// SPDX-License-Identifier: GPL-2.0
/*
 * AD8366 and similar Gain Amplifiers
 * This driver supports the following gain amplifiers:
 *   AD8366 Dual-Digital Variable Gain Amplifier (VGA)
 *   ADA4961 BiCMOS RF Digital Gain Amplifier (DGA)
 *   ADL5240 Digitally controlled variable gain amplifier (VGA)
 *   ADRF5702: 0.125 dB LSB, 8-Bit, Silicon Digital Attenuator, 50 MHz to 20 GHz
 *   ADRF5703: 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator, 9 kHz to 20 GHz
 *   ADRF5720: 0.5 dB LSB, 6-Bit, Silicon Digital Attenuator, 9 kHz to 40 GHz
 *   ADRF5730: 0.5 dB LSB, 6-Bit, Silicon Digital Attenuator, 100 MHz to 40 GHz
 *   ADRF5731: 2 dB LSB, 4-Bit, Silicon Digital Attenuator, 100 MHz to 40 GHz
 *   HMC271A: 1dB LSB 5-Bit Digital Attenuator SMT, 0.7 - 3.7 GHz
 *   HMC792A 0.25 dB LSB GaAs MMIC 6-Bit Digital Attenuator
 *   HMC1018A: 1.0 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz
 *   HMC1019A: 0.5 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz
 *   HMC1119 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator
 *
 * Copyright 2012-2026 Analog Devices Inc.
 */

#include <linux/bitrev.h>
#include <linux/bits.h>
#include <linux/dev_printk.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/math.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/spi/spi.h>
#include <linux/types.h>
#include <linux/unaligned.h>

#include <linux/iio/iio.h>

struct ad8366_info {
        const char *name;
        int gain_min;
        int gain_max;
        int gain_step;
        size_t num_channels;
        size_t (*pack_code)(const unsigned char *code, size_t num_channels,
                            unsigned char *data);
};

struct ad8366_state {
        struct spi_device       *spi;
        struct mutex            lock; /* protect sensor state */
        unsigned char           ch[2];
        const struct ad8366_info *info;
        /*
         * DMA (thus cache coherency maintenance) may require the
         * transfer buffers to live in their own cache lines.
         */
        unsigned char           data[2] __aligned(IIO_DMA_MINALIGN);
};

static size_t ad8366_pack_code(const unsigned char *code, size_t num_channels,
                               unsigned char *data)
{
        u8 ch_a = bitrev8(code[0]) >> 2;
        u8 ch_b = bitrev8(code[1]) >> 2;

        put_unaligned_be16((ch_b << 6) | ch_a, &data[0]);
        return sizeof(__be16);
}

static size_t adrf5731_pack_code(const unsigned char *code, size_t num_channels,
                                 unsigned char *data)
{
        data[0] = code[0] << 2;
        return 1;
}

static size_t hmc271_pack_code(const unsigned char *code, size_t num_channels,
                               unsigned char *data)
{
        data[0] = bitrev8(code[0]) >> 3;
        return 1;
}

static const struct ad8366_info ad8366_chip_info = {
        .name = "ad8366",
        .gain_min = 4500,
        .gain_max = 20500,
        .gain_step = 253,
        .num_channels = 2,
        .pack_code = ad8366_pack_code,
};

static const struct ad8366_info ada4961_chip_info = {
        .name = "ada4961",
        .gain_min = -6000,
        .gain_max = 15000,
        .gain_step = -1000,
        .num_channels = 1,
};

static const struct ad8366_info adl5240_chip_info = {
        .name = "adl5240",
        .gain_min = -11500,
        .gain_max = 20000,
        .gain_step = 500,
        .num_channels = 1,
};

static const struct ad8366_info adrf5702_chip_info = {
        .name = "adrf5702",
        .gain_min = -31875,
        .gain_max = 0,
        .gain_step = -125,
        .num_channels = 1,
};

static const struct ad8366_info adrf5703_chip_info = {
        .name = "adrf5703",
        .gain_min = -31750,
        .gain_max = 0,
        .gain_step = -250,
        .num_channels = 1,
};

static const struct ad8366_info adrf5720_chip_info = {
        .name = "adrf5720",
        .gain_min = -31500,
        .gain_max = 0,
        .gain_step = -500,
        .num_channels = 1,
};

