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
7 * This file is subject to the terms and conditions of version 2 of
8 * the GNU General Public License. See the file COPYING in the main
9 * directory of this archive for more details.
11 * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
13 * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
15 * To wake up from sleep mode, the SDA line must be held low while SCL is high
16 * for at least 33ms. This is achieved with an extra GPIO that can be connected
17 * directly to the SDA line. In normal operation, the GPIO is set as input and
18 * will not interfere in I2C communication. While the GPIO is driven low, the
19 * i2c adapter is locked since it cannot be used by other clients. The SCL line
20 * always has a pull-up so we do not need an extra GPIO to drive it high. If
21 * the "wakeup" GPIO is not given, power management will be disabled.
23 * TODO: filter configuration
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>
36 #define MLX90614_OP_RAM 0x00
37 #define MLX90614_OP_EEPROM 0x20
38 #define MLX90614_OP_SLEEP 0xff
40 /* RAM offsets with 16-bit data, MSB first */
41 #define MLX90614_RAW1 (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */
42 #define MLX90614_RAW2 (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */
43 #define MLX90614_TA (MLX90614_OP_RAM | 0x06) /* ambient temperature */
44 #define MLX90614_TOBJ1 (MLX90614_OP_RAM | 0x07) /* object 1 temperature */
45 #define MLX90614_TOBJ2 (MLX90614_OP_RAM | 0x08) /* object 2 temperature */
47 /* EEPROM offsets with 16-bit data, MSB first */
48 #define MLX90614_EMISSIVITY (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */
49 #define MLX90614_CONFIG (MLX90614_OP_EEPROM | 0x05) /* configuration register */
51 /* Control bits in configuration register */
52 #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
53 #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
54 #define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */
55 #define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT)
56 #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
57 #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
58 #define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */
59 #define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT)
62 #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
63 #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
64 #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
66 #define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
68 struct mlx90614_data
{
69 struct i2c_client
*client
;
70 struct mutex lock
; /* for EEPROM access only */
71 struct gpio_desc
*wakeup_gpio
; /* NULL to disable sleep/wake-up */
72 unsigned long ready_timestamp
; /* in jiffies */
76 * Erase an address and write word.
77 * The mutex must be locked before calling.
79 static s32
mlx90614_write_word(const struct i2c_client
*client
, u8 command
,
83 * Note: The mlx90614 requires a PEC on writing but does not send us a
84 * valid PEC on reading. Hence, we cannot set I2C_CLIENT_PEC in
85 * i2c_client.flags. As a workaround, we use i2c_smbus_xfer here.
87 union i2c_smbus_data data
;
90 dev_dbg(&client
->dev
, "Writing 0x%x to address 0x%x", value
, command
);
92 data
.word
= 0x0000; /* erase command */
93 ret
= i2c_smbus_xfer(client
->adapter
, client
->addr
,
94 client
->flags
| I2C_CLIENT_PEC
,
95 I2C_SMBUS_WRITE
, command
,
96 I2C_SMBUS_WORD_DATA
, &data
);
100 msleep(MLX90614_TIMING_EEPROM
);
102 data
.word
= value
; /* actual write */
103 ret
= i2c_smbus_xfer(client
->adapter
, client
->addr
,
104 client
->flags
| I2C_CLIENT_PEC
,
105 I2C_SMBUS_WRITE
, command
,
106 I2C_SMBUS_WORD_DATA
, &data
);
108 msleep(MLX90614_TIMING_EEPROM
);
115 * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
116 * the last wake-up. This is normally only needed to get a valid temperature
117 * reading. EEPROM access does not need such delay.
118 * Return 0 on success, <0 on error.
