1 // SPDX-License-Identifier: GPL-2.0-only
3 * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
6 * Copyright (c) 2015 Essensium NV
7 * Copyright (c) 2015 Melexis
9 * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
11 * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
13 * To wake up from sleep mode, the SDA line must be held low while SCL is high
14 * for at least 33ms. This is achieved with an extra GPIO that can be connected
15 * directly to the SDA line. In normal operation, the GPIO is set as input and
16 * will not interfere in I2C communication. While the GPIO is driven low, the
17 * i2c adapter is locked since it cannot be used by other clients. The SCL line
18 * always has a pull-up so we do not need an extra GPIO to drive it high. If
19 * the "wakeup" GPIO is not given, power management will be disabled.
22 #include <linux/err.h>
23 #include <linux/i2c.h>
24 #include <linux/module.h>
25 #include <linux/delay.h>
26 #include <linux/jiffies.h>
27 #include <linux/gpio/consumer.h>
28 #include <linux/pm_runtime.h>
30 #include <linux/iio/iio.h>
31 #include <linux/iio/sysfs.h>
33 #define MLX90614_OP_RAM 0x00
34 #define MLX90614_OP_EEPROM 0x20
35 #define MLX90614_OP_SLEEP 0xff
37 /* RAM offsets with 16-bit data, MSB first */
38 #define MLX90614_RAW1 (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */
39 #define MLX90614_RAW2 (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */
40 #define MLX90614_TA (MLX90614_OP_RAM | 0x06) /* ambient temperature */
41 #define MLX90614_TOBJ1 (MLX90614_OP_RAM | 0x07) /* object 1 temperature */
42 #define MLX90614_TOBJ2 (MLX90614_OP_RAM | 0x08) /* object 2 temperature */
44 /* EEPROM offsets with 16-bit data, MSB first */
45 #define MLX90614_EMISSIVITY (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */
46 #define MLX90614_CONFIG (MLX90614_OP_EEPROM | 0x05) /* configuration register */
48 /* Control bits in configuration register */
49 #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
50 #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
51 #define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */
52 #define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT)
53 #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
54 #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
55 #define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */
56 #define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT)
59 #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
60 #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
61 #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
63 #define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
66 #define MLX90614_CONST_OFFSET_DEC -13657 /* decimal part of the Kelvin offset */
67 #define MLX90614_CONST_OFFSET_REM 500000 /* remainder of offset (273.15*50) */
68 #define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
69 #define MLX90614_CONST_RAW_EMISSIVITY_MAX 65535 /* max value for emissivity */
70 #define MLX90614_CONST_EMISSIVITY_RESOLUTION 15259 /* 1/65535 ~ 0.000015259 */
71 #define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */
73 struct mlx90614_data {
74 struct i2c_client *client;
75 struct mutex lock; /* for EEPROM access only */
76 struct gpio_desc *wakeup_gpio; /* NULL to disable sleep/wake-up */
77 unsigned long ready_timestamp; /* in jiffies */
80 /* Bandwidth values for IIR filtering */
81 static const int mlx90614_iir_values[] = {77, 31, 20, 15, 723, 153, 110, 86};
82 static IIO_CONST_ATTR(in_temp_object_filter_low_pass_3db_frequency_available,
83 "0.15 0.20 0.31 0.77 0.86 1.10 1.53 7.23");
85 static struct attribute *mlx90614_attributes[] = {
86 &iio_const_attr_in_temp_object_filter_low_pass_3db_frequency_available.dev_attr.attr,
90 static const struct attribute_group mlx90614_attr_group = {
91 .attrs = mlx90614_attributes,
95 * Erase an address and write word.
96 * The mutex must be locked before calling.
98 static s32 mlx90614_write_word(const struct i2c_client *client, u8 command,
102 * Note: The mlx90614 requires a PEC on writing but does not send us a
103 * valid PEC on reading. Hence, we cannot set I2C_CLIENT_PEC in
104 * i2c_client.flags. As a workaround, we use i2c_smbus_xfer here.
