linux/drivers/hwmon/tmp421.c
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   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 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22/*
  23 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
  24 * Supported models: TMP421, TMP422, TMP423
  25 */
  26
  27#include <linux/module.h>
  28#include <linux/init.h>
  29#include <linux/slab.h>
  30#include <linux/jiffies.h>
  31#include <linux/i2c.h>
  32#include <linux/hwmon.h>
  33#include <linux/hwmon-sysfs.h>
  34#include <linux/err.h>
  35#include <linux/mutex.h>
  36#include <linux/sysfs.h>
  37
  38/* Addresses to scan */
  39static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  40                                             I2C_CLIENT_END };
  41
  42enum chips { tmp421, tmp422, tmp423 };
  43
  44/* The TMP421 registers */
  45#define TMP421_CONFIG_REG_1                     0x09
  46#define TMP421_CONVERSION_RATE_REG              0x0B
  47#define TMP421_MANUFACTURER_ID_REG              0xFE
  48#define TMP421_DEVICE_ID_REG                    0xFF
  49
  50static const u8 TMP421_TEMP_MSB[4]              = { 0x00, 0x01, 0x02, 0x03 };
  51static const u8 TMP421_TEMP_LSB[4]              = { 0x10, 0x11, 0x12, 0x13 };
  52
  53/* Flags */
  54#define TMP421_CONFIG_SHUTDOWN                  0x40
  55#define TMP421_CONFIG_RANGE                     0x04
  56
  57/* Manufacturer / Device ID's */
  58#define TMP421_MANUFACTURER_ID                  0x55
  59#define TMP421_DEVICE_ID                        0x21
  60#define TMP422_DEVICE_ID                        0x22
  61#define TMP423_DEVICE_ID                        0x23
  62
  63static const struct i2c_device_id tmp421_id[] = {
  64        { "tmp421", 2 },
  65        { "tmp422", 3 },
  66        { "tmp423", 4 },
  67        { }
  68};
  69MODULE_DEVICE_TABLE(i2c, tmp421_id);
  70
  71struct tmp421_data {
  72        struct device *hwmon_dev;
  73        struct mutex update_lock;
  74        char valid;
  75        unsigned long last_updated;
  76        int channels;
  77        u8 config;
  78        s16 temp[4];
  79};
  80
  81static int temp_from_s16(s16 reg)
  82{
  83        /* Mask out status bits */
  84        int temp = reg & ~0xf;
  85
  86        return (temp * 1000 + 128) / 256;
  87}
  88
  89static int temp_from_u16(u16 reg)
  90{
  91        /* Mask out status bits */
  92        int temp = reg & ~0xf;
  93
  94        /* Add offset for extended temperature range. */
  95        temp -= 64 * 256;
  96
  97        return (temp * 1000 + 128) / 256;
  98}
  99
 100static struct tmp421_data *tmp421_update_device(struct device *dev)
 101{
 102        struct i2c_client *client = to_i2c_client(dev);
 103        struct tmp421_data *data = i2c_get_clientdata(client);
 104        int i;
 105
 106        mutex_lock(&data->update_lock);
 107
 108        if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
 109                data->config = i2c_smbus_read_byte_data(client,
 110                        TMP421_CONFIG_REG_1);
 111
 112                for (i = 0; i < data->channels; i++) {
 113                        data->temp[i] = i2c_smbus_read_byte_data(client,
 114                                TMP421_TEMP_MSB[i]) << 8;
 115                        data->temp[i] |= i2c_smbus_read_byte_data(client,
 116                                TMP421_TEMP_LSB[i]);
 117                }
 118                data->last_updated = jiffies;
 119                data->valid = 1;
 120        }
 121
 122        mutex_unlock(&data->update_lock);
 123
 124        return data;
 125}
 126
 127static ssize_t show_temp_value(struct device *dev,
 128                               struct device_attribute *devattr, char *buf)
 129{
 130        int index = to_sensor_dev_attr(devattr)->index;
 131        struct tmp421_data *data = tmp421_update_device(dev);
 132        int temp;
 133
 134        mutex_lock(&data->update_lock);
 135        if (data->config & TMP421_CONFIG_RANGE)
 136                temp = temp_from_u16(data->temp[index]);
 137        else
 138                temp = temp_from_s16(data->temp[index]);
 139        mutex_unlock(&data->update_lock);
 140
 141        return sprintf(buf, "%d\n", temp);
 142}
 143
 144static ssize_t show_fault(struct device *dev,
 145                          struct device_attribute *devattr, char *buf)
 146{
 147        int index = to_sensor_dev_attr(devattr)->index;
 148        struct tmp421_data *data = tmp421_update_device(dev);
 149
 150        /*
 151         * The OPEN bit signals a fault. This is bit 0 of the temperature
 152         * register (low byte).
