linux/drivers/hwmon/tmp102.c
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   1/* Texas Instruments TMP102 SMBus temperature sensor driver
   2 *
   3 * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
  18 */
  19
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/slab.h>
  23#include <linux/i2c.h>
  24#include <linux/hwmon.h>
  25#include <linux/hwmon-sysfs.h>
  26#include <linux/err.h>
  27#include <linux/mutex.h>
  28#include <linux/device.h>
  29#include <linux/jiffies.h>
  30
  31#define DRIVER_NAME "tmp102"
  32
  33#define TMP102_TEMP_REG                 0x00
  34#define TMP102_CONF_REG                 0x01
  35/* note: these bit definitions are byte swapped */
  36#define         TMP102_CONF_SD          0x0100
  37#define         TMP102_CONF_TM          0x0200
  38#define         TMP102_CONF_POL         0x0400
  39#define         TMP102_CONF_F0          0x0800
  40#define         TMP102_CONF_F1          0x1000
  41#define         TMP102_CONF_R0          0x2000
  42#define         TMP102_CONF_R1          0x4000
  43#define         TMP102_CONF_OS          0x8000
  44#define         TMP102_CONF_EM          0x0010
  45#define         TMP102_CONF_AL          0x0020
  46#define         TMP102_CONF_CR0         0x0040
  47#define         TMP102_CONF_CR1         0x0080
  48#define TMP102_TLOW_REG                 0x02
  49#define TMP102_THIGH_REG                0x03
  50
  51struct tmp102 {
  52        struct device *hwmon_dev;
  53        struct mutex lock;
  54        u16 config_orig;
  55        unsigned long last_update;
  56        int temp[3];
  57};
  58
  59/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  60static inline int tmp102_reg_to_mC(s16 val)
  61{
  62        return ((val & ~0x01) * 1000) / 128;
  63}
  64
  65/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  66static inline u16 tmp102_mC_to_reg(int val)
  67{
  68        return (val * 128) / 1000;
  69}
  70
  71static const u8 tmp102_reg[] = {
  72        TMP102_TEMP_REG,
  73        TMP102_TLOW_REG,
  74        TMP102_THIGH_REG,
  75};
  76
  77static struct tmp102 *tmp102_update_device(struct i2c_client *client)
  78{
  79        struct tmp102 *tmp102 = i2c_get_clientdata(client);
  80
  81        mutex_lock(&tmp102->lock);
  82        if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  83                int i;
  84                for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  85                        int status = i2c_smbus_read_word_swapped(client,
  86                                                                 tmp102_reg[i]);
  87                        if (status > -1)
  88                                tmp102->temp[i] = tmp102_reg_to_mC(status);
  89                }
  90                tmp102->last_update = jiffies;
  91        }
  92        mutex_unlock(&tmp102->lock);
  93        return tmp102;
  94}
  95
  96static ssize_t tmp102_show_temp(struct device *dev,
  97                                struct device_attribute *attr,
  98                                char *buf)
  99{
 100        struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 101        struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
 102
 103        return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 104}
 105
 106static ssize_t tmp102_set_temp(struct device *dev,
 107                               struct device_attribute *attr,
 108                               const char *buf, size_t count)
 109{
 110        struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 111        struct i2c_client *client = to_i2c_client(dev);
 112        struct tmp102 *tmp102 = i2c_get_clientdata(client);
 113        long val;
 114        int status;
 115
 116        if (kstrtol(buf, 10, &val) < 0)
 117                return -EINVAL;
 118        val = clamp_val(val, -256000, 255000);
 119
 120        mutex_lock(&tmp102->lock);
 121        tmp102->temp[sda->index] = val;
 122        status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 123                                              tmp102_mC_to_reg(val));
 124        mutex_unlock(&tmp102->lock);
 125        return status ? : count;
 126}
 127
 128static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 129
 130static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 131                          tmp102_set_temp, 1);
 132
 133static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 134                          tmp102_set_temp, 2);
 135
 136static struct attribute *tmp102_attributes[] = {
 137        &sensor_dev_attr_temp1_input.dev_attr.attr,
 138        &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 139        &sensor_dev_attr_temp1_max.dev_attr.attr,
 140        NULL
 141};
 142
 143static const struct attribute_group tmp102_attr_group = {
 144        .attrs = tmp102_attributes,
 145};
 146
 147#define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 148#define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 149
 150static int tmp102_probe(struct i2c_client *client,
 151                                  const struct i2c_device_id *id)
 152{
 153        struct tmp102 *tmp102;
 154        int status;
