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 */
69 #define MLX90614_CONST_OFFSET_DEC -13657 /* decimal part of the Kelvin offset */
70 #define MLX90614_CONST_OFFSET_REM 500000 /* remainder of offset (273.15*50) */
71 #define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
72 #define MLX90614_CONST_RAW_EMISSIVITY_MAX 65535 /* max value for emissivity */
73 #define MLX90614_CONST_EMISSIVITY_RESOLUTION 15259 /* 1/65535 ~ 0.000015259 */
75 struct mlx90614_data {
76 struct i2c_client *client;
77 struct mutex lock; /* for EEPROM access only */
78 struct gpio_desc *wakeup_gpio; /* NULL to disable sleep/wake-up */
79 unsigned long ready_timestamp; /* in jiffies */
83 * Erase an address and write word.
84 * The mutex must be locked before calling.
86 static s32 mlx90614_write_word(const struct i2c_client *client, u8 command,
90 * Note: The mlx90614 requires a PEC on writing but does not send us a
91 * valid PEC on reading. Hence, we cannot set I2C_CLIENT_PEC in
92 * i2c_client.flags. As a workaround, we use i2c_smbus_xfer here.
94 union i2c_smbus_data data;
97 dev_dbg(&client->dev, "Writing 0x%x to address 0x%x", value, command);
99 data.word = 0x0000; /* erase command */
100 ret = i2c_smbus_xfer(client->adapter, client->addr,
101 client->flags | I2C_CLIENT_PEC,
102 I2C_SMBUS_WRITE, command,
103 I2C_SMBUS_WORD_DATA, &data);
107 msleep(MLX90614_TIMING_EEPROM);
109 data.word = value; /* actual write */
110 ret = i2c_smbus_xfer(client->adapter, client->addr,
111 client->flags | I2C_CLIENT_PEC,
112 I2C_SMBUS_WRITE, command,
113 I2C_SMBUS_WORD_DATA, &data);
115 msleep(MLX90614_TIMING_EEPROM);
122 * If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
123 * the last wake-up. This is normally only needed to get a valid temperature
124 * reading. EEPROM access does not need such delay.
125 * Return 0 on success, <0 on error.
127 static int mlx90614_power_get(struct mlx90614_data *data, bool startup)
131 if (!data->wakeup_gpio)
134 pm_runtime_get_sync(&data->client->dev);
138 if (time_before(now, data->ready_timestamp) &&
139 msleep_interruptible(jiffies_to_msecs(
140 data->ready_timestamp - now)) != 0) {
141 pm_runtime_put_autosuspend(&data->client->dev);
149 static void mlx90614_power_put(struct mlx90614_data *data)
151 if (!data->wakeup_gpio)
154 pm_runtime_mark_last_busy(&data->client->dev);
155 pm_runtime_put_autosuspend(&data->client->dev);
158 static inline int mlx90614_power_get(struct mlx90614_data *data, bool startup)
163 static inline void mlx90614_power_put(struct mlx90614_data *data)
168 static int mlx90614_read_raw(struct iio_dev *indio_dev,
169 struct iio_chan_spec const *channel, int *val,
170 int *val2, long mask)
172 struct mlx90614_data *data = iio_priv(indio_dev);
177 case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
178 switch (channel->channel2) {
179 case IIO_MOD_TEMP_AMBIENT:
182 case IIO_MOD_TEMP_OBJECT:
183 switch (channel->channel) {
185 cmd = MLX90614_TOBJ1;
188 cmd = MLX90614_TOBJ2;
198 ret = mlx90614_power_get(data, true);
201 ret = i2c_smbus_read_word_data(data->client, cmd);
202 mlx90614_power_put(data);
207 /* MSB is an error flag */
213 case IIO_CHAN_INFO_OFFSET:
214 *val = MLX90614_CONST_OFFSET_DEC;
215 *val2 = MLX90614_CONST_OFFSET_REM;
216 return IIO_VAL_INT_PLUS_MICRO;
217 case IIO_CHAN_INFO_SCALE:
