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  * 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 #include <linux/thermal.h>
  31 #include <linux/of.h>
  32
  33 #define DRIVER_NAME "tmp102"
  34
  35 #define TMP102_TEMP_REG                 0x00
  36 #define TMP102_CONF_REG                 0x01
  37 /* note: these bit definitions are byte swapped */
  38 #define         TMP102_CONF_SD          0x0100
  39 #define         TMP102_CONF_TM          0x0200
  40 #define         TMP102_CONF_POL         0x0400
  41 #define         TMP102_CONF_F0          0x0800
  42 #define         TMP102_CONF_F1          0x1000
  43 #define         TMP102_CONF_R0          0x2000
  44 #define         TMP102_CONF_R1          0x4000
  45 #define         TMP102_CONF_OS          0x8000
  46 #define         TMP102_CONF_EM          0x0010
  47 #define         TMP102_CONF_AL          0x0020
  48 #define         TMP102_CONF_CR0         0x0040
  49 #define         TMP102_CONF_CR1         0x0080
  50 #define TMP102_TLOW_REG                 0x02
  51 #define TMP102_THIGH_REG                0x03
  52
  53 struct tmp102 {
  54         struct i2c_client *client;
  55         struct mutex lock;
  56         u16 config_orig;
  57         unsigned long last_update;
  58         int temp[3];
  59         bool first_time;
  60 };
  61
  62 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  63 static inline int tmp102_reg_to_mC(s16 val)
  64 {
  65         return ((val & ~0x01) * 1000) / 128;
  66 }
  67
  68 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  69 static inline u16 tmp102_mC_to_reg(int val)
  70 {
  71         return (val * 128) / 1000;
  72 }
  73
  74 static const u8 tmp102_reg[] = {
  75         TMP102_TEMP_REG,
  76         TMP102_TLOW_REG,
  77         TMP102_THIGH_REG,
  78 };
  79
  80 static struct tmp102 *tmp102_update_device(struct device *dev)
  81 {
  82         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  83         struct i2c_client *client = tmp102->client;
  84
  85         mutex_lock(&tmp102->lock);
  86         if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
  87                 int i;
  88                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
  89                         int status = i2c_smbus_read_word_swapped(client,
  90                                                                  tmp102_reg[i]);
  91                         if (status > -1)
  92                                 tmp102->temp[i] = tmp102_reg_to_mC(status);
  93                 }
  94                 tmp102->last_update = jiffies;
  95                 tmp102->first_time = false;
  96         }
  97         mutex_unlock(&tmp102->lock);
  98         return tmp102;
  99 }
 100
 101 static int tmp102_read_temp(void *dev, int *temp)
 102 {
 103         struct tmp102 *tmp102 = tmp102_update_device(dev);
 104
 105         /* Is it too early even to return a conversion? */
 106         if (tmp102->first_time) {
 107                 dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
 108                 return -EAGAIN;
 109         }
 110
 111         *temp = tmp102->temp[0];
 112
 113         return 0;
 114 }
 115
 116 static ssize_t tmp102_show_temp(struct device *dev,
 117                                 struct device_attribute *attr,
 118                                 char *buf)
 119 {
 120         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 121         struct tmp102 *tmp102 = tmp102_update_device(dev);
 122
 123         /* Is it too early even to return a read? */
 124         if (tmp102->first_time)
 125                 return -EAGAIN;
 126
 127         return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
 128 }
 129
 130 static ssize_t tmp102_set_temp(struct device *dev,
 131                                struct device_attribute *attr,
 132                                const char *buf, size_t count)
 133 {
 134         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 135         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 136         struct i2c_client *client = tmp102->client;
 137         long val;
 138         int status;
 139
 140         if (kstrtol(buf, 10, &val) < 0)
 141                 return -EINVAL;
 142         val = clamp_val(val, -256000, 255000);
 143
 144         mutex_lock(&tmp102->lock);
 145         tmp102->temp[sda->index] = val;
 146         status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
 147                                               tmp102_mC_to_reg(val));
 148         mutex_unlock(&tmp102->lock);
 149         return status ? : count;
 150 }
 151
 152 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
 153
 154 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 155                           tmp102_set_temp, 1);
 156
 157 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 158                           tmp102_set_temp, 2);
 159
 160 static struct attribute *tmp102_attrs[] = {
 161         &sensor_dev_attr_temp1_input.dev_attr.attr,
