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Add htu21 meas-spec driver support 

Support for HTU21 temperature & humidity sensor

Signed-off-by: Ludovic Tancerel <ludovic.tancerel@maplehightech.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Ludovic Tancerel 2015-10-01 16:13:39 +02:00 committed by Jonathan Cameron
parent 53bf4d067d
commit 2b5c53d2c9
4 changed files with 248 additions and 0 deletions
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10
Documentation/ABI/testing/sysfs-bus-iio
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@ -1481,3 +1481,13 @@ Contact: linux-iio@vger.kernel.org
Description:
Raw (unscaled no offset etc.) resistance reading that can be processed
into an ohm value.
What: /sys/bus/iio/devices/iio:deviceX/heater_enable
KernelVersion: 4.1.0
Contact: linux-iio@vger.kernel.org
Description:
'1' (enable) or '0' (disable) specifying the enable
of heater function. Same reading values apply
This ABI is especially applicable for humidity sensors
to heatup the device and get rid of any condensation
in some humidity environment

11
drivers/iio/humidity/Kconfig
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@ -22,6 +22,17 @@ config HDC100X
To compile this driver as a module, choose M here: the module
will be called hdc100x.
config HTU21
tristate "Measurement Specialties HTU21 humidity & temperature sensor"
depends on I2C
select IIO_MS_SENSORS_I2C
help
If you say yes here you get support for the Measurement Specialties
HTU21 humidity and temperature sensor.
This driver can also be built as a module. If so, the module will
be called htu21.
config SI7005
tristate "SI7005 relative humidity and temperature sensor"
depends on I2C

1
drivers/iio/humidity/Makefile
View File

@ -4,5 +4,6 @@
obj-$(CONFIG_DHT11) += dht11.o
obj-$(CONFIG_HDC100X) += hdc100x.o
obj-$(CONFIG_HTU21) += htu21.o
obj-$(CONFIG_SI7005) += si7005.o
obj-$(CONFIG_SI7020) += si7020.o

226
drivers/iio/humidity/htu21.c Normal file
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@ -0,0 +1,226 @@
/*
* htu21.c - Support for Measurement-Specialties
* htu21 temperature & humidity sensor
*
* Copyright (c) 2014 Measurement-Specialties
*
* Licensed under the GPL-2.
*
* (7-bit I2C slave address 0x40)
*
* Datasheet:
* http://www.meas-spec.com/downloads/HTU21D.pdf
*/
#include <linux/init.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/stat.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include "../common/ms_sensors/ms_sensors_i2c.h"
#define HTU21_RESET 0xFE
static const int htu21_samp_freq[4] = { 20, 40, 70, 120 };
/* String copy of the above const for readability purpose */
static const char htu21_show_samp_freq[] = "20 40 70 120";
static int htu21_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
int ret, temperature;
unsigned int humidity;
struct ms_ht_dev *dev_data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
switch (channel->type) {
case IIO_TEMP: /* in milli °C */
ret = ms_sensors_ht_read_temperature(dev_data,
&temperature);
if (ret)
return ret;
*val = temperature;
return IIO_VAL_INT;
case IIO_HUMIDITYRELATIVE: /* in milli %RH */
ret = ms_sensors_ht_read_humidity(dev_data,
&humidity);
if (ret)
return ret;
*val = humidity;
return IIO_VAL_INT;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_SAMP_FREQ:
*val = htu21_samp_freq[dev_data->res_index];
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int htu21_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct ms_ht_dev *dev_data = iio_priv(indio_dev);
int i, ret;
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
i = ARRAY_SIZE(htu21_samp_freq);
while (i-- > 0)
if (val == htu21_samp_freq[i])
break;
if (i < 0)
return -EINVAL;
mutex_lock(&dev_data->lock);
dev_data->res_index = i;
ret = ms_sensors_write_resolution(dev_data, i);
mutex_unlock(&dev_data->lock);
return ret;
default:
return -EINVAL;
}
}
static const struct iio_chan_spec htu21_channels[] = {
{
.type = IIO_TEMP,
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
},
{
.type = IIO_HUMIDITYRELATIVE,
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
}
};
static ssize_t htu21_show_battery_low(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ms_ht_dev *dev_data = iio_priv(indio_dev);
return ms_sensors_show_battery_low(dev_data, buf);
}
static ssize_t htu21_show_heater(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ms_ht_dev *dev_data = iio_priv(indio_dev);
return ms_sensors_show_heater(dev_data, buf);
}
static ssize_t htu21_write_heater(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ms_ht_dev *dev_data = iio_priv(indio_dev);
return ms_sensors_write_heater(dev_data, buf, len);
}
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(htu21_show_samp_freq);
static IIO_DEVICE_ATTR(battery_low, S_IRUGO,
htu21_show_battery_low, NULL, 0);
static IIO_DEVICE_ATTR(heater_enable, S_IRUGO | S_IWUSR,
htu21_show_heater, htu21_write_heater, 0);
static struct attribute *htu21_attributes[] = {
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
&iio_dev_attr_battery_low.dev_attr.attr,
&iio_dev_attr_heater_enable.dev_attr.attr,
NULL,
};
static const struct attribute_group htu21_attribute_group = {
.attrs = htu21_attributes,
};
static const struct iio_info htu21_info = {
.read_raw = htu21_read_raw,
.write_raw = htu21_write_raw,
.attrs = &htu21_attribute_group,
.driver_module = THIS_MODULE,
};
static int htu21_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ms_ht_dev *dev_data;
struct iio_dev *indio_dev;
int ret;
u64 serial_number;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
I2C_FUNC_SMBUS_WRITE_BYTE |
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
dev_err(&client->dev,
"Adapter does not support some i2c transaction\n");
return -ENODEV;
}
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
if (!indio_dev)
return -ENOMEM;
dev_data = iio_priv(indio_dev);
dev_data->client = client;
dev_data->res_index = 0;
mutex_init(&dev_data->lock);
indio_dev->info = &htu21_info;
indio_dev->name = id->name;
indio_dev->dev.parent = &client->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = htu21_channels;
indio_dev->num_channels = ARRAY_SIZE(htu21_channels);
i2c_set_clientdata(client, indio_dev);
ret = ms_sensors_reset(client, HTU21_RESET, 15000);
if (ret)
return ret;
ret = ms_sensors_read_serial(client, &serial_number);
if (ret)
return ret;
dev_info(&client->dev, "Serial number : %llx", serial_number);
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id htu21_id[] = {
{"htu21", 0},
{}
};
static struct i2c_driver htu21_driver = {
.probe = htu21_probe,
.id_table = htu21_id,
.driver = {
.name = "htu21",
},
};
module_i2c_driver(htu21_driver);
MODULE_DESCRIPTION("Measurement-Specialties htu21 temperature and humidity driver");
MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
MODULE_LICENSE("GPL v2");