/* * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor * * Copyright (c) 2014 Peter Meerwald * Copyright (c) 2015 Essensium NV * Copyright (c) 2015 Melexis * * This file is subject to the terms and conditions of version 2 of * the GNU General Public License. See the file COPYING in the main * directory of this archive for more details. * * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor * * (7-bit I2C slave address 0x5a, 100KHz bus speed only!) * * To wake up from sleep mode, the SDA line must be held low while SCL is high * for at least 33ms. This is achieved with an extra GPIO that can be connected * directly to the SDA line. In normal operation, the GPIO is set as input and * will not interfere in I2C communication. While the GPIO is driven low, the * i2c adapter is locked since it cannot be used by other clients. The SCL line * always has a pull-up so we do not need an extra GPIO to drive it high. If * the "wakeup" GPIO is not given, power management will be disabled. * */ #include #include #include #include #include #include #include #include #include #define MLX90614_OP_RAM 0x00 #define MLX90614_OP_EEPROM 0x20 #define MLX90614_OP_SLEEP 0xff /* RAM offsets with 16-bit data, MSB first */ #define MLX90614_RAW1 (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */ #define MLX90614_RAW2 (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */ #define MLX90614_TA (MLX90614_OP_RAM | 0x06) /* ambient temperature */ #define MLX90614_TOBJ1 (MLX90614_OP_RAM | 0x07) /* object 1 temperature */ #define MLX90614_TOBJ2 (MLX90614_OP_RAM | 0x08) /* object 2 temperature */ /* EEPROM offsets with 16-bit data, MSB first */ #define MLX90614_EMISSIVITY (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */ #define MLX90614_CONFIG (MLX90614_OP_EEPROM | 0x05) /* configuration register */ /* Control bits in configuration register */ #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */ #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT) #define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */ #define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT) #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */ #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT) #define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */ #define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT) /* Timings (in ms) */ #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */ #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */ #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */ #define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */ /* Magic constants */ #define MLX90614_CONST_OFFSET_DEC -13657 /* decimal part of the Kelvin offset */ #define MLX90614_CONST_OFFSET_REM 500000 /* remainder of offset (273.15*50) */ #define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */ #define MLX90614_CONST_RAW_EMISSIVITY_MAX 65535 /* max value for emissivity */ #define MLX90614_CONST_EMISSIVITY_RESOLUTION 15259 /* 1/65535 ~ 0.000015259 */ #define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */ struct mlx90614_data { struct i2c_client *client; struct mutex lock; /* for EEPROM access only */ struct gpio_desc *wakeup_gpio; /* NULL to disable sleep/wake-up */ unsigned long ready_timestamp; /* in jiffies */ }; /* Bandwidth values for IIR filtering */ static const int mlx90614_iir_values[] = {77, 31, 20, 15, 723, 153, 110, 86}; static IIO_CONST_ATTR(in_temp_object_filter_low_pass_3db_frequency_available, "0.15 0.20 0.31 0.77 0.86 1.10 1.53 7.23"); static struct attribute *mlx90614_attributes[] = { &iio_const_attr_in_temp_object_filter_low_pass_3db_frequency_available.dev_attr.attr, NULL, }; static const struct attribute_group mlx90614_attr_group = { .attrs = mlx90614_attributes, }; /* * Erase an address and write word. * The mutex must be locked before calling. */ static s32 mlx90614_write_word(const struct i2c_client *client, u8 command, u16 value) { /* * Note: The mlx90614 requires a PEC on writing but does not send us a * valid PEC on reading. Hence, we cannot set I2C_CLIENT_PEC in * i2c_client.flags. As a workaround, we use i2c_smbus_xfer