static const struct ad8366_info adrf5730_chip_info = {
        .name = "adrf5730",
        .gain_min = -31500,
        .gain_max = 0,
        .gain_step = -500,
        .num_channels = 1,
};

static const struct ad8366_info adrf5731_chip_info = {
        .name = "adrf5731",
        .gain_min = -30000,
        .gain_max = 0,
        .gain_step = -2000,
        .num_channels = 1,
        .pack_code = adrf5731_pack_code,
};

static const struct ad8366_info hmc271_chip_info = {
        .name = "hmc271a",
        .gain_min = -31000,
        .gain_max = 0,
        .gain_step = 1000,
        .num_channels = 1,
        .pack_code = hmc271_pack_code,
};

static const struct ad8366_info hmc792_chip_info = {
        .name = "hmc792a",
        .gain_min = -15750,
        .gain_max = 0,
        .gain_step = 250,
        .num_channels = 1,
};

static const struct ad8366_info hmc1018_chip_info = {
        .name = "hmc1018a",
        .gain_min = -31000,
        .gain_max = 0,
        .gain_step = 1000,
        .num_channels = 1,
};

static const struct ad8366_info hmc1019_chip_info = {
        .name = "hmc1019a",
        .gain_min = -15500,
        .gain_max = 0,
        .gain_step = 500,
        .num_channels = 1,
};

static const struct ad8366_info hmc1119_chip_info = {
        .name = "hmc1119",
        .gain_min = -31750,
        .gain_max = 0,
        .gain_step = -250,
        .num_channels = 1,
};

static int ad8366_write_code(struct ad8366_state *st)
{
        const struct ad8366_info *inf = st->info;
        size_t len = 1;

        if (inf->pack_code)
                len = inf->pack_code(st->ch, inf->num_channels, st->data);
        else
                st->data[0] = st->ch[0];

        return spi_write(st->spi, st->data, len);
}

static int ad8366_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val,
                           int *val2,
                           long m)
{
        struct ad8366_state *st = iio_priv(indio_dev);
        const struct ad8366_info *inf = st->info;
        int ret;
        int code, gain = 0;

        mutex_lock(&st->lock);
        switch (m) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                code = st->ch[chan->channel];
                gain = inf->gain_step > 0 ? inf->gain_min : inf->gain_max;
                gain += inf->gain_step * code;
                /* Values in dB */
                *val = gain / 1000;
                *val2 = (gain % 1000) * 1000;

                ret = IIO_VAL_INT_PLUS_MICRO_DB;
                break;
        default:
                ret = -EINVAL;
        }
        mutex_unlock(&st->lock);

        return ret;
};

static int ad8366_write_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int val,
                            int val2,
                            long mask)
{
        struct ad8366_state *st = iio_priv(indio_dev);
        const struct ad8366_info *inf = st->info;
        int code = 0, gain;
        int ret;

        /* Values in dB */
        if (val < 0)
                gain = (val * 1000) - (val2 / 1000);
        else
                gain = (val * 1000) + (val2 / 1000);

        if (gain > inf->gain_max || gain < inf->gain_min)
                return -EINVAL;

        gain -= inf->gain_step > 0 ? inf->gain_min : inf->gain_max;
        code = DIV_ROUND_CLOSEST(gain, inf->gain_step);

        mutex_lock(&st->lock);
        switch (mask) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                st->ch[chan->channel] = code;
                ret = ad8366_write_code(st);
                break;
        default:
                ret = -EINVAL;
        }
        mutex_unlock(&st->lock);

        return ret;
}

static int ad8366_write_raw_get_fmt(struct iio_dev *indio_dev,
                                    struct iio_chan_spec const *chan,
                                    long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                return IIO_VAL_INT_PLUS_MICRO_DB;
        default:
                return -EINVAL;
        }
}

static const struct iio_info ad8366_info = {
        .read_raw = &ad8366_read_raw,
        .write_raw = &ad8366_write_raw,
        .write_raw_get_fmt = &ad8366_write_raw_get_fmt,
};

