1 // SPDX-License-Identifier: GPL-2.0-only
3 * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
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
)
180 if (!data
->wakeup_gpio
)
183 pm_runtime_get_sync(&data
->client
->dev
);
187 if (time_before(now
, data
->ready_timestamp
) &&
188 msleep_interruptible(jiffies_to_msecs(
189 data
->ready_timestamp
- now
)) != 0) {
190 pm_runtime_put_autosuspend(&data
->client
->dev
);
198 static void mlx90614_power_put(struct mlx90614_data
*data
)
200 if (!data
->wakeup_gpio
)
203 pm_runtime_mark_last_busy(&data
->client
->dev
);
204 pm_runtime_put_autosuspend(&data
->client
->dev
);
207 static inline int mlx90614_power_get(struct mlx90614_data
*data
, bool startup
)
212 static inline void mlx90614_power_put(struct mlx90614_data
*data
)
217 static int mlx90614_read_raw(struct iio_dev
*indio_dev
,
218 struct iio_chan_spec
const *channel
, int *val
,
219 int *val2
, long mask
)
221 struct mlx90614_data
*data
= iio_priv(indio_dev
);
226 case IIO_CHAN_INFO_RAW
: /* 0.02K / LSB */
227 switch (channel
->channel2
) {
228 case IIO_MOD_TEMP_AMBIENT
:
231 case IIO_MOD_TEMP_OBJECT
:
232 switch (channel
->channel
) {
234 cmd
= MLX90614_TOBJ1
;
237 cmd
= MLX90614_TOBJ2
;
247 ret
= mlx90614_power_get(data
, true);
250 ret
= i2c_smbus_read_word_data(data
->client
, cmd
);
251 mlx90614_power_put(data
);
256 /* MSB is an error flag */
262 case IIO_CHAN_INFO_OFFSET
:
263 *val
= MLX90614_CONST_OFFSET_DEC
;
264 *val2
= MLX90614_CONST_OFFSET_REM
;
265 return IIO_VAL_INT_PLUS_MICRO
;
266 case IIO_CHAN_INFO_SCALE
:
267 *val
= MLX90614_CONST_SCALE
;
269 case IIO_CHAN_INFO_CALIBEMISSIVITY
: /* 1/65535 / LSB */
270 mlx90614_power_get(data
, false);
271 mutex_lock(&data
->lock
);
272 ret
= i2c_smbus_read_word_data(data
->client
,
273 MLX90614_EMISSIVITY
);
274 mutex_unlock(&data
->lock
);
275 mlx90614_power_put(data
);
280 if (ret
== MLX90614_CONST_RAW_EMISSIVITY_MAX
) {
285 *val2
= ret
* MLX90614_CONST_EMISSIVITY_RESOLUTION
;
287 return IIO_VAL_INT_PLUS_NANO
;
288 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
: /* IIR setting with
290 mlx90614_power_get(data
, false);
291 mutex_lock(&data
->lock
);
292 ret
= i2c_smbus_read_word_data(data
->client
, MLX90614_CONFIG
);
293 mutex_unlock(&data
->lock
);
294 mlx90614_power_put(data
);
299 *val
= mlx90614_iir_values
[ret
& MLX90614_CONFIG_IIR_MASK
] / 100;
300 *val2
= (mlx90614_iir_values
[ret
& MLX90614_CONFIG_IIR_MASK
] % 100) *
302 return IIO_VAL_INT_PLUS_MICRO
;
308 static int mlx90614_write_raw(struct iio_dev
*indio_dev
,
309 struct iio_chan_spec
const *channel
, int val
,
312 struct mlx90614_data
*data
= iio_priv(indio_dev
);
316 case IIO_CHAN_INFO_CALIBEMISSIVITY
: /* 1/65535 / LSB */
317 if (val
< 0 || val2
< 0 || val
> 1 || (val
== 1 && val2
!= 0))
319 val
= val
* MLX90614_CONST_RAW_EMISSIVITY_MAX
+
320 val2
/ MLX90614_CONST_EMISSIVITY_RESOLUTION
;
322 mlx90614_power_get(data
, false);
323 mutex_lock(&data
->lock
);
324 ret
= mlx90614_write_word(data
->client
, MLX90614_EMISSIVITY
,
