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/*
* 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");
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