drivers/hwmon/tmp102.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Texas Instruments TMP102 SMBus temperature sensor driver
   3  *
   4  * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/slab.h>
  11 #include <linux/i2c.h>
  12 #include <linux/hwmon.h>
  13 #include <linux/hwmon-sysfs.h>
  14 #include <linux/err.h>
  15 #include <linux/mutex.h>
  16 #include <linux/device.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/regmap.h>
  19 #include <linux/of.h>
  20
  21 #define DRIVER_NAME "tmp102"
  22
  23 #define TMP102_TEMP_REG                 0x00
  24 #define TMP102_CONF_REG                 0x01
  25 /* note: these bit definitions are byte swapped */
  26 #define         TMP102_CONF_SD          0x0100
  27 #define         TMP102_CONF_TM          0x0200
  28 #define         TMP102_CONF_POL         0x0400
  29 #define         TMP102_CONF_F0          0x0800
  30 #define         TMP102_CONF_F1          0x1000
  31 #define         TMP102_CONF_R0          0x2000
  32 #define         TMP102_CONF_R1          0x4000
  33 #define         TMP102_CONF_OS          0x8000
  34 #define         TMP102_CONF_EM          0x0010
  35 #define         TMP102_CONF_AL          0x0020
  36 #define         TMP102_CONF_CR0         0x0040
  37 #define         TMP102_CONF_CR1         0x0080
  38 #define TMP102_TLOW_REG                 0x02
  39 #define TMP102_THIGH_REG                0x03
  40
  41 #define TMP102_CONFREG_MASK     (TMP102_CONF_SD | TMP102_CONF_TM | \
  42                                  TMP102_CONF_POL | TMP102_CONF_F0 | \
  43                                  TMP102_CONF_F1 | TMP102_CONF_OS | \
  44                                  TMP102_CONF_EM | TMP102_CONF_AL | \
  45                                  TMP102_CONF_CR0 | TMP102_CONF_CR1)
  46
  47 #define TMP102_CONFIG_CLEAR     (TMP102_CONF_SD | TMP102_CONF_OS | \
  48                                  TMP102_CONF_CR0)
  49 #define TMP102_CONFIG_SET       (TMP102_CONF_TM | TMP102_CONF_EM | \
  50                                  TMP102_CONF_CR1)
  51
  52 #define CONVERSION_TIME_MS              35      /* in milli-seconds */
  53
  54 struct tmp102 {
  55         struct regmap *regmap;
  56         u16 config_orig;
  57         unsigned long ready_time;
  58 };
  59
  60 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  61 static inline int tmp102_reg_to_mC(s16 val)
  62 {
  63         return ((val & ~0x01) * 1000) / 128;
  64 }
  65
  66 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  67 static inline u16 tmp102_mC_to_reg(int val)
  68 {
  69         return (val * 128) / 1000;
  70 }
  71
  72 static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
  73                        u32 attr, int channel, long *temp)
  74 {
  75         struct tmp102 *tmp102 = dev_get_drvdata(dev);
  76         unsigned int regval;
  77         int err, reg;
  78
  79         switch (attr) {
  80         case hwmon_temp_input:
  81                 /* Is it too early to return a conversion ? */
  82                 if (time_before(jiffies, tmp102->ready_time)) {
  83                         dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
  84                         return -EAGAIN;
  85                 }
  86                 reg = TMP102_TEMP_REG;
  87                 break;
  88         case hwmon_temp_max_hyst:
  89                 reg = TMP102_TLOW_REG;
  90                 break;
  91         case hwmon_temp_max:
  92                 reg = TMP102_THIGH_REG;
  93                 break;
  94         default:
  95                 return -EOPNOTSUPP;
  96         }
  97
  98         err = regmap_read(tmp102->regmap, reg, &regval);
  99         if (err < 0)
 100                 return err;
 101         *temp = tmp102_reg_to_mC(regval);
 102
 103         return 0;
 104 }
 105
 106 static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
 107                         u32 attr, int channel, long temp)
 108 {
 109         struct tmp102 *tmp102 = dev_get_drvdata(dev);
 110         int reg;
 111
 112         switch (attr) {
 113         case hwmon_temp_max_hyst:
 114                 reg = TMP102_TLOW_REG;
 115                 break;
 116         case hwmon_temp_max:
 117                 reg = TMP102_THIGH_REG;
 118                 break;
 119         default:
 120                 return -EOPNOTSUPP;
 121         }
 122
 123         temp = clamp_val(temp, -256000, 255000);
 124         return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
 125 }
 126
 127 static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
 128                                  u32 attr, int channel)
 129 {
 130         if (type != hwmon_temp)
 131                 return 0;
 132
 133         switch (attr) {
 134         case hwmon_temp_input:
 135                 return 0444;
 136         case hwmon_temp_max_hyst:
 137         case hwmon_temp_max:
 138                 return 0644;
 139         default:
 140                 return 0;
 141         }
 142 }
 143
 144 static const struct hwmon_channel_info *tmp102_info[] = {
 145         HWMON_CHANNEL_INFO(chip,
 146                            HWMON_C_REGISTER_TZ),
 147         HWMON_CHANNEL_INFO(temp,
 148                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
 149         NULL
 150 };
 151
 152 static const struct hwmon_ops tmp102_hwmon_ops = {
 153         .is_visible = tmp102_is_visible,
 154         .read = tmp102_read,
 155         .write = tmp102_write,
 156 };
 157