326 mutex_unlock(&data
->lock
);
327 mlx90614_power_put(data
);
330 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
: /* IIR Filter setting */
331 if (val
< 0 || val2
< 0)
334 mlx90614_power_get(data
, false);
335 mutex_lock(&data
->lock
);
336 ret
= mlx90614_iir_search(data
->client
,
337 val
* 100 + val2
/ 10000);
338 mutex_unlock(&data
->lock
);
339 mlx90614_power_put(data
);
347 static int mlx90614_write_raw_get_fmt(struct iio_dev
*indio_dev
,
348 struct iio_chan_spec
const *channel
,
352 case IIO_CHAN_INFO_CALIBEMISSIVITY
:
353 return IIO_VAL_INT_PLUS_NANO
;
354 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
:
355 return IIO_VAL_INT_PLUS_MICRO
;
361 static const struct iio_chan_spec mlx90614_channels
[] = {
365 .channel2
= IIO_MOD_TEMP_AMBIENT
,
366 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
),
367 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
368 BIT(IIO_CHAN_INFO_SCALE
),
373 .channel2
= IIO_MOD_TEMP_OBJECT
,
374 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
) |
375 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY
) |
376 BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
),
377 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
378 BIT(IIO_CHAN_INFO_SCALE
),
385 .channel2
= IIO_MOD_TEMP_OBJECT
,
386 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
) |
387 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY
) |
388 BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
),
389 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
390 BIT(IIO_CHAN_INFO_SCALE
),
394 static const struct iio_info mlx90614_info
= {
395 .read_raw
= mlx90614_read_raw
,
396 .write_raw
= mlx90614_write_raw
,
397 .write_raw_get_fmt
= mlx90614_write_raw_get_fmt
,
398 .attrs
= &mlx90614_attr_group
,
402 static int mlx90614_sleep(struct mlx90614_data
*data
)
406 if (!data
->wakeup_gpio
) {
407 dev_dbg(&data
->client
->dev
, "Sleep disabled");
411 dev_dbg(&data
->client
->dev
, "Requesting sleep");
413 mutex_lock(&data
->lock
);
414 ret
= i2c_smbus_xfer(data
->client
->adapter
, data
->client
->addr
,
415 data
->client
->flags
| I2C_CLIENT_PEC
,
416 I2C_SMBUS_WRITE
, MLX90614_OP_SLEEP
,
417 I2C_SMBUS_BYTE
, NULL
);
418 mutex_unlock(&data
->lock
);
423 static int mlx90614_wakeup(struct mlx90614_data
*data
)
425 if (!data
->wakeup_gpio
) {
426 dev_dbg(&data
->client
->dev
, "Wake-up disabled");
430 dev_dbg(&data
->client
->dev
, "Requesting wake-up");
432 i2c_lock_bus(data
->client
->adapter
, I2C_LOCK_ROOT_ADAPTER
);
433 gpiod_direction_output(data
->wakeup_gpio
, 0);
434 msleep(MLX90614_TIMING_WAKEUP
);
435 gpiod_direction_input(data
->wakeup_gpio
);
436 i2c_unlock_bus(data
->client
->adapter
, I2C_LOCK_ROOT_ADAPTER
);
438 data
->ready_timestamp
= jiffies
+
439 msecs_to_jiffies(MLX90614_TIMING_STARTUP
);
442 * Quirk: the i2c controller may get confused right after the
443 * wake-up signal has been sent. As a workaround, do a dummy read.
444 * If the read fails, the controller will probably be reset so that
445 * further reads will work.
