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/of_device.h>
  33 #include <linux/sysfs.h>
  34
  35 /* Addresses to scan */
  36 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  37                                              I2C_CLIENT_END };
  38
  39 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
  40
  41 /* The TMP421 registers */
  42 #define TMP421_STATUS_REG                       0x08
  43 #define TMP421_CONFIG_REG_1                     0x09
  44 #define TMP421_CONVERSION_RATE_REG              0x0B
  45 #define TMP421_MANUFACTURER_ID_REG              0xFE
  46 #define TMP421_DEVICE_ID_REG                    0xFF
  47
  48 static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  49 static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  50
  51 /* Flags */
  52 #define TMP421_CONFIG_SHUTDOWN                  0x40
  53 #define TMP421_CONFIG_RANGE                     0x04
  54
  55 /* Manufacturer / Device ID's */
  56 #define TMP421_MANUFACTURER_ID                  0x55
  57 #define TMP421_DEVICE_ID                        0x21
  58 #define TMP422_DEVICE_ID                        0x22
  59 #define TMP423_DEVICE_ID                        0x23
  60 #define TMP441_DEVICE_ID                        0x41
  61 #define TMP442_DEVICE_ID                        0x42
  62
  63 static const struct i2c_device_id tmp421_id[] = {
  64         { "tmp421", 2 },
  65         { "tmp422", 3 },
  66         { "tmp423", 4 },
  67         { "tmp441", 2 },
  68         { "tmp442", 3 },
  69         { }
  70 };
  71 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  72
  73 static const struct of_device_id tmp421_of_match[] = {
  74         {
  75                 .compatible = "ti,tmp421",
  76                 .data = (void *)2
  77         },
  78         {
  79                 .compatible = "ti,tmp422",
  80                 .data = (void *)3
  81         },
  82         {
  83                 .compatible = "ti,tmp423",
  84                 .data = (void *)4
  85         },
  86         {
  87                 .compatible = "ti,tmp441",
  88                 .data = (void *)2
  89         },
  90         {
  91                 .compatible = "ti,tmp422",
  92                 .data = (void *)3
  93         },
  94         { },
  95 };
  96 MODULE_DEVICE_TABLE(of, tmp421_of_match);
  97
  98 struct tmp421_data {
  99         struct i2c_client *client;
 100         struct mutex update_lock;
 101         u32 temp_config[5];
 102         struct hwmon_channel_info temp_info;
 103         const struct hwmon_channel_info *info[2];
 104         struct hwmon_chip_info chip;
 105         char valid;
 106         unsigned long last_updated;
 107         unsigned long channels;
 108         u8 config;
 109         s16 temp[4];
 110 };
 111
 112 static int temp_from_s16(s16 reg)
 113 {
 114         /* Mask out status bits */
 115         int temp = reg & ~0xf;
 116
 117         return (temp * 1000 + 128) / 256;
 118 }
 119
 120 static int temp_from_u16(u16 reg)
 121 {
 122         /* Mask out status bits */
 123         int temp = reg & ~0xf;
 124
 125         /* Add offset for extended temperature range. */
 126         temp -= 64 * 256;
 127
 128         return (temp * 1000 + 128) / 256;
 129 }
 130
 131 static struct tmp421_data *tmp421_update_device(struct device *dev)
 132 {
 133         struct tmp421_data *data = dev_get_drvdata(dev);
 134         struct i2c_client *client = data->client;
 135         int i;
 136
 137         mutex_lock(&data->update_lock);
 138
 139         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 140                 data->config = i2c_smbus_read_byte_data(client,
 141                         TMP421_CONFIG_REG_1);
 142
 143                 for (i = 0; i < data->channels; i++) {
 144                         data->temp[i] = i2c_smbus_read_byte_data(client,
 145                                 TMP421_TEMP_MSB[i]) << 8;
 146                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 147                                 TMP421_TEMP_LSB[i]);
 148                 }
 149                 data->last_updated = jiffies;
 150                 data->valid = 1;
 151         }
 152
 153         mutex_unlock(&data->update_lock);
 154
 155         return data;
 156 }
 157
 158 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 159                        u32 attr, int channel, long *val)
 160 {
 161         struct tmp421_data *tmp421 = tmp421_update_device(dev);
 162
 163         switch (attr) {
 164         case hwmon_temp_input:
 165                 if (tmp421->config & TMP421_CONFIG_RANGE)
 166                         *val = temp_from_u16(tmp421->temp[channel]);
 167                 else
 168                         *val = temp_from_s16(tmp421->temp[channel]);
 169                 return 0;
 170         case hwmon_temp_fault:
 171                 /*
 172                  * The OPEN bit signals a fault. This is bit 0 of the temperature
 173                  * register (low byte).
