mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-23 09:56:00 +00:00
iio: humidity: Add support for AM2315
Add basic support for the Aosong AM2315 relative humidity and ambient temperature sensor. Includes support for raw readings and ACPI detection. Datasheet: http://www.aosong.com/asp_bin/Products/en/AM2315.pdf Signed-off-by: Tiberiu Breana <tiberiu.a.breana@intel.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Tiberiu Breana
Jonathan Cameron
parent
d8469e93a4
commit
366a3270c1
@ -3,6 +3,16 @@
|
||||
#
|
||||
menu "Humidity sensors"
|
||||
|
||||
config AM2315
|
||||
tristate "Aosong AM2315 relative humidity and temperature sensor"
|
||||
depends on I2C
|
||||
help
|
||||
If you say yes here you get support for the Aosong AM2315
|
||||
relative humidity and ambient temperature sensor.
|
||||
|
||||
This driver can also be built as a module. If so, the module will
|
||||
be called am2315.
|
||||
|
||||
config DHT11
|
||||
tristate "DHT11 (and compatible sensors) driver"
|
||||
depends on GPIOLIB || COMPILE_TEST
|
||||
|
||||
@ -2,6 +2,7 @@
|
||||
# Makefile for IIO humidity sensor drivers
|
||||
#
|
||||
|
||||
obj-$(CONFIG_AM2315) += am2315.o
|
||||
obj-$(CONFIG_DHT11) += dht11.o
|
||||
obj-$(CONFIG_HDC100X) += hdc100x.o
|
||||
obj-$(CONFIG_HTU21) += htu21.o
|
||||
|
||||
228
drivers/iio/humidity/am2315.c
Normal file
228
drivers/iio/humidity/am2315.c
Normal file
@ -0,0 +1,228 @@
|
||||
/**
|
||||
* Aosong AM2315 relative humidity and temperature
|
||||
*
|
||||
* Copyright (c) 2016, Intel Corporation.
|
||||
*
|
||||
* 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 address: 0x5C.
|
||||
*/
|
||||
|
||||
#include <linux/acpi.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/i2c.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/iio/iio.h>
|
||||
#include <linux/iio/sysfs.h>
|
||||
|
||||
#define AM2315_REG_HUM_MSB 0x00
|
||||
#define AM2315_REG_HUM_LSB 0x01
|
||||
#define AM2315_REG_TEMP_MSB 0x02
|
||||
#define AM2315_REG_TEMP_LSB 0x03
|
||||
|
||||
#define AM2315_FUNCTION_READ 0x03
|
||||
#define AM2315_HUM_OFFSET 2
|
||||
#define AM2315_TEMP_OFFSET 4
|
||||
|
||||
#define AM2315_DRIVER_NAME "am2315"
|
||||
|
||||
struct am2315_data {
|
||||
struct i2c_client *client;
|
||||
struct mutex lock;
|
||||
};
|
||||
|
||||
struct am2315_sensor_data {
|
||||
s16 hum_data;
|
||||
s16 temp_data;
|
||||
};
|
||||
|
||||
static const struct iio_chan_spec am2315_channels[] = {
|
||||
{
|
||||
.type = IIO_HUMIDITYRELATIVE,
|
||||
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
|
||||
BIT(IIO_CHAN_INFO_SCALE)
|
||||
},
|
||||
{
|
||||
.type = IIO_TEMP,
|
||||
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
|
||||
BIT(IIO_CHAN_INFO_SCALE)
|
||||
},
|
||||
};
|
||||
|
||||
/* CRC calculation algorithm, as specified in the datasheet (page 13). */
|
||||
static u16 am2315_crc(u8 *data, u8 nr_bytes)
|
||||
{
|
||||
int i;
|
||||
u16 crc = 0xffff;
|
||||
|
||||
while (nr_bytes--) {
|
||||
crc ^= *data++;
|
||||
for (i = 0; i < 8; i++) {
|
||||
if (crc & 0x01) {
|
||||
crc >>= 1;
|
||||
crc ^= 0xA001;
|
||||
} else {
|
||||
crc >>= 1;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return crc;
|
||||
}
|
||||
|
||||
/* Simple function that sends a few bytes to the device to wake it up. */
|
||||
static void am2315_ping(struct i2c_client *client)
|
||||
{
|
||||
i2c_smbus_read_byte_data(client, AM2315_REG_HUM_MSB);
|
||||
}
|
||||
|
||||
static int am2315_read_data(struct am2315_data *data,
|
||||
struct am2315_sensor_data *sensor_data)
|
||||
{
|
||||
int ret;
|
||||
/* tx_buf format: <function code> <start addr> <nr of regs to read> */
|
||||
u8 tx_buf[3] = { AM2315_FUNCTION_READ, AM2315_REG_HUM_MSB, 4 };
|
||||
/*
|
||||
* rx_buf format:
|
||||
* <function code> <number of registers read>
|
||||
* <humidity MSB> <humidity LSB> <temp MSB> <temp LSB>
|
||||
* <CRC LSB> <CRC MSB>
|
||||
*/
|
||||
u8 rx_buf[8];
|
||||
u16 crc;
|
||||
|
||||
/* First wake up the device. */
|
||||
am2315_ping(data->client);
|
||||
|
||||
mutex_lock(&data->lock);
|
||||
ret = i2c_master_send(data->client, tx_buf, sizeof(tx_buf));
|
||||
if (ret < 0) {
|
||||
dev_err(&data->client->dev, "failed to send read request\n");
|
||||
goto exit_unlock;
|
||||
}
|
||||
/* Wait 2-3 ms, then read back the data sent by the device. */
|
||||
usleep_range(2000, 3000);
|
||||
/* Do a bulk data read, then pick out what we need. */
|
||||
ret = i2c_master_recv(data->client, rx_buf, sizeof(rx_buf));
|
||||
if (ret < 0) {
|
||||
dev_err(&data->client->dev, "failed to read sensor data\n");
|
||||
goto exit_unlock;
|
||||
}
|
||||
mutex_unlock(&data->lock);
|
||||
/*
|
||||
* Do a CRC check on the data and compare it to the value
|
||||
* calculated by the device.