106 union i2c_smbus_data data;
109 dev_dbg(&client->dev, "Writing 0x%x to address 0x%x", value, command);
111 data.word = 0x0000; /* erase command */
112 ret = i2c_smbus_xfer(client->adapter, client->addr,
113 client->flags | I2C_CLIENT_PEC,
114 I2C_SMBUS_WRITE, command,
115 I2C_SMBUS_WORD_DATA, &data);
119 msleep(MLX90614_TIMING_EEPROM);
121 data.word = value; /* actual write */
122 ret = i2c_smbus_xfer(client->adapter, client->addr,
123 client->flags | I2C_CLIENT_PEC,
124 I2C_SMBUS_WRITE, command,
125 I2C_SMBUS_WORD_DATA, &data);
127 msleep(MLX90614_TIMING_EEPROM);
133 * Find the IIR value inside mlx90614_iir_values array and return its position
134 * which is equivalent to the bit value in sensor register
136 static inline s32 mlx90614_iir_search(const struct i2c_client *client,
142 for (i = 0; i < ARRAY_SIZE(mlx90614_iir_values); ++i) {
143 if (value == mlx90614_iir_values[i])
147 if (i == ARRAY_SIZE(mlx90614_iir_values))
151 * CONFIG register values must not be changed so
152 * we must read them before we actually write
155 ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
159 ret &= ~MLX90614_CONFIG_FIR_MASK;
160 ret |= MLX90614_CONST_FIR << MLX90614_CONFIG_FIR_SHIFT;
161 ret &= ~MLX90614_CONFIG_IIR_MASK;
162 ret |= i << MLX90614_CONFIG_IIR_SHIFT;
164 /* Write changed values */
165 ret = mlx90614_write_word(client, MLX90614_CONFIG, ret);
171 * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
172 * the last wake-up. This is normally only needed to get a valid temperature
173 * reading. EEPROM access does not need such delay.
174 * Return 0 on success, <0 on error.
176 static int mlx90614_power_get(struct mlx90614_data *data, bool startup)
181 if (!data->wakeup_gpio)
184 ret = pm_runtime_resume_and_get(&data->client->dev);
190 if (time_before(now, data->ready_timestamp) &&
191 msleep_interruptible(jiffies_to_msecs(
192 data->ready_timestamp - now)) != 0) {
193 pm_runtime_put_autosuspend(&data->client->dev);
201 static void mlx90614_power_put(struct mlx90614_data *data)
203 if (!data->wakeup_gpio)
206 pm_runtime_mark_last_busy(&data->client->dev);
207 pm_runtime_put_autosuspend(&data->client->dev);
210 static inline int mlx90614_power_get(struct mlx90614_data *data, bool startup)
215 static inline void mlx90614_power_put(struct mlx90614_data *data)
220 static int mlx90614_read_raw(struct iio_dev *indio_dev,
221 struct iio_chan_spec const *channel, int *val,
222 int *val2, long mask)
224 struct mlx90614_data *data = iio_priv(indio_dev);
229 case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
230 switch (channel->channel2) {
231 case IIO_MOD_TEMP_AMBIENT:
234 case IIO_MOD_TEMP_OBJECT:
235 switch (channel->channel) {
237 cmd = MLX90614_TOBJ1;
240 cmd = MLX90614_TOBJ2;
250 ret = mlx90614_power_get(data, true);
253 ret = i2c_smbus_read_word_data(data->client, cmd);
254 mlx90614_power_put(data);
259 /* MSB is an error flag */
265 case IIO_CHAN_INFO_OFFSET:
266 *val = MLX90614_CONST_OFFSET_DEC;
267 *val2 = MLX90614_CONST_OFFSET_REM;
268 return IIO_VAL_INT_PLUS_MICRO;
269 case IIO_CHAN_INFO_SCALE:
270 *val = MLX90614_CONST_SCALE;
272 case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
273 ret = mlx90614_power_get(data, false);
277 mutex_lock(&data->lock);
278 ret = i2c_smbus_read_word_data(data->client,
279 MLX90614_EMISSIVITY);
280 mutex_unlock(&data->lock);
281 mlx90614_power_put(data);
286 if (ret == MLX90614_CONST_RAW_EMISSIVITY_MAX) {
291 *val2 = ret * MLX90614_CONST_EMISSIVITY_RESOLUTION;
293 return IIO_VAL_INT_PLUS_NANO;
294 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR setting with
296 ret = mlx90614_power_get(data, false);
300 mutex_lock(&data->lock);
301 ret = i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