218 *val = MLX90614_CONST_SCALE;
220 case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
221 mlx90614_power_get(data, false);
222 mutex_lock(&data->lock);
223 ret = i2c_smbus_read_word_data(data->client,
224 MLX90614_EMISSIVITY);
225 mutex_unlock(&data->lock);
226 mlx90614_power_put(data);
231 if (ret == MLX90614_CONST_RAW_EMISSIVITY_MAX) {
236 *val2 = ret * MLX90614_CONST_EMISSIVITY_RESOLUTION;
238 return IIO_VAL_INT_PLUS_NANO;
244 static int mlx90614_write_raw(struct iio_dev *indio_dev,
245 struct iio_chan_spec const *channel, int val,
248 struct mlx90614_data *data = iio_priv(indio_dev);
252 case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
253 if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0))
255 val = val * MLX90614_CONST_RAW_EMISSIVITY_MAX +
256 val2 / MLX90614_CONST_EMISSIVITY_RESOLUTION;
258 mlx90614_power_get(data, false);
259 mutex_lock(&data->lock);
260 ret = mlx90614_write_word(data->client, MLX90614_EMISSIVITY,
262 mutex_unlock(&data->lock);
263 mlx90614_power_put(data);
271 static int mlx90614_write_raw_get_fmt(struct iio_dev *indio_dev,
272 struct iio_chan_spec const *channel,
276 case IIO_CHAN_INFO_CALIBEMISSIVITY:
277 return IIO_VAL_INT_PLUS_NANO;
283 static const struct iio_chan_spec mlx90614_channels[] = {
287 .channel2 = IIO_MOD_TEMP_AMBIENT,
288 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
289 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
290 BIT(IIO_CHAN_INFO_SCALE),
295 .channel2 = IIO_MOD_TEMP_OBJECT,
296 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
297 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
298 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
299 BIT(IIO_CHAN_INFO_SCALE),
306 .channel2 = IIO_MOD_TEMP_OBJECT,
307 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
308 BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
309 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
310 BIT(IIO_CHAN_INFO_SCALE),
314 static const struct iio_info mlx90614_info = {
315 .read_raw = mlx90614_read_raw,
316 .write_raw = mlx90614_write_raw,
317 .write_raw_get_fmt = mlx90614_write_raw_get_fmt,
318 .driver_module = THIS_MODULE,
322 static int mlx90614_sleep(struct mlx90614_data *data)
326 if (!data->wakeup_gpio) {
327 dev_dbg(&data->client->dev, "Sleep disabled");
331 dev_dbg(&data->client->dev, "Requesting sleep");
333 mutex_lock(&data->lock);
334 ret = i2c_smbus_xfer(data->client->adapter, data->client->addr,
335 data->client->flags | I2C_CLIENT_PEC,
336 I2C_SMBUS_WRITE, MLX90614_OP_SLEEP,
337 I2C_SMBUS_BYTE, NULL);
338 mutex_unlock(&data->lock);
343 static int mlx90614_wakeup(struct mlx90614_data *data)
345 if (!data->wakeup_gpio) {
346 dev_dbg(&data->client->dev, "Wake-up disabled");
350 dev_dbg(&data->client->dev, "Requesting wake-up");
352 i2c_lock_adapter(data->client->adapter);
353 gpiod_direction_output(data->wakeup_gpio, 0);
354 msleep(MLX90614_TIMING_WAKEUP);
355 gpiod_direction_input(data->wakeup_gpio);
356 i2c_unlock_adapter(data->client->adapter);
358 data->ready_timestamp = jiffies +
359 msecs_to_jiffies(MLX90614_TIMING_STARTUP);
362 * Quirk: the i2c controller may get confused right after the
363 * wake-up signal has been sent. As a workaround, do a dummy read.
364 * If the read fails, the controller will probably be reset so that
365 * further reads will work.
