- 根目录:
- drivers
- iio
- temperature
- mlx90614.c
/*
* mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
*
* Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
* Copyright (c) 2015 Essensium NV
* Copyright (c) 2015 Melexis
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
*
* (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
*
* To wake up from sleep mode, the SDA line must be held low while SCL is high
* for at least 33ms. This is achieved with an extra GPIO that can be connected
* directly to the SDA line. In normal operation, the GPIO is set as input and
* will not interfere in I2C communication. While the GPIO is driven low, the
* i2c adapter is locked since it cannot be used by other clients. The SCL line
* always has a pull-up so we do not need an extra GPIO to drive it high. If
* the "wakeup" GPIO is not given, power management will be disabled.
*
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/gpio/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define MLX90614_OP_RAM 0x00
#define MLX90614_OP_EEPROM 0x20
#define MLX90614_OP_SLEEP 0xff
/* RAM offsets with 16-bit data, MSB first */
#define MLX90614_RAW1 (MLX90614_OP_RAM | 0x04) /* raw data IR channel 1 */
#define MLX90614_RAW2 (MLX90614_OP_RAM | 0x05) /* raw data IR channel 2 */
#define MLX90614_TA (MLX90614_OP_RAM | 0x06) /* ambient temperature */
#define MLX90614_TOBJ1 (MLX90614_OP_RAM | 0x07) /* object 1 temperature */
#define MLX90614_TOBJ2 (MLX90614_OP_RAM | 0x08) /* object 2 temperature */
/* EEPROM offsets with 16-bit data, MSB first */
#define MLX90614_EMISSIVITY (MLX90614_OP_EEPROM | 0x04) /* emissivity correction coefficient */
#define MLX90614_CONFIG (MLX90614_OP_EEPROM | 0x05) /* configuration register */
/* Control bits in configuration register */
#define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
#define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
#define MLX90614_CONFIG_DUAL_SHIFT 6 /* single (0) or dual (1) IR sensor */
#define MLX90614_CONFIG_DUAL_MASK (1 << MLX90614_CONFIG_DUAL_SHIFT)
#define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
#define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
#define MLX90614_CONFIG_GAIN_SHIFT 11 /* gain */
#define MLX90614_CONFIG_GAIN_MASK (0x7 << MLX90614_CONFIG_GAIN_SHIFT)
/* Timings (in ms) */
#define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
#define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
#define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
#define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
/* Magic constants */
#define MLX90614_CONST_OFFSET_DEC -13657 /* decimal part of the Kelvin offset */
#define MLX90614_CONST_OFFSET_REM 500000 /* remainder of offset (273.15*50) */
#define MLX90614_CONST_SCALE 20 /* Scale in milliKelvin (0.02 * 1000) */
#define MLX90614_CONST_RAW_EMISSIVITY_MAX 65535 /* max value for emissivity */
#define MLX90614_CONST_EMISSIVITY_RESOLUTION 15259 /* 1/65535 ~ 0.000015259 */
#define MLX90614_CONST_FIR 0x7 /* Fixed value for FIR part of low pass filter */
struct mlx90614_data {
struct i2c_client *client;
struct mutex lock; /* for EEPROM access only */
struct gpio_desc *wakeup_gpio; /* NULL to disable sleep/wake-up */
unsigned long ready_timestamp; /* in jiffies */
};
/* Bandwidth values for IIR filtering */
static const int mlx90614_iir_values[] = {77, 31, 20, 15, 723, 153, 110, 86};
static IIO_CONST_ATTR(in_temp_object_filter_low_pass_3db_frequency_available,
"0.15 0.20 0.31 0.77 0.86 1.10 1.53 7.23");
static struct attribute *mlx90614_attributes[] = {
&iio_const_attr_in_temp_object_filter_low_pass_3db_frequency_available.dev_attr.attr,
NULL,
};
static const struct attribute_group mlx90614_attr_group = {
.attrs = mlx90614_attributes,
};
/*
* Erase an address and write word.
* The mutex must be locked before calling.
*/
static s32 mlx90614_write_word(const struct i2c_client *client, u8 command,
u16 value)
{
/*
* Note: The mlx90614 requires a PEC on writing but does not send us a
* valid PEC on reading. Hence, we cannot set I2C_CLIENT_PEC in
* i2c_client.flags. As a workaround, we use i2c_smbus_xfer here.
