diff options
Diffstat (limited to 'drivers/iio/pressure/sdp500.c')
| -rw-r--r-- | drivers/iio/pressure/sdp500.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/drivers/iio/pressure/sdp500.c b/drivers/iio/pressure/sdp500.c new file mode 100644 index 000000000000..6ff32e3fa637 --- /dev/null +++ b/drivers/iio/pressure/sdp500.c @@ -0,0 +1,156 @@ +// 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 <asm/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"); |