/* Texas Instruments TMP108 SMBus temperature sensor driver * * Copyright (C) 2016 John Muir <john@jmuir.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/delay.h> #include <linux/device.h> #include <linux/err.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> #include <linux/i2c.h> #include <linux/init.h> #include <linux/jiffies.h> #include <linux/regmap.h> #include <linux/slab.h> #define DRIVER_NAME "tmp108" #define TMP108_REG_TEMP 0x00 #define TMP108_REG_CONF 0x01 #define TMP108_REG_TLOW 0x02 #define TMP108_REG_THIGH 0x03 #define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */ #define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */ /* Configuration register bits. * Note: these bit definitions are byte swapped. */ #define TMP108_CONF_M0 0x0100 /* Sensor mode. */ #define TMP108_CONF_M1 0x0200 #define TMP108_CONF_TM 0x0400 /* Thermostat mode. */ #define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */ #define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */ #define TMP108_CONF_CR0 0x2000 /* Conversion rate. */ #define TMP108_CONF_CR1 0x4000 #define TMP108_CONF_ID 0x8000 #define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */ #define TMP108_CONF_HYS1 0x0020 #define TMP108_CONF_POL 0x0080 /* Polarity of alert. */ /* Defaults set by the hardware upon reset. */ #define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\ TMP108_CONF_HYS0 | TMP108_CONF_M1) /* These bits are read-only. */ #define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\ TMP108_CONF_ID) #define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1) #define TMP108_MODE_SHUTDOWN 0x0000 #define TMP108_MODE_ONE_SHOT TMP108_CONF_M0 #define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */ /* When M1 is set, M0 is ignored. */ #define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1) #define TMP108_CONVRATE_0P25HZ 0x0000 #define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */ #define TMP108_CONVRATE_4HZ TMP108_CONF_CR1 #define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1) #define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1) #define TMP108_HYSTERESIS_0C 0x0000 #define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */ #define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1 #define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1) #define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */ struct tmp108 { struct regmap *regmap; u16 orig_config; unsigned long ready_time; }; /* convert 12-bit TMP108 register value to milliCelsius */ static inline int tmp108_temp_reg_to_mC(s16 val) { return (val & ~0x0f) * 1000 / 256; } /* convert milliCelsius to left adjusted 12-bit TMP108 register value */ static inline u16 tmp108_mC_to_temp_reg(int val) { return (val * 256) / 1000; } static int tmp108_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *temp) { struct tmp108 *tmp108 = dev_get_drvdata(dev); unsigned int regval; int err, hyst; if (type == hwmon_chip) { if (attr == hwmon_chip_update_interval) { err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); if (err < 0) return err; switch (regval & TMP108_CONF_CONVRATE_MASK) { case TMP108_CONVRATE_0P25HZ: default: *temp = 4000; break; case TMP108_CONVRATE_1HZ: *temp = 1000; break; case TMP108_CONVRATE_4HZ: *temp = 250; break; case TMP108_CONVRATE_16HZ: *temp = 63; break; } return 0; } return -EOPNOTSUPP; } switch (attr) { case hwmon_temp_input: /* Is it too early to return a conversion ? */ if (time_before(jiffies, tmp108->ready_time)) { dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__); return -EAGAIN; } err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, ®val); if (err < 0) return err; *temp = tmp108_temp_reg_to_mC(regval); break; case hwmon_temp_min: case hwmon_temp_max: err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ? TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); if (err < 0) return err; *temp = tmp108_temp_reg_to_mC(regval); break; case hwmon_temp_min_alarm: case hwmon_temp_max_alarm: err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); if (err < 0) return err; *temp = !!(regval & (attr == hwmon_temp_min_alarm ? TMP108_CONF_FL : TMP108_CONF_FH)); break; case hwmon_temp_min_hyst: case hwmon_temp_max_hyst: err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val); if (err < 0) return err; switch (regval & TMP108_CONF_HYSTERESIS_MASK) { case TMP108_HYSTERESIS_0C: default: hyst = 0; break; case TMP108_HYSTERESIS_1C: hyst = 1000; break; case TMP108_HYSTERESIS_2C: hyst = 2000; break; case TMP108_HYSTERESIS_4C: hyst = 4000; break; } err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ? TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); if (err < 0) return err; *temp = tmp108_temp_reg_to_mC(regval); if (attr == hwmon_temp_min_hyst) *temp += hyst; else *temp -= hyst; break; default: return -EOPNOTSUPP; } return 0; } static int tmp108_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long temp) { struct tmp108 *tmp108 = dev_get_drvdata(dev); u32 regval, mask; int err; if (type == hwmon_chip) { if (attr == hwmon_chip_update_interval) { if (temp < 156) mask = TMP108_CONVRATE_16HZ; else if (temp < 625) mask = TMP108_CONVRATE_4HZ; else if (temp < 2500) mask = TMP108_CONVRATE_1HZ; else mask = TMP108_CONVRATE_0P25HZ; return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, TMP108_CONF_CONVRATE_MASK, mask); } return -EOPNOTSUPP; } switch (attr) { case hwmon_temp_min: case hwmon_temp_max: temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC); return