|
||||
*/
|
||||
crc = am2315_crc(rx_buf, sizeof(rx_buf) - 2);
|
||||
if ((crc & 0xff) != rx_buf[6] || (crc >> 8) != rx_buf[7]) {
|
||||
dev_err(&data->client->dev, "failed to verify sensor data\n");
|
||||
return -EIO;
|
||||
}
|
||||
|
||||
sensor_data->hum_data = (rx_buf[AM2315_HUM_OFFSET] << 8) |
|
||||
rx_buf[AM2315_HUM_OFFSET + 1];
|
||||
sensor_data->temp_data = (rx_buf[AM2315_TEMP_OFFSET] << 8) |
|
||||
rx_buf[AM2315_TEMP_OFFSET + 1];
|
||||
|
||||
return ret;
|
||||
|
||||
exit_unlock:
|
||||
mutex_unlock(&data->lock);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int am2315_read_raw(struct iio_dev *indio_dev,
|
||||
struct iio_chan_spec const *chan,
|
||||
int *val, int *val2, long mask)
|
||||
{
|
||||
int ret;
|
||||
struct am2315_sensor_data sensor_data;
|
||||
struct am2315_data *data = iio_priv(indio_dev);
|
||||
|
||||
switch (mask) {
|
||||
case IIO_CHAN_INFO_RAW:
|
||||
ret = am2315_read_data(data, &sensor_data);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
*val = (chan->type == IIO_HUMIDITYRELATIVE) ?
|
||||
sensor_data.hum_data : sensor_data.temp_data;
|
||||
return IIO_VAL_INT;
|
||||
case IIO_CHAN_INFO_SCALE:
|
||||
*val = 100;
|
||||
return IIO_VAL_INT;
|
||||
}
|
||||
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
static const struct iio_info am2315_info = {
|
||||
.driver_module = THIS_MODULE,
|
||||
.read_raw = am2315_read_raw,
|
||||
};
|
||||
|
||||
static int am2315_probe(struct i2c_client *client,
|
||||
const struct i2c_device_id *id)
|
||||
{
|
||||
struct iio_dev *indio_dev;
|
||||
struct am2315_data *data;
|
||||
|
||||
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
|
||||
if (!indio_dev) {
|
||||
dev_err(&client->dev, "iio allocation failed!\n");
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
data = iio_priv(indio_dev);
|
||||
data->client = client;
|
||||
i2c_set_clientdata(client, indio_dev);
|
||||
mutex_init(&data->lock);
|
||||
|
||||
indio_dev->dev.parent = &client->dev;
|
||||
indio_dev->info = &am2315_info;
|
||||
indio_dev->name = AM2315_DRIVER_NAME;
|
||||
indio_dev->modes = INDIO_DIRECT_MODE;
|
||||
indio_dev->channels = am2315_channels;
|
||||
indio_dev->num_channels = ARRAY_SIZE(am2315_channels);
|
||||
|
||||
return iio_device_register(indio_dev);
|
||||
}
|
||||
|
||||
static int am2315_remove(struct i2c_client *client)
|
||||
{
|
||||
struct iio_dev *indio_dev = i2c_get_clientdata(client);
|
||||
|
||||
iio_device_unregister(indio_dev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct i2c_device_id am2315_i2c_id[] = {
|
||||
{"am2315", 0},
|
||||
{}
|
||||
};
|
||||
|
||||
static const struct acpi_device_id am2315_acpi_id[] = {
|
||||
{"AOS2315", 0},
|
||||
{}
|
||||
};
|
||||
|
||||
MODULE_DEVICE_TABLE(acpi, am2315_acpi_id);
|
||||
|
||||
static struct i2c_driver am2315_driver = {
|
||||
.driver = {
|
||||
.name = "am2315",
|
||||
.acpi_match_table = ACPI_PTR(am2315_acpi_id),
|
||||
},
|
||||
.probe = am2315_probe,
|
||||
.remove = am2315_remove,
|
||||
.id_table = am2315_i2c_id,
|
||||
};
|
||||
|
||||
module_i2c_driver(am2315_driver);
|
||||
|
||||
MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
|
||||
MODULE_DESCRIPTION("Aosong AM2315 relative humidity and temperature");
|
||||
MODULE_LICENSE("GPL v2");
|
||||
Loading…
Reference in New Issue
Block a user