2 * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
4 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
5 * Copyright (c) 2015 Essensium NV
6 * Copyright (c) 2015 Melexis
8 * This file is subject to the terms and conditions of version 2 of
9 * the GNU General Public License. See the file COPYING in the main
10 * directory of this archive for more details.
12 * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
14 * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
16 * To wake up from sleep mode, the SDA line must be held low while SCL is high
17 * for at least 33ms. This is achieved with an extra GPIO that can be connected
18 * directly to the SDA line. In normal operation, the GPIO is set as input and
19 * will not interfere in I2C communication. While the GPIO is driven low, the
20 * i2c adapter is locked since it cannot be used by other clients. The SCL line
21 * always has a pull-up so we do not need an extra GPIO to drive it high. If
22 * the "wakeup" GPIO is not given, power management will be disabled.
26 #include <linux/err.h>
27 #include <linux/i2c.h>
28 #include <linux/module.h>
29 #include <linux/delay.h>
30 #include <linux/jiffies.h>
31 #include <linux/gpio/consumer.h>
32 #include <linux/pm_runtime.h>
34 #include <linux/iio/iio.h>
35 #include <linux/iio/sysfs.h>
37 #define MLX90614_OP_RAM 0x00
38 #define MLX90614_OP_EEPROM 0x20
39 #define MLX90614_OP_SLEEP 0xff
41 /* RAM offsets with 16-bit data, MSB first */
42 #define MLX90614_RAW1 (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */
43 #define MLX90614_RAW2 (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */
44 #define MLX90614_TA (MLX90614_OP_RAM | 0x06) /* ambient temperature */
45 #define MLX90614_TOBJ1 (MLX90614_OP_RAM | 0x07) /* object 1 temperature */
46 #define MLX90614_TOBJ2 (MLX90614_OP_RAM | 0x08) /* object 2 temperature */
48 /* EEPROM offsets with 16-bit data, MSB first */
49 #define MLX90614_EMISSIVITY (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */
50 #define MLX90614_CONFIG (MLX90614_OP_EEPROM | 0x05) /* configuration register */
52 /* Control bits in configuration register */
53 #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
54 #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
55 #define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */
56 #define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT)
57 #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
58 #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
59 #define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */
60 #define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT)
63 #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
64 #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
65 #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
67 #define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
70 #define MLX90614_CONST_OFFSET_DEC -13657 /* decimal part of the Kelvin offset */
71 #define MLX90614_CONST_OFFSET_REM 500000 /* remainder of offset (273.15*50) */
72 #define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
73 #define MLX90614_CONST_RAW_EMISSIVITY_MAX 65535 /* max value for emissivity */
74 #define MLX90614_CONST_EMISSIVITY_RESOLUTION 15259 /* 1/65535 ~ 0.000015259 */
75 #define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */
77 struct mlx90614_data
{
78 struct i2c_client
*client
;
79 struct mutex lock
; /* for EEPROM access only */
80 struct gpio_desc
*wakeup_gpio
; /* NULL to disable sleep/wake-up */
81 unsigned long ready_timestamp
; /* in jiffies */
84 /* Bandwidth values for IIR filtering */
85 static const int mlx90614_iir_values
[] = {77, 31, 20, 15, 723, 153, 110, 86};
86 static IIO_CONST_ATTR(in_temp_object_filter_low_pass_3db_frequency_available
,
87 "0.15 0.20 0.31 0.77 0.86 1.10 1.53 7.23");
89 static struct attribute
*mlx90614_attributes
[] = {
90 &iio_const_attr_in_temp_object_filter_low_pass_3db_frequency_available
.dev_attr
.attr
,
94 static const struct attribute_group mlx90614_attr_group
= {
95 .attrs
= mlx90614_attributes
,
99 * Erase an address and write word.
100 * The mutex must be locked before calling.
