root/drivers/iio/frequency/admfm2000.c
// SPDX-License-Identifier: GPL-2.0
/*
 * ADMFM2000 Dual Microwave Down Converter
 *
 * Copyright 2024 Analog Devices Inc.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/iio/iio.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#define ADMFM2000_MIXER_MODE            0
#define ADMFM2000_DIRECT_IF_MODE        1
#define ADMFM2000_DSA_GPIOS             5
#define ADMFM2000_MODE_GPIOS            2
#define ADMFM2000_MAX_GAIN              0
#define ADMFM2000_MIN_GAIN              -31000
#define ADMFM2000_DEFAULT_GAIN          -0x20

struct admfm2000_state {
        struct mutex                    lock; /* protect sensor state */
        struct gpio_desc                *sw1_ch[2];
        struct gpio_desc                *sw2_ch[2];
        struct gpio_desc                *dsa1_gpios[5];
        struct gpio_desc                *dsa2_gpios[5];
        u32                             gain[2];
};

static int admfm2000_mode(struct iio_dev *indio_dev, u32 chan, u32 mode)
{
        struct admfm2000_state *st = iio_priv(indio_dev);
        int i;

        switch (mode) {
        case ADMFM2000_MIXER_MODE:
                for (i = 0; i < ADMFM2000_MODE_GPIOS; i++) {
                        gpiod_set_value_cansleep(st->sw1_ch[i], (chan == 0) ? 1 : 0);
                        gpiod_set_value_cansleep(st->sw2_ch[i], (chan == 0) ? 0 : 1);
                }
                return 0;
        case ADMFM2000_DIRECT_IF_MODE:
                for (i = 0; i < ADMFM2000_MODE_GPIOS; i++) {
                        gpiod_set_value_cansleep(st->sw1_ch[i], (chan == 0) ? 0 : 1);
                        gpiod_set_value_cansleep(st->sw2_ch[i], (chan == 0) ? 1 : 0);
                }
                return 0;
        default:
                return -EINVAL;
        }
}

static int admfm2000_attenuation(struct iio_dev *indio_dev, u32 chan, u32 value)
{
        struct admfm2000_state *st = iio_priv(indio_dev);
        int i;

        switch (chan) {
        case 0:
                for (i = 0; i < ADMFM2000_DSA_GPIOS; i++)
                        gpiod_set_value_cansleep(st->dsa1_gpios[i], value & (1 << i));
                return 0;
        case 1:
                for (i = 0; i < ADMFM2000_DSA_GPIOS; i++)
                        gpiod_set_value_cansleep(st->dsa2_gpios[i], value & (1 << i));
                return 0;
        default:
                return -EINVAL;
        }
}

static int admfm2000_read_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan, int *val,
                              int *val2, long mask)
{
        struct admfm2000_state *st = iio_priv(indio_dev);
        int gain;

        switch (mask) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                mutex_lock(&st->lock);
                gain = ~(st->gain[chan->channel]) * -1000;
                *val = gain / 1000;
                *val2 = (gain % 1000) * 1000;
                mutex_unlock(&st->lock);

                return IIO_VAL_INT_PLUS_MICRO_DB;
        default:
                return -EINVAL;
        }
}

static int admfm2000_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan, int val,
                               int val2, long mask)
{
        struct admfm2000_state *st = iio_priv(indio_dev);
        int gain, ret;

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

        if (gain > ADMFM2000_MAX_GAIN || gain < ADMFM2000_MIN_GAIN)
                return -EINVAL;

        switch (mask) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                mutex_lock(&st->lock);
                st->gain[chan->channel] = ~((abs(gain) / 1000) & 0x1F);

                ret = admfm2000_attenuation(indio_dev, chan->channel,
                                            st->gain[chan->channel]);
                mutex_unlock(&st->lock);
                return ret;
        default:
                return -EINVAL;
        }
}

static int admfm2000_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 admfm2000_info = {
        .read_raw = &admfm2000_read_raw,
        .write_raw = &admfm2000_write_raw,
        .write_raw_get_fmt = &admfm2000_write_raw_get_fmt,
};

