linux/drivers/iio/amplifiers/hmc425a.c

// SPDX-License-Identifier: GPL-2.0
/*
 * HMC425A and similar Gain Amplifiers
 *
 * Copyright 2020, 2024 Analog Devices Inc.
 */

#include <linux/bits.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/kernel.h>
#include <linux/math.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/sysfs.h>

/*
 * The LTC6373 amplifier supports configuring gain using GPIO's with the following
 *  values (OUTPUT_V / INPUT_V): 0(shutdown), 0.25, 0.5, 1, 2, 4, 8, 16
 *
 * Except for the shutdown value, all can be converted to dB using 20 * log10(x)
 * From here, it is observed that all values are multiples of the '2' gain setting,
 *  with the correspondent of 6.020dB.
 */
#define LTC6373_CONVERSION_CONSTANT …
#define LTC6373_MIN_GAIN_CODE …
#define LTC6373_CONVERSION_MASK …
#define LTC6373_SHUTDOWN …

enum hmc425a_type { … };

struct hmc425a_chip_info { … };

struct hmc425a_state { … };

static int gain_dB_to_code(struct hmc425a_state *st, int val, int val2, int *code)
{ … }

static int hmc425a_gain_dB_to_code(int gain, int *code)
{ … }

static int hmc540s_gain_dB_to_code(int gain, int *code)
{ … }

static int adrf5740_gain_dB_to_code(int gain, int *code)
{ … }

static int ltc6373_gain_dB_to_code(int gain, int *code)
{ … }

static int code_to_gain_dB(struct hmc425a_state *st, int *val, int *val2)
{ … }

static int hmc425a_code_to_gain_dB(int code, int *val, int *val2)
{ … }

static int hmc540s_code_to_gain_dB(int code, int *val, int *val2)
{ … }

static int adrf5740_code_to_gain_dB(int code, int *val, int *val2)
{ … }

static int ltc6373_code_to_gain_dB(int code, int *val, int *val2)
{ … }

static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
{ … }

static int hmc425a_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan, int *val,
			    int *val2, long m)
{
	struct hmc425a_state *st = iio_priv(indio_dev);
	int ret;

	mutex_lock(&st->lock);
	switch (m) {
	case IIO_CHAN_INFO_HARDWAREGAIN:
		ret = code_to_gain_dB(st, val, val2);
		if (ret)
			break;
		ret = IIO_VAL_INT_PLUS_MICRO_DB;
		break;
	default:
		ret = -EINVAL;
	}
	mutex_unlock(&st->lock);

	return ret;
};

static int hmc425a_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan, int val,
			     int val2, long mask)
{ … }

static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
				     struct iio_chan_spec const *chan,
				     long mask)
{ … }

static const struct iio_info hmc425a_info = …;

static ssize_t ltc6373_read_powerdown(struct iio_dev *indio_dev,
				      uintptr_t private,
				      const struct iio_chan_spec *chan,
				      char *buf)
{ … }

static ssize_t ltc6373_write_powerdown(struct iio_dev *indio_dev,
				       uintptr_t private,
				       const struct iio_chan_spec *chan,
				       const char *buf,
				       size_t len)
{ … }

static const struct iio_chan_spec_ext_info ltc6373_ext_info[] = …;

#define HMC425A_CHAN(_channel) …

#define LTC6373_CHAN(_channel) …

static const struct iio_chan_spec hmc425a_channels[] = …;

static const struct iio_chan_spec ltc6373_channels[] = …;

static const struct hmc425a_chip_info hmc425a_chip_info_tbl[] = …;

static int hmc425a_probe(struct platform_device *pdev)
{ … }

/* Match table for of_platform binding */
static const struct of_device_id hmc425a_of_match[] = …;
MODULE_DEVICE_TABLE(of, hmc425a_of_match);

static struct platform_driver hmc425a_driver = …;
module_platform_driver(…) …;

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