102 static s32
mlx90614_write_word(const struct i2c_client
*client
, u8 command
,
106 * Note: The mlx90614 requires a PEC on writing but does not send us a
107 * valid PEC on reading. Hence, we cannot set I2C_CLIENT_PEC in
108 * i2c_client.flags. As a workaround, we use i2c_smbus_xfer here.
110 union i2c_smbus_data data
;
113 dev_dbg(&client
->dev
, "Writing 0x%x to address 0x%x", value
, command
);
115 data
.word
= 0x0000; /* erase command */
116 ret
= i2c_smbus_xfer(client
->adapter
, client
->addr
,
117 client
->flags
| I2C_CLIENT_PEC
,
118 I2C_SMBUS_WRITE
, command
,
119 I2C_SMBUS_WORD_DATA
, &data
);
123 msleep(MLX90614_TIMING_EEPROM
);
125 data
.word
= value
; /* actual write */
126 ret
= i2c_smbus_xfer(client
->adapter
, client
->addr
,
127 client
->flags
| I2C_CLIENT_PEC
,
128 I2C_SMBUS_WRITE
, command
,
129 I2C_SMBUS_WORD_DATA
, &data
);
131 msleep(MLX90614_TIMING_EEPROM
);
137 * Find the IIR value inside mlx90614_iir_values array and return its position
138 * which is equivalent to the bit value in sensor register
140 static inline s32
mlx90614_iir_search(const struct i2c_client
*client
,
146 for (i
= 0; i
< ARRAY_SIZE(mlx90614_iir_values
); ++i
) {
147 if (value
== mlx90614_iir_values
[i
])
151 if (i
== ARRAY_SIZE(mlx90614_iir_values
))
155 * CONFIG register values must not be changed so
156 * we must read them before we actually write
159 ret
= i2c_smbus_read_word_data(client
, MLX90614_CONFIG
);
163 ret
&= ~MLX90614_CONFIG_FIR_MASK
;
164 ret
|= MLX90614_CONST_FIR
<< MLX90614_CONFIG_FIR_SHIFT
;
165 ret
&= ~MLX90614_CONFIG_IIR_MASK
;
166 ret
|= i
<< MLX90614_CONFIG_IIR_SHIFT
;
168 /* Write changed values */
169 ret
= mlx90614_write_word(client
, MLX90614_CONFIG
, ret
);
175 * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
176 * the last wake-up. This is normally only needed to get a valid temperature
177 * reading. EEPROM access does not need such delay.
178 * Return 0 on success, <0 on error.
180 static int mlx90614_power_get(struct mlx90614_data
*data
, bool startup
)
184 if (!data
->wakeup_gpio
)
187 pm_runtime_get_sync(&data
->client
->dev
);
191 if (time_before(now
, data
->ready_timestamp
) &&
192 msleep_interruptible(jiffies_to_msecs(
193 data
->ready_timestamp
- now
)) != 0) {
194 pm_runtime_put_autosuspend(&data
->client
->dev
);
202 static void mlx90614_power_put(struct mlx90614_data
*data
)
204 if (!data
->wakeup_gpio
)
207 pm_runtime_mark_last_busy(&data
->client
->dev
);
208 pm_runtime_put_autosuspend(&data
->client
->dev
);
211 static inline int mlx90614_power_get(struct mlx90614_data
*data
, bool startup
)
216 static inline void mlx90614_power_put(struct mlx90614_data
*data
)
221 static int mlx90614_read_raw(struct iio_dev
*indio_dev
,
222 struct iio_chan_spec
const *channel
, int *val
,
223 int *val2
, long mask
)
225 struct mlx90614_data
*data
= iio_priv(indio_dev
);
230 case IIO_CHAN_INFO_RAW
: /* 0.02K / LSB */
231 switch (channel
->channel2
) {
232 case IIO_MOD_TEMP_AMBIENT
:
235 case IIO_MOD_TEMP_OBJECT
:
236 switch (channel
->channel
) {
238 cmd
= MLX90614_TOBJ1
;
241 cmd
= MLX90614_TOBJ2
;
251 ret
= mlx90614_power_get(data
, true);
254 ret
= i2c_smbus_read_word_data(data
->client
, cmd
);