here. */ union i2c_smbus_data data; s32 ret; dev_dbg(&client->dev, "Writing 0x%x to address 0x%x", value, command); data.word = 0x0000; /* erase command */ ret = i2c_smbus_xfer(client->adapter, client->addr, client->flags | I2C_CLIENT_PEC, I2C_SMBUS_WRITE, command, I2C_SMBUS_WORD_DATA, &data); if (ret < 0) return ret; msleep(MLX90614_TIMING_EEPROM); data.word = value; /* actual write */ ret = i2c_smbus_xfer(client->adapter, client->addr, client->flags | I2C_CLIENT_PEC, I2C_SMBUS_WRITE, command, I2C_SMBUS_WORD_DATA, &data); msleep(MLX90614_TIMING_EEPROM); return ret; } /* * Find the IIR value inside mlx90614_iir_values array and return its position * which is equivalent to the bit value in sensor register */ static inline s32 mlx90614_iir_search(const struct i2c_client *client, int value) { int i; s32 ret; for (i = 0; i < ARRAY_SIZE(mlx90614_iir_values); ++i) { if (value == mlx90614_iir_values[i]) break; } if (i == ARRAY_SIZE(mlx90614_iir_values)) return -EINVAL; /* * CONFIG register values must not be changed so * we must read them before we actually write * changes */ ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG); if (ret < 0) return ret; ret &= ~MLX90614_CONFIG_FIR_MASK; ret |= MLX90614_CONST_FIR << MLX90614_CONFIG_FIR_SHIFT; ret &= ~MLX90614_CONFIG_IIR_MASK; ret |= i << MLX90614_CONFIG_IIR_SHIFT; /* Write changed values */ ret = mlx90614_write_word(client, MLX90614_CONFIG, ret); return ret; } #ifdef CONFIG_PM /* * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since * the last wake-up. This is normally only needed to get a valid temperature * reading. EEPROM access does not need such delay. * Return 0 on success, <0 on error. */ static int mlx90614_power_get(struct mlx90614_data *data, bool startup) { unsigned long now; if (!data->wakeup_gpio) return 0; pm_runtime_get_sync(&data->client->dev); if (startup) { now = jiffies; if (time_before(now, data->ready_timestamp) && msleep_interruptible(jiffies_to_msecs( data->ready_timestamp - now)) != 0) { pm_runtime_put_autosuspend(&data->client->dev); return -EINTR; } } return 0; } static void mlx90614_power_put(struct mlx90614_data *data) { if (!data->wakeup_gpio) return; pm_runtime_mark_last_busy(&data->client->dev); pm_runtime_put_autosuspend(&data->client->dev); } #else static inline int mlx90614_power_get(struct mlx90614_data *data, bool startup) { return 0; } static inline void mlx90614_power_put(struct mlx90614_data *data) { } #endif static int mlx90614_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *channel, int *val, int *val2, long mask) { struct mlx90614_data *data = iio_priv(indio_dev); u8 cmd; s32 ret; switch (mask) { case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */ switch (channel->channel2) { case IIO_MOD_TEMP_AMBIENT: cmd = MLX90614_TA; break; case IIO_MOD_TEMP_OBJECT: switch (channel->channel) { case 0: cmd = MLX90614_TOBJ1; break; case 1: cmd = MLX90614_TOBJ2; break; default: return -EINVAL; } break; default: return -EINVAL; } ret = mlx90614_power_get(data, true); if (ret < 0) return ret; ret = i2c_smbus_read_word_data(data->client, cmd); mlx90614_power_put(data); if (ret < 0) return ret; /* MSB is an error flag */ if (ret & 0x8000) return -EIO; *val = ret; return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: *val = MLX90614_CONST_OFFSET_DEC; *val2 = MLX90614_CONST_OFFSET_REM; return IIO_VAL_INT_PLUS_MICRO; case IIO_CHAN_INFO_SCALE: *val = MLX90614_CONST_SCALE; return IIO_VAL_INT; case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */ mlx90614_power_get(data, false); mutex_lock(&data->lock); ret = i2c_smbus_read_word_data(data->client, MLX90614_EMISSIVITY); mutex_unlock(&data->lock); mlx90614_power_put(data); if (ret < 0) return ret; if (ret == MLX90614_CONST_RAW_EMISSIVITY_MAX) { *val = 1; *val2 = 0; } else { *val = 0; *val2 = ret * MLX90614_CONST_EMISSIVITY_RESOLUTION; } return IIO_VAL_INT_PLUS_NANO; case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR setting with FIR = 1024 */ mlx90614_power_get(data, false); mutex_lock(&data->lock); ret = i2c_smbus_read_word_data(data->client, MLX90614_CONFIG); mutex_unlock(&data->lock); mlx90614_power_put(data); if (ret < 0) return ret; *val = mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] / 100; *val2 = (mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] % 100) * 10000; return IIO_VAL_INT_PLUS_MICRO; default: return -EINVAL; } } static int mlx90614_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *channel, int val, int val2, long mask) { struct mlx90614_data *data = iio_priv(indio_dev); s32 ret; switch (mask) { case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */ if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0)) return -EINVAL; val = val * MLX90614_CONST_RAW_EMISSIVITY_MAX + val2 / MLX90614_CONST_EMISSIVITY_RESOLUTION; mlx90614_power_get(data, false); mutex_lock(&data->lock); ret = mlx90614_write_word(data->client, MLX90614_EMISSIVITY, val); mutex_unlock(&data->lock); mlx90614_power_put(data); return ret; case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR Filter setting */ if (val < 0 || val2 < 0) return -EINVAL; mlx90614_power_get(data, false); mutex_lock(&data->lock); ret = mlx90614_iir_search(data->client, val * 100 + val2 / 10000); mutex_unlock(&data->lock); mlx90614_power_put(data); return ret; default: return -EINVAL; } } static int mlx90614_write_raw_get_fmt(struct iio_dev *indio_dev, struct iio_chan_spec const *channel, long mask) { switch (mask) { case IIO_CHAN_INFO_CALIBEMISSIVITY: return IIO_VAL_INT_PLUS_NANO; case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: return IIO_VAL_INT_PLUS_MICRO; default: return -EINVAL; } } static const struct iio_chan_spec mlx90614_channels[] = { { .type = IIO_TEMP, .modified = 1, .channel2 = IIO_MOD_TEMP_AMBIENT, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), }, { .type = IIO_TEMP, .modified = 1, .channel2 = IIO_MOD_TEMP_OBJECT, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) | BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), }, { .type = IIO_TEMP, .indexed = 1, .modified = 1, .channel = 1, .channel2 = IIO_MOD_TEMP_OBJECT, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) | BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), }, }; static const struct iio_info mlx90614_info = { .read_raw = mlx90614_read_raw, .write_raw = mlx90614_write_raw, .write_raw_get_fmt = mlx90614_write_raw_get_fmt, .attrs = &mlx90614_attr_group, }; #ifdef CONFIG_PM static int mlx90614_sleep(struct mlx90614_data *data) { s32 ret; if (!data->wakeup_gpio) { dev_dbg(&data->client->dev, "Sleep disabled"); return -ENOSYS; } dev_dbg(&data->client->dev, "Requesting sleep"); mutex_lock(&data->lock); ret = i2c_smbus_xfer(data->client->adapter, data->client->addr, data->client->flags | I2C_CLIENT_PEC, I2C_SMBUS_WRITE, MLX90614_OP_SLEEP, I2C_SMBUS_BYTE, NULL); mutex_unlock(&data->lock); return ret; } static int mlx90614_wakeup(struct mlx90614_data *data) { if (!data->wakeup_gpio) { dev_dbg(&data->client->dev, "Wake-up disabled"); return -ENOSYS; } dev_dbg(&data->client->dev, "Requesting wake-up"); i2c_lock_bus(data->client->adapter, I2C_LOCK_ROOT_ADAPTER); gpiod_direction_output(data->wakeup_gpio, 0); msleep(MLX90614_TIMING_WAKEUP); gpiod_direction_input(data->wakeup_gpio); i2c_unlock_bus(data->client->adapter, I2C_LOCK_ROOT_ADAPTER); data->ready_timestamp = jiffies + msecs_to_jiffies(MLX90614_TIMING_STARTUP); /* * Quirk: the i2c controller may get confused right after the * wake-up signal has been sent. As a workaround, do a dummy read. * If the read fails, the controller will probably be reset so that * further reads will work. */ i2c_smbus_read_word_data(data->client, MLX90614_CONFIG); return 0; } /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */ static struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client) { struct gpio_desc *gpio; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) { dev_info(&client->dev, "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled"); return NULL; } gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_IN); if (IS_ERR(gpio)) { dev_warn(&client->dev, "gpio acquisition failed with error %ld, sleep disabled", PTR_ERR(gpio)); return NULL; } else if (!gpio) { dev_info(&client->dev, "wakeup-gpio not found, sleep