120 static int mlx90614_power_get(struct mlx90614_data
*data
, bool startup
)
124 if (!data
->wakeup_gpio
)
127 pm_runtime_get_sync(&data
->client
->dev
);
131 if (time_before(now
, data
->ready_timestamp
) &&
132 msleep_interruptible(jiffies_to_msecs(
133 data
->ready_timestamp
- now
)) != 0) {
134 pm_runtime_put_autosuspend(&data
->client
->dev
);
142 static void mlx90614_power_put(struct mlx90614_data
*data
)
144 if (!data
->wakeup_gpio
)
147 pm_runtime_mark_last_busy(&data
->client
->dev
);
148 pm_runtime_put_autosuspend(&data
->client
->dev
);
151 static inline int mlx90614_power_get(struct mlx90614_data
*data
, bool startup
)
156 static inline void mlx90614_power_put(struct mlx90614_data
*data
)
161 static int mlx90614_read_raw(struct iio_dev
*indio_dev
,
162 struct iio_chan_spec
const *channel
, int *val
,
163 int *val2
, long mask
)
165 struct mlx90614_data
*data
= iio_priv(indio_dev
);
170 case IIO_CHAN_INFO_RAW
: /* 0.02K / LSB */
171 switch (channel
->channel2
) {
172 case IIO_MOD_TEMP_AMBIENT
:
175 case IIO_MOD_TEMP_OBJECT
:
176 switch (channel
->channel
) {
178 cmd
= MLX90614_TOBJ1
;
181 cmd
= MLX90614_TOBJ2
;
191 ret
= mlx90614_power_get(data
, true);
194 ret
= i2c_smbus_read_word_data(data
->client
, cmd
);
195 mlx90614_power_put(data
);
200 /* MSB is an error flag */
206 case IIO_CHAN_INFO_OFFSET
:
209 return IIO_VAL_INT_PLUS_MICRO
;
210 case IIO_CHAN_INFO_SCALE
:
213 case IIO_CHAN_INFO_CALIBEMISSIVITY
: /* 1/65535 / LSB */
214 mlx90614_power_get(data
, false);
215 mutex_lock(&data
->lock
);
216 ret
= i2c_smbus_read_word_data(data
->client
,
217 MLX90614_EMISSIVITY
);
218 mutex_unlock(&data
->lock
);
219 mlx90614_power_put(data
);
229 *val2
= ret
* 15259; /* 1/65535 ~ 0.000015259 */
231 return IIO_VAL_INT_PLUS_NANO
;
237 static int mlx90614_write_raw(struct iio_dev
*indio_dev
,
238 struct iio_chan_spec
const *channel
, int val
,
241 struct mlx90614_data
*data
= iio_priv(indio_dev
);
245 case IIO_CHAN_INFO_CALIBEMISSIVITY
: /* 1/65535 / LSB */
246 if (val
< 0 || val2
< 0 || val
> 1 || (val
== 1 && val2
!= 0))
248 val
= val
* 65535 + val2
/ 15259; /* 1/65535 ~ 0.000015259 */
250 mlx90614_power_get(data
, false);
251 mutex_lock(&data
->lock
);
252 ret
= mlx90614_write_word(data
->client
, MLX90614_EMISSIVITY
,
254 mutex_unlock(&data
->lock
);
255 mlx90614_power_put(data
);
263 static int mlx90614_write_raw_get_fmt(struct iio_dev
*indio_dev
,
264 struct iio_chan_spec
const *channel
,
268 case IIO_CHAN_INFO_CALIBEMISSIVITY
:
269 return IIO_VAL_INT_PLUS_NANO
;
275 static const struct iio_chan_spec mlx90614_channels
[] = {
279 .channel2
= IIO_MOD_TEMP_AMBIENT
,
280 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
),
281 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
282 BIT(IIO_CHAN_INFO_SCALE
),
287 .channel2
= IIO_MOD_TEMP_OBJECT
,
288 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
) |
289 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY
),
290 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
291 BIT(IIO_CHAN_INFO_SCALE
),
298 .channel2
= IIO_MOD_TEMP_OBJECT
,
299 .info_mask_separate
= BIT(IIO_CHAN_INFO_RAW
) |
