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/delay.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/i2c.h>
  21 #include <linux/hwmon.h>
  22 #include <linux/hwmon-sysfs.h>
  23 #include <linux/err.h>
  24 #include <linux/mutex.h>
  25 #include <linux/device.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/regmap.h>
  28 #include <linux/thermal.h>
  29 #include <linux/of.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
  51 #define TMP102_CONFREG_MASK     (TMP102_CONF_SD | TMP102_CONF_TM | \
  52                                  TMP102_CONF_POL | TMP102_CONF_F0 | \
  53                                  TMP102_CONF_F1 | TMP102_CONF_OS | \
  54                                  TMP102_CONF_EM | TMP102_CONF_AL | \
  55                                  TMP102_CONF_CR0 | TMP102_CONF_CR1)
  56
  57 #define TMP102_CONFIG_CLEAR     (TMP102_CONF_SD | TMP102_CONF_OS | \
  58                                  TMP102_CONF_CR0)
  59 #define TMP102_CONFIG_SET       (TMP102_CONF_TM | TMP102_CONF_EM | \
  60                                  TMP102_CONF_CR1)
  61
  62 #define CONVERSION_TIME_MS              35      /* in milli-seconds */
  63
  64 struct tmp102 {
  65         struct regmap *regmap;
  66         u16 config_orig;
  67         unsigned long ready_time;
  68 };
  69
  70 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  71 static inline int tmp102_reg_to_mC(s16 val)
  72 {
  73         return ((val & ~0x01) * 1000) / 128;
  74 }
  75
  76 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  77 static inline u16 tmp102_mC_to_reg(int val)
  78 {
  79         return (val * 128) / 1000;
  80 }
  81
  82 static int tmp102_read_temp(void *dev, int *temp)
  83 {
  84         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  85         unsigned int reg;
  86         int ret;
  87
  88         if (time_before(jiffies, tmp102->ready_time)) {
  89                 dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
  90                 return -EAGAIN;
  91         }
  92
  93         ret = regmap_read(tmp102->regmap, TMP102_TEMP_REG, &reg);
  94         if (ret < 0)
  95                 return ret;
  96
  97         *temp = tmp102_reg_to_mC(reg);
  98
  99         return 0;
 100 }
 101
 102 static ssize_t tmp102_show_temp(struct device *dev,
 103                                 struct device_attribute *attr,
 104                                 char *buf)
 105 {
 106         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 107         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 108         int regaddr = sda->index;
 109         unsigned int reg;
 110         int err;
 111
 112         if (regaddr == TMP102_TEMP_REG &&
 113             time_before(jiffies, tmp102->ready_time))
 114                 return -EAGAIN;
 115
 116         err = regmap_read(tmp102->regmap, regaddr, &reg);
 117         if (err < 0)
 118                 return err;
 119
 120         return sprintf(buf, "%d\n", tmp102_reg_to_mC(reg));
 121 }
 122
 123 static ssize_t tmp102_set_temp(struct device *dev,
 124                                struct device_attribute *attr,
 125                                const char *buf, size_t count)
 126 {
 127         struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
 128         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 129         int reg = sda->index;
 130         long val;
 131         int err;
 132
 133         if (kstrtol(buf, 10, &val) < 0)
 134                 return -EINVAL;
 135         val = clamp_val(val, -256000, 255000);
 136
 137         err = regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(val));
 138         return err ? : count;
 139 }
 140
 141 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL,
 142                           TMP102_TEMP_REG);
 143
 144 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
 145                           tmp102_set_temp, TMP102_TLOW_REG);
 146
 147 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
 148                           tmp102_set_temp, TMP102_THIGH_REG);
 149
 150 static struct attribute *tmp102_attrs[] = {
 151         &sensor_dev_attr_temp1_input.dev_attr.attr,
 152         &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
 153         &sensor_dev_attr_temp1_max.dev_attr.attr,
 154         NULL
 155 };
 156 ATTRIBUTE_GROUPS(tmp102);
 157
 158 static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
 159         .get_temp = tmp102_read_temp,
 160 };
 161
 162 static void tmp102_restore_config(void *data)
 163 {
 164         struct tmp102 *tmp102 = data;
 165
 166         regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
 167 }
 168
 169 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
 170 {
 171         return reg != TMP102_TEMP_REG;
 172 }
 173
 174 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
 175 {
