drivers/hwmon/tmp102.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /* Texas Instruments TMP102 SMBus temperature sensor driver
0003  *
0004  * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
0005  */
0006
0007 #include <linux/delay.h>
0008 #include <linux/module.h>
0009 #include <linux/init.h>
0010 #include <linux/slab.h>
0011 #include <linux/i2c.h>
0012 #include <linux/hwmon.h>
0013 #include <linux/hwmon-sysfs.h>
0014 #include <linux/err.h>
0015 #include <linux/mutex.h>
0016 #include <linux/device.h>
0017 #include <linux/jiffies.h>
0018 #include <linux/regmap.h>
0019 #include <linux/of.h>
0020
0021 #define DRIVER_NAME "tmp102"
0022
0023 #define TMP102_TEMP_REG         0x00
0024 #define TMP102_CONF_REG         0x01
0025 /* note: these bit definitions are byte swapped */
0026 #define     TMP102_CONF_SD      0x0100
0027 #define     TMP102_CONF_TM      0x0200
0028 #define     TMP102_CONF_POL     0x0400
0029 #define     TMP102_CONF_F0      0x0800
0030 #define     TMP102_CONF_F1      0x1000
0031 #define     TMP102_CONF_R0      0x2000
0032 #define     TMP102_CONF_R1      0x4000
0033 #define     TMP102_CONF_OS      0x8000
0034 #define     TMP102_CONF_EM      0x0010
0035 #define     TMP102_CONF_AL      0x0020
0036 #define     TMP102_CONF_CR0     0x0040
0037 #define     TMP102_CONF_CR1     0x0080
0038 #define TMP102_TLOW_REG         0x02
0039 #define TMP102_THIGH_REG        0x03
0040
0041 #define TMP102_CONFREG_MASK (TMP102_CONF_SD | TMP102_CONF_TM | \
0042                  TMP102_CONF_POL | TMP102_CONF_F0 | \
0043                  TMP102_CONF_F1 | TMP102_CONF_OS | \
0044                  TMP102_CONF_EM | TMP102_CONF_AL | \
0045                  TMP102_CONF_CR0 | TMP102_CONF_CR1)
0046
0047 #define TMP102_CONFIG_CLEAR (TMP102_CONF_SD | TMP102_CONF_OS | \
0048                  TMP102_CONF_CR0)
0049 #define TMP102_CONFIG_SET   (TMP102_CONF_TM | TMP102_CONF_EM | \
0050                  TMP102_CONF_CR1)
0051
0052 #define CONVERSION_TIME_MS      35  /* in milli-seconds */
0053
0054 struct tmp102 {
0055     struct regmap *regmap;
0056     u16 config_orig;
0057     unsigned long ready_time;
0058 };
0059
0060 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
0061 static inline int tmp102_reg_to_mC(s16 val)
0062 {
0063     return ((val & ~0x01) * 1000) / 128;
0064 }
0065
0066 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
0067 static inline u16 tmp102_mC_to_reg(int val)
0068 {
0069     return (val * 128) / 1000;
0070 }
0071
0072 static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
0073                u32 attr, int channel, long *temp)
0074 {
0075     struct tmp102 *tmp102 = dev_get_drvdata(dev);
0076     unsigned int regval;
0077     int err, reg;
0078
0079     switch (attr) {
0080     case hwmon_temp_input:
0081         /* Is it too early to return a conversion ? */
0082         if (time_before(jiffies, tmp102->ready_time)) {
0083             dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
0084             return -EAGAIN;
0085         }
0086         reg = TMP102_TEMP_REG;
0087         break;
0088     case hwmon_temp_max_hyst:
0089         reg = TMP102_TLOW_REG;
0090         break;
0091     case hwmon_temp_max:
0092         reg = TMP102_THIGH_REG;
0093         break;
0094     default:
0095         return -EOPNOTSUPP;
0096     }
0097
0098     err = regmap_read(tmp102->regmap, reg, &regval);
0099     if (err < 0)
0100         return err;
0101     *temp = tmp102_reg_to_mC(regval);
0102
0103     return 0;
0104 }
0105
0106 static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
0107             u32 attr, int channel, long temp)
0108 {
0109     struct tmp102 *tmp102 = dev_get_drvdata(dev);
0110     int reg;
0111
0112     switch (attr) {
0113     case hwmon_temp_max_hyst:
0114         reg = TMP102_TLOW_REG;
0115         break;
0116     case hwmon_temp_max:
0117         reg = TMP102_THIGH_REG;
0118         break;
0119     default:
0120         return -EOPNOTSUPP;
0121     }
0122
0123     temp = clamp_val(temp, -256000, 255000);
0124     return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
0125 }
0126
0127 static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
0128                  u32 attr, int channel)
0129 {
0130     if (type != hwmon_temp)
0131         return 0;
0132
0133     switch (attr) {
0134     case hwmon_temp_input:
0135         return 0444;
0136     case hwmon_temp_max_hyst:
0137     case hwmon_temp_max:
0138         return 0644;
0139     default:
0140         return 0;
0141     }
0142 }
0143
0144 static const struct hwmon_channel_info *tmp102_info[] = {
0145     HWMON_CHANNEL_INFO(chip,
0146                HWMON_C_REGISTER_TZ),
0147     HWMON_CHANNEL_INFO(temp,
0148                HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
0149     NULL
0150 };
0151
0152 static const struct hwmon_ops tmp102_hwmon_ops = {
0153     .is_visible = tmp102_is_visible,
0154     .read = tmp102_read,
