root/drivers/hwmon/tmp421.c

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DEFINITIONS

This source file includes following definitions.
  1. temp_from_s16
  2. temp_from_u16
  3. tmp421_update_device
  4. tmp421_read
  5. tmp421_is_visible
  6. tmp421_init_client
  7. tmp421_detect
  8. tmp421_probe

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* tmp421.c
   3  *
   4  * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
   5  * Preliminary support by:
   6  * Melvin Rook, Raymond Ng
   7  */
   8 
   9 /*
  10  * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
  11  * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
  12  */
  13 
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/i2c.h>
  19 #include <linux/hwmon.h>
  20 #include <linux/hwmon-sysfs.h>
  21 #include <linux/err.h>
  22 #include <linux/mutex.h>
  23 #include <linux/of_device.h>
  24 #include <linux/sysfs.h>
  25 
  26 /* Addresses to scan */
  27 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  28                                              I2C_CLIENT_END };
  29 
  30 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
  31 
  32 /* The TMP421 registers */
  33 #define TMP421_STATUS_REG                       0x08
  34 #define TMP421_CONFIG_REG_1                     0x09
  35 #define TMP421_CONVERSION_RATE_REG              0x0B
  36 #define TMP421_MANUFACTURER_ID_REG              0xFE
  37 #define TMP421_DEVICE_ID_REG                    0xFF
  38 
  39 static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  40 static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  41 
  42 /* Flags */
  43 #define TMP421_CONFIG_SHUTDOWN                  0x40
  44 #define TMP421_CONFIG_RANGE                     0x04
  45 
  46 /* Manufacturer / Device ID's */
  47 #define TMP421_MANUFACTURER_ID                  0x55
  48 #define TMP421_DEVICE_ID                        0x21
  49 #define TMP422_DEVICE_ID                        0x22
  50 #define TMP423_DEVICE_ID                        0x23
  51 #define TMP441_DEVICE_ID                        0x41
  52 #define TMP442_DEVICE_ID                        0x42
  53 
  54 static const struct i2c_device_id tmp421_id[] = {
  55         { "tmp421", 2 },
  56         { "tmp422", 3 },
  57         { "tmp423", 4 },
  58         { "tmp441", 2 },
  59         { "tmp442", 3 },
  60         { }
  61 };
  62 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  63 
  64 static const struct of_device_id __maybe_unused tmp421_of_match[] = {
  65         {
  66                 .compatible = "ti,tmp421",
  67                 .data = (void *)2
  68         },
  69         {
  70                 .compatible = "ti,tmp422",
  71                 .data = (void *)3
  72         },
  73         {
  74                 .compatible = "ti,tmp423",
  75                 .data = (void *)4
  76         },
  77         {
  78                 .compatible = "ti,tmp441",
  79                 .data = (void *)2
  80         },
  81         {
  82                 .compatible = "ti,tmp442",
  83                 .data = (void *)3
  84         },
  85         { },
  86 };
  87 MODULE_DEVICE_TABLE(of, tmp421_of_match);
  88 
  89 struct tmp421_data {
  90         struct i2c_client *client;
  91         struct mutex update_lock;
  92         u32 temp_config[5];
  93         struct hwmon_channel_info temp_info;
  94         const struct hwmon_channel_info *info[2];
  95         struct hwmon_chip_info chip;
  96         char valid;
  97         unsigned long last_updated;
  98         unsigned long channels;
  99         u8 config;
 100         s16 temp[4];
 101 };
 102 
 103 static int temp_from_s16(s16 reg)
 104 {
 105         /* Mask out status bits */
 106         int temp = reg & ~0xf;
 107 
 108         return (temp * 1000 + 128) / 256;
 109 }
 110 
 111 static int temp_from_u16(u16 reg)
 112 {
 113         /* Mask out status bits */
 114         int temp = reg & ~0xf;
 115 
 116         /* Add offset for extended temperature range. */
 117         temp -= 64 * 256;
 118 
 119         return (temp * 1000 + 128) / 256;
 120 }
 121 
 122 static struct tmp421_data *tmp421_update_device(struct device *dev)
 123 {
 124         struct tmp421_data *data = dev_get_drvdata(dev);
 125         struct i2c_client *client = data->client;
 126         int i;
 127 
 128         mutex_lock(&data->update_lock);
 129 
 130         if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 131                 data->config = i2c_smbus_read_byte_data(client,
 132                         TMP421_CONFIG_REG_1);
 133 
 134                 for (i = 0; i < data->channels; i++) {
 135                         data->temp[i] = i2c_smbus_read_byte_data(client,
 136                                 TMP421_TEMP_MSB[i]) << 8;
 137                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 138                                 TMP421_TEMP_LSB[i]);
 139                 }
 140                 data->last_updated = jiffies;
 141                 data->valid = 1;
 142         }
 143 
 144         mutex_unlock(&data->update_lock);
 145 
 146         return data;
 147 }
 148 
 149 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 150                        u32 attr, int channel, long *val)
 151 {
 152         struct tmp421_data *tmp421 = tmp421_update_device(dev);
 153 
 154         switch (attr) {
 155         case hwmon_temp_input:
 156                 if (tmp421->config & TMP421_CONFIG_RANGE)
 157                         *val = temp_from_u16(tmp421->temp[channel]);
 158                 else
 159                         *val = temp_from_s16(tmp421->temp[channel]);
 160                 return 0;
 161         case hwmon_temp_fault:
 162                 /*
 163                  * The OPEN bit signals a fault. This is bit 0 of the temperature
 164                  * register (low byte).
 165                  */
 166                 *val = tmp421->temp[channel] & 0x01;
 167                 return 0;