447 i2c_smbus_read_word_data(data
->client
, MLX90614_CONFIG
);
452 /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
453 static struct gpio_desc
*mlx90614_probe_wakeup(struct i2c_client
*client
)
455 struct gpio_desc
*gpio
;
457 if (!i2c_check_functionality(client
->adapter
,
458 I2C_FUNC_SMBUS_WRITE_BYTE
)) {
459 dev_info(&client
->dev
,
460 "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
464 gpio
= devm_gpiod_get_optional(&client
->dev
, "wakeup", GPIOD_IN
);
467 dev_warn(&client
->dev
,
468 "gpio acquisition failed with error %ld, sleep disabled",
472 dev_info(&client
->dev
,
473 "wakeup-gpio not found, sleep disabled");
479 static inline int mlx90614_sleep(struct mlx90614_data
*data
)
483 static inline int mlx90614_wakeup(struct mlx90614_data
*data
)
487 static inline struct gpio_desc
*mlx90614_probe_wakeup(struct i2c_client
*client
)
493 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
494 static int mlx90614_probe_num_ir_sensors(struct i2c_client
*client
)
498 ret
= i2c_smbus_read_word_data(client
, MLX90614_CONFIG
);
503 return (ret
& MLX90614_CONFIG_DUAL_MASK
) ? 1 : 0;
506 static int mlx90614_probe(struct i2c_client
*client
,
507 const struct i2c_device_id
*id
)
509 struct iio_dev
*indio_dev
;
510 struct mlx90614_data
*data
;
513 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_WORD_DATA
))
516 indio_dev
= devm_iio_device_alloc(&client
->dev
, sizeof(*data
));
520 data
= iio_priv(indio_dev
);
521 i2c_set_clientdata(client
, indio_dev
);
522 data
->client
= client
;
523 mutex_init(&data
->lock
);
524 data
->wakeup_gpio
= mlx90614_probe_wakeup(client
);
526 mlx90614_wakeup(data
);
528 indio_dev
->dev
.parent
= &client
->dev
;
529 indio_dev
->name
= id
->name
;
530 indio_dev
->modes
= INDIO_DIRECT_MODE
;
531 indio_dev
->info
= &mlx90614_info
;
533 ret
= mlx90614_probe_num_ir_sensors(client
);
536 dev_dbg(&client
->dev
, "Found single sensor");
537 indio_dev
->channels
= mlx90614_channels
;
538 indio_dev
->num_channels
= 2;
541 dev_dbg(&client
->dev
, "Found dual sensor");
542 indio_dev
->channels
= mlx90614_channels
;
543 indio_dev
->num_channels
= 3;
549 if (data
->wakeup_gpio
) {
550 pm_runtime_set_autosuspend_delay(&client
->dev
,
551 MLX90614_AUTOSLEEP_DELAY
);
552 pm_runtime_use_autosuspend(&client
->dev
);
553 pm_runtime_set_active(&client
->dev
);
554 pm_runtime_enable(&client
->dev
);
557 return iio_device_register(indio_dev
);
560 static int mlx90614_remove(struct i2c_client
*client
)
562 struct iio_dev
*indio_dev
= i2c_get_clientdata(client
);
563 struct mlx90614_data
*data
= iio_priv(indio_dev
);
565 iio_device_unregister(indio_dev
);
567 if (data
->wakeup_gpio
) {
568 pm_runtime_disable(&client
->dev
);
569 if (!pm_runtime_status_suspended(&client
->dev
))
570 mlx90614_sleep(data
);
571 pm_runtime_set_suspended(&client
->dev
);
577 static const struct i2c_device_id mlx90614_id
[] = {
581 MODULE_DEVICE_TABLE(i2c
, mlx90614_id
);
583 static const struct of_device_id mlx90614_of_match
[] = {
584 { .compatible
= "melexis,mlx90614" },
587 MODULE_DEVICE_TABLE(of
, mlx90614_of_match
);
589 #ifdef CONFIG_PM_SLEEP
590 static int mlx90614_pm_suspend(struct device
*dev
)
592 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
593 struct mlx90614_data
*data
= iio_priv(indio_dev
);
595 if (data
->wakeup_gpio
&& pm_runtime_active(dev
))
596 return mlx90614_sleep(data
);
601 static int mlx90614_pm_resume(struct device
*dev
)
603 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
604 struct mlx90614_data
*data
= iio_priv(indio_dev
);
607 if (data
->wakeup_gpio
) {
608 err
= mlx90614_wakeup(data
);
612 pm_runtime_disable(dev
);
613 pm_runtime_set_active(dev
);
614 pm_runtime_enable(dev
);
622 static int mlx90614_pm_runtime_suspend(struct device
*dev
)
624 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
625 struct mlx90614_data
*data
= iio_priv(indio_dev
);
627 return mlx90614_sleep(data
);
630 static int mlx90614_pm_runtime_resume(struct device
*dev
)
632 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
633 struct mlx90614_data
*data
= iio_priv(indio_dev
);
635 return mlx90614_wakeup(data
);
639 static const struct dev_pm_ops mlx90614_pm_ops
= {
640 SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend
, mlx90614_pm_resume
)
641 SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend
,
642 mlx90614_pm_runtime_resume
, NULL
)
645 static struct i2c_driver mlx90614_driver
= {
648 .of_match_table
= mlx90614_of_match
,
649 .pm
= &mlx90614_pm_ops
,
651 .probe
= mlx90614_probe
,
652 .remove
= mlx90614_remove
,
653 .id_table
= mlx90614_id
,
655 module_i2c_driver(mlx90614_driver
);
657 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
658 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
659 MODULE_AUTHOR("Crt Mori <cmo@melexis.com>");
660 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
661 MODULE_LICENSE("GPL");