*/
union i2c_smbus_data data;
s32 ret;
dev_dbg(&client->dev, "Writing 0x%x to address 0x%x", value, command);
data.word = 0x0000; /* erase command */
ret = i2c_smbus_xfer(client->adapter, client->addr,
client->flags | I2C_CLIENT_PEC,
I2C_SMBUS_WRITE, command,
I2C_SMBUS_WORD_DATA, &data);
if (ret < 0)
return ret;
msleep(MLX90614_TIMING_EEPROM);
data.word = value; /* actual write */
ret = i2c_smbus_xfer(client->adapter, client->addr,
client->flags | I2C_CLIENT_PEC,
I2C_SMBUS_WRITE, command,
I2C_SMBUS_WORD_DATA, &data);
msleep(MLX90614_TIMING_EEPROM);
return ret;
}
/*
* Find the IIR value inside mlx90614_iir_values array and return its position
* which is equivalent to the bit value in sensor register
*/
static inline s32 mlx90614_iir_search(const struct i2c_client *client,
int value)
{
int i;
s32 ret;
for (i = 0; i < ARRAY_SIZE(mlx90614_iir_values); ++i) {
if (value == mlx90614_iir_values[i])
break;
}
if (i == ARRAY_SIZE(mlx90614_iir_values))
return -EINVAL;
/*
* CONFIG register values must not be changed so
* we must read them before we actually write
* changes
*/
ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
if (ret < 0)
return ret;
ret &= ~MLX90614_CONFIG_FIR_MASK;
ret |= MLX90614_CONST_FIR << MLX90614_CONFIG_FIR_SHIFT;
ret &= ~MLX90614_CONFIG_IIR_MASK;
ret |= i << MLX90614_CONFIG_IIR_SHIFT;
/* Write changed values */
ret = mlx90614_write_word(client, MLX90614_CONFIG, ret);
return ret;
}
#ifdef CONFIG_PM
/*
* If @startup is true, make sure MLX90614_TIMING_STARTUP ms have elapsed since
* the last wake-up. This is normally only needed to get a valid temperature
* reading. EEPROM access does not need such delay.
* Return 0 on success, <0 on error.
*/
static int mlx90614_power_get(struct mlx90614_data *data, bool startup)
{
unsigned long now;
if (!data->wakeup_gpio)
return 0;
pm_runtime_get_sync(&data->client->dev);
if (startup) {
now = jiffies;
if (time_before(now, data->ready_timestamp) &&
msleep_interruptible(jiffies_to_msecs(
data->ready_timestamp - now)) != 0) {
pm_runtime_put_autosuspend(&data->client->dev);
return -EINTR;
}
}
return 0;
}
static void mlx90614_power_put(struct mlx90614_data *data)
{
if (!data->wakeup_gpio)
return;
pm_runtime_mark_last_busy(&data->client->dev);
pm_runtime_put_autosuspend(&data->client->dev);
}
#else
static inline int mlx90614_power_get(struct mlx90614_data *data, bool startup)
{
return 0;
}
static inline void mlx90614_power_put(struct mlx90614_data *data)
{
}
#endif
static int mlx90614_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct mlx90614_data *data = iio_priv(indio_dev);
u8 cmd;
s32 ret;
switch (mask) {
case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
switch (channel->channel2) {
case IIO_MOD_TEMP_AMBIENT:
cmd = MLX90614_TA;
break;
case IIO_MOD_TEMP_OBJECT:
switch (channel->channel) {
case 0:
cmd = MLX90614_TOBJ1;
break;
case 1:
cmd = MLX90614_TOBJ2;
break;
default:
return -EINVAL;
}
break;
default:
return -EINVAL;
}
ret = mlx90614_power_get(data, true);
if (ret < 0)
return ret;
ret = i2c_smbus_read_word_data(data->client, cmd);
mlx90614_power_put(data);
if (ret < 0)
return ret;
/* MSB is an error flag */
if (ret & 0x8000)
return -EIO;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = MLX90614_CONST_OFFSET_DEC;
*val2 = MLX90614_CONST_OFFSET_REM;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SCALE:
*val = MLX90614_CONST_SCALE;
return IIO_VAL_INT;
case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
mlx90614_power_get(data, false);
mutex_lock(&data->lock);
ret = i2c_smbus_read_word_data(data->client,
MLX90614_EMISSIVITY);
mutex_unlock(&data->lock);
mlx90614_power_put(data);
if (ret < 0)
return ret;
if (ret == MLX90614_CONST_RAW_EMISSIVITY_MAX) {
*val = 1;