302 mutex_unlock(&data->lock);
303 mlx90614_power_put(data);
308 *val = mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] / 100;
309 *val2 = (mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] % 100) *
311 return IIO_VAL_INT_PLUS_MICRO;
317 static int mlx90614_write_raw(struct iio_dev *indio_dev,
318 struct iio_chan_spec const *channel, int val,
321 struct mlx90614_data *data = iio_priv(indio_dev);
325 case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
326 if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0))
328 val = val * MLX90614_CONST_RAW_EMISSIVITY_MAX +
329 val2 / MLX90614_CONST_EMISSIVITY_RESOLUTION;
331 ret = mlx90614_power_get(data, false);
335 mutex_lock(&data->lock);
336 ret = mlx90614_write_word(data->client, MLX90614_EMISSIVITY,
338 mutex_unlock(&data->lock);
339 mlx90614_power_put(data);
342 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR Filter setting */
343 if (val < 0 || val2 < 0)
346 ret = mlx90614_power_get(data, false);
350 mutex_lock(&data->lock);
351 ret = mlx90614_iir_search(data->client,
352 val * 100 + val2 / 10000);
353 mutex_unlock(&data->lock);
354 mlx90614_power_put(data);
362 static int mlx90614_write_raw_get_fmt(struct iio_dev *indio_dev,
363 struct iio_chan_spec const *channel,
367 case IIO_CHAN_INFO_CALIBEMISSIVITY:
368 return IIO_VAL_INT_PLUS_NANO;
369 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
370 return IIO_VAL_INT_PLUS_MICRO;
376 static const struct iio_chan_spec mlx90614_channels[] = {
380 .channel2 = IIO_MOD_TEMP_AMBIENT,
381 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
382 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
383 BIT(IIO_CHAN_INFO_SCALE),
388 .channel2 = IIO_MOD_TEMP_OBJECT,
389 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
390 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) |
391 BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
392 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
393 BIT(IIO_CHAN_INFO_SCALE),
400 .channel2 = IIO_MOD_TEMP_OBJECT,
401 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
402 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) |
403 BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
404 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
405 BIT(IIO_CHAN_INFO_SCALE),
409 static const struct iio_info mlx90614_info = {
410 .read_raw = mlx90614_read_raw,
411 .write_raw = mlx90614_write_raw,
412 .write_raw_get_fmt = mlx90614_write_raw_get_fmt,
413 .attrs = &mlx90614_attr_group,
417 static int mlx90614_sleep(struct mlx90614_data *data)
421 if (!data->wakeup_gpio) {
422 dev_dbg(&data->client->dev, "Sleep disabled");
426 dev_dbg(&data->client->dev, "Requesting sleep");
428 mutex_lock(&data->lock);
429 ret = i2c_smbus_xfer(data->client->adapter, data->client->addr,
430 data->client->flags | I2C_CLIENT_PEC,
431 I2C_SMBUS_WRITE, MLX90614_OP_SLEEP,
432 I2C_SMBUS_BYTE, NULL);
433 mutex_unlock(&data->lock);
438 static int mlx90614_wakeup(struct mlx90614_data *data)
440 if (!data->wakeup_gpio) {
441 dev_dbg(&data->client->dev, "Wake-up disabled");
445 dev_dbg(&data->client->dev, "Requesting wake-up");
447 i2c_lock_bus(data->client->adapter, I2C_LOCK_ROOT_ADAPTER);
448 gpiod_direction_output(data->wakeup_gpio, 0);
449 msleep(MLX90614_TIMING_WAKEUP);
450 gpiod_direction_input(data->wakeup_gpio);
451 i2c_unlock_bus(data->client->adapter, I2C_LOCK_ROOT_ADAPTER);
453 data->ready_timestamp = jiffies +
454 msecs_to_jiffies(MLX90614_TIMING_STARTUP);
457 * Quirk: the i2c controller may get confused right after the
458 * wake-up signal has been sent. As a workaround, do a dummy read.
459 * If the read fails, the controller will probably be reset so that
460 * further reads will work.
