drivers/hwmon/tmp421.c

   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_raw(u16 reg, bool extended)
 104 {
 105         /* Mask out status bits */
 106         int temp = reg & ~0xf;
 107
 108         if (extended)
 109                 temp = temp - 64 * 256;
 110         else
 111                 temp = (s16)temp;
 112
 113         return DIV_ROUND_CLOSEST(temp * 1000, 256);
 114 }
 115
 116 static int tmp421_update_device(struct tmp421_data *data)
 117 {
 118         struct i2c_client *client = data->client;
 119         int ret = 0;
 120         int i;
 121
 122         mutex_lock(&data->update_lock);
 123
 124         if (time_after(jiffies, data->last_updated + (HZ / 2)) ||
 125             !data->valid) {
 126                 ret = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 127                 if (ret < 0)
 128                         goto exit;
 129                 data->config = ret;
 130
 131                 for (i = 0; i < data->channels; i++) {
 132                         ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_MSB[i]);
 133                         if (ret < 0)
 134                                 goto exit;
 135                         data->temp[i] = ret << 8;
 136
 137                         ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_LSB[i]);
 138                         if (ret < 0)
 139                                 goto exit;
 140                         data->temp[i] |= ret;
 141                 }
 142                 data->last_updated = jiffies;
 143                 data->valid = 1;
 144         }
 145
 146 exit:
 147         mutex_unlock(&data->update_lock);
 148
 149         if (ret < 0) {
 150                 data->valid = 0;
 151                 return ret;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 158                        u32 attr, int channel, long *val)
 159 {
 160         struct tmp421_data *tmp421 = dev_get_drvdata(dev);
 161         int ret = 0;
 162
 163         ret = tmp421_update_device(tmp421);
 164         if (ret)
 165                 return ret;
 166
 167         switch (attr) {
 168         case hwmon_temp_input:
 169                 *val = temp_from_raw(tmp421->temp[channel],
 170                                      tmp421->config & TMP421_CONFIG_RANGE);
 171                 return 0;
 172         case hwmon_temp_fault:
 173                 /*
 174                  * Any of OPEN or /PVLD bits indicate a hardware mulfunction
 175                  * and the conversion result may be incorrect
 176                  */
 177                 *val = !!(tmp421->temp[channel] & 0x03);
 178                 return 0;
 179         default:
 180                 return -EOPNOTSUPP;
 181         }
 182
 183 }
 184
 185 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 186                                  u32 attr, int channel)
 187 {
 188         switch (attr) {
 189         case hwmon_temp_fault:
 190         case hwmon_temp_input:
 191                 return 0444;
 192         default:
 193                 return 0;
 194         }
 195 }
 196
 197 static int tmp421_init_client(struct i2c_client *client)
 198 {
 199         int config, config_orig;
 200
 201         /* Set the conversion rate to 2 Hz */
 202         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 203
 204         /* Start conversions (disable shutdown if necessary) */
 205         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 206         if (config < 0) {
 207                 dev_err(&client->dev,
 208                         "Could not read configuration register (%d)\n", config);
 209                 return config;
 210         }
 211
 212         config_orig = config;
 213         config &= ~TMP421_CONFIG_SHUTDOWN;
 214
 215         if (config != config_orig) {
 216                 dev_info(&client->dev, "Enable monitoring chip\n");
 217                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 218         }
 219
 220         return 0;
 221 }
 222
 223 static int tmp421_detect(struct i2c_client *client,
 224                          struct i2c_board_info *info)
 225 {
 226         enum chips kind;
 227         struct i2c_adapter *adapter = client->adapter;
 228         static const char * const names[] = {
 229                 "TMP421", "TMP422", "TMP423",
 230                 "TMP441", "TMP442"
 231         };
 232         int addr = client->addr;
 233         u8 reg;
 234
 235         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 236                 return -ENODEV;
 237
 238         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 239         if (reg != TMP421_MANUFACTURER_ID)
 240                 return -ENODEV;
 241
 242         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 243         if (reg & 0xf8)
 244                 return -ENODEV;
 245
 246         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 247         if (reg & 0x7f)
 248                 return -ENODEV;
 249
 250         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 251         switch (reg) {
 252         case TMP421_DEVICE_ID:
 253                 kind = tmp421;
 254                 break;
 255         case TMP422_DEVICE_ID:
 256                 if (addr == 0x2a)
 257                         return -ENODEV;
 258                 kind = tmp422;
 259                 break;
 260         case TMP423_DEVICE_ID:
 261                 if (addr != 0x4c && addr != 0x4d)
 262                         return -ENODEV;
 263                 kind = tmp423;
 264                 break;
 265         case TMP441_DEVICE_ID:
 266                 kind = tmp441;
 267                 break;
 268         case TMP442_DEVICE_ID:
 269                 if (addr != 0x4c && addr != 0x4d)
 270                         return -ENODEV;
 271                 kind = tmp442;
 272                 break;
 273         default:
 274                 return -ENODEV;
 275         }
 276
 277         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 278         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 279                  names[kind], client->addr);
 280
 281         return 0;
 282 }
 283
 284 static const struct hwmon_ops tmp421_ops = {
 285         .is_visible = tmp421_is_visible,
 286         .read = tmp421_read,
 287 };
 288
 289 static int tmp421_probe(struct i2c_client *client)
 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 = i2c_match_id(tmp421_id, client)->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_new = 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");