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/of.h>
  29
  30 #define DRIVER_NAME "tmp102"
  31
  32 #define TMP102_TEMP_REG                 0x00
  33 #define TMP102_CONF_REG                 0x01
  34 /* note: these bit definitions are byte swapped */
  35 #define         TMP102_CONF_SD          0x0100
  36 #define         TMP102_CONF_TM          0x0200
  37 #define         TMP102_CONF_POL         0x0400
  38 #define         TMP102_CONF_F0          0x0800
  39 #define         TMP102_CONF_F1          0x1000
  40 #define         TMP102_CONF_R0          0x2000
  41 #define         TMP102_CONF_R1          0x4000
  42 #define         TMP102_CONF_OS          0x8000
  43 #define         TMP102_CONF_EM          0x0010
  44 #define         TMP102_CONF_AL          0x0020
  45 #define         TMP102_CONF_CR0         0x0040
  46 #define         TMP102_CONF_CR1         0x0080
  47 #define TMP102_TLOW_REG                 0x02
  48 #define TMP102_THIGH_REG                0x03
  49
  50 #define TMP102_CONFREG_MASK     (TMP102_CONF_SD | TMP102_CONF_TM | \
  51                                  TMP102_CONF_POL | TMP102_CONF_F0 | \
  52                                  TMP102_CONF_F1 | TMP102_CONF_OS | \
  53                                  TMP102_CONF_EM | TMP102_CONF_AL | \
  54                                  TMP102_CONF_CR0 | TMP102_CONF_CR1)
  55
  56 #define TMP102_CONFIG_CLEAR     (TMP102_CONF_SD | TMP102_CONF_OS | \
  57                                  TMP102_CONF_CR0)
  58 #define TMP102_CONFIG_SET       (TMP102_CONF_TM | TMP102_CONF_EM | \
  59                                  TMP102_CONF_CR1)
  60
  61 #define CONVERSION_TIME_MS              35      /* in milli-seconds */
  62
  63 struct tmp102 {
  64         struct regmap *regmap;
  65         u16 config_orig;
  66         unsigned long ready_time;
  67 };
  68
  69 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  70 static inline int tmp102_reg_to_mC(s16 val)
  71 {
  72         return ((val & ~0x01) * 1000) / 128;
  73 }
  74
  75 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  76 static inline u16 tmp102_mC_to_reg(int val)
  77 {
  78         return (val * 128) / 1000;
  79 }
  80
  81 static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
  82                        u32 attr, int channel, long *temp)
  83 {
  84         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  85         unsigned int regval;
  86         int err, reg;
  87
  88         switch (attr) {
  89         case hwmon_temp_input:
  90                 /* Is it too early to return a conversion ? */
  91                 if (time_before(jiffies, tmp102->ready_time)) {
  92                         dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
  93                         return -EAGAIN;
  94                 }
  95                 reg = TMP102_TEMP_REG;
  96                 break;
  97         case hwmon_temp_max_hyst:
  98                 reg = TMP102_TLOW_REG;
  99                 break;
 100         case hwmon_temp_max:
 101                 reg = TMP102_THIGH_REG;
 102                 break;
 103         default:
 104                 return -EOPNOTSUPP;
 105         }
 106
 107         err = regmap_read(tmp102->regmap, reg, &regval);
 108         if (err < 0)
 109                 return err;
 110         *temp = tmp102_reg_to_mC(regval);
 111
 112         return 0;
 113 }
 114
 115 static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
 116                         u32 attr, int channel, long temp)
 117 {
 118         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 119         int reg;
 120
 121         switch (attr) {
 122         case hwmon_temp_max_hyst:
 123                 reg = TMP102_TLOW_REG;
 124                 break;
 125         case hwmon_temp_max:
 126                 reg = TMP102_THIGH_REG;
 127                 break;
 128         default:
 129                 return -EOPNOTSUPP;
 130         }
 131
 132         temp = clamp_val(temp, -256000, 255000);
 133         return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
 134 }
 135
 136 static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
 137                                  u32 attr, int channel)
 138 {
 139         if (type != hwmon_temp)
 140                 return 0;
 141
 142         switch (attr) {
 143         case hwmon_temp_input:
 144                 return 0444;
 145         case hwmon_temp_max_hyst:
 146         case hwmon_temp_max:
 147                 return 0644;
 148         default:
 149                 return 0;
 150         }
 151 }
 152
 153 static const struct hwmon_channel_info *tmp102_info[] = {
 154         HWMON_CHANNEL_INFO(chip,
 155                            HWMON_C_REGISTER_TZ),
 156         HWMON_CHANNEL_INFO(temp,
 157                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
 158         NULL
 159 };
 160
 161 static const struct hwmon_ops tmp102_hwmon_ops = {
 162         .is_visible = tmp102_is_visible,
 163         .read = tmp102_read,
 164         .write = tmp102_write,
 165 };
 166
 167 static const struct hwmon_chip_info tmp102_chip_info = {
 168         .ops = &tmp102_hwmon_ops,
 169         .info = tmp102_info,
 170 };
 171
 172 static void tmp102_restore_config(void *data)
 173 {
