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/*
* ams-iaq-core.c - Support for AMS iAQ-Core VOC sensors
*
* Copyright (C) 2015 Matt Ranostay <mranostay@gmail.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.
*
*/
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#define AMS_IAQCORE_DATA_SIZE 9
#define AMS_IAQCORE_VOC_CO2_IDX 0
#define AMS_IAQCORE_VOC_RESISTANCE_IDX 1
#define AMS_IAQCORE_VOC_TVOC_IDX 2
struct ams_iaqcore_reading {
__be16 co2_ppm;
u8 status;
__be32 resistance;
__be16 voc_ppb;
} __attribute__((__packed__));
struct ams_iaqcore_data {
struct i2c_client *client;
struct mutex lock;
unsigned long last_update;
struct ams_iaqcore_reading buffer;
};
static const struct iio_chan_spec ams_iaqcore_channels[] = {
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_CO2,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = AMS_IAQCORE_VOC_CO2_IDX,
},
{
.type = IIO_RESISTANCE,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = AMS_IAQCORE_VOC_RESISTANCE_IDX,
},
{
.type = IIO_CONCENTRATION,
.channel2 = IIO_MOD_VOC,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
.address = AMS_IAQCORE_VOC_TVOC_IDX,
},
};
static int ams_iaqcore_read_measurement(struct ams_iaqcore_data *data)
{
struct i2c_client *client = data->client;
int ret;
struct i2c_msg msg = {
.addr = client->addr,
.flags = client->flags | I2C_M_RD,
.len = AMS_IAQCORE_DATA_SIZE,
.buf = (char *) &data->buffer,
};
ret = i2c_transfer(client->adapter, &msg, 1);
return (ret == AMS_IAQCORE_DATA_SIZE) ? 0 : ret;
}
static int ams_iaqcore_get_measurement(struct ams_iaqcore_data *data)
{
int ret;
/* sensor can only be polled once a second max per datasheet */
if (!time_after(jiffies, data->last_update + HZ))
return 0;
ret = ams_iaqcore_read_measurement(data);
if (ret < 0)
return ret;
data->last_update = jiffies;
return 0;
}
static int ams_iaqcore_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct ams_iaqcore_data *data = iio_priv(indio_dev);
int ret;
if (mask != IIO_CHAN_INFO_PROCESSED)
return -EINVAL;
mutex_lock(&data->lock);
ret = ams_iaqcore_get_measurement(data);
if (ret)
goto err_out;
switch (chan->address) {
case AMS_IAQCORE_VOC_CO2_IDX:
*val = 0;
*val2 = be16_to_cpu(data->buffer.co2_ppm);
ret = IIO_VAL_INT_PLUS_MICRO;
break;
case AMS_IAQCORE_VOC_RESISTANCE_IDX:
*val = be32_to_cpu(data->buffer.resistance);
ret = IIO_VAL_INT;
break;
case AMS_IAQCORE_VOC_TVOC_IDX:
*val = 0;
*val2 = be16_to_cpu(data->buffer.voc_ppb);
ret = IIO_VAL_INT_PLUS_NANO;
break;
default:
ret = -EINVAL;
}
err_out:
mutex_unlock(&data->lock);
return ret;
}
static const struct iio_info ams_iaqcore_info = {
.read_raw = ams_iaqcore_read_raw,
.driver_module = THIS_MODULE,
};
static int ams_iaqcore_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct ams_iaqcore_data *data;
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;
/* so initial reading will complete */
data->last_update = jiffies - HZ;
mutex_init(&data->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->info = &ams_iaqcore_info,
indio_dev->name = dev_name(&client->dev);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ams_iaqcore_channels;
indio_dev->num_channels = ARRAY_SIZE(ams_iaqcore_channels);
return devm_iio_device_register(&client->dev, indio_dev);
}
static const struct i2c_device_id ams_iaqcore_id[] = {
{ "ams-iaq-core", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ams_iaqcore_id);
static const struct of_device_id ams_iaqcore_dt_ids[] = {
{ .compatible = "ams,iaq-core" },
{ }
};
MODULE_DEVICE_TABLE(of, ams_iaqcore_dt_ids);
static struct i2c_driver ams_iaqcore_driver = {
.driver = {
.name = "ams-iaq-core",
.of_match_table = of_match_ptr(ams_iaqcore_dt_ids),
},
.probe = ams_iaqcore_probe,
.id_table = ams_iaqcore_id,
};
module_i2c_driver(ams_iaqcore_driver);
MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
MODULE_DESCRIPTION("AMS iAQ-Core VOC sensors");
MODULE_LICENSE("GPL v2");
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