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/*
* hdc100x.c - Support for the TI HDC100x temperature + humidity 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/delay.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#define HDC100X_REG_TEMP 0x00
#define HDC100X_REG_HUMIDITY 0x01
#define HDC100X_REG_CONFIG 0x02
#define HDC100X_REG_CONFIG_HEATER_EN BIT(13)
struct hdc100x_data {
struct i2c_client *client;
struct mutex lock;
u16 config;
/* integration time of the sensor */
int adc_int_us[2];
};
/* integration time in us */
static const int hdc100x_int_time[][3] = {
{ 6350, 3650, 0 }, /* IIO_TEMP channel*/
{ 6500, 3850, 2500 }, /* IIO_HUMIDITYRELATIVE channel */
};
/* HDC100X_REG_CONFIG shift and mask values */
static const struct {
int shift;
int mask;
} hdc100x_resolution_shift[2] = {
{ /* IIO_TEMP channel */
.shift = 10,
.mask = 1
},
{ /* IIO_HUMIDITYRELATIVE channel */
.shift = 8,
.mask = 3,
},
};
static IIO_CONST_ATTR(temp_integration_time_available,
"0.00365 0.00635");
static IIO_CONST_ATTR(humidityrelative_integration_time_available,
"0.0025 0.00385 0.0065");
static IIO_CONST_ATTR(out_current_heater_raw_available,
"0 1");
static struct attribute *hdc100x_attributes[] = {
&iio_const_attr_temp_integration_time_available.dev_attr.attr,
&iio_const_attr_humidityrelative_integration_time_available.dev_attr.attr,
&iio_const_attr_out_current_heater_raw_available.dev_attr.attr,
NULL
};
static struct attribute_group hdc100x_attribute_group = {
.attrs = hdc100x_attributes,
};
static const struct iio_chan_spec hdc100x_channels[] = {
{
.type = IIO_TEMP,
.address = HDC100X_REG_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_INT_TIME) |
BIT(IIO_CHAN_INFO_OFFSET),
},
{
.type = IIO_HUMIDITYRELATIVE,
.address = HDC100X_REG_HUMIDITY,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_INT_TIME)
},
{
.type = IIO_CURRENT,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.extend_name = "heater",
.output = 1,
},
};
static int hdc100x_update_config(struct hdc100x_data *data, int mask, int val)
{
int tmp = (~mask & data->config) | val;
int ret;
ret = i2c_smbus_write_word_swapped(data->client,
HDC100X_REG_CONFIG, tmp);
if (!ret)
data->config = tmp;
return ret;
}
static int hdc100x_set_it_time(struct hdc100x_data *data, int chan, int val2)
{
int shift = hdc100x_resolution_shift[chan].shift;
int ret = -EINVAL;
int i;
for (i = 0; i < ARRAY_SIZE(hdc100x_int_time[chan]); i++) {
if (val2 && val2 == hdc100x_int_time[chan][i]) {
ret = hdc100x_update_config(data,
hdc100x_resolution_shift[chan].mask << shift,
i << shift);
if (!ret)
data->adc_int_us[chan] = val2;
break;
}
}
return ret;
}
static int hdc100x_get_measurement(struct hdc100x_data *data,
struct iio_chan_spec const *chan)
{
struct i2c_client *client = data->client;
int delay = data->adc_int_us[chan->address];
int ret;
int val;
/* start measurement */
ret = i2c_smbus_write_byte(client, chan->address);
if (ret < 0) {
dev_err(&client->dev, "cannot start measurement");
return ret;
}
/* wait for integration time to pass */
usleep_range(delay, delay + 1000);
/*
* i2c_smbus_read_word_data cannot() be used here due to the command
* value not being understood and causes NAKs preventing any reading
* from being accessed.
*/
ret = i2c_smbus_read_byte(client);
if (ret < 0) {
dev_err(&client->dev, "cannot read high byte measurement");
return ret;
}
val = ret << 6;
ret = i2c_smbus_read_byte(client);
if (ret < 0) {
dev_err(&client->dev, "cannot read low byte measurement");
return ret;
}
val |= ret >> 2;
return val;
}
static int hdc100x_get_heater_status(struct hdc100x_data *data)
{
return !!(data->config & HDC100X_REG_CONFIG_HEATER_EN);
}
static int hdc100x_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
struct hdc100x_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW: {
int ret;
mutex_lock(&data->lock);
if (chan->type == IIO_CURRENT) {
*val = hdc100x_get_heater_status(data);
ret = IIO_VAL_INT;
} else {
ret = hdc100x_get_measurement(data, chan);
if (ret >= 0) {
*val = ret;
ret = IIO_VAL_INT;
}
}
mutex_unlock(&data->lock);
return ret;
}
case IIO_CHAN_INFO_INT_TIME:
*val = 0;
*val2 = data->adc_int_us[chan->address];
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SCALE:
if (chan->type == IIO_TEMP) {
*val = 165000;
*val2 = 65536 >> 2;
return IIO_VAL_FRACTIONAL;
} else {
*val = 0;
*val2 = 10000;
return IIO_VAL_INT_PLUS_MICRO;
}
break;
case IIO_CHAN_INFO_OFFSET:
*val = -3971;
*val2 = 879096;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
}
static int hdc100x_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct hdc100x_data *data = iio_priv(indio_dev);
int ret = -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_INT_TIME:
if (val != 0)
return -EINVAL;
mutex_lock(&data->lock);
ret = hdc100x_set_it_time(data, chan->address, val2);
mutex_unlock(&data->lock);
return ret;
case IIO_CHAN_INFO_RAW:
if (chan->type != IIO_CURRENT || val2 != 0)
return -EINVAL;
mutex_lock(&data->lock);
ret = hdc100x_update_config(data, HDC100X_REG_CONFIG_HEATER_EN,
val ? HDC100X_REG_CONFIG_HEATER_EN : 0);
mutex_unlock(&data->lock);
return ret;
default:
return -EINVAL;
}
}
static const struct iio_info hdc100x_info = {
.read_raw = hdc100x_read_raw,
.write_raw = hdc100x_write_raw,
.attrs = &hdc100x_attribute_group,
.driver_module = THIS_MODULE,
};
static int hdc100x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct hdc100x_data *data;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE))
return -EOPNOTSUPP;
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(&clien
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