linux/drivers/iio/pressure/hsc030pa.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Honeywell TruStability HSC Series pressure/temperature sensor
 *
 * Copyright (c) 2023 Petre Rodan <[email protected]>
 *
 * Datasheet: https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/products/sensors/pressure-sensors/board-mount-pressure-sensors/trustability-hsc-series/documents/sps-siot-trustability-hsc-series-high-accuracy-board-mount-pressure-sensors-50099148-a-en-ciid-151133.pdf
 */

#include <linux/array_size.h>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/init.h>
#include <linux/math64.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/units.h>

#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include <linux/unaligned.h>

#include "hsc030pa.h"

/*
 * HSC_PRESSURE_TRIPLET_LEN - length for the string that defines the
 * pressure range, measurement unit and type as per the part nomenclature.
 * Consult honeywell,pressure-triplet in the bindings file for details.
 */
#define HSC_PRESSURE_TRIPLET_LEN …
#define HSC_STATUS_MASK …
#define HSC_TEMPERATURE_MASK …
#define HSC_PRESSURE_MASK …

struct hsc_func_spec { … };

/*
 * function A: 10% - 90% of 2^14
 * function B:  5% - 95% of 2^14
 * function C:  5% - 85% of 2^14
 * function F:  4% - 94% of 2^14
 */
static const struct hsc_func_spec hsc_func_spec[] = …;

enum hsc_variants { … };

static const char * const hsc_triplet_variants[HSC_VARIANTS_MAX] = …;

/**
 * struct hsc_range_config - list of pressure ranges based on nomenclature
 * @pmin: lowest pressure that can be measured
 * @pmax: highest pressure that can be measured
 */
struct hsc_range_config { … };

/* All min max limits have been converted to pascals */
static const struct hsc_range_config hsc_range_config[HSC_VARIANTS_MAX] = …;

/**
 * hsc_measurement_is_valid() - validate last conversion via status bits
 * @data: structure containing instantiated sensor data
 * Return: true only if both status bits are zero
 *
 * the two MSB from the first transfered byte contain a status code
 *   00 - normal operation, valid data
 *   01 - device in factory programming mode
 *   10 - stale data
 *   11 - diagnostic condition
 */
static bool hsc_measurement_is_valid(struct hsc_data *data)
{ … }

static int hsc_get_measurement(struct hsc_data *data)
{ … }

static irqreturn_t hsc_trigger_handler(int irq, void *private)
{ … }

/*
 * IIO ABI expects
 * value = (conv + offset) * scale
 *
 * datasheet provides the following formula for determining the temperature
 * temp[C] = conv * a + b
 *   where a = 200/2047; b = -50
 *
 *  temp[C] = (conv + (b/a)) * a * (1000)
 *  =>
 *  scale = a * 1000 = .097703957 * 1000 = 97.703957
 *  offset = b/a = -50 / .097703957 = -50000000 / 97704
 *
 *  based on the datasheet
 *  pressure = (conv - Omin) * Q + Pmin =
 *          ((conv - Omin) + Pmin/Q) * Q
 *  =>
 *  scale = Q = (Pmax - Pmin) / (Omax - Omin)
 *  offset = Pmin/Q - Omin = Pmin * (Omax - Omin) / (Pmax - Pmin) - Omin
 */
static int hsc_read_raw(struct iio_dev *indio_dev,
			struct iio_chan_spec const *channel, int *val,
			int *val2, long mask)
{ … }

static const struct iio_chan_spec hsc_channels[] = …;

static const struct iio_info hsc_info = …;

static const struct hsc_chip_data hsc_chip = …;

int hsc_common_probe(struct device *dev, hsc_recv_fn recv)
{ … }
EXPORT_SYMBOL_NS(…);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;