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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Sensirion sdp500 and sdp510 pressure sensors
*
* Datasheet: https://sensirion.com/resource/datasheet/sdp600
*/
#include <linux/i2c.h>
#include <linux/crc8.h>
#include <linux/iio/iio.h>
#include <linux/mod_devicetable.h>
#include <linux/regulator/consumer.h>
#include <linux/unaligned.h>
#define SDP500_CRC8_POLYNOMIAL 0x31 /* x8+x5+x4+1 (normalized to 0x31) */
#define SDP500_READ_SIZE 3
#define SDP500_I2C_START_MEAS 0xF1
struct sdp500_data {
struct device *dev;
};
DECLARE_CRC8_TABLE(sdp500_crc8_table);
static int sdp500_start_measurement(struct sdp500_data *data)
{
struct i2c_client *client = to_i2c_client(data->dev);
return i2c_smbus_write_byte(client, SDP500_I2C_START_MEAS);
}
static const struct iio_chan_spec sdp500_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
},
};
static int sdp500_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret;
u8 rxbuf[SDP500_READ_SIZE];
u8 received_crc, calculated_crc;
struct sdp500_data *data = iio_priv(indio_dev);
struct i2c_client *client = to_i2c_client(data->dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
if (ret < 0) {
dev_err(data->dev, "Failed to receive data");
return ret;
}
if (ret != SDP500_READ_SIZE) {
dev_err(data->dev, "Data is received wrongly");
return -EIO;
}
received_crc = rxbuf[2];
calculated_crc = crc8(sdp500_crc8_table, rxbuf,
sizeof(rxbuf) - 1, 0x00);
if (received_crc != calculated_crc) {
dev_err(data->dev,
"calculated crc = 0x%.2X, received 0x%.2X",
calculated_crc, received_crc);
return -EIO;
}
*val = get_unaligned_be16(rxbuf);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = 1;
*val2 = 60;
return IIO_VAL_FRACTIONAL;
default:
return -EINVAL;
}
}
static const struct iio_info sdp500_info = {
.read_raw = &sdp500_read_raw,
};
static int sdp500_probe(struct i2c_client *client)
{
struct iio_dev *indio_dev;
struct sdp500_data *data;
struct device *dev = &client->dev;
int ret;
u8 rxbuf[SDP500_READ_SIZE];
ret = devm_regulator_get_enable(dev, "vdd");
if (ret)
return dev_err_probe(dev, ret,
"Failed to get and enable regulator\n");
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
/* has to be done before the first i2c communication */
crc8_populate_msb(sdp500_crc8_table, SDP500_CRC8_POLYNOMIAL);
data = iio_priv(indio_dev);
data->dev = dev;
indio_dev->name = "sdp500";
indio_dev->channels = sdp500_channels;
indio_dev->info = &sdp500_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->num_channels = ARRAY_SIZE(sdp500_channels);
ret = sdp500_start_measurement(data);
if (ret)
return dev_err_probe(dev, ret, "Failed to start measurement");
/* First measurement is not correct, read it out to get rid of it */
i2c_master_recv(client, rxbuf, SDP500_READ_SIZE);
ret = devm_iio_device_register(dev, indio_dev);
if (ret)
return dev_err_probe(dev, ret, "Failed to register indio_dev");
return 0;
}
static const struct i2c_device_id sdp500_id[] = {
{ "sdp500" },
{ }
};
MODULE_DEVICE_TABLE(i2c, sdp500_id);
static const struct of_device_id sdp500_of_match[] = {
{ .compatible = "sensirion,sdp500" },
{ }
};
MODULE_DEVICE_TABLE(of, sdp500_of_match);
static struct i2c_driver sdp500_driver = {
.driver = {
.name = "sensirion,sdp500",
.of_match_table = sdp500_of_match,
},
.probe = sdp500_probe,
.id_table = sdp500_id,
};
module_i2c_driver(sdp500_driver);
MODULE_AUTHOR("Thomas Sioutas <thomas.sioutas@prodrive-technologies.com>");
MODULE_DESCRIPTION("Driver for Sensirion SDP500 differential pressure sensor");
MODULE_LICENSE("GPL");
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