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_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 + (HZ / 2)) ||
 131             !data->valid) {
 132                 data->config = i2c_smbus_read_byte_data(client,
 133                         TMP421_CONFIG_REG_1);
 134
 135                 for (i = 0; i < data->channels; i++) {
 136                         data->temp[i] = i2c_smbus_read_byte_data(client,
 137                                 TMP421_TEMP_MSB[i]) << 8;
 138                         data->temp[i] |= i2c_smbus_read_byte_data(client,
 139                                 TMP421_TEMP_LSB[i]);
 140                 }
 141                 data->last_updated = jiffies;
 142                 data->valid = 1;
 143         }
 144
 145         mutex_unlock(&data->update_lock);
 146
 147         return data;
 148 }
 149
 150 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 151                        u32 attr, int channel, long *val)
 152 {
 153         struct tmp421_data *tmp421 = tmp421_update_device(dev);
 154
 155         switch (attr) {
 156         case hwmon_temp_input:
 157                 if (tmp421->config & TMP421_CONFIG_RANGE)
 158                         *val = temp_from_u16(tmp421->temp[channel]);
 159                 else
 160                         *val = temp_from_s16(tmp421->temp[channel]);
 161                 return 0;
 162         case hwmon_temp_fault:
 163                 /*
 164                  * The OPEN bit signals a fault. This is bit 0 of the temperature
 165                  * register (low byte).
 166                  */
 167                 *val = tmp421->temp[channel] & 0x01;
 168                 return 0;
 169         default:
 170                 return -EOPNOTSUPP;
 171         }
 172
 173 }
 174
 175 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 176                                  u32 attr, int channel)
 177 {
 178         switch (attr) {
 179         case hwmon_temp_fault:
 180                 if (channel == 0)
 181                         return 0;
 182                 return 0444;
 183         case hwmon_temp_input:
 184                 return 0444;
 185         default:
 186                 return 0;
 187         }
 188 }
 189
 190 static int tmp421_init_client(struct i2c_client *client)
 191 {
 192         int config, config_orig;
 193
 194         /* Set the conversion rate to 2 Hz */
 195         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 196
 197         /* Start conversions (disable shutdown if necessary) */
 198         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 199         if (config < 0) {
 200                 dev_err(&client->dev,
 201                         "Could not read configuration register (%d)\n", config);
 202                 return config;
 203         }
 204
 205         config_orig = config;
 206         config &= ~TMP421_CONFIG_SHUTDOWN;
 207
 208         if (config != config_orig) {
 209                 dev_info(&client->dev, "Enable monitoring chip\n");
 210                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 211         }
 212
 213         return 0;
 214 }
 215
 216 static int tmp421_detect(struct i2c_client *client,
 217                          struct i2c_board_info *info)
 218 {
 219         enum chips kind;
 220         struct i2c_adapter *adapter = client->adapter;
 221         static const char * const names[] = {
 222                 "TMP421", "TMP422", "TMP423",
 223                 "TMP441", "TMP442"
 224         };
 225         int addr = client->addr;
 226         u8 reg;
 227
 228         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 229                 return -ENODEV;
 230
 231         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 232         if (reg != TMP421_MANUFACTURER_ID)
 233                 return -ENODEV;
 234
 235         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 236         if (reg & 0xf8)
 237                 return -ENODEV;
 238
 239         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 240         if (reg & 0x7f)
 241                 return -ENODEV;
 242
 243         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 244         switch (reg) {
 245         case TMP421_DEVICE_ID:
 246                 kind = tmp421;
 247                 break;
 248         case TMP422_DEVICE_ID:
 249                 if (addr == 0x2a)
 250                         return -ENODEV;
 251                 kind = tmp422;
 252                 break;
 253         case TMP423_DEVICE_ID:
 254                 if (addr != 0x4c && addr != 0x4d)
 255                         return -ENODEV;
 256                 kind = tmp423;
 257                 break;
 258         case TMP441_DEVICE_ID:
 259                 kind = tmp441;
 260                 break;
 261         case TMP442_DEVICE_ID:
 262                 if (addr != 0x4c && addr != 0x4d)
 263                         return -ENODEV;
 264                 kind = tmp442;
 265                 break;
 266         default:
 267                 return -ENODEV;
 268         }
 269
 270         strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 271         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 272                  names[kind], client->addr);
 273
 274         return 0;
 275 }
 276
 277 static const struct hwmon_ops tmp421_ops = {
 278         .is_visible = tmp421_is_visible,
 279         .read = tmp421_read,
 280 };
 281
 282 static int tmp421_probe(struct i2c_client *client,
 283                         const struct i2c_device_id *id)
 284 {
 285         struct device *dev = &client->dev;
 286         struct device *hwmon_dev;
 287         struct tmp421_data *data;
 288         int i, err;
 289
 290         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 291         if (!data)
 292                 return -ENOMEM;
 293
 294         mutex_init(&data->update_lock);
 295         if (client->dev.of_node)
 296                 data->channels = (unsigned long)
 297                         of_device_get_match_data(&client->dev);
 298         else
 299                 data->channels = id->driver_data;
 300         data->client = client;
 301
 302         err = tmp421_init_client(client);
 303         if (err)
 304                 return err;
 305
 306         for (i = 0; i < data->channels; i++)
 307                 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
 308
 309         data->chip.ops = &tmp421_ops;
 310         data->chip.info = data->info;
 311
 312         data->info[0] = &data->temp_info;
 313
 314         data->temp_info.type = hwmon_temp;
 315         data->temp_info.config = data->temp_config;
 316
 317         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 318                                                          data,
 319                                                          &data->chip,
 320                                                          NULL);
 321         return PTR_ERR_OR_ZERO(hwmon_dev);
 322 }
 323
 324 static struct i2c_driver tmp421_driver = {
 325         .class = I2C_CLASS_HWMON,
 326         .driver = {
 327                 .name   = "tmp421",
 328                 .of_match_table = of_match_ptr(tmp421_of_match),
 329         },
 330         .probe = tmp421_probe,
 331         .id_table = tmp421_id,
 332         .detect = tmp421_detect,
 333         .address_list = normal_i2c,
 334 };
 335
 336 module_i2c_driver(tmp421_driver);
 337
 338 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 339 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 340 MODULE_LICENSE("GPL");