 153         */
 154        if (data->temp[index] & 0x01)
 155                return sprintf(buf, "1\n");
 156        else
 157                return sprintf(buf, "0\n");
 158}
 159
 160static umode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
 161                                int n)
 162{
 163        struct device *dev = container_of(kobj, struct device, kobj);
 164        struct tmp421_data *data = dev_get_drvdata(dev);
 165        struct device_attribute *devattr;
 166        unsigned int index;
 167
 168        devattr = container_of(a, struct device_attribute, attr);
 169        index = to_sensor_dev_attr(devattr)->index;
 170
 171        if (index < data->channels)
 172                return a->mode;
 173
 174        return 0;
 175}
 176
 177static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
 178static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
 179static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
 180static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
 181static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
 182static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
 183static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
 184
 185static struct attribute *tmp421_attr[] = {
 186        &sensor_dev_attr_temp1_input.dev_attr.attr,
 187        &sensor_dev_attr_temp2_input.dev_attr.attr,
 188        &sensor_dev_attr_temp2_fault.dev_attr.attr,
 189        &sensor_dev_attr_temp3_input.dev_attr.attr,
 190        &sensor_dev_attr_temp3_fault.dev_attr.attr,
 191        &sensor_dev_attr_temp4_input.dev_attr.attr,
 192        &sensor_dev_attr_temp4_fault.dev_attr.attr,
 193        NULL
 194};
 195
 196static const struct attribute_group tmp421_group = {
 197        .attrs = tmp421_attr,
 198        .is_visible = tmp421_is_visible,
 199};
 200
 201static int tmp421_init_client(struct i2c_client *client)
 202{
 203        int config, config_orig;
 204
 205        /* Set the conversion rate to 2 Hz */
 206        i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 207
 208        /* Start conversions (disable shutdown if necessary) */
 209        config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 210        if (config < 0) {
 211                dev_err(&client->dev, "Could not read configuration"
 212                         " register (%d)\n", config);
 213                return -ENODEV;
 214        }
 215
 216        config_orig = config;
 217        config &= ~TMP421_CONFIG_SHUTDOWN;
 218
 219        if (config != config_orig) {
 220                dev_info(&client->dev, "Enable monitoring chip\n");
 221                i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 222        }
 223
 224        return 0;
 225}
 226
 227static int tmp421_detect(struct i2c_client *client,
 228                         struct i2c_board_info *info)
 229{
 230        enum chips kind;
 231        struct i2c_adapter *adapter = client->adapter;
 232        const char *names[] = { "TMP421", "TMP422", "TMP423" };
 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_DEVICE_ID_REG);
 243        switch (reg) {
 244        case TMP421_DEVICE_ID:
 245                kind = tmp421;
 246                break;
 247        case TMP422_DEVICE_ID:
 248                kind = tmp422;
 249                break;
 250        case TMP423_DEVICE_ID:
 251                kind = tmp423;
 252                break;
 253        default:
 254                return -ENODEV;
 255        }
 256
 257        strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 258        dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 259                 names[kind], client->addr);
 260
 261        return 0;
 262}
 263
 264static int tmp421_probe(struct i2c_client *client,
 265                        const struct i2c_device_id *id)
 266{
 267        struct tmp421_data *data;
 268        int err;
 269
 270        data = devm_kzalloc(&client->dev, sizeof(struct tmp421_data),
 271                            GFP_KERNEL);
 272        if (!data)
 273                return -ENOMEM;
 274
 275        i2c_set_clientdata(client, data);
 276        mutex_init(&data->update_lock);
 277        data->channels = id->driver_data;
 278
 279        err = tmp421_init_client(client);
 280        if (err)
 281                return err;
 282
 283        err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
 284        if (err)
 285                return err;
 286
 287        data->hwmon_dev = hwmon_device_register(&client->dev);
 288        if (IS_ERR(data->hwmon_dev)) {
 289                err = PTR_ERR(data->hwmon_dev);
 290                data->hwmon_dev = NULL;
 291                goto exit_remove;
 292        }
 293        return 0;
 294
 295exit_remove:
 296        sysfs_remove_group(&client->dev.kobj, &tmp421_group);
 297        return err;
 298}
 299
 300static int tmp421_remove(struct i2c_client *client)
 301{
 302        struct tmp421_data *data = i2c_get_clientdata(client);
 303
 304        hwmon_device_unregister(data->hwmon_dev);
 305        sysfs_remove_group(&client->dev.kobj, &tmp421_group);
 306
 307        return 0;
 308}
 309
 310static struct i2c_driver tmp421_driver = {
 311        .class = I2C_CLASS_HWMON,
 312        .driver = {
 313                .name   = "tmp421",
 314        },
 315        .probe = tmp421_probe,
 316        .remove = tmp421_remove,
 317        .id_table = tmp421_id,
 318        .detect = tmp421_detect,
 319        .address_list = normal_i2c,
 320};
 321
 322module_i2c_driver(tmp421_driver);
 323
 324MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 325MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
 326                   " driver");
 327MODULE_LICENSE("GPL");
 328
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