#define AD8366_CHAN(_channel) {                         \
        .type = IIO_VOLTAGE,                            \
        .output = 1,                                    \
        .indexed = 1,                                   \
        .channel = _channel,                            \
        .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN),\
}

static const struct iio_chan_spec ad8366_channels[] = {
        AD8366_CHAN(0),
        AD8366_CHAN(1),
};

static int ad8366_probe(struct spi_device *spi)
{
        struct device *dev = &spi->dev;
        struct gpio_desc *enable_gpio;
        struct reset_control *rstc;
        struct iio_dev *indio_dev;
        struct ad8366_state *st;
        int ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
        if (indio_dev == NULL)
                return -ENOMEM;

        st = iio_priv(indio_dev);

        ret = devm_mutex_init(dev, &st->lock);
        if (ret)
                return ret;

        ret = devm_regulator_get_enable(dev, "vcc");
        if (ret)
                return dev_err_probe(dev, ret, "Failed to get regulator\n");

        st->spi = spi;
        st->info = spi_get_device_match_data(spi);

        enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
        if (IS_ERR(enable_gpio))
                return dev_err_probe(dev, PTR_ERR(enable_gpio),
                                     "Failed to get enable GPIO\n");

        rstc = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
        if (IS_ERR(rstc))
                return dev_err_probe(dev, PTR_ERR(rstc),
                                     "Failed to get reset controller\n");

        indio_dev->name = st->info->name;
        indio_dev->info = &ad8366_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = ad8366_channels;
        indio_dev->num_channels = st->info->num_channels;

        ret = ad8366_write_code(st);
        if (ret < 0)
                return dev_err_probe(dev, ret, "failed to write initial gain\n");

        return devm_iio_device_register(dev, indio_dev);
}

static const struct spi_device_id ad8366_id[] = {
        { "ad8366", (kernel_ulong_t)&ad8366_chip_info },
        { "ada4961", (kernel_ulong_t)&ada4961_chip_info },
        { "adl5240", (kernel_ulong_t)&adl5240_chip_info },
        { "adrf5702", (kernel_ulong_t)&adrf5702_chip_info },
        { "adrf5703", (kernel_ulong_t)&adrf5703_chip_info },
        { "adrf5720", (kernel_ulong_t)&adrf5720_chip_info },
        { "adrf5730", (kernel_ulong_t)&adrf5730_chip_info },
        { "adrf5731", (kernel_ulong_t)&adrf5731_chip_info },
        { "hmc271a", (kernel_ulong_t)&hmc271_chip_info },
        { "hmc792a", (kernel_ulong_t)&hmc792_chip_info },
        { "hmc1018a", (kernel_ulong_t)&hmc1018_chip_info },
        { "hmc1019a", (kernel_ulong_t)&hmc1019_chip_info },
        { "hmc1119", (kernel_ulong_t)&hmc1119_chip_info },
        { }
};
MODULE_DEVICE_TABLE(spi, ad8366_id);

static const struct of_device_id ad8366_of_match[] = {
        { .compatible = "adi,ad8366", .data = &ad8366_chip_info },
        { .compatible = "adi,ada4961", .data = &ada4961_chip_info },
        { .compatible = "adi,adl5240", .data = &adl5240_chip_info },
        { .compatible = "adi,adrf5702", .data = &adrf5702_chip_info },
        { .compatible = "adi,adrf5703", .data = &adrf5703_chip_info },
        { .compatible = "adi,adrf5720", .data = &adrf5720_chip_info },
        { .compatible = "adi,adrf5730", .data = &adrf5730_chip_info },
        { .compatible = "adi,adrf5731", .data = &adrf5731_chip_info },
        { .compatible = "adi,hmc271a", .data = &hmc271_chip_info },
        { .compatible = "adi,hmc792a", .data = &hmc792_chip_info },
        { .compatible = "adi,hmc1018a", .data = &hmc1018_chip_info },
        { .compatible = "adi,hmc1019a", .data = &hmc1019_chip_info },
        { .compatible = "adi,hmc1119", .data = &hmc1119_chip_info },
        { }
};
MODULE_DEVICE_TABLE(of, ad8366_of_match);

static struct spi_driver ad8366_driver = {
        .driver = {
                .name           = KBUILD_MODNAME,
                .of_match_table = ad8366_of_match,
        },
        .probe          = ad8366_probe,
        .id_table       = ad8366_id,
};

module_spi_driver(ad8366_driver);

MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD8366 and similar Gain Amplifiers");
MODULE_LICENSE("GPL v2");