255 mlx90614_power_put(data
);
260 /* MSB is an error flag */
266 case IIO_CHAN_INFO_OFFSET
:
267 *val
= MLX90614_CONST_OFFSET_DEC
;
268 *val2
= MLX90614_CONST_OFFSET_REM
;
269 return IIO_VAL_INT_PLUS_MICRO
;
270 case IIO_CHAN_INFO_SCALE
:
271 *val
= MLX90614_CONST_SCALE
;
273 case IIO_CHAN_INFO_CALIBEMISSIVITY
: /* 1/65535 / LSB */
274 mlx90614_power_get(data
, false);
275 mutex_lock(&data
->lock
);
276 ret
= i2c_smbus_read_word_data(data
->client
,
277 MLX90614_EMISSIVITY
);
278 mutex_unlock(&data
->lock
);
279 mlx90614_power_put(data
);
284 if (ret
== MLX90614_CONST_RAW_EMISSIVITY_MAX
) {
289 *val2
= ret
* MLX90614_CONST_EMISSIVITY_RESOLUTION
;
291 return IIO_VAL_INT_PLUS_NANO
;
292 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
: /* IIR setting with
294 mlx90614_power_get(data
, false);
295 mutex_lock(&data
->lock
);
296 ret
= i2c_smbus_read_word_data(data
->client
, MLX90614_CONFIG
);
297 mutex_unlock(&data
->lock
);
298 mlx90614_power_put(data
);
303 *val
= mlx90614_iir_values
[ret
& MLX90614_CONFIG_IIR_MASK
] / 100;
304 *val2
= (mlx90614_iir_values
[ret
& MLX90614_CONFIG_IIR_MASK
] % 100) *
306 return IIO_VAL_INT_PLUS_MICRO
;
312 static int mlx90614_write_raw(struct iio_dev
*indio_dev
,
313 struct iio_chan_spec
const *channel
, int val
,
316 struct mlx90614_data
*data
= iio_priv(indio_dev
);
320 case IIO_CHAN_INFO_CALIBEMISSIVITY
: /* 1/65535 / LSB */
321 if (val
< 0 || val2
< 0 || val
> 1 || (val
== 1 && val2
!= 0))
323 val
= val
* MLX90614_CONST_RAW_EMISSIVITY_MAX
+
324 val2
/ MLX90614_CONST_EMISSIVITY_RESOLUTION
;
326 mlx90614_power_get(data
, false);
327 mutex_lock(&data
->lock
);
328 ret
= mlx90614_write_word(data
->client
, MLX90614_EMISSIVITY
,
330 mutex_unlock(&data
->lock
);
331 mlx90614_power_put(data
);
334 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
: /* IIR Filter setting */
335 if (val
< 0 || val2
< 0)
338 mlx90614_power_get(data
, false);
339 mutex_lock(&data
->lock
);
340 ret
= mlx90614_iir_search(data
->client
,
341 val
* 100 + val2
/ 10000);
342 mutex_unlock(&data
->lock
);
343 mlx90614_power_put(data
);
351 static int mlx90614_write_raw_get_fmt(struct iio_dev
*indio_dev
,
352 struct iio_chan_spec
const *channel
,
356 case IIO_CHAN_INFO_CALIBEMISSIVITY
:
357 return IIO_VAL_INT_PLUS_NANO
;
358 case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
:
359 return IIO_VAL_INT_PLUS_MICRO
;
365 static const struct iio_chan_spec mlx90614_channels
[] = {
369 .channel2
= IIO_MOD_TEMP_AMBIENT
,
370 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
),
371 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
372 BIT(IIO_CHAN_INFO_SCALE
),
377 .channel2
= IIO_MOD_TEMP_OBJECT
,
378 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
) |
379 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY
) |
380 BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
),
381 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
382 BIT(IIO_CHAN_INFO_SCALE
),
389 .channel2
= IIO_MOD_TEMP_OBJECT
,
390 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
) |
391 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY
) |
392 BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY
),
393 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