disabled"); } return gpio; } #else static inline int mlx90614_sleep(struct mlx90614_data *data) { return -ENOSYS; } static inline int mlx90614_wakeup(struct mlx90614_data *data) { return -ENOSYS; } static inline struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client) { return NULL; } #endif /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */ static int mlx90614_probe_num_ir_sensors(struct i2c_client *client) { s32 ret; ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG); if (ret < 0) return ret; return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0; } static int mlx90614_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct iio_dev *indio_dev; struct mlx90614_data *data; int ret; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA)) return -EOPNOTSUPP; indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; data = iio_priv(indio_dev); i2c_set_clientdata(client, indio_dev); data->client = client; mutex_init(&data->lock); data->wakeup_gpio = mlx90614_probe_wakeup(client); mlx90614_wakeup(data); indio_dev->dev.parent = &client->dev; indio_dev->name = id->name; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->info = &mlx90614_info; ret = mlx90614_probe_num_ir_sensors(client); switch (ret) { case 0: dev_dbg(&client->dev, "Found single sensor"); indio_dev->channels = mlx90614_channels; indio_dev->num_channels = 2; break; case 1: dev_dbg(&client->dev, "Found dual sensor"); indio_dev->channels = mlx90614_channels; indio_dev->num_channels = 3; break; default: return ret; } if (data->wakeup_gpio) { pm_runtime_set_autosuspend_delay(&client->dev, MLX90614_AUTOSLEEP_DELAY); pm_runtime_use_autosuspend(&client->dev); pm_runtime_set_active(&client->dev); pm_runtime_enable(&client->dev); } return iio_device_register(indio_dev); } static int mlx90614_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); struct mlx90614_data *data = iio_priv(indio_dev); iio_device_unregister(indio_dev); if (data->wakeup_gpio) { pm_runtime_disable(&client->dev); if (!pm_runtime_status_suspended(&client->dev)) mlx90614_sleep(data); pm_runtime_set_suspended(&client->dev); } return 0; } static const struct i2c_device_id mlx90614_id[] = { { "mlx90614", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, mlx90614_id); static const struct of_device_id mlx90614_of_match[] = { { .compatible = "melexis,mlx90614" }, { } }; MODULE_DEVICE_TABLE(of, mlx90614_of_match); #ifdef CONFIG_PM_SLEEP static int mlx90614_pm_suspend(struct device *dev) { struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); struct mlx90614_data *data = iio_priv(indio_dev); if (data->wakeup_gpio && pm_runtime_active(dev)) return mlx90614_sleep(data); return 0; } static int mlx90614_pm_resume(struct device *dev) { struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); struct mlx90614_data *data = iio_priv(indio_dev); int err; if (data->wakeup_gpio) { err = mlx90614_wakeup(data); if (err < 0) return err; pm_runtime_disable(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); } return 0; } #endif #ifdef CONFIG_PM static int mlx90614_pm_runtime_suspend(struct device *dev) { struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); struct mlx90614_data *data = iio_priv(indio_dev); return mlx90614_sleep(data); } static int mlx90614_pm_runtime_resume(struct device *dev) { struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev)); struct mlx90614_data *data = iio_priv(indio_dev); return mlx90614_wakeup(data); } #endif static const struct dev_pm_ops mlx90614_pm_ops = { SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend, mlx90614_pm_resume) SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend, mlx90614_pm_runtime_resume, NULL) }; static struct i2c_driver mlx90614_driver = { .driver = { .name = "mlx90614", .of_match_table = mlx90614_of_match, .pm = &mlx90614_pm_ops, }, .probe = mlx90614_probe, .remove = mlx90614_remove, .id_table = mlx90614_id, }; module_i2c_driver(mlx90614_driver); MODULE_AUTHOR("Peter Meerwald "); MODULE_AUTHOR("Vianney le Clément de Saint-Marcq "); MODULE_AUTHOR("Crt Mori "); MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver"); MODULE_LICENSE("GPL");