 168         default:
 169                 return -EOPNOTSUPP;
 170         }
 171 
 172 }
 173 
 174 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 175                                  u32 attr, int channel)
 176 {
 177         switch (attr) {
 178         case hwmon_temp_fault:
 179                 if (channel == 0)
 180                         return 0;
 181                 return 0444;
 182         case hwmon_temp_input:
 183                 return 0444;
 184         default:
 185                 return 0;
 186         }
 187 }
 188 
 189 static int tmp421_init_client(struct i2c_client *client)
 190 {
 191         int config, config_orig;
 192 
 193         /* Set the conversion rate to 2 Hz */
 194         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 195 
 196         /* Start conversions (disable shutdown if necessary) */
 197         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 198         if (config < 0) {
 199                 dev_err(&client->dev,
 200                         "Could not read configuration register (%d)\n", config);
 201                 return config;
 202         }
 203 
 204         config_orig = config;
 205         config &= ~TMP421_CONFIG_SHUTDOWN;
 206 
 207         if (config != config_orig) {
 208                 dev_info(&client->dev, "Enable monitoring chip\n");
 209                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 210         }
 211 
 212         return 0;
 213 }
 214 
 215 static int tmp421_detect(struct i2c_client *client,
 216                          struct i2c_board_info *info)
 217 {
 218         enum chips kind;
 219         struct i2c_adapter *adapter = client->adapter;
 220         static const char * const names[] = {
 221                 "TMP421", "TMP422", "TMP423",
 222                 "TMP441", "TMP442"
 223         };
 224         int addr = client->addr;
 225         u8 reg;
 226 
 227         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 228                 return -ENODEV;
 229 
 230         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 231         if (reg != TMP421_MANUFACTURER_ID)
 232                 return -ENODEV;
 233 
 234         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 235         if (reg & 0xf8)
 236                 return -ENODEV;
 237 
 238         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 239         if (reg & 0x7f)
 240                 return -ENODEV;
 241 
 242         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 243         switch (reg) {
 244         case TMP421_DEVICE_ID:
 245                 kind = tmp421;
 246                 break;
 247         case TMP422_DEVICE_ID:
 248                 if (addr == 0x2a)
 249                         return -ENODEV;
 250                 kind = tmp422;
 251                 break;
 252         case TMP423_DEVICE_ID:
 253                 if (addr != 0x4c && addr != 0x4d)
 254                         return -ENODEV;
 255                 kind = tmp423;
 256                 break;
 257         case TMP441_DEVICE_ID:
 258                 kind = tmp441;
 259                 break;
 260         case TMP442_DEVICE_ID:
 261                 if (addr != 0x4c && addr != 0x4d)
 262                         return -ENODEV;
 263                 kind = tmp442;
 264                 break;
 265         default:
 266                 return -ENODEV;
 267         }
 268 
 269         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 270         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 271                  names[kind], client->addr);
 272 
 273         return 0;
 274 }
 275 
 276 static const struct hwmon_ops tmp421_ops = {
 277         .is_visible = tmp421_is_visible,
 278         .read = tmp421_read,
 279 };
 280 
 281 static int tmp421_probe(struct i2c_client *client,
 282                         const struct i2c_device_id *id)
 283 {
 284         struct device *dev = &client->dev;
 285         struct device *hwmon_dev;
 286         struct tmp421_data *data;
 287         int i, err;
 288 
 289         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 290         if (!data)
 291                 return -ENOMEM;
 292 
 293         mutex_init(&data->update_lock);
 294         if (client->dev.of_node)
 295                 data->channels = (unsigned long)
 296                         of_device_get_match_data(&client->dev);
 297         else
 298                 data->channels = id->driver_data;
 299         data->client = client;
 300 
 301         err = tmp421_init_client(client);
 302         if (err)
 303                 return err;
 304 
 305         for (i = 0; i < data->channels; i++)
 306                 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
 307 
 308         data->chip.ops = &tmp421_ops;
 309         data->chip.info = data->info;
 310 
 311         data->info[0] = &data->temp_info;
 312 
 313         data->temp_info.type = hwmon_temp;
 314         data->temp_info.config = data->temp_config;
 315 
 316         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 317                                                          data,
 318                                                          &data->chip,
 319                                                          NULL);
 320         return PTR_ERR_OR_ZERO(hwmon_dev);
 321 }
 322 
 323 static struct i2c_driver tmp421_driver = {
 324         .class = I2C_CLASS_HWMON,
 325         .driver = {
 326                 .name   = "tmp421",
 327                 .of_match_table = of_match_ptr(tmp421_of_match),
 328         },
 329         .probe = tmp421_probe,
 330         .id_table = tmp421_id,
 331         .detect = tmp421_detect,
 332         .address_list = normal_i2c,
 333 };
 334 
 335 module_i2c_driver(tmp421_driver);
 336 
 337 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 338 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 339 MODULE_LICENSE("GPL");

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