367 i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
372 /* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
373 static struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
375 struct gpio_desc *gpio;
377 if (!i2c_check_functionality(client->adapter,
378 I2C_FUNC_SMBUS_WRITE_BYTE)) {
379 dev_info(&client->dev,
380 "i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
384 gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_IN);
387 dev_warn(&client->dev,
388 "gpio acquisition failed with error %ld, sleep disabled",
392 dev_info(&client->dev,
393 "wakeup-gpio not found, sleep disabled");
399 static inline int mlx90614_sleep(struct mlx90614_data *data)
403 static inline int mlx90614_wakeup(struct mlx90614_data *data)
407 static inline struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
413 /* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
414 static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
418 ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
423 return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0;
426 static int mlx90614_probe(struct i2c_client *client,
427 const struct i2c_device_id *id)
429 struct iio_dev *indio_dev;
430 struct mlx90614_data *data;
433 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
436 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
440 data = iio_priv(indio_dev);
441 i2c_set_clientdata(client, indio_dev);
442 data->client = client;
443 mutex_init(&data->lock);
444 data->wakeup_gpio = mlx90614_probe_wakeup(client);
446 mlx90614_wakeup(data);
448 indio_dev->dev.parent = &client->dev;
449 indio_dev->name = id->name;
450 indio_dev->modes = INDIO_DIRECT_MODE;
451 indio_dev->info = &mlx90614_info;
453 ret = mlx90614_probe_num_ir_sensors(client);
456 dev_dbg(&client->dev, "Found single sensor");
457 indio_dev->channels = mlx90614_channels;
458 indio_dev->num_channels = 2;
461 dev_dbg(&client->dev, "Found dual sensor");
462 indio_dev->channels = mlx90614_channels;
463 indio_dev->num_channels = 3;
469 if (data->wakeup_gpio) {
470 pm_runtime_set_autosuspend_delay(&client->dev,
471 MLX90614_AUTOSLEEP_DELAY);
472 pm_runtime_use_autosuspend(&client->dev);
473 pm_runtime_set_active(&client->dev);
474 pm_runtime_enable(&client->dev);
477 return iio_device_register(indio_dev);
480 static int mlx90614_remove(struct i2c_client *client)
482 struct iio_dev *indio_dev = i2c_get_clientdata(client);
483 struct mlx90614_data *data = iio_priv(indio_dev);
485 iio_device_unregister(indio_dev);
487 if (data->wakeup_gpio) {
488 pm_runtime_disable(&client->dev);
489 if (!pm_runtime_status_suspended(&client->dev))
490 mlx90614_sleep(data);
491 pm_runtime_set_suspended(&client->dev);
497 static const struct i2c_device_id mlx90614_id[] = {
501 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
503 #ifdef CONFIG_PM_SLEEP
504 static int mlx90614_pm_suspend(struct device *dev)
506 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
507 struct mlx90614_data *data = iio_priv(indio_dev);
509 if (data->wakeup_gpio && pm_runtime_active(dev))
510 return mlx90614_sleep(data);
515 static int mlx90614_pm_resume(struct device *dev)
517 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
518 struct mlx90614_data *data = iio_priv(indio_dev);
521 if (data->wakeup_gpio) {
522 err = mlx90614_wakeup(data);
526 pm_runtime_disable(dev);
527 pm_runtime_set_active(dev);
528 pm_runtime_enable(dev);
536 static int mlx90614_pm_runtime_suspend(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_sleep(data);
544 static int mlx90614_pm_runtime_resume(struct device *dev)
546 struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
547 struct mlx90614_data *data = iio_priv(indio_dev);
549 return mlx90614_wakeup(data);
553 static const struct dev_pm_ops mlx90614_pm_ops = {
554 SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend, mlx90614_pm_resume)
555 SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend,
556 mlx90614_pm_runtime_resume, NULL)
559 static struct i2c_driver mlx90614_driver = {
562 .pm = &mlx90614_pm_ops,
564 .probe = mlx90614_probe,
565 .remove = mlx90614_remove,
566 .id_table = mlx90614_id,
568 module_i2c_driver(mlx90614_driver);
570 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
571 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
572 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
573 MODULE_LICENSE("GPL");