*val2 = 0;
} else {
*val = 0;
*val2 = ret * MLX90614_CONST_EMISSIVITY_RESOLUTION;
}
return IIO_VAL_INT_PLUS_NANO;
case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR setting with
FIR = 1024 */
mlx90614_power_get(data, false);
mutex_lock(&data->lock);
ret = i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
mutex_unlock(&data->lock);
mlx90614_power_put(data);
if (ret < 0)
return ret;
*val = mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] / 100;
*val2 = (mlx90614_iir_values[ret & MLX90614_CONFIG_IIR_MASK] % 100) *
10000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static int mlx90614_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int val,
int val2, long mask)
{
struct mlx90614_data *data = iio_priv(indio_dev);
s32 ret;
switch (mask) {
case IIO_CHAN_INFO_CALIBEMISSIVITY: /* 1/65535 / LSB */
if (val < 0 || val2 < 0 || val > 1 || (val == 1 && val2 != 0))
return -EINVAL;
val = val * MLX90614_CONST_RAW_EMISSIVITY_MAX +
val2 / MLX90614_CONST_EMISSIVITY_RESOLUTION;
mlx90614_power_get(data, false);
mutex_lock(&data->lock);
ret = mlx90614_write_word(data->client, MLX90614_EMISSIVITY,
val);
mutex_unlock(&data->lock);
mlx90614_power_put(data);
return ret;
case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR Filter setting */
if (val < 0 || val2 < 0)
return -EINVAL;
mlx90614_power_get(data, false);
mutex_lock(&data->lock);
ret = mlx90614_iir_search(data->client,
val * 100 + val2 / 10000);
mutex_unlock(&data->lock);
mlx90614_power_put(data);
return ret;
default:
return -EINVAL;
}
}
static int mlx90614_write_raw_get_fmt(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_CALIBEMISSIVITY:
return IIO_VAL_INT_PLUS_NANO;
case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static const struct iio_chan_spec mlx90614_channels[] = {
{
.type = IIO_TEMP,
.modified = 1,
.channel2 = IIO_MOD_TEMP_AMBIENT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE),
},
{
.type = IIO_TEMP,
.modified = 1,
.channel2 = IIO_MOD_TEMP_OBJECT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) |
BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE),
},
{
.type = IIO_TEMP,
.indexed = 1,
.modified = 1,
.channel = 1,
.channel2 = IIO_MOD_TEMP_OBJECT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_CALIBEMISSIVITY) |
BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE),
},
};
static const struct iio_info mlx90614_info = {
.read_raw = mlx90614_read_raw,
.write_raw = mlx90614_write_raw,
.write_raw_get_fmt = mlx90614_write_raw_get_fmt,
.attrs = &mlx90614_attr_group,
.driver_module = THIS_MODULE,
};
#ifdef CONFIG_PM
static int mlx90614_sleep(struct mlx90614_data *data)
{
s32 ret;
if (!data->wakeup_gpio) {
dev_dbg(&data->client->dev, "Sleep disabled");
return -ENOSYS;
}
dev_dbg(&data->client->dev, "Requesting sleep");
mutex_lock(&data->lock);
ret = i2c_smbus_xfer(data->client->adapter, data->client->addr,
data->client->flags | I2C_CLIENT_PEC,
I2C_SMBUS_WRITE, MLX90614_OP_SLEEP,
I2C_SMBUS_BYTE, NULL);
mutex_unlock(&data->lock);
return ret;
}
static int mlx90614_wakeup(struct mlx90614_data *data)
{
if (!data->wakeup_gpio) {
dev_dbg(&data->client->dev, "Wake-up disabled");
return -ENOSYS;
}
dev_dbg(&data->client->dev, "Requesting wake-up");
i2c_lock_adapter(data->client->adapter);
gpiod_direction_output(data->wakeup_gpio, 0);
msleep(MLX90614_TIMING_WAKEUP);
gpiod_direction_input(data->wakeup_gpio);
i2c_unlock_adapter(data->client->adapter);
data->ready_timestamp = jiffies +
msecs_to_jiffies(MLX90614_TIMING_STARTUP);
/*
* Quirk: the i2c controller may get confused right after the
* wake-up signal has been sent. As a workaround, do a dummy read.
* If the read fails, the controller will probably be reset so that
* further reads will work.
