Commit 27f8b135 authored by Iain Paton's avatar Iain Paton Committed by Guenter Roeck
Browse files

hwmon: Honeywell Humidicon HIH-6130/HIH-6131 humidity and temperature sensor driver 



This is a new driver for the Honeywell Humidicon HIH-6130/HIH-6131 humidity sensor.

The driver is based on the existing Sensiron sht21 driver with the necessary changes
to the probe, update_measurements and conversion functions necessary to use the
Honeywell sensors.

There's no difference between the 6130 & 6131 other than the 6131 having an external
condensation filter attached.

Signed-off-by: default avatarIain Paton <ipaton0@gmail.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent edf48f3a

Documentation/hwmon/hih6130

0 → 100644
+37 −0
Original line number Diff line number Diff line 
Kernel driver hih6130

=====================



Supported chips:

  * Honeywell HIH-6130 / HIH-6131

    Prefix: 'hih6130'

    Addresses scanned: none

    Datasheet: Publicly available at the Honeywell website

    http://sensing.honeywell.com/index.php?ci_id=3106&la_id=1&defId=44872



Author:

  Iain Paton <ipaton0@gmail.com>



Description

-----------



The HIH-6130 & HIH-6131 are humidity and temperature sensors in a SO8 package.

The difference between the two devices is that the HIH-6131 has a condensation

filter.



The devices communicate with the I2C protocol. All sensors are set to the same

I2C address 0x27 by default, so an entry with I2C_BOARD_INFO("hih6130", 0x27)

can be used in the board setup code.



Please see Documentation/i2c/instantiating-devices for details on how to

instantiate I2C devices.



sysfs-Interface

---------------



temp1_input - temperature input

humidity1_input - humidity input



Notes

-----



Command mode and alarms are not currently supported.

drivers/hwmon/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -443,6 +443,16 @@ config SENSORS_GPIO_FAN 
	  This driver can also be built as a module.  If so, the module

	  will be called gpio-fan.



config SENSORS_HIH6130

	tristate "Honeywell Humidicon HIH-6130 humidity/temperature sensor"

	depends on I2C && EXPERIMENTAL

	help

	  If you say yes here you get support for Honeywell Humidicon

	  HIH-6130 and HIH-6131 Humidicon humidity sensors.



	  This driver can also be built as a module.  If so, the module

	  will be called hih6130.



config SENSORS_CORETEMP

	tristate "Intel Core/Core2/Atom temperature sensor"

	depends on X86 && PCI && EXPERIMENTAL

drivers/hwmon/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ obj-$(CONFIG_SENSORS_G760A) += g760a.o 
obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o

obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o

obj-$(CONFIG_SENSORS_GPIO_FAN)	+= gpio-fan.o

obj-$(CONFIG_SENSORS_HIH6130)	+= hih6130.o

obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o

obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o

obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o

drivers/hwmon/hih6130.c

0 → 100644
+293 −0
Original line number Diff line number Diff line 
/* Honeywell HIH-6130/HIH-6131 humidity and temperature sensor driver

 *

 * Copyright (C) 2012 Iain Paton <ipaton0@gmail.com>

 *

 * heavily based on the sht21 driver

 * Copyright (C) 2010 Urs Fleisch <urs.fleisch@sensirion.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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA

 *

 * Data sheets available (2012-06-22) at

 * http://sensing.honeywell.com/index.php?ci_id=3106&la_id=1&defId=44872

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/i2c.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/err.h>

#include <linux/mutex.h>

#include <linux/device.h>

#include <linux/delay.h>



/**

 * struct hih6130 - HIH-6130 device specific data

 * @hwmon_dev: device registered with hwmon

 * @lock: mutex to protect measurement values

 * @valid: only false before first measurement is taken

 * @last_update: time of last update (jiffies)

