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/*
* si7005.c - Support for Silabs Si7005 humidity and temperature sensor
*
* Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* (7-bit I2C slave address 0x40)
*
* TODO: heater, fast mode, processed mode (temp. / linearity compensation)
*/
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define SI7005_STATUS 0x00
#define SI7005_DATA 0x01 /* 16-bit, MSB */
#define SI7005_CONFIG 0x03
#define SI7005_ID 0x11
#define SI7005_STATUS_NRDY BIT(0)
#define SI7005_CONFIG_TEMP BIT(4)
#define SI7005_CONFIG_START BIT(0)
#define SI7005_ID_7005 0x50
#define SI7005_ID_7015 0xf0
struct si7005_data {
struct i2c_client *client;
struct mutex lock;
u8 config;
};
static int si7005_read_measurement(struct si7005_data *data, bool temp)
{
int tries = 50;
int ret;
mutex_lock(&data->lock);
ret = i2c_smbus_write_byte_data(data->client, SI7005_CONFIG,
data->config | SI7005_CONFIG_START |
(temp ? SI7005_CONFIG_TEMP : 0));
if (ret < 0)
goto done;
while (tries-- > 0) {
msleep(20);
ret = i2c_smbus_read_byte_data(data->client, SI7005_STATUS);
if (ret < 0)
goto done;
if (!(ret & SI7005_STATUS_NRDY))
break;
}
if (tries < 0) {
ret = -EIO;
goto done;
}
ret = i2c_smbus_read_word_swapped(data->client, SI7005_DATA);
done:
mutex_unlock(&data->lock);
return ret;
}
static int si7005_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct si7005_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = si7005_read_measurement(data, chan->type == IIO_TEMP);
if (ret < 0)
return ret;
*val = ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
if (chan->type == IIO_TEMP) {
*val = 7;
*val2 = 812500;
} else {
*val = 3;
*val2 = 906250;
}
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_OFFSET:
if (chan->type == IIO_TEMP)
*val = -50 * 32 * 4;
else
*val = -24 * 16 * 16;
return IIO_VAL_INT;
default:
break;
}
return -EINVAL;
}
static const struct iio_chan_spec si7005_channels[] = {
{
.type = IIO_HUMIDITYRELATIVE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
}
};
static const struct iio_info si7005_info = {
.read_raw = si7005_read_raw,
.driver_module = THIS_MODULE,
};
static int si7005_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct si7005_data *data;
int ret;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
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 = &si7005_info;
indio_dev->channels = si7005_channels;
indio_dev->num_channels = ARRAY_SIZE(si7005_channels);
ret = i2c_smbus_read_byte_data(client, SI7005_ID);
if (ret < 0)
return ret;
if (ret != SI7005_ID_7005 && ret != SI7005_ID_7015)
return -ENODEV;
ret = i2c_smbus_read_byte_data(client, SI7005_CONFIG);
if (ret < 0)
return ret;
data->config = ret;
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id si7005_id[] = {
{ "si7005", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, si7005_id);
static struct i2c_driver si7005_driver = {
.driver = {
.name = "si7005",
.owner = THIS_MODULE,
},
.probe = si7005_probe,
.id_table = si7005_id,
};
module_i2c_driver(si7005_driver);
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("Silabs Si7005 humidity and temperature sensor driver");
MODULE_LICENSE("GPL");
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