linux/drivers/hwmon/tmp421.c
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   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 */
  27static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  28                                             I2C_CLIENT_END };
  29
  30enum 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
  39static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  40static 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
  54static const struct i2c_device_id tmp421_id[] = {
  55        { "tmp421", 2 },
  56        { "tmp422", 3 },
  57        { "tmp423", 4 },
  58        { "tmp441", 2 },
  59        { "tmp442", 3 },
  60        { }
  61};
  62MODULE_DEVICE_TABLE(i2c, tmp421_id);
  63
  64static 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};
  87MODULE_DEVICE_TABLE(of, tmp421_of_match);
  88
  89struct 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
 103static 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
 111static 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
 122static 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
 150static 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
 175static 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
 190static 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
 216static 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
 277static const struct hwmon_ops tmp421_ops = {
 278        .is_visible = tmp421_is_visible,
 279        .read = tmp421_read,
 280};
 281
 282static int tmp421_probe(struct i2c_client *client)
 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 = i2c_match_id(tmp421_id, client)->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
 323static 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_new = tmp421_probe,
 330        .id_table = tmp421_id,
 331        .detect = tmp421_detect,
 332        .address_list = normal_i2c,
 333};
 334
 335module_i2c_driver(tmp421_driver);
 336
 337MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 338MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 339MODULE_LICENSE("GPL");
 340