Re: [PATCH v4 2/2] iio: pressure: add Sensirion SDP31 driver

[Andy Shevchenko]

On Tue, Sep 29, 2026 at 02:54:22AM +0500, Muhammad Abu Bakar wrote:
> Add an IIO driver for the Sensirion SDP3x family of differential pressure
> sensors (SDP31, SDP32 and SDP33). The devices are accessed over I2C and
> report differential pressure and temperature. Each measurement is
> validated using the sensor's CRC-8 checksum. The scale factor is read
> from the sensor at runtime, so all three parts are supported.
> 
> Tested on an SDP31 connected to a Raspberry Pi 4 I2C bus.

...

> +#include <linux/cleanup.h>
> +#include <linux/crc8.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/once.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/unaligned.h>

Follow IWYU principle.
At least types.h, err.h or errno.h are absent.

...

> +static int sdp31_read_measurement(struct sdp31_data *data, s16 *pressure,
> +				  s16 *temp)
> +{
> +	u8 rx[6];
> +	int ret;
> +
> +	ret = sdp31_trigger_read(data, rx, sizeof(rx));
> +	if (ret)
> +		return ret;
> +
> +	if (sdp31_check_crc(&rx[0]) || sdp31_check_crc(&rx[3]))
> +		return -EIO;

> +	*pressure = (s16)get_unaligned_be16(&rx[0]);
> +	*temp = (s16)get_unaligned_be16(&rx[3]);

And casting is for...?

> +	return 0;
> +}

...

> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_PRESSURE:
> +			*val = 1;
> +			*val2 = data->dp_scale * 1000;

KILO?

> +			return IIO_VAL_FRACTIONAL;
> +		case IIO_TEMP:
> +			/* raw / 200 = degC, so raw * 5 = milli-degC */
> +			*val = 5;
> +			return IIO_VAL_INT;
> +		default:
> +			return -EINVAL;
> +		}

-- 
With Best Regards,
Andy Shevchenko