drivers/hwmon/tmp102.c

   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
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/i2c.h>
  20 #include <linux/hwmon.h>
  21 #include <linux/hwmon-sysfs.h>
  22 #include <linux/err.h>
  23 #include <linux/mutex.h>
  24 #include <linux/device.h>
  25 #include <linux/jiffies.h>
  26 #include <linux/thermal.h>
  27 #include <linux/of.h>
  28
  29 #define DRIVER_NAME "tmp102"
  30
  31 #define TMP102_TEMP_REG                 0x00
  32 #define TMP102_CONF_REG                 0x01
  33 /* note: these bit definitions are byte swapped */
  34 #define         TMP102_CONF_SD          0x0100
  35 #define         TMP102_CONF_TM          0x0200
  36 #define         TMP102_CONF_POL         0x0400
  37 #define         TMP102_CONF_F0          0x0800
  38 #define         TMP102_CONF_F1          0x1000
  39 #define         TMP102_CONF_R0          0x2000
  40 #define         TMP102_CONF_R1          0x4000
  41 #define         TMP102_CONF_OS          0x8000
  42 #define         TMP102_CONF_EM          0x0010
  43 #define         TMP102_CONF_AL          0x0020
  44 #define         TMP102_CONF_CR0         0x0040
  45 #define         TMP102_CONF_CR1         0x0080
  46 #define TMP102_TLOW_REG                 0x02
  47 #define TMP102_THIGH_REG                0x03
  48
  49 struct tmp102 {
  50         struct i2c_client *client;
  51         struct mutex lock;
  52         u16 config_orig;
  53         unsigned long last_update;
  54         int temp[3];
  55         bool first_time;
  56 };
  57
  58 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  59 static inline int tmp102_reg_to_mC(s16 val)
  60 {
  61         return ((val & ~0x01) * 1000) / 128;
  62 }
  63
  64 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  65 static inline u16 tmp102_mC_to_reg(int val)
  66 {
  67         return (val * 128) / 1000;
  68 }
  69
  70 static const u8 tmp102_reg[] = {
  71         TMP102_TEMP_REG,
  72         TMP102_TLOW_REG,
  73         TMP102_THIGH_REG,
  74 };
  75
  76 static struct tmp102 *tmp102_update_device(struct device *dev)
  77 {
  78         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  79         struct i2c_client *client = tmp102->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                 tmp102->first_time = false;
  92         }
  93         mutex_unlock(&tmp102->lock);
  94         return tmp102;
  95 }
  96
  97 static int tmp102_read_temp(void *dev, int *temp)
  98 {
  99         struct tmp102 *tmp102 = tmp102_update_device(dev);
 100
 101         /* Is it too early even to return a conversion? */
 102         if (tmp102->first_time) {
 103                 dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
 104                 return -EAGAIN;
 105         }
 106
 107         *temp = tmp102->temp[0];
 108
 109         return 0;
 110 }
 111
 112 static ssize_t tmp102_show_temp(struct device *dev,
 113                                 struct device_attribute *attr,
 114                                 char *buf)
 115 {
 116         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 117         struct tmp102 *tmp102 = tmp102_update_device(dev);
 118
 119         /* Is it too early even to return a read? */
 120         if (tmp102->first_time)
 121                 return -EAGAIN;
 122
 123         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 124 }
 125
 126 static ssize_t tmp102_set_temp(struct device *dev,
 127                                struct device_attribute *attr,
 128                                const char *buf, size_t count)
 129 {
 130         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 131         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 132         struct i2c_client *client = tmp102->client;
 133         long val;
 134         int status;
 135
 136         if (kstrtol(buf, 10, &val) < 0)
 137                 return -EINVAL;
 138         val = clamp_val(val, -256000, 255000);
 139
 140         mutex_lock(&tmp102->lock);
 141         tmp102->temp[sda->index] = val;
 142         status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 143                                               tmp102_mC_to_reg(val));
 144         mutex_unlock(&tmp102->lock);
 145         return status ? : count;
 146 }
 147
 148 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 149
 150 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 151                           tmp102_set_temp, 1);
 152
 153 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 154                           tmp102_set_temp, 2);
 155
 156 static struct attribute *tmp102_attrs[] = {
 157         &sensor_dev_attr_temp1_input.dev_attr.attr,
 158         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 159         &sensor_dev_attr_temp1_max.dev_attr.attr,
 160         NULL