0155     .write = tmp102_write,
0156 };
0157
0158 static const struct hwmon_chip_info tmp102_chip_info = {
0159     .ops = &tmp102_hwmon_ops,
0160     .info = tmp102_info,
0161 };
0162
0163 static void tmp102_restore_config(void *data)
0164 {
0165     struct tmp102 *tmp102 = data;
0166
0167     regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
0168 }
0169
0170 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
0171 {
0172     return reg != TMP102_TEMP_REG;
0173 }
0174
0175 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
0176 {
0177     return reg == TMP102_TEMP_REG;
0178 }
0179
0180 static const struct regmap_config tmp102_regmap_config = {
0181     .reg_bits = 8,
0182     .val_bits = 16,
0183     .max_register = TMP102_THIGH_REG,
0184     .writeable_reg = tmp102_is_writeable_reg,
0185     .volatile_reg = tmp102_is_volatile_reg,
0186     .val_format_endian = REGMAP_ENDIAN_BIG,
0187     .cache_type = REGCACHE_RBTREE,
0188     .use_single_read = true,
0189     .use_single_write = true,
0190 };
0191
0192 static int tmp102_probe(struct i2c_client *client)
0193 {
0194     struct device *dev = &client->dev;
0195     struct device *hwmon_dev;
0196     struct tmp102 *tmp102;
0197     unsigned int regval;
0198     int err;
0199
0200     if (!i2c_check_functionality(client->adapter,
0201                      I2C_FUNC_SMBUS_WORD_DATA)) {
0202         dev_err(dev,
0203             "adapter doesn't support SMBus word transactions\n");
0204         return -ENODEV;
0205     }
0206
0207     tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
0208     if (!tmp102)
0209         return -ENOMEM;
0210
0211     i2c_set_clientdata(client, tmp102);
0212
0213     tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
0214     if (IS_ERR(tmp102->regmap))
0215         return PTR_ERR(tmp102->regmap);
0216
0217     err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
0218     if (err < 0) {
0219         dev_err(dev, "error reading config register\n");
0220         return err;
0221     }
0222
0223     if ((regval & ~TMP102_CONFREG_MASK) !=
0224         (TMP102_CONF_R0 | TMP102_CONF_R1)) {
0225         dev_err(dev, "unexpected config register value\n");
0226         return -ENODEV;
0227     }
0228
0229     tmp102->config_orig = regval;
0230
0231     err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
0232     if (err)
0233         return err;
0234
0235     regval &= ~TMP102_CONFIG_CLEAR;
0236     regval |= TMP102_CONFIG_SET;
0237
0238     err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
0239     if (err < 0) {
0240         dev_err(dev, "error writing config register\n");
0241         return err;
0242     }
0243
0244     /*
0245      * Mark that we are not ready with data until the first
0246      * conversion is complete
0247      */
0248     tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
0249
0250     hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
0251                              tmp102,
0252                              &tmp102_chip_info,
0253                              NULL);
0254     if (IS_ERR(hwmon_dev)) {
0255         dev_dbg(dev, "unable to register hwmon device\n");
0256         return PTR_ERR(hwmon_dev);
0257     }
0258     dev_info(dev, "initialized\n");
0259
0260     return 0;
0261 }
0262
0263 #ifdef CONFIG_PM_SLEEP
0264 static int tmp102_suspend(struct device *dev)
0265 {
0266     struct i2c_client *client = to_i2c_client(dev);
0267     struct tmp102 *tmp102 = i2c_get_clientdata(client);
0268
0269     return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
0270                   TMP102_CONF_SD, TMP102_CONF_SD);
0271 }
0272
0273 static int tmp102_resume(struct device *dev)
0274 {
0275     struct i2c_client *client = to_i2c_client(dev);
0276     struct tmp102 *tmp102 = i2c_get_clientdata(client);
0277     int err;
0278
0279     err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
0280                  TMP102_CONF_SD, 0);
0281
0282     tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
0283
0284     return err;
0285 }
0286 #endif /* CONFIG_PM */
0287
0288 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
0289
0290 static const struct i2c_device_id tmp102_id[] = {
0291     { "tmp102", 0 },
0292     { }
0293 };
0294 MODULE_DEVICE_TABLE(i2c, tmp102_id);
0295
0296 static const struct of_device_id __maybe_unused tmp102_of_match[] = {
0297     { .compatible = "ti,tmp102" },
0298     { },
0299 };
0300 MODULE_DEVICE_TABLE(of, tmp102_of_match);
0301
0302 static struct i2c_driver tmp102_driver = {
0303     .driver.name    = DRIVER_NAME,
0304     .driver.of_match_table = of_match_ptr(tmp102_of_match),
0305     .driver.pm  = &tmp102_dev_pm_ops,
0306     .probe_new  = tmp102_probe,
0307     .id_table   = tmp102_id,
0308 };
0309
0310 module_i2c_driver(tmp102_driver);
0311
0312 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
0313 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
0314 MODULE_LICENSE("GPL");