 174         struct tmp102 *tmp102 = data;
 175
 176         regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
 177 }
 178
 179 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
 180 {
 181         return reg != TMP102_TEMP_REG;
 182 }
 183
 184 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
 185 {
 186         return reg == TMP102_TEMP_REG;
 187 }
 188
 189 static const struct regmap_config tmp102_regmap_config = {
 190         .reg_bits = 8,
 191         .val_bits = 16,
 192         .max_register = TMP102_THIGH_REG,
 193         .writeable_reg = tmp102_is_writeable_reg,
 194         .volatile_reg = tmp102_is_volatile_reg,
 195         .val_format_endian = REGMAP_ENDIAN_BIG,
 196         .cache_type = REGCACHE_RBTREE,
 197         .use_single_read = true,
 198         .use_single_write = true,
 199 };
 200
 201 static int tmp102_probe(struct i2c_client *client,
 202                         const struct i2c_device_id *id)
 203 {
 204         struct device *dev = &client->dev;
 205         struct device *hwmon_dev;
 206         struct tmp102 *tmp102;
 207         unsigned int regval;
 208         int err;
 209
 210         if (!i2c_check_functionality(client->adapter,
 211                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 212                 dev_err(dev,
 213                         "adapter doesn't support SMBus word transactions\n");
 214                 return -ENODEV;
 215         }
 216
 217         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 218         if (!tmp102)
 219                 return -ENOMEM;
 220
 221         i2c_set_clientdata(client, tmp102);
 222
 223         tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
 224         if (IS_ERR(tmp102->regmap))
 225                 return PTR_ERR(tmp102->regmap);
 226
 227         err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
 228         if (err < 0) {
 229                 dev_err(dev, "error reading config register\n");
 230                 return err;
 231         }
 232
 233         if ((regval & ~TMP102_CONFREG_MASK) !=
 234             (TMP102_CONF_R0 | TMP102_CONF_R1)) {
 235                 dev_err(dev, "unexpected config register value\n");
 236                 return -ENODEV;
 237         }
 238
 239         tmp102->config_orig = regval;
 240
 241         err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
 242         if (err)
 243                 return err;
 244
 245         regval &= ~TMP102_CONFIG_CLEAR;
 246         regval |= TMP102_CONFIG_SET;
 247
 248         err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
 249         if (err < 0) {
 250                 dev_err(dev, "error writing config register\n");
 251                 return err;
 252         }
 253
 254         /*
 255          * Mark that we are not ready with data until the first
 256          * conversion is complete
 257          */
 258         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 259
 260         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 261                                                          tmp102,
 262                                                          &tmp102_chip_info,
 263                                                          NULL);
 264         if (IS_ERR(hwmon_dev)) {
 265                 dev_dbg(dev, "unable to register hwmon device\n");
 266                 return PTR_ERR(hwmon_dev);
 267         }
 268         dev_info(dev, "initialized\n");
 269
 270         return 0;
 271 }
 272
 273 #ifdef CONFIG_PM_SLEEP
 274 static int tmp102_suspend(struct device *dev)
 275 {
 276         struct i2c_client *client = to_i2c_client(dev);
 277         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 278
 279         return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 280                                   TMP102_CONF_SD, TMP102_CONF_SD);
 281 }
 282
 283 static int tmp102_resume(struct device *dev)
 284 {
 285         struct i2c_client *client = to_i2c_client(dev);
 286         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 287         int err;
 288
 289         err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 290                                  TMP102_CONF_SD, 0);
 291
 292         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 293
 294         return err;
 295 }
 296 #endif /* CONFIG_PM */
 297
 298 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 299
 300 static const struct i2c_device_id tmp102_id[] = {
 301         { "tmp102", 0 },
 302         { }
 303 };
 304 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 305
 306 static const struct of_device_id __maybe_unused tmp102_of_match[] = {
 307         { .compatible = "ti,tmp102" },
 308         { },
 309 };
 310 MODULE_DEVICE_TABLE(of, tmp102_of_match);
 311
 312 static struct i2c_driver tmp102_driver = {
 313         .driver.name    = DRIVER_NAME,
 314         .driver.of_match_table = of_match_ptr(tmp102_of_match),
 315         .driver.pm      = &tmp102_dev_pm_ops,
 316         .probe          = tmp102_probe,
 317         .id_table       = tmp102_id,
 318 };
 319
 320 module_i2c_driver(tmp102_driver);
 321
 322 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 323 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 324 MODULE_LICENSE("GPL");