 155
 156        if (!i2c_check_functionality(client->adapter,
 157                                     I2C_FUNC_SMBUS_WORD_DATA)) {
 158                dev_err(&client->dev,
 159                        "adapter doesn't support SMBus word transactions\n");
 160                return -ENODEV;
 161        }
 162
 163        tmp102 = devm_kzalloc(&client->dev, sizeof(*tmp102), GFP_KERNEL);
 164        if (!tmp102)
 165                return -ENOMEM;
 166
 167        i2c_set_clientdata(client, tmp102);
 168
 169        status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 170        if (status < 0) {
 171                dev_err(&client->dev, "error reading config register\n");
 172                return status;
 173        }
 174        tmp102->config_orig = status;
 175        status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 176                                              TMP102_CONFIG);
 177        if (status < 0) {
 178                dev_err(&client->dev, "error writing config register\n");
 179                goto fail_restore_config;
 180        }
 181        status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 182        if (status < 0) {
 183                dev_err(&client->dev, "error reading config register\n");
 184                goto fail_restore_config;
 185        }
 186        status &= ~TMP102_CONFIG_RD_ONLY;
 187        if (status != TMP102_CONFIG) {
 188                dev_err(&client->dev, "config settings did not stick\n");
 189                status = -ENODEV;
 190                goto fail_restore_config;
 191        }
 192        tmp102->last_update = jiffies - HZ;
 193        mutex_init(&tmp102->lock);
 194
 195        status = sysfs_create_group(&client->dev.kobj, &tmp102_attr_group);
 196        if (status) {
 197                dev_dbg(&client->dev, "could not create sysfs files\n");
 198                goto fail_restore_config;
 199        }
 200        tmp102->hwmon_dev = hwmon_device_register(&client->dev);
 201        if (IS_ERR(tmp102->hwmon_dev)) {
 202                dev_dbg(&client->dev, "unable to register hwmon device\n");
 203                status = PTR_ERR(tmp102->hwmon_dev);
 204                goto fail_remove_sysfs;
 205        }
 206
 207        dev_info(&client->dev, "initialized\n");
 208
 209        return 0;
 210
 211fail_remove_sysfs:
 212        sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 213fail_restore_config:
 214        i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 215                                     tmp102->config_orig);
 216        return status;
 217}
 218
 219static int tmp102_remove(struct i2c_client *client)
 220{
 221        struct tmp102 *tmp102 = i2c_get_clientdata(client);
 222
 223        hwmon_device_unregister(tmp102->hwmon_dev);
 224        sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);
 225
 226        /* Stop monitoring if device was stopped originally */
 227        if (tmp102->config_orig & TMP102_CONF_SD) {
 228                int config;
 229
 230                config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 231                if (config >= 0)
 232                        i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 233                                                     config | TMP102_CONF_SD);
 234        }
 235
 236        return 0;
 237}
 238
 239#ifdef CONFIG_PM
 240static int tmp102_suspend(struct device *dev)
 241{
 242        struct i2c_client *client = to_i2c_client(dev);
 243        int config;
 244
 245        config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 246        if (config < 0)
 247                return config;
 248
 249        config |= TMP102_CONF_SD;
 250        return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 251}
 252
 253static int tmp102_resume(struct device *dev)
 254{
 255        struct i2c_client *client = to_i2c_client(dev);
 256        int config;
 257
 258        config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 259        if (config < 0)
 260                return config;
 261
 262        config &= ~TMP102_CONF_SD;
 263        return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 264}
 265
 266static const struct dev_pm_ops tmp102_dev_pm_ops = {
 267        .suspend        = tmp102_suspend,
 268        .resume         = tmp102_resume,
 269};
 270
 271#define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
 272#else
 273#define TMP102_DEV_PM_OPS NULL
 274#endif /* CONFIG_PM */
 275
 276static const struct i2c_device_id tmp102_id[] = {
 277        { "tmp102", 0 },
 278        { }
 279};
 280MODULE_DEVICE_TABLE(i2c, tmp102_id);
 281
 282static struct i2c_driver tmp102_driver = {
 283        .driver.name    = DRIVER_NAME,
 284        .driver.pm      = TMP102_DEV_PM_OPS,
 285        .probe          = tmp102_probe,
 286        .remove         = tmp102_remove,
 287        .id_table       = tmp102_id,
 288};
 289
 290module_i2c_driver(tmp102_driver);
 291
 292MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 293MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 294MODULE_LICENSE("GPL");
 295
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