*/
i2c_smbus_read_word_data(data->client, MLX90614_CONFIG);
return 0;
}
/* Return wake-up GPIO or NULL if sleep functionality should be disabled. */
static struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
{
struct gpio_desc *gpio;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_BYTE)) {
dev_info(&client->dev,
"i2c adapter does not support SMBUS_WRITE_BYTE, sleep disabled");
return NULL;
}
gpio = devm_gpiod_get_optional(&client->dev, "wakeup", GPIOD_IN);
if (IS_ERR(gpio)) {
dev_warn(&client->dev,
"gpio acquisition failed with error %ld, sleep disabled",
PTR_ERR(gpio));
return NULL;
} else if (!gpio) {
dev_info(&client->dev,
"wakeup-gpio not found, sleep disabled");
}
return gpio;
}
#else
static inline int mlx90614_sleep(struct mlx90614_data *data)
{
return -ENOSYS;
}
static inline int mlx90614_wakeup(struct mlx90614_data *data)
{
return -ENOSYS;
}
static inline struct gpio_desc *mlx90614_probe_wakeup(struct i2c_client *client)
{
return NULL;
}
#endif
/* Return 0 for single sensor, 1 for dual sensor, <0 on error. */
static int mlx90614_probe_num_ir_sensors(struct i2c_client *client)
{
s32 ret;
ret = i2c_smbus_read_word_data(client, MLX90614_CONFIG);
if (ret < 0)
return ret;
return (ret & MLX90614_CONFIG_DUAL_MASK) ? 1 : 0;
}
static int mlx90614_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct mlx90614_data *data;
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
mutex_init(&data->lock);
data->wakeup_gpio = mlx90614_probe_wakeup(client);
mlx90614_wakeup(data);
indio_dev->dev.parent = &client->dev;
indio_dev->name = id->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &mlx90614_info;
ret = mlx90614_probe_num_ir_sensors(client);
switch (ret) {
case 0:
dev_dbg(&client->dev, "Found single sensor");
indio_dev->channels = mlx90614_channels;
indio_dev->num_channels = 2;
break;
case 1:
dev_dbg(&client->dev, "Found dual sensor");
indio_dev->channels = mlx90614_channels;
indio_dev->num_channels = 3;
break;
default:
return ret;
}
if (data->wakeup_gpio) {
pm_runtime_set_autosuspend_delay(&client->dev,
MLX90614_AUTOSLEEP_DELAY);
pm_runtime_use_autosuspend(&client->dev);
pm_runtime_set_active(&client->dev);
pm_runtime_enable(&client->dev);
}
return iio_device_register(indio_dev);
}
static int mlx90614_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct mlx90614_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
if (data->wakeup_gpio) {
pm_runtime_disable(&client->dev);
if (!pm_runtime_status_suspended(&client->dev))
mlx90614_sleep(data);
pm_runtime_set_suspended(&client->dev);
}
return 0;
}
static const struct i2c_device_id mlx90614_id[] = {
{ "mlx90614", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mlx90614_id);
#ifdef CONFIG_PM_SLEEP
static int mlx90614_pm_suspend(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mlx90614_data *data = iio_priv(indio_dev);
if (data->wakeup_gpio && pm_runtime_active(dev))
return mlx90614_sleep(data);
return 0;
}
static int mlx90614_pm_resume(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mlx90614_data *data = iio_priv(indio_dev);
int err;
if (data->wakeup_gpio) {
err = mlx90614_wakeup(data);
if (err < 0)
return err;
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
}
return 0;
}
#endif
#ifdef CONFIG_PM
static int mlx90614_pm_runtime_suspend(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mlx90614_data *data = iio_priv(indio_dev);
return mlx90614_sleep(data);
}
static int mlx90614_pm_runtime_resume(struct device *dev)
{
struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
struct mlx90614_data *data = iio_priv(indio_dev);
return mlx90614_wakeup(data);
}
#endif
static const struct dev_pm_ops mlx90614_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mlx90614_pm_suspend, mlx90614_pm_resume)
SET_RUNTIME_PM_OPS(mlx90614_pm_runtime_suspend,
mlx90614_pm_runtime_resume, NULL)
};
static struct i2c_driver mlx90614_driver = {
.driver = {
.name = "mlx90614",
.pm = &mlx90614_pm_ops,
},
.probe = mlx90614_probe,
.remove = mlx90614_remove,
.id_table = mlx90614_id,
};
module_i2c_driver(mlx90614_driver);
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_AUTHOR("Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>");
MODULE_AUTHOR("Crt Mori <cmo@melexis.com>");
MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
MODULE_LICENSE("GPL");