394 BIT(IIO_CHAN_INFO_SCALE
),
398 static const struct iio_info mlx90614_info
= {
399 .read_raw
= mlx90614_read_raw
,
400 .write_raw
= mlx90614_write_raw
,
401 .write_raw_get_fmt
= mlx90614_write_raw_get_fmt
,
402 .attrs
= &mlx90614_attr_group
,
406 static int mlx90614_sleep(struct mlx90614_data
*data
)
410 if (!data
->wakeup_gpio
) {
411 dev_dbg(&data
->client
->dev
, "Sleep disabled");
415 dev_dbg(&data
->client
->dev
, "Requesting sleep");
417 mutex_lock(&data
->lock
);
418 ret
= i2c_smbus_xfer(data
->client
->adapter
, data
->client
->addr
,
419 data
->client
->flags
| I2C_CLIENT_PEC
,
420 I2C_SMBUS_WRITE
, MLX90614_OP_SLEEP
,
421 I2C_SMBUS_BYTE
, NULL
);
422 mutex_unlock(&data
->lock
);
427 static int mlx90614_wakeup(struct mlx90614_data
*data
)
429 if (!data
->wakeup_gpio
) {
430 dev_dbg(&data
->client
->dev
, "Wake-up disabled");
434 dev_dbg(&data
->client
->dev
, "Requesting wake-up");
436 i2c_lock_bus(data
->client
->adapter
, I2C_LOCK_ROOT_ADAPTER
);
437 gpiod_direction_output(data
->wakeup_gpio
, 0);
438 msleep(MLX90614_TIMING_WAKEUP
);
439 gpiod_direction_input(data
->wakeup_gpio
);
440 i2c_unlock_bus(data
->client
->adapter
, I2C_LOCK_ROOT_ADAPTER
);
442 data
->ready_timestamp
= jiffies
+
443 msecs_to_jiffies(MLX90614_TIMING_STARTUP
);
446 * Quirk: the i2c controller may get confused right after the
447 * wake-up signal has been sent. As a workaround, do a dummy read.
448 * If the read fails, the controller will probably be reset so that
449 * further reads will work.
451 i2c_smbus_read_word_data(data
->client
, MLX90614_CONFIG
);
456 /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
457 static struct gpio_desc
*mlx90614_probe_wakeup(struct i2c_client
*client
)
459 struct gpio_desc
*gpio
;
461 if (!i2c_check_functionality(client
->adapter
,
462 I2C_FUNC_SMBUS_WRITE_BYTE
)) {
463 dev_info(&client
->dev
,
464 "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
468 gpio
= devm_gpiod_get_optional(&client
->dev
, "wakeup", GPIOD_IN
);
471 dev_warn(&client
->dev
,
472 "gpio acquisition failed with error %ld, sleep disabled",
476 dev_info(&client
->dev
,
477 "wakeup-gpio not found, sleep disabled");
483 static inline int mlx90614_sleep(struct mlx90614_data
*data
)
487 static inline int mlx90614_wakeup(struct mlx90614_data
*data
)
491 static inline struct gpio_desc
*mlx90614_probe_wakeup(struct i2c_client
*client
)
497 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
498 static int mlx90614_probe_num_ir_sensors(struct i2c_client
*client
)
502 ret
= i2c_smbus_read_word_data(client
, MLX90614_CONFIG
);
507 return (ret
& MLX90614_CONFIG_DUAL_MASK
) ? 1 : 0;
510 static int mlx90614_probe(struct i2c_client
*client
,
511 const struct i2c_device_id
*id
)
513 struct iio_dev
*indio_dev
;
514 struct mlx90614_data
*data
;
517 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_WORD_DATA
))
520 indio_dev
= devm_iio_device_alloc(&client
->dev
, sizeof(*data
));
524 data
= iio_priv(indio_dev
);
525 i2c_set_clientdata(client
, indio_dev
);
526 data
->client
= client
;
527 mutex_init(&data
->lock
);
528 data
->wakeup_gpio
= mlx90614_probe_wakeup(client
);
530 mlx90614_wakeup(data
);
532 indio_dev
->dev
