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Commit 4839367d authored by Matt Ranostay's avatar Matt Ranostay Committed by Jonathan Cameron
Browse files

iio: humidity: add HDC100x support 



Add support for the HDC100x temperature and humidity sensors
including the resistive heater element.

Signed-off-by: default avatarMatt Ranostay <mranostay@gmail.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 7db75fd6

Documentation/ABI/testing/sysfs-bus-iio-humidity-hdc100x

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What:		/sys/bus/iio/devices/iio:deviceX/out_current_heater_raw

What:		/sys/bus/iio/devices/iio:deviceX/out_current_heater_raw_available

KernelVersion:	4.3

Contact:	linux-iio@vger.kernel.org

Description:

		Controls the heater device within the humidity sensor to get

		rid of excess condensation.



		Valid control values are 0 = OFF, and 1 = ON.

drivers/iio/humidity/Kconfig

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@@ -12,6 +12,16 @@ config DHT11 
	  Other sensors should work as well as long as they speak the

	  same protocol.



config HDC100X

	tristate "TI HDC100x relative humidity and temperature sensor"

	depends on I2C

	help

	 Say yes here to build support for the TI HDC100x series of

	 relative humidity and temperature sensors.



	 To compile this driver as a module, choose M here: the module

	 will be called hdc100x.



config SI7005

	tristate "SI7005 relative humidity and temperature sensor"

	depends on I2C

drivers/iio/humidity/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -3,5 +3,6 @@ 
#



obj-$(CONFIG_DHT11) += dht11.o

obj-$(CONFIG_HDC100X) += hdc100x.o

obj-$(CONFIG_SI7005) += si7005.o

obj-$(CONFIG_SI7020) += si7020.o

drivers/iio/humidity/hdc100x.c

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+319 −0
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/*

 * hdc100x.c - Support for the TI HDC100x temperature + humidity sensors

 *

 * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 *

 */



#include <linux/delay.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/i2c.h>



#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>



#define HDC100X_REG_TEMP			0x00

#define HDC100X_REG_HUMIDITY			0x01



#define HDC100X_REG_CONFIG			0x02

#define HDC100X_REG_CONFIG_HEATER_EN		BIT(13)



struct hdc100x_data {

	struct i2c_client *client;

	struct mutex lock;

	u16 config;



	/* integration time of the sensor */

	int adc_int_us[2];

};



/* integration time in us */

static const int hdc100x_int_time[][3] = {

	{ 6350, 3650, 0 },	/* IIO_TEMP channel*/

	{ 6500, 3850, 2500 },	/* IIO_HUMIDITYRELATIVE channel */

};



/* HDC100X_REG_CONFIG shift and mask values */

static const struct {

	int shift;

	int mask;

} hdc100x_resolution_shift[2] = {

	{ /* IIO_TEMP channel */

		.shift = 10,

		.mask = 1

	},

	{ /* IIO_HUMIDITYRELATIVE channel */

		.shift = 8,

		.mask = 2,

	},

};



static IIO_CONST_ATTR(temp_integration_time_available,

		"0.00365 0.00635");



static IIO_CONST_ATTR(humidityrelative_integration_time_available,

		"0.0025 0.00385 0.0065");



static IIO_CONST_ATTR(out_current_heater_raw_available,

		"0 1");



static struct attribute *hdc100x_attributes[] = {

	&iio_const_attr_temp_integration_time_available.dev_attr.attr,

	&iio_const_attr_humidityrelative_integration_time_available.dev_attr.attr,

	&iio_const_attr_out_current_heater_raw_available.dev_attr.attr,

	NULL

};



static struct attribute_group hdc100x_attribute_group = {

	.attrs = hdc100x_attributes,

};



static const struct iio_chan_spec hdc100x_channels[] = {

	{

		.type = IIO_TEMP,

		.address = HDC100X_REG_TEMP,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |

			BIT(IIO_CHAN_INFO_SCALE) |

			BIT(IIO_CHAN_INFO_INT_TIME) |

			BIT(IIO_CHAN_INFO_OFFSET),

	},

	{

		.type = IIO_HUMIDITYRELATIVE,

		.address = HDC100X_REG_HUMIDITY,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |

			BIT(IIO_CHAN_INFO_SCALE) |

			BIT(IIO_CHAN_INFO_INT_TIME)

	},

	{

		.type = IIO_CURRENT,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),

		.extend_name = "heater",

		.output = 1,

	},

};



static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)

{

	int tmp = (~mask & data->config) | val;

	int ret;



	ret = i2c_smbus_write_word_swapped(data->client,

						HDC100X_REG_CONFIG, tmp);

	if (!ret)

		data->config = tmp;



	return ret;

}



static int hdc100x_set_it_time(struct hdc100x_data *data, int chan, int val2)

{

	int shift = hdc100x_resolution_shift[chan].shift;

	int ret = -EINVAL;

	int i;



	for (i = 0; i < ARRAY_SIZE(hdc100x_int_time[chan]); i++) {

		if (val2 && val2 == hdc100x_int_time[chan][i]) {

			ret = hdc100x_update_config(data,

				hdc100x_resolution_shift[chan].mask << shift,

				i << shift);

			if (!ret)

				data->adc_int_us[chan] = val2;

			break;

