diff options
Diffstat (limited to 'drivers/hwmon/tmp108.c')
| -rw-r--r-- | drivers/hwmon/tmp108.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/drivers/hwmon/tmp108.c b/drivers/hwmon/tmp108.c new file mode 100644 index 0000000..91bb9463 --- /dev/null +++ b/drivers/hwmon/tmp108.c @@ -0,0 +1,469 @@ +/* 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"); 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