300 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY
),
301 .info_mask_shared_by_type
= BIT(IIO_CHAN_INFO_OFFSET
) |
302 BIT(IIO_CHAN_INFO_SCALE
),
306 static const struct iio_info mlx90614_info
= {
307 .read_raw
= mlx90614_read_raw
,
308 .write_raw
= mlx90614_write_raw
,
309 .write_raw_get_fmt
= mlx90614_write_raw_get_fmt
,
310 .driver_module
= THIS_MODULE
,
314 static int mlx90614_sleep(struct mlx90614_data
*data
)
318 if (!data
->wakeup_gpio
) {
319 dev_dbg(&data
->client
->dev
, "Sleep disabled");
323 dev_dbg(&data
->client
->dev
, "Requesting sleep");
325 mutex_lock(&data
->lock
);
326 ret
= i2c_smbus_xfer(data
->client
->adapter
, data
->client
->addr
,
327 data
->client
->flags
| I2C_CLIENT_PEC
,
328 I2C_SMBUS_WRITE
, MLX90614_OP_SLEEP
,
329 I2C_SMBUS_BYTE
, NULL
);
330 mutex_unlock(&data
->lock
);
335 static int mlx90614_wakeup(struct mlx90614_data
*data
)
337 if (!data
->wakeup_gpio
) {
338 dev_dbg(&data
->client
->dev
, "Wake-up disabled");
342 dev_dbg(&data
->client
->dev
, "Requesting wake-up");
344 i2c_lock_adapter(data
->client
->adapter
);
345 gpiod_direction_output(data
->wakeup_gpio
, 0);
346 msleep(MLX90614_TIMING_WAKEUP
);
347 gpiod_direction_input(data
->wakeup_gpio
);
348 i2c_unlock_adapter(data
->client
->adapter
);
350 data
->ready_timestamp
= jiffies
+
351 msecs_to_jiffies(MLX90614_TIMING_STARTUP
);
354 * Quirk: the i2c controller may get confused right after the
355 * wake-up signal has been sent. As a workaround, do a dummy read.
356 * If the read fails, the controller will probably be reset so that
357 * further reads will work.
359 i2c_smbus_read_word_data(data
->client
, MLX90614_CONFIG
);
364 /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
365 static struct gpio_desc
*mlx90614_probe_wakeup(struct i2c_client
*client
)
367 struct gpio_desc
*gpio
;
369 if (!i2c_check_functionality(client
->adapter
,
370 I2C_FUNC_SMBUS_WRITE_BYTE
)) {
371 dev_info(&client
->dev
,
372 "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
376 gpio
= devm_gpiod_get_optional(&client
->dev
, "wakeup", GPIOD_IN
);
379 dev_warn(&client
->dev
,
380 "gpio acquisition failed with error %ld, sleep disabled",
384 dev_info(&client
->dev
,
385 "wakeup-gpio not found, sleep disabled");
391 static inline int mlx90614_sleep(struct mlx90614_data
*data
)
395 static inline int mlx90614_wakeup(struct mlx90614_data
*data
)
399 static inline struct gpio_desc
*mlx90614_probe_wakeup(struct i2c_client
*client
)
405 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
406 static int mlx90614_probe_num_ir_sensors(struct i2c_client
*client
)
410 ret
= i2c_smbus_read_word_data(client
, MLX90614_CONFIG
);
415 return (ret
& MLX90614_CONFIG_DUAL_MASK
) ? 1 : 0;
418 static int mlx90614_probe(struct i2c_client
*client
,
419 const struct i2c_device_id
*id
)
421 struct iio_dev
*indio_dev
;
422 struct mlx90614_data
*data
;
425 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_WORD_DATA
))
428 indio_dev
= devm_iio_device_alloc(&client
->dev
, sizeof(*data
));
432 data
= iio_priv(indio_dev
);
433 i2c_set_clientdata(client
, indio_dev
);
434 data
->client
= client
;
435 mutex_init(&data