#define ADMFM2000_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 admfm2000_channels[] = {
        ADMFM2000_CHAN(0),
        ADMFM2000_CHAN(1),
};

static int admfm2000_channel_config(struct admfm2000_state *st,
                                    struct iio_dev *indio_dev)
{
        struct platform_device *pdev = to_platform_device(indio_dev->dev.parent);
        struct device *dev = &pdev->dev;
        struct gpio_desc **dsa;
        struct gpio_desc **sw;
        int ret, i;
        bool mode;
        u32 reg;

        device_for_each_child_node_scoped(dev, child) {
                ret = fwnode_property_read_u32(child, "reg", &reg);
                if (ret)
                        return dev_err_probe(dev, ret,
                                             "Failed to get reg property\n");

                if (reg >= indio_dev->num_channels)
                        return dev_err_probe(dev, -EINVAL, "reg bigger than: %d\n",
                                             indio_dev->num_channels);

                if (fwnode_property_present(child, "adi,mixer-mode"))
                        mode = ADMFM2000_MIXER_MODE;
                else
                        mode = ADMFM2000_DIRECT_IF_MODE;

                switch (reg) {
                case 0:
                        sw = st->sw1_ch;
                        dsa = st->dsa1_gpios;
                        break;
                case 1:
                        sw = st->sw2_ch;
                        dsa = st->dsa2_gpios;
                        break;
                default:
                        return -EINVAL;
                }

                for (i = 0; i < ADMFM2000_MODE_GPIOS; i++) {
                        sw[i] = devm_fwnode_gpiod_get_index(dev, child, "switch",
                                                            i, GPIOD_OUT_LOW, NULL);
                        if (IS_ERR(sw[i]))
                                return dev_err_probe(dev, PTR_ERR(sw[i]),
                                                     "Failed to get gpios\n");
                }

                for (i = 0; i < ADMFM2000_DSA_GPIOS; i++) {
                        dsa[i] = devm_fwnode_gpiod_get_index(dev, child,
                                                             "attenuation", i,
                                                             GPIOD_OUT_LOW, NULL);
                        if (IS_ERR(dsa[i]))
                                return dev_err_probe(dev, PTR_ERR(dsa[i]),
                                                     "Failed to get gpios\n");
                }

                ret = admfm2000_mode(indio_dev, reg, mode);
                if (ret)
                        return ret;
        }

        return 0;
}

static int admfm2000_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct admfm2000_state *st;
        struct iio_dev *indio_dev;
        int ret;

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

        st = iio_priv(indio_dev);

        indio_dev->name = "admfm2000";
        indio_dev->num_channels = ARRAY_SIZE(admfm2000_channels);
        indio_dev->channels = admfm2000_channels;
        indio_dev->info = &admfm2000_info;
        indio_dev->modes = INDIO_DIRECT_MODE;

        st->gain[0] = ADMFM2000_DEFAULT_GAIN;
        st->gain[1] = ADMFM2000_DEFAULT_GAIN;

        mutex_init(&st->lock);

        ret = admfm2000_channel_config(st, indio_dev);
        if (ret)
                return ret;

        return devm_iio_device_register(dev, indio_dev);
}

static const struct of_device_id admfm2000_of_match[] = {
        { .compatible = "adi,admfm2000" },
        { }
};
MODULE_DEVICE_TABLE(of, admfm2000_of_match);

static struct platform_driver admfm2000_driver = {
        .driver = {
                .name = "admfm2000",
                .of_match_table = admfm2000_of_match,
        },
        .probe = admfm2000_probe,
};
module_platform_driver(admfm2000_driver);

MODULE_AUTHOR("Kim Seer Paller <kimseer.paller@analog.com>");
MODULE_DESCRIPTION("ADMFM2000 Dual Microwave Down Converter");
MODULE_LICENSE("GPL");