 162         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 163         &sensor_dev_attr_temp1_max.dev_attr.attr,
 164         NULL
 165 };
 166 ATTRIBUTE_GROUPS(tmp102);
 167
 168 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 169 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 170
 171 static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
 172         .get_temp = tmp102_read_temp,
 173 };
 174
 175 static void tmp102_restore_config(void *data)
 176 {
 177         struct tmp102 *tmp102 = data;
 178         struct i2c_client *client = tmp102->client;
 179
 180         i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 181                                      tmp102->config_orig);
 182 }
 183
 184 static int tmp102_probe(struct i2c_client *client,
 185                                   const struct i2c_device_id *id)
 186 {
 187         struct device *dev = &client->dev;
 188         struct device *hwmon_dev;
 189         struct tmp102 *tmp102;
 190         int status;
 191
 192         if (!i2c_check_functionality(client->adapter,
 193                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 194                 dev_err(dev,
 195                         "adapter doesn't support SMBus word transactions\n");
 196                 return -ENODEV;
 197         }
 198
 199         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 200         if (!tmp102)
 201                 return -ENOMEM;
 202
 203         i2c_set_clientdata(client, tmp102);
 204         tmp102->client = client;
 205
 206         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 207         if (status < 0) {
 208                 dev_err(dev, "error reading config register\n");
 209                 return status;
 210         }
 211         tmp102->config_orig = status;
 212
 213         devm_add_action(dev, tmp102_restore_config, tmp102);
 214
 215         status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
 216                                               TMP102_CONFIG);
 217         if (status < 0) {
 218                 dev_err(dev, "error writing config register\n");
 219                 return status;
 220         }
 221         status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 222         if (status < 0) {
 223                 dev_err(dev, "error reading config register\n");
 224                 return status;
 225         }
 226         status &= ~TMP102_CONFIG_RD_ONLY;
 227         if (status != TMP102_CONFIG) {
 228                 dev_err(dev, "config settings did not stick\n");
 229                 return -ENODEV;
 230         }
 231         tmp102->last_update = jiffies;
 232         /* Mark that we are not ready with data until conversion is complete */
 233         tmp102->first_time = true;
 234         mutex_init(&tmp102->lock);
 235
 236         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 237                                                            tmp102,
 238                                                            tmp102_groups);
 239         if (IS_ERR(hwmon_dev)) {
 240                 dev_dbg(dev, "unable to register hwmon device\n");
 241                 return PTR_ERR(hwmon_dev);
 242         }
 243         devm_thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
 244                                              &tmp102_of_thermal_ops);
 245
 246         dev_info(dev, "initialized\n");
 247
 248         return 0;
 249 }
 250
 251 #ifdef CONFIG_PM_SLEEP
 252 static int tmp102_suspend(struct device *dev)
 253 {
 254         struct i2c_client *client = to_i2c_client(dev);
 255         int config;
 256
 257         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 258         if (config < 0)
 259                 return config;
 260
 261         config |= TMP102_CONF_SD;
 262         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 263 }
 264
 265 static int tmp102_resume(struct device *dev)
 266 {
 267         struct i2c_client *client = to_i2c_client(dev);
 268         int config;
 269
 270         config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
 271         if (config < 0)
 272                 return config;
 273
 274         config &= ~TMP102_CONF_SD;
 275         return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
 276 }
 277 #endif /* CONFIG_PM */
 278
 279 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 280
 281 static const struct i2c_device_id tmp102_id[] = {
 282         { "tmp102", 0 },
 283         { }
 284 };
 285 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 286
 287 static struct i2c_driver tmp102_driver = {
 288         .driver.name    = DRIVER_NAME,
 289         .driver.pm      = &tmp102_dev_pm_ops,
 290         .probe          = tmp102_probe,
 291         .id_table       = tmp102_id,
 292 };
 293
 294 module_i2c_driver(tmp102_driver);
 295
 296 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 297 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 298 MODULE_LICENSE("GPL");