regmap_write(tmp108->regmap, attr == hwmon_temp_min ? TMP108_REG_TLOW : TMP108_REG_THIGH, tmp108_mC_to_temp_reg(temp)); case hwmon_temp_min_hyst: case hwmon_temp_max_hyst: temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC); err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ? TMP108_REG_TLOW : TMP108_REG_THIGH, ®val); if (err < 0) return err; if (attr == hwmon_temp_min_hyst) temp -= tmp108_temp_reg_to_mC(regval); else temp = tmp108_temp_reg_to_mC(regval) - temp; if (temp < 500) mask = TMP108_HYSTERESIS_0C; else if (temp < 1500) mask = TMP108_HYSTERESIS_1C; else if (temp < 3000) mask = TMP108_HYSTERESIS_2C; else mask = TMP108_HYSTERESIS_4C; return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, TMP108_CONF_HYSTERESIS_MASK, mask); default: return -EOPNOTSUPP; } } static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel) { if (type == hwmon_chip && attr == hwmon_chip_update_interval) return 0644; if (type != hwmon_temp) return 0; switch (attr) { case hwmon_temp_input: case hwmon_temp_min_alarm: case hwmon_temp_max_alarm: return 0444; case hwmon_temp_min: case hwmon_temp_max: case hwmon_temp_min_hyst: case hwmon_temp_max_hyst: return 0644; default: return 0; } } static u32 tmp108_chip_config[] = { HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL, 0 }; static const struct hwmon_channel_info tmp108_chip = { .type = hwmon_chip, .config = tmp108_chip_config, }; static u32 tmp108_temp_config[] = { HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_MIN_HYST | HWMON_T_MAX_HYST | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM, 0 }; static const struct hwmon_channel_info tmp108_temp = { .type = hwmon_temp, .config = tmp108_temp_config, }; static const struct hwmon_channel_info *tmp108_info[] = { &tmp108_chip, &tmp108_temp, NULL }; static const struct hwmon_ops tmp108_hwmon_ops = { .is_visible = tmp108_is_visible, .read = tmp108_read, .write = tmp108_write, }; static const struct hwmon_chip_info tmp108_chip_info = { .ops = &tmp108_hwmon_ops, .info = tmp108_info, }; static void tmp108_restore_config(void *data) { struct tmp108 *tmp108 = data; regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config); } static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg) { return reg != TMP108_REG_TEMP; } static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg) { /* Configuration register must be volatile to enable FL and FH. */ return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF; } static const struct regmap_config tmp108_regmap_config = { .reg_bits = 8, .val_bits = 16, .max_register = TMP108_REG_THIGH, .writeable_reg = tmp108_is_writeable_reg, .volatile_reg = tmp108_is_volatile_reg, .val_format_endian = REGMAP_ENDIAN_BIG, .cache_type = REGCACHE_RBTREE, .use_single_rw = true, }; static int tmp108_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct device *hwmon_dev; struct tmp108 *tmp108; int err; u32 config; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) { dev_err(dev, "adapter doesn't support SMBus word transactions\n"); return -ENODEV; } tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL); if (!tmp108) return -ENOMEM; dev_set_drvdata(dev, tmp108); tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config); if (IS_ERR(tmp108->regmap)) { err = PTR_ERR(tmp108->regmap); dev_err(dev, "regmap init failed: %d", err); return err; } err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config); if (err < 0) { dev_err(dev, "error reading config register: %d", err); return err; } tmp108->orig_config = config; /* Only continuous mode is supported. */ config &= ~TMP108_CONF_MODE_MASK; config |= TMP108_MODE_CONTINUOUS; /* Only comparator mode is supported. */ config &= ~TMP108_CONF_TM; err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config); if (err < 0) { dev_err(dev, "error writing config register: %d", err); return err; } tmp108->ready_time = jiffies; if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) == TMP108_MODE_SHUTDOWN) tmp108->ready_time += msecs_to_jiffies(TMP108_CONVERSION_TIME_MS); err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108); if (err) { dev_err(dev, "add action or reset failed: %d", err); return err; } hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, tmp108, &tmp108_chip_info, NULL); return PTR_ERR_OR_ZERO(hwmon_dev); } static int __maybe_unused tmp108_suspend(struct device *dev) { struct tmp108 *tmp108 = dev_get_drvdata(dev); return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN); } static int __maybe_unused tmp108_resume(struct device *dev) { struct tmp108 *tmp108 = dev_get_drvdata(dev); int err; err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF, TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS); tmp108->ready_time = jiffies + msecs_to_jiffies(TMP108_CONVERSION_TIME_MS); return err; } static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume); static const struct i2c_device_id tmp108_i2c_ids[] = { { "tmp108", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids); #ifdef CONFIG_OF static const struct of_device_id tmp108_of_ids[] = { { .compatible = "ti,tmp108", }, {} }; MODULE_DEVICE_TABLE(of, tmp108_of_ids); #endif static struct i2c_driver tmp108_driver = { .driver = { .name = DRIVER_NAME, .pm = &tmp108_dev_pm_ops, .of_match_table = of_match_ptr(tmp108_of_ids), }, .probe = tmp108_probe, .id_table = tmp108_i2c_ids, }; module_i2c_driver(tmp108_driver); MODULE_AUTHOR("John Muir <john@jmuir.com>"); MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver"); MODULE_LICENSE("GPL");