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

Hi,

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.

Changed for v2:
renamed driver to hih6130
added Documentation/hwmon/hih6130
calcuations now use DIV_ROUND_CLOSEST and shouldn't cause 32bit int overflow addressed other minor review comments

addressing the alignment concern for the hih6130_show_temperature function gives me an 82 char line and a checkpatch fail, I've left it that way for now as there's a couple of other things I'm not sure about, so I think there'll be at least another version of this anyway.

Signed-off-by Iain Paton <[email protected]>

Documentation/hwmon/hih6130 new file +7 -0

new file mode 100644
index 0000000..2958648
@@ -0,0 +1,34 @@
+Kernel driver hih6130
+==========> +
+Supported chips:
+  * Honeywell HIH-6130 / HIH-6131
+    Prefix: 'hih6130'
+    Addresses scanned: none
+    Datasheet: Publicly available at the Honeywell website

Documentation/hwmon/hih6130 new file +10 -0

+sysfs-Interface
+---------------
+
+temp1_input - temperature input
+humidity1_input - humidity input
+
+Notes
+-----
+
+Command mode and alarms are not currently supported.

drivers/hwmon/Kconfig +0 -0

index 6f1d167..033c8c6 100644

drivers/hwmon/Kconfig +3 -0

+	  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

index e1eeac1..5c4e2e9 100644
@@ -58,6 +58,7 @@ 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 new file +28 -0

new file mode 100644
index 0000000..d238868
@@ -0,0 +1,285 @@
+/* Honeywell HIH-6130/HIH-6131 humidity and temperature sensor driver
+ *
+ * Copyright (C) 2012 Iain Paton <[email protected]>
+ *
+ * heavily based on the sht21 driver
+ * Copyright (C) 2010 Urs Fleisch <[email protected]>
+ *
+ * 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_id106&la_id=1&defIdD872
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>

drivers/hwmon/hih6130.c new file +17 -0

+ * @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

drivers/hwmon/hih6130.c new file +6 -0

+}
+
+/**
+ * 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

drivers/hwmon/hih6130.c new file +17 -0

+}
+
+/**
+ * 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,

drivers/hwmon/hih6130.c new file +20 -0

+	 * nothing to gain from reading any faster
+	 */
+	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;

drivers/hwmon/hih6130.c new file +64 -0

+	}
+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,
+};
+
+/**

drivers/hwmon/hih6130.c new file +60 -0

+{
+	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",