:
 166                 return S_IRUGO;
 167         default:
 168                 return 0;
 169         }
 170 }
 171
 172 static int tmp421_init_client(struct i2c_client *client)
 173 {
 174         int config, config_orig;
 175
 176         /* Set the conversion rate to 2 Hz */
 177         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 178
 179         /* Start conversions (disable shutdown if necessary) */
 180         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 181         if (config < 0) {
 182                 dev_err(&client->dev,
 183                         "Could not read configuration register (%d)\n", config);
 184                 return config;
 185         }
 186
 187         config_orig = config;
 188         config &= ~TMP421_CONFIG_SHUTDOWN;
 189
 190         if (config != config_orig) {
 191                 dev_info(&client->dev, "Enable monitoring chip\n");
 192                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 193         }
 194
 195         return 0;
 196 }
 197
 198 static int tmp421_detect(struct i2c_client *client,
 199                          struct i2c_board_info *info)
 200 {
 201         enum chips kind;
 202         struct i2c_adapter *adapter = client->adapter;
 203         const char * const names[] = { "TMP421", "TMP422", "TMP423",
 204                                        "TMP441", "TMP442" };
 205         int addr = client->addr;
 206         u8 reg;
 207
 208         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 209                 return -ENODEV;
 210
 211         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 212         if (reg != TMP421_MANUFACTURER_ID)
 213                 return -ENODEV;
 214
 215         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 216         if (reg & 0xf8)
 217                 return -ENODEV;
 218
 219         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 220         if (reg & 0x7f)
 221                 return -ENODEV;
 222
 223         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 224         switch (reg) {
 225         case TMP421_DEVICE_ID:
 226                 kind = tmp421;
 227                 break;
 228         case TMP422_DEVICE_ID:
 229                 if (addr == 0x2a)
 230                         return -ENODEV;
 231                 kind = tmp422;
 232                 break;
 233         case TMP423_DEVICE_ID:
 234                 if (addr != 0x4c && addr != 0x4d)
 235                         return -ENODEV;
 236                 kind = tmp423;
 237                 break;
 238         case TMP441_DEVICE_ID:
 239                 kind = tmp441;
 240                 break;
 241         case TMP442_DEVICE_ID:
 242                 if (addr != 0x4c && addr != 0x4d)
 243                         return -ENODEV;
 244                 kind = tmp442;
 245                 break;
 246         default:
 247                 return -ENODEV;
 248         }
 249
 250         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 251         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 252                  names[kind], client->addr);
 253
 254         return 0;
 255 }
 256
 257 static const struct hwmon_ops tmp421_ops = {
 258         .is_visible = tmp421_is_visible,
 259         .read = tmp421_read,
 260 };
 261
 262 static int tmp421_probe(struct i2c_client *client,
 263                         const struct i2c_device_id *id)
 264 {
 265         struct device *dev = &client->dev;
 266         struct device *hwmon_dev;
 267         struct tmp421_data *data;
 268         int i, err;
 269
 270         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 271         if (!data)
 272                 return -ENOMEM;
 273
 274         mutex_init(&data->update_lock);
 275         data->channels = id->driver_data;
 276         data->client = client;
 277
 278         err = tmp421_init_client(client);
 279         if (err)
 280                 return err;
 281
 282         for (i = 0; i < data->channels; i++)
 283                 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
 284
 285         data->chip.ops = &tmp421_ops;
 286         data->chip.info = data->info;
 287
 288         data->info[0] = &data->temp_info;
 289
 290         data->temp_info.type = hwmon_temp;
 291         data->temp_info.config = data->temp_config;
 292
 293         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 294                                                          data,
 295                                                          &data->chip,
 296                                                          NULL);
 297         return PTR_ERR_OR_ZERO(hwmon_dev);
 298 }
 299
 300 static struct i2c_driver tmp421_driver = {
 301         .class = I2C_CLASS_HWMON,
 302         .driver = {
 303                 .name   = "tmp421",
 304         },
 305         .probe = tmp421_probe,
 306         .id_table = tmp421_id,
 307         .detect = tmp421_detect,
 308         .address_list = normal_i2c,
 309 };
 310
 311 module_i2c_driver(tmp421_driver);
 312
 313 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 314 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 315 MODULE_LICENSE("GPL");