 161 };
 162 ATTRIBUTE_GROUPS(tmp102);
 163
 164 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 165 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 166
 167 static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
 168         .get_temp = tmp102_read_temp,
 169 };
 170
 171 static void tmp102_restore_config(void *data)
 172 {
 173         struct tmp102 *tmp102 = data;
 174         struct i2c_client *client = tmp102->client;
 175
 176         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 177                                      tmp102->config_orig);
 178 }
 179
 180 static int tmp102_probe(struct i2c_client *client,
 181                                   const struct i2c_device_id *id)
 182 {
 183         struct device *dev = &client->dev;
 184         struct device *hwmon_dev;
 185         struct tmp102 *tmp102;
 186         int status;
 187
 188         if (!i2c_check_functionality(client->adapter,
 189                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 190                 dev_err(dev,
 191                         "adapter doesn't support SMBus word transactions\n");
 192                 return -ENODEV;
 193         }
 194
 195         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 196         if (!tmp102)
 197                 return -ENOMEM;
 198
 199         i2c_set_clientdata(client, tmp102);
 200         tmp102->client = client;
 201
 202         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 203         if (status < 0) {
 204                 dev_err(dev, "error reading config register\n");
 205                 return status;
 206         }
 207         tmp102->config_orig = status;
 208
 209         devm_add_action(dev, tmp102_restore_config, tmp102);
 210
 211         status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 212                                               TMP102_CONFIG);
 213         if (status < 0) {
 214                 dev_err(dev, "error writing config register\n");
 215                 return status;
 216         }
 217         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 218         if (status < 0) {
 219                 dev_err(dev, "error reading config register\n");
 220                 return status;
 221         }
 222         status &= ~TMP102_CONFIG_RD_ONLY;
 223         if (status != TMP102_CONFIG) {
 224                 dev_err(dev, "config settings did not stick\n");
 225                 return -ENODEV;
 226         }
 227         tmp102->last_update = jiffies;
 228         /* Mark that we are not ready with data until conversion is complete */
 229         tmp102->first_time = true;
 230         mutex_init(&tmp102->lock);
 231
 232         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 233                                                            tmp102,
 234                                                            tmp102_groups);
 235         if (IS_ERR(hwmon_dev)) {
 236                 dev_dbg(dev, "unable to register hwmon device\n");
 237                 return PTR_ERR(hwmon_dev);
 238         }
 239         devm_thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
 240                                              &tmp102_of_thermal_ops);
 241
 242         dev_info(dev, "initialized\n");
 243
 244         return 0;
 245 }
 246
 247 #ifdef CONFIG_PM_SLEEP
 248 static int tmp102_suspend(struct device *dev)
 249 {
 250         struct i2c_client *client = to_i2c_client(dev);
 251         int config;
 252
 253         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 254         if (config < 0)
 255                 return config;
 256
 257         config |= TMP102_CONF_SD;
 258         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 259 }
 260
 261 static int tmp102_resume(struct device *dev)
 262 {
 263         struct i2c_client *client = to_i2c_client(dev);
 264         int config;
 265
 266         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 267         if (config < 0)
 268                 return config;
 269
 270         config &= ~TMP102_CONF_SD;
 271         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 272 }
 273 #endif /* CONFIG_PM */
 274
 275 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 276
 277 static const struct i2c_device_id tmp102_id[] = {
 278         { "tmp102", 0 },
 279         { }
 280 };
 281 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 282
 283 static struct i2c_driver tmp102_driver = {
 284         .driver.name    = DRIVER_NAME,
 285         .driver.pm      = &tmp102_dev_pm_ops,
 286         .probe          = tmp102_probe,
 287         .id_table       = tmp102_id,
 288 };
 289
 290 module_i2c_driver(tmp102_driver);
 291
 292 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 293 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 294 MODULE_LICENSE("GPL");