.parent
= &client
->dev
;
533 indio_dev
->name
= id
->name
;
534 indio_dev
->modes
= INDIO_DIRECT_MODE
;
535 indio_dev
->info
= &mlx90614_info
;
537 ret
= mlx90614_probe_num_ir_sensors(client
);
540 dev_dbg(&client
->dev
, "Found single sensor");
541 indio_dev
->channels
= mlx90614_channels
;
542 indio_dev
->num_channels
= 2;
545 dev_dbg(&client
->dev
, "Found dual sensor");
546 indio_dev
->channels
= mlx90614_channels
;
547 indio_dev
->num_channels
= 3;
553 if (data
->wakeup_gpio
) {
554 pm_runtime_set_autosuspend_delay(&client
->dev
,
555 MLX90614_AUTOSLEEP_DELAY
);
556 pm_runtime_use_autosuspend(&client
->dev
);
557 pm_runtime_set_active(&client
->dev
);
558 pm_runtime_enable(&client
->dev
);
561 return iio_device_register(indio_dev
);
564 static int mlx90614_remove(struct i2c_client
*client
)
566 struct iio_dev
*indio_dev
= i2c_get_clientdata(client
);
567 struct mlx90614_data
*data
= iio_priv(indio_dev
);
569 iio_device_unregister(indio_dev
);
571 if (data
->wakeup_gpio
) {
572 pm_runtime_disable(&client
->dev
);
573 if (!pm_runtime_status_suspended(&client
->dev
))
574 mlx90614_sleep(data
);
575 pm_runtime_set_suspended(&client
->dev
);
581 static const struct i2c_device_id mlx90614_id
[] = {
585 MODULE_DEVICE_TABLE(i2c
, mlx90614_id
);
587 static const struct of_device_id mlx90614_of_match
[] = {
588 { .compatible
= "melexis,mlx90614" },
591 MODULE_DEVICE_TABLE(of
, mlx90614_of_match
);
593 #ifdef CONFIG_PM_SLEEP
594 static int mlx90614_pm_suspend(struct device
*dev
)
596 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
597 struct mlx90614_data
*data
= iio_priv(indio_dev
);
599 if (data
->wakeup_gpio
&& pm_runtime_active(dev
))
600 return mlx90614_sleep(data
);
605 static int mlx90614_pm_resume(struct device
*dev
)
607 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
608 struct mlx90614_data
*data
= iio_priv(indio_dev
);
611 if (data
->wakeup_gpio
) {
612 err
= mlx90614_wakeup(data
);
616 pm_runtime_disable(dev
);
617 pm_runtime_set_active(dev
);
618 pm_runtime_enable(dev
);
626 static int mlx90614_pm_runtime_suspend(struct device
*dev
)
628 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
629 struct mlx90614_data
*data
= iio_priv(indio_dev
);
631 return mlx90614_sleep(data
);
634 static int mlx90614_pm_runtime_resume(struct device
*dev
)
636 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
637 struct mlx90614_data
*data
= iio_priv(indio_dev
);
639 return mlx90614_wakeup(data
);
643 static const struct dev_pm_ops mlx90614_pm_ops
= {
644 SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend
, mlx90614_pm_resume
)
645 SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend
,
646 mlx90614_pm_runtime_resume
, NULL
)
649 static struct i2c_driver mlx90614_driver
= {
652 .of_match_table
= mlx90614_of_match
,
653 .pm
= &mlx90614_pm_ops
,
655 .probe
= mlx90614_probe
,
656 .remove
= mlx90614_remove
,
657 .id_table
= mlx90614_id
,
659 module_i2c_driver(mlx90614_driver
);
661 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
662 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
663 MODULE_AUTHOR("Crt Mori <cmo@melexis.com>");
664 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
665 MODULE_LICENSE("GPL");