 176         return reg == TMP102_TEMP_REG;
 177 }
 178
 179 static const struct regmap_config tmp102_regmap_config = {
 180         .reg_bits = 8,
 181         .val_bits = 16,
 182         .max_register = TMP102_THIGH_REG,
 183         .writeable_reg = tmp102_is_writeable_reg,
 184         .volatile_reg = tmp102_is_volatile_reg,
 185         .val_format_endian = REGMAP_ENDIAN_BIG,
 186         .cache_type = REGCACHE_RBTREE,
 187         .use_single_rw = true,
 188 };
 189
 190 static int tmp102_probe(struct i2c_client *client,
 191                                   const struct i2c_device_id *id)
 192 {
 193         struct device *dev = &client->dev;
 194         struct device *hwmon_dev;
 195         struct tmp102 *tmp102;
 196         unsigned int regval;
 197         int err;
 198
 199         if (!i2c_check_functionality(client->adapter,
 200                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 201                 dev_err(dev,
 202                         "adapter doesn't support SMBus word transactions\n");
 203                 return -ENODEV;
 204         }
 205
 206         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 207         if (!tmp102)
 208                 return -ENOMEM;
 209
 210         i2c_set_clientdata(client, tmp102);
 211
 212         tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
 213         if (IS_ERR(tmp102->regmap))
 214                 return PTR_ERR(tmp102->regmap);
 215
 216         err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
 217         if (err < 0) {
 218                 dev_err(dev, "error reading config register\n");
 219                 return err;
 220         }
 221
 222         if ((regval & ~TMP102_CONFREG_MASK) !=
 223             (TMP102_CONF_R0 | TMP102_CONF_R1)) {
 224                 dev_err(dev, "unexpected config register value\n");
 225                 return -ENODEV;
 226         }
 227
 228         tmp102->config_orig = regval;
 229
 230         devm_add_action(dev, tmp102_restore_config, tmp102);
 231
 232         regval &= ~TMP102_CONFIG_CLEAR;
 233         regval |= TMP102_CONFIG_SET;
 234
 235         err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
 236         if (err < 0) {
 237                 dev_err(dev, "error writing config register\n");
 238                 return err;
 239         }
 240
 241         tmp102->ready_time = jiffies;
 242         if (tmp102->config_orig & TMP102_CONF_SD) {
 243                 /*
 244                  * Mark that we are not ready with data until the first
 245                  * conversion is complete
 246                  */
 247                 tmp102->ready_time += msecs_to_jiffies(CONVERSION_TIME_MS);
 248         }
 249
 250         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 251                                                            tmp102,
 252                                                            tmp102_groups);
 253         if (IS_ERR(hwmon_dev)) {
 254                 dev_dbg(dev, "unable to register hwmon device\n");
 255                 return PTR_ERR(hwmon_dev);
 256         }
 257         devm_thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
 258                                              &tmp102_of_thermal_ops);
 259
 260         dev_info(dev, "initialized\n");
 261
 262         return 0;
 263 }
 264
 265 #ifdef CONFIG_PM_SLEEP
 266 static int tmp102_suspend(struct device *dev)
 267 {
 268         struct i2c_client *client = to_i2c_client(dev);
 269         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 270
 271         return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 272                                   TMP102_CONF_SD, TMP102_CONF_SD);
 273 }
 274
 275 static int tmp102_resume(struct device *dev)
 276 {
 277         struct i2c_client *client = to_i2c_client(dev);
 278         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 279         int err;
 280
 281         err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 282                                  TMP102_CONF_SD, 0);
 283
 284         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 285
 286         return err;
 287 }
 288 #endif /* CONFIG_PM */
 289
 290 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 291
 292 static const struct i2c_device_id tmp102_id[] = {
 293         { "tmp102", 0 },
 294         { }
 295 };
 296 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 297
 298 static struct i2c_driver tmp102_driver = {
 299         .driver.name    = DRIVER_NAME,
 300         .driver.pm      = &tmp102_dev_pm_ops,
 301         .probe          = tmp102_probe,
 302         .id_table       = tmp102_id,
 303 };
 304
 305 module_i2c_driver(tmp102_driver);
 306
 307 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 308 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 309 MODULE_LICENSE("GPL");