->lock
);
436 data
->wakeup_gpio
= mlx90614_probe_wakeup(client
);
438 mlx90614_wakeup(data
);
440 indio_dev
->dev
.parent
= &client
->dev
;
441 indio_dev
->name
= id
->name
;
442 indio_dev
->modes
= INDIO_DIRECT_MODE
;
443 indio_dev
->info
= &mlx90614_info
;
445 ret
= mlx90614_probe_num_ir_sensors(client
);
448 dev_dbg(&client
->dev
, "Found single sensor");
449 indio_dev
->channels
= mlx90614_channels
;
450 indio_dev
->num_channels
= 2;
453 dev_dbg(&client
->dev
, "Found dual sensor");
454 indio_dev
->channels
= mlx90614_channels
;
455 indio_dev
->num_channels
= 3;
461 if (data
->wakeup_gpio
) {
462 pm_runtime_set_autosuspend_delay(&client
->dev
,
463 MLX90614_AUTOSLEEP_DELAY
);
464 pm_runtime_use_autosuspend(&client
->dev
);
465 pm_runtime_set_active(&client
->dev
);
466 pm_runtime_enable(&client
->dev
);
469 return iio_device_register(indio_dev
);
472 static int mlx90614_remove(struct i2c_client
*client
)
474 struct iio_dev
*indio_dev
= i2c_get_clientdata(client
);
475 struct mlx90614_data
*data
= iio_priv(indio_dev
);
477 iio_device_unregister(indio_dev
);
479 if (data
->wakeup_gpio
) {
480 pm_runtime_disable(&client
->dev
);
481 if (!pm_runtime_status_suspended(&client
->dev
))
482 mlx90614_sleep(data
);
483 pm_runtime_set_suspended(&client
->dev
);
489 static const struct i2c_device_id mlx90614_id
[] = {
493 MODULE_DEVICE_TABLE(i2c
, mlx90614_id
);
495 #ifdef CONFIG_PM_SLEEP
496 static int mlx90614_pm_suspend(struct device
*dev
)
498 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
499 struct mlx90614_data
*data
= iio_priv(indio_dev
);
501 if (data
->wakeup_gpio
&& pm_runtime_active(dev
))
502 return mlx90614_sleep(data
);
507 static int mlx90614_pm_resume(struct device
*dev
)
509 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
510 struct mlx90614_data
*data
= iio_priv(indio_dev
);
513 if (data
->wakeup_gpio
) {
514 err
= mlx90614_wakeup(data
);
518 pm_runtime_disable(dev
);
519 pm_runtime_set_active(dev
);
520 pm_runtime_enable(dev
);
528 static int mlx90614_pm_runtime_suspend(struct device
*dev
)
530 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
531 struct mlx90614_data
*data
= iio_priv(indio_dev
);
533 return mlx90614_sleep(data
);
536 static int mlx90614_pm_runtime_resume(struct device
*dev
)
538 struct iio_dev
*indio_dev
= i2c_get_clientdata(to_i2c_client(dev
));
539 struct mlx90614_data
*data
= iio_priv(indio_dev
);
541 return mlx90614_wakeup(data
);
545 static const struct dev_pm_ops mlx90614_pm_ops
= {
546 SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend
, mlx90614_pm_resume
)
547 SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend
,
548 mlx90614_pm_runtime_resume
, NULL
)
551 static struct i2c_driver mlx90614_driver
= {
554 .owner
= THIS_MODULE
,
555 .pm
= &mlx90614_pm_ops
,
557 .probe
= mlx90614_probe
,
558 .remove
= mlx90614_remove
,
559 .id_table
= mlx90614_id
,
561 module_i2c_driver(mlx90614_driver
);
563 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
564 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
565 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
566 MODULE_LICENSE("GPL");