 * @temperature: cached temperature measurement value

 * @humidity: cached humidity measurement value

 */

struct hih6130 {

	struct device *hwmon_dev;

	struct mutex lock;

	bool valid;

	unsigned long last_update;

	int temperature;

	int humidity;

};



/**

 * hih6130_temp_ticks_to_millicelsius() - convert raw temperature ticks to

 * milli celsius

 * @ticks: temperature ticks value received from sensor

 */

static inline int hih6130_temp_ticks_to_millicelsius(int ticks)

{



	ticks = ticks >> 2;

	/*

	 * from data sheet section 5.0

	 * Formula T = ( ticks / ( 2^14 - 2 ) ) * 165 -40

	 */

	return (DIV_ROUND_CLOSEST(ticks * 1650, 16382) - 400) * 100;

}



/**

 * hih6130_rh_ticks_to_per_cent_mille() - convert raw humidity ticks to

 * one-thousandths of a percent relative humidity

 * @ticks: humidity ticks value received from sensor

 */

static inline int hih6130_rh_ticks_to_per_cent_mille(int ticks)

{



	ticks &= ~0xC000; /* clear status bits */

	/*

	 * from data sheet section 4.0

	 * Formula RH = ( ticks / ( 2^14 -2 ) ) * 100

	 */

	return DIV_ROUND_CLOSEST(ticks * 1000, 16382) * 100;

}



/**

 * hih6130_update_measurements() - get updated measurements from device

 * @client: I2C client device

 *

 * Returns 0 on success, else negative errno.

 */

static int hih6130_update_measurements(struct i2c_client *client)

{

	int ret = 0;

	int t;

	struct hih6130 *hih6130 = i2c_get_clientdata(client);

	unsigned char tmp[4];

	struct i2c_msg msgs[1] = {

		{

			.addr = client->addr,

			.flags = I2C_M_RD,

			.len = 4,

			.buf = tmp,

		}

	};



	mutex_lock(&hih6130->lock);



	/*

	 * While the measurement can be completed in ~40ms the sensor takes

	 * much longer to react to a change in external conditions. How quickly

	 * it reacts depends on airflow and other factors outwith our control.

	 * The datasheet specifies maximum 'Response time' for humidity at 8s

	 * and temperature at 30s under specified conditions.

	 * We therefore choose to only read the sensor at most once per second.

	 * This trades off pointless activity polling the sensor much faster

	 * than it can react against better response times in conditions more

	 * favourable than specified in the datasheet.

	 */

	if (time_after(jiffies, hih6130->last_update + HZ) || !hih6130->valid) {



		/* write to slave address, no data, to request a measurement */

		ret = i2c_master_send(client, tmp, 0);

		if (ret < 0)

			goto out;



		/* measurement cycle time is ~36.65msec */

		msleep(40);



		ret = i2c_transfer(client->adapter, msgs, 1);

		if (ret < 0)

			goto out;



		if ((tmp[0] & 0xC0) != 0) {

			dev_err(&client->dev, "Error while reading measurement result\n");

			ret = -EIO;

			goto out;

		}



		t = (tmp[0] << 8) + tmp[1];

		hih6130->humidity = hih6130_rh_ticks_to_per_cent_mille(t);



		t = (tmp[2] << 8) + tmp[3];

		hih6130->temperature = hih6130_temp_ticks_to_millicelsius(t);



		hih6130->last_update = jiffies;

		hih6130->valid = true;

	}

out:

	mutex_unlock(&hih6130->lock);



	return ret >= 0 ? 0 : ret;

}



/**

 * hih6130_show_temperature() - show temperature measurement value in sysfs

 * @dev: device

 * @attr: device attribute

 * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to

 *

 * Will be called on read access to temp1_input sysfs attribute.

 * Returns number of bytes written into buffer, negative errno on error.

