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 .pm = &mlx90614_pm_ops,
556 .probe = mlx90614_probe,
557 .remove = mlx90614_remove,
558 .id_table = mlx90614_id,
560 module_i2c_driver(mlx90614_driver);
562 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
563 MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
564 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
565 MODULE_LICENSE("GPL");