 174                  */
 175                 *val = tmp421->temp[channel] & 0x01;
 176                 return 0;
 177         default:
 178                 return -EOPNOTSUPP;
 179         }
 180
 181 }
 182
 183 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 184                                  u32 attr, int channel)
 185 {
 186         switch (attr) {
 187         case hwmon_temp_fault:
 188                 if (channel == 0)
 189                         return 0;
 190                 return S_IRUGO;
 191         case hwmon_temp_input:
 192                 return S_IRUGO;
 193         default:
 194                 return 0;
 195         }
 196 }
 197
 198 static int tmp421_init_client(struct i2c_client *client)
 199 {
 200         int config, config_orig;
 201
 202         /* Set the conversion rate to 2 Hz */
 203         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 204
 205         /* Start conversions (disable shutdown if necessary) */
 206         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 207         if (config < 0) {
 208                 dev_err(&client->dev,
 209                         "Could not read configuration register (%d)\n", config);
 210                 return config;
 211         }
 212
 213         config_orig = config;
 214         config &= ~TMP421_CONFIG_SHUTDOWN;
 215
 216         if (config != config_orig) {
 217                 dev_info(&client->dev, "Enable monitoring chip\n");
 218                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 219         }
 220
 221         return 0;
 222 }
 223
 224 static int tmp421_detect(struct i2c_client *client,
 225                          struct i2c_board_info *info)
 226 {
 227         enum chips kind;
 228         struct i2c_adapter *adapter = client->adapter;
 229         const char * const names[] = { "TMP421", "TMP422", "TMP423",
 230                                        "TMP441", "TMP442" };
 231         int addr = client->addr;
 232         u8 reg;
 233
 234         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 235                 return -ENODEV;
 236
 237         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 238         if (reg != TMP421_MANUFACTURER_ID)
 239                 return -ENODEV;
 240
 241         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 242         if (reg & 0xf8)
 243                 return -ENODEV;
 244
 245         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 246         if (reg & 0x7f)
 247                 return -ENODEV;
 248
 249         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 250         switch (reg) {
 251         case TMP421_DEVICE_ID:
 252                 kind = tmp421;
 253                 break;
 254         case TMP422_DEVICE_ID:
 255                 if (addr == 0x2a)
 256                         return -ENODEV;
 257                 kind = tmp422;
 258                 break;
 259         case TMP423_DEVICE_ID:
 260                 if (addr != 0x4c && addr != 0x4d)
 261                         return -ENODEV;
 262                 kind = tmp423;
 263                 break;
 264         case TMP441_DEVICE_ID:
 265                 kind = tmp441;
 266                 break;
 267         case TMP442_DEVICE_ID:
 268                 if (addr != 0x4c && addr != 0x4d)
 269                         return -ENODEV;
 270                 kind = tmp442;
 271                 break;
 272         default:
 273                 return -ENODEV;
 274         }
 275
 276         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 277         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 278                  names[kind], client->addr);
 279
 280         return 0;
 281 }
 282
 283 static const struct hwmon_ops tmp421_ops = {
 284         .is_visible = tmp421_is_visible,
 285         .read = tmp421_read,
 286 };
 287
 288 static int tmp421_probe(struct i2c_client *client,
 289                         const struct i2c_device_id *id)
 290 {
 291         struct device *dev = &client->dev;
 292         struct device *hwmon_dev;
 293         struct tmp421_data *data;
 294         int i, err;
 295
 296         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 297         if (!data)
 298                 return -ENOMEM;
 299
 300         mutex_init(&data->update_lock);
 301         if (client->dev.of_node)
 302                 data->channels = (unsigned long)
 303                         of_device_get_match_data(&client->dev);
 304         else
 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         for (i = 0; i < data->channels; i++)
 313                 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
 314
 315         data->chip.ops = &tmp421_ops;
 316         data->chip.info = data->info;
 317
 318         data->info[0] = &data->temp_info;
 319
 320         data->temp_info.type = hwmon_temp;
 321         data->temp_info.config = data->temp_config;
 322
 323         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 324                                                          data,
 325                                                          &data->chip,
 326                                                          NULL);
 327         return PTR_ERR_OR_ZERO(hwmon_dev);
 328 }
 329
 330 static struct i2c_driver tmp421_driver = {
 331         .class = I2C_CLASS_HWMON,
 332         .driver = {
 333                 .name   = "tmp421",
 334                 .of_match_table = of_match_ptr(tmp421_of_match),
 335         },
 336         .probe = tmp421_probe,
 337         .id_table = tmp421_id,
 338         .detect = tmp421_detect,
 339         .address_list = normal_i2c,
 340 };
 341
 342 module_i2c_driver(tmp421_driver);
 343
 344 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 345 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 346 MODULE_LICENSE("GPL");