		}

	}



	return ret;

}



static int hdc100x_get_measurement(struct hdc100x_data *data,

				   struct iio_chan_spec const *chan)

{

	struct i2c_client *client = data->client;

	int delay = data->adc_int_us[chan->address];

	int ret;

	int val;



	/* start measurement */

	ret = i2c_smbus_write_byte(client, chan->address);

	if (ret < 0) {

		dev_err(&client->dev, "cannot start measurement");

		return ret;

	}



	/* wait for integration time to pass */

	usleep_range(delay, delay + 1000);



	/*

	 * i2c_smbus_read_word_data cannot() be used here due to the command

	 * value not being understood and causes NAKs preventing any reading

	 * from being accessed.

	 */

	ret = i2c_smbus_read_byte(client);

	if (ret < 0) {

		dev_err(&client->dev, "cannot read high byte measurement");

		return ret;

	}

	val = ret << 6;



	ret = i2c_smbus_read_byte(client);

	if (ret < 0) {

		dev_err(&client->dev, "cannot read low byte measurement");

		return ret;

	}

	val |= ret >> 2;



	return val;

}



static int hdc100x_get_heater_status(struct hdc100x_data *data)

{

	return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN);

}



static int hdc100x_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan, int *val,

			    int *val2, long mask)

{

	struct hdc100x_data *data = iio_priv(indio_dev);



	switch (mask) {

	case IIO_CHAN_INFO_RAW: {

		int ret;



		mutex_lock(&data->lock);

		if (chan->type == IIO_CURRENT) {

			*val = hdc100x_get_heater_status(data);

			ret = IIO_VAL_INT;

		} else {

			ret = hdc100x_get_measurement(data, chan);

			if (ret >= 0) {

				*val = ret;

				ret = IIO_VAL_INT;

			}

		}

		mutex_unlock(&data->lock);

		return ret;

	}

	case IIO_CHAN_INFO_INT_TIME:

		*val = 0;

		*val2 = data->adc_int_us[chan->address];

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_SCALE:

		if (chan->type == IIO_TEMP) {

			*val = 165;

			*val2 = 65536 >> 2;

			return IIO_VAL_FRACTIONAL;

		} else {

			*val = 0;

			*val2 = 10000;

			return IIO_VAL_INT_PLUS_MICRO;

		}

		break;

	case IIO_CHAN_INFO_OFFSET:

		*val = -40;

		return IIO_VAL_INT;

	default:

		return -EINVAL;

	}

}



static int hdc100x_write_raw(struct iio_dev *indio_dev,

			     struct iio_chan_spec const *chan,

			     int val, int val2, long mask)

{

	struct hdc100x_data *data = iio_priv(indio_dev);

	int ret = -EINVAL;



	switch (mask) {

	case IIO_CHAN_INFO_INT_TIME:

		if (val != 0)

			return -EINVAL;



		mutex_lock(&data->lock);

		ret = hdc100x_set_it_time(data, chan->address, val2);

		mutex_unlock(&data->lock);

		return ret;

	case IIO_CHAN_INFO_RAW:

		if (chan->type != IIO_CURRENT || val2 != 0)

			return -EINVAL;



		mutex_lock(&data->lock);

		ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,

					val ? HDC100X_REG_CONFIG_HEATER_EN : 0);

		mutex_unlock(&data->lock);

		return ret;

	default:

		return -EINVAL;

	}

}



static const struct iio_info hdc100x_info = {

	.read_raw = hdc100x_read_raw,

	.write_raw = hdc100x_write_raw,

	.attrs = &hdc100x_attribute_group,

	.driver_module = THIS_MODULE,

};



static int hdc100x_probe(struct i2c_client *client,

			 const struct i2c_device_id *id)

{

	struct iio_dev *indio_dev;

	struct hdc100x_data *data;



	if (!i2c_check_functionality(client->adapter,

				I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))

		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);



	indio_dev->dev.parent = &client->dev;

	indio_dev->name = dev_name(&client->dev);

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->info = &hdc100x_info;



	indio_dev->channels = hdc100x_channels;

	indio_dev->num_channels = ARRAY_SIZE(hdc100x_channels);



	/* be sure we are in a known state */

	hdc100x_set_it_time(data, 0, hdc100x_int_time[0][0]);

	hdc100x_set_it_time(data, 1, hdc100x_int_time[1][0]);



	return devm_iio_device_register(&client->dev, indio_dev);

}



static const struct i2c_device_id hdc100x_id[] = {

	{ "hdc100x", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, hdc100x_id);



static struct i2c_driver hdc100x_driver = {

	.driver = {

		.name	= "hdc100x",

	},

	.probe = hdc100x_probe,

	.id_table = hdc100x_id,

};

module_i2c_driver(hdc100x_driver);



MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");

MODULE_DESCRIPTION("TI HDC100x humidity and temperature sensor driver");

MODULE_LICENSE("GPL");