462 i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
467 /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
468 static struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
470 struct gpio_desc *gpio;
472 if (!i2c_check_functionality(client->adapter,
473 I2C_FUNC_SMBUS_WRITE_BYTE)) {
474 dev_info(&client->dev,
475 "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
479 gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_IN);
482 dev_warn(&client->dev,
483 "gpio acquisition failed with error %ld, sleep disabled",
487 dev_info(&client->dev,
488 "wakeup-gpio not found, sleep disabled");
494 static inline int mlx90614_sleep(struct mlx90614_data *data)
498 static inline int mlx90614_wakeup(struct mlx90614_data *data)
502 static inline struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
508 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
509 static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
513 ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
518 return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0;
521 static int mlx90614_probe(struct i2c_client *client,
522 const struct i2c_device_id *id)
524 struct iio_dev *indio_dev;
525 struct mlx90614_data *data;
528 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
531 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
535 data = iio_priv(indio_dev);
536 i2c_set_clientdata(client, indio_dev);
537 data->client = client;
538 mutex_init(&data->lock);
539 data->wakeup_gpio = mlx90614_probe_wakeup(client);
541 mlx90614_wakeup(data);
543 indio_dev->name = id->name;
544 indio_dev->modes = INDIO_DIRECT_MODE;
545 indio_dev->info = &mlx90614_info;
547 ret = mlx90614_probe_num_ir_sensors(client);
550 dev_dbg(&client->dev, "Found single sensor");
551 indio_dev->channels = mlx90614_channels;
552 indio_dev->num_channels = 2;
555 dev_dbg(&client->dev, "Found dual sensor");
556 indio_dev->channels = mlx90614_channels;
557 indio_dev->num_channels = 3;
563 if (data->wakeup_gpio) {
564 pm_runtime_set_autosuspend_delay(&client->dev,
565 MLX90614_AUTOSLEEP_DELAY);
566 pm_runtime_use_autosuspend(&client->dev);
567 pm_runtime_set_active(&client->dev);
568 pm_runtime_enable(&client->dev);
571 return iio_device_register(indio_dev);
574 static int mlx90614_remove(struct i2c_client *client)
576 struct iio_dev *indio_dev = i2c_get_clientdata(client);
577 struct mlx90614_data *data = iio_priv(indio_dev);
579 iio_device_unregister(indio_dev);
581 if (data->wakeup_gpio) {
582 pm_runtime_disable(&client->dev);
583 if (!pm_runtime_status_suspended(&client->dev))
584 mlx90614_sleep(data);
585 pm_runtime_set_suspended(&client->dev);
591 static const struct i2c_device_id mlx90614_id[] = {
595 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
597 static const struct of_device_id mlx90614_of_match[] = {
598 { .compatible = "melexis,mlx90614" },
601 MODULE_DEVICE_TABLE(of, mlx90614_of_match);
603 #ifdef CONFIG_PM_SLEEP
604 static int mlx90614_pm_suspend(struct device *dev)
606 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
607 struct mlx90614_data *data = iio_priv(indio_dev);
609 if (data->wakeup_gpio && pm_runtime_active(dev))
610 return mlx90614_sleep(data);
615 static int mlx90614_pm_resume(struct device *dev)
617 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
618 struct mlx90614_data *data = iio_priv(indio_dev);
621 if (data->wakeup_gpio) {
622 err = mlx90614_wakeup(data);
626 pm_runtime_disable(dev);
627 pm_runtime_set_active(dev);
628 pm_runtime_enable(dev);
636 static int mlx90614_pm_runtime_suspend(struct device *dev)
638 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
639 struct mlx90614_data *data = iio_priv(indio_dev);
641 return mlx90614_sleep(data);
644 static int mlx90614_pm_runtime_resume(struct device *dev)
646 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
647 struct mlx90614_data *data = iio_priv(indio_dev);
649 return mlx90614_wakeup(data);
653 static const struct dev_pm_ops mlx90614_pm_ops = {
654 SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend, mlx90614_pm_resume)
655 SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend,
656 mlx90614_pm_runtime_resume, NULL)
659 static struct i2c_driver mlx90614_driver = {
662 .of_match_table = mlx90614_of_match,
663 .pm = &mlx90614_pm_ops,
665 .probe = mlx90614_probe,
666 .remove = mlx90614_remove,
667 .id_table = mlx90614_id,
669 module_i2c_driver(mlx90614_driver);
674 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
675 MODULE_LICENSE("GPL");