 */

static ssize_t hih6130_show_temperature(struct device *dev,

					struct device_attribute *attr,

					char *buf)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct hih6130 *hih6130 = i2c_get_clientdata(client);

	int ret = hih6130_update_measurements(client);

	if (ret < 0)

		return ret;

	return sprintf(buf, "%d\n", hih6130->temperature);

}



/**

 * hih6130_show_humidity() - show humidity measurement value in sysfs

 * @dev: device

 * @attr: device attribute

 * @buf: sysfs buffer (PAGE_SIZE) where measurement values are written to

 *

 * Will be called on read access to humidity1_input sysfs attribute.

 * Returns number of bytes written into buffer, negative errno on error.

 */

static ssize_t hih6130_show_humidity(struct device *dev,

				     struct device_attribute *attr, char *buf)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct hih6130 *hih6130 = i2c_get_clientdata(client);

	int ret = hih6130_update_measurements(client);

	if (ret < 0)

		return ret;

	return sprintf(buf, "%d\n", hih6130->humidity);

}



/* sysfs attributes */

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, hih6130_show_temperature,

	NULL, 0);

static SENSOR_DEVICE_ATTR(humidity1_input, S_IRUGO, hih6130_show_humidity,

	NULL, 0);



static struct attribute *hih6130_attributes[] = {

	&sensor_dev_attr_temp1_input.dev_attr.attr,

	&sensor_dev_attr_humidity1_input.dev_attr.attr,

	NULL

};



static const struct attribute_group hih6130_attr_group = {

	.attrs = hih6130_attributes,

};



/**

 * hih6130_probe() - probe device

 * @client: I2C client device

 * @id: device ID

 *

 * Called by the I2C core when an entry in the ID table matches a

 * device's name.

 * Returns 0 on success.

 */

static int __devinit hih6130_probe(struct i2c_client *client,

				   const struct i2c_device_id *id)

{

	struct hih6130 *hih6130;

	int err;



	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {

		dev_err(&client->dev, "adapter does not support true I2C\n");

		return -ENODEV;

	}



	hih6130 = devm_kzalloc(&client->dev, sizeof(*hih6130), GFP_KERNEL);

	if (!hih6130)

		return -ENOMEM;



	i2c_set_clientdata(client, hih6130);



	mutex_init(&hih6130->lock);



	err = sysfs_create_group(&client->dev.kobj, &hih6130_attr_group);

	if (err) {

		dev_dbg(&client->dev, "could not create sysfs files\n");

		return err;

	}



	hih6130->hwmon_dev = hwmon_device_register(&client->dev);

	if (IS_ERR(hih6130->hwmon_dev)) {

		dev_dbg(&client->dev, "unable to register hwmon device\n");

		err = PTR_ERR(hih6130->hwmon_dev);

		goto fail_remove_sysfs;

	}



	return 0;



fail_remove_sysfs:

	sysfs_remove_group(&client->dev.kobj, &hih6130_attr_group);

	return err;

}



/**

 * hih6130_remove() - remove device

 * @client: I2C client device

 */

static int __devexit hih6130_remove(struct i2c_client *client)

{

	struct hih6130 *hih6130 = i2c_get_clientdata(client);



	hwmon_device_unregister(hih6130->hwmon_dev);

	sysfs_remove_group(&client->dev.kobj, &hih6130_attr_group);



	return 0;

}



/* Device ID table */

static const struct i2c_device_id hih6130_id[] = {

	{ "hih6130", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, hih6130_id);



static struct i2c_driver hih6130_driver = {

	.driver.name = "hih6130",

	.probe       = hih6130_probe,

	.remove      = __devexit_p(hih6130_remove),

	.id_table    = hih6130_id,

};



module_i2c_driver(hih6130_driver);



MODULE_AUTHOR("Iain Paton <ipaton0@gmail.com>");

MODULE_DESCRIPTION("Honeywell HIH-6130 humidity and temperature sensor driver");

MODULE_LICENSE("GPL");

CRA Git | Maintained and supported by SUSTech CRA and CCSE