 158 static const struct hwmon_chip_info tmp102_chip_info = {
 159         .ops = &tmp102_hwmon_ops,
 160         .info = tmp102_info,
 161 };
 162
 163 static void tmp102_restore_config(void *data)
 164 {
 165         struct tmp102 *tmp102 = data;
 166
 167         regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
 168 }
 169
 170 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
 171 {
 172         return reg != TMP102_TEMP_REG;
 173 }
 174
 175 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
 176 {
 177         return reg == TMP102_TEMP_REG;
 178 }
 179
 180 static const struct regmap_config tmp102_regmap_config = {
 181         .reg_bits = 8,
 182         .val_bits = 16,
 183         .max_register = TMP102_THIGH_REG,
 184         .writeable_reg = tmp102_is_writeable_reg,
 185         .volatile_reg = tmp102_is_volatile_reg,
 186         .val_format_endian = REGMAP_ENDIAN_BIG,
 187         .cache_type = REGCACHE_RBTREE,
 188         .use_single_read = true,
 189         .use_single_write = true,
 190 };
 191
 192 static int tmp102_probe(struct i2c_client *client,
 193                         const struct i2c_device_id *id)
 194 {
 195         struct device *dev = &client->dev;
 196         struct device *hwmon_dev;
 197         struct tmp102 *tmp102;
 198         unsigned int regval;
 199         int err;
 200
 201         if (!i2c_check_functionality(client->adapter,
 202                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 203                 dev_err(dev,
 204                         "adapter doesn't support SMBus word transactions\n");
 205                 return -ENODEV;
 206         }
 207
 208         tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
 209         if (!tmp102)
 210                 return -ENOMEM;
 211
 212         i2c_set_clientdata(client, tmp102);
 213
 214         tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
 215         if (IS_ERR(tmp102->regmap))
 216                 return PTR_ERR(tmp102->regmap);
 217
 218         err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
 219         if (err < 0) {
 220                 dev_err(dev, "error reading config register\n");
 221                 return err;
 222         }
 223
 224         if ((regval & ~TMP102_CONFREG_MASK) !=
 225             (TMP102_CONF_R0 | TMP102_CONF_R1)) {
 226                 dev_err(dev, "unexpected config register value\n");
 227                 return -ENODEV;
 228         }
 229
 230         tmp102->config_orig = regval;
 231
 232         err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
 233         if (err)
 234                 return err;
 235
 236         regval &= ~TMP102_CONFIG_CLEAR;
 237         regval |= TMP102_CONFIG_SET;
 238
 239         err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
 240         if (err < 0) {
 241                 dev_err(dev, "error writing config register\n");
 242                 return err;
 243         }
 244
 245         /*
 246          * Mark that we are not ready with data until the first
 247          * conversion is complete
 248          */
 249         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 250
 251         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 252                                                          tmp102,
 253                                                          &tmp102_chip_info,
 254                                                          NULL);
 255         if (IS_ERR(hwmon_dev)) {
 256                 dev_dbg(dev, "unable to register hwmon device\n");
 257                 return PTR_ERR(hwmon_dev);
 258         }
 259         dev_info(dev, "initialized\n");
 260
 261         return 0;
 262 }
 263
 264 #ifdef CONFIG_PM_SLEEP
 265 static int tmp102_suspend(struct device *dev)
 266 {
 267         struct i2c_client *client = to_i2c_client(dev);
 268         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 269
 270         return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 271                                   TMP102_CONF_SD, TMP102_CONF_SD);
 272 }
 273
 274 static int tmp102_resume(struct device *dev)
 275 {
 276         struct i2c_client *client = to_i2c_client(dev);
 277         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 278         int err;
 279
 280         err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
 281                                  TMP102_CONF_SD, 0);
 282
 283         tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
 284
 285         return err;
 286 }
 287 #endif /* CONFIG_PM */
 288
 289 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
 290
 291 static const struct i2c_device_id tmp102_id[] = {
 292         { "tmp102", 0 },
 293         { }
 294 };
 295 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 296
 297 static const struct of_device_id __maybe_unused tmp102_of_match[] = {
 298         { .compatible = "ti,tmp102" },
 299         { },
 300 };
 301 MODULE_DEVICE_TABLE(of, tmp102_of_match);
 302
 303 static struct i2c_driver tmp102_driver = {
 304         .driver.name    = DRIVER_NAME,
 305         .driver.of_match_table = of_match_ptr(tmp102_of_match),
 306         .driver.pm      = &tmp102_dev_pm_ops,
 307         .probe          = tmp102_probe,
 308         .id_table       = tmp102_id,
 309 };
 310
 311 module_i2c_driver(tmp102_driver);
 312
 313 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 314 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 315 MODULE_LICENSE("GPL");