// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * AD7766/AD7767 SPI ADC driver
 *
 * Copyright 2016 Analog Devices Inc.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>

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

struct ad7766_chip_info {
        unsigned int decimation_factor;
};

enum {
        AD7766_SUPPLY_AVDD = 0,
        AD7766_SUPPLY_DVDD = 1,
        AD7766_SUPPLY_VREF = 2,
        AD7766_NUM_SUPPLIES = 3
};

struct ad7766 {
        const struct ad7766_chip_info *chip_info;
        struct spi_device *spi;
        struct clk *mclk;
        struct gpio_desc *pd_gpio;
        struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES];

        struct iio_trigger *trig;

        struct spi_transfer xfer;
        struct spi_message msg;

        /*
         * DMA (thus cache coherency maintenance) requires the
         * transfer buffers to live in their own cache lines.
         * Make the buffer large enough for one 24 bit sample and one 64 bit
         * aligned 64 bit timestamp.
         */
        unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)]
                        ____cacheline_aligned;
};

/*
 * AD7766 and AD7767 variations are interface compatible, the main difference is
 * analog performance. Both parts will use the same ID.
 */
enum ad7766_device_ids {
        ID_AD7766,
        ID_AD7766_1,
        ID_AD7766_2,
};

static irqreturn_t ad7766_trigger_handler(int irq, void *p)
{
        struct iio_poll_func *pf = p;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct ad7766 *ad7766 = iio_priv(indio_dev);
        int ret;

        ret = spi_sync(ad7766->spi, &ad7766->msg);
        if (ret < 0)
                goto done;

        iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
                pf->timestamp);
done:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static int ad7766_preenable(struct iio_dev *indio_dev)
{
        struct ad7766 *ad7766 = iio_priv(indio_dev);
        int ret;

        ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
        if (ret < 0) {
                dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
                        ret);
                return ret;
        }

        ret = clk_prepare_enable(ad7766->mclk);
        if (ret < 0) {
                dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
                regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
                return ret;
        }

        gpiod_set_value(ad7766->pd_gpio, 0);

        return 0;
}

static int ad7766_postdisable(struct iio_dev *indio_dev)
{
        struct ad7766 *ad7766 = iio_priv(indio_dev);

        gpiod_set_value(ad7766->pd_gpio, 1);

        /*
         * The PD pin is synchronous to the clock, so give it some time to
         * notice the change before we disable the clock.
         */
        msleep(20);

        clk_disable_unprepare(ad7766->mclk);
        regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);

        return 0;
}

static int ad7766_read_raw(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, int *val, int *val2, long info)
{
        struct ad7766 *ad7766 = iio_priv(indio_dev);
        struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
        int scale_uv;

        switch (info) {
        case IIO_CHAN_INFO_SCALE:
                scale_uv = regulator_get_voltage(vref);
                if (scale_uv < 0)
                        return scale_uv;
                *val = scale_uv / 1000;
                *val2 = chan->scan_type.realbits;
                return IIO_VAL_FRACTIONAL_LOG2;
        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = clk_get_rate(ad7766->mclk) /
                        ad7766->chip_info->decimation_factor;
                return IIO_VAL_INT;
        }
        return -EINVAL;
}

static const struct iio_chan_spec ad7766_channels[] = {
        {
                .type = IIO_VOLTAGE,
                .indexed = 1,
                .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
                .scan_type = {
                        .sign = 's',
                        .realbits = 24,
                        .storagebits = 32,
                        .endianness = IIO_BE,
                },
        },
        IIO_CHAN_SOFT_TIMESTAMP(1),
};

static const struct ad7766_chip_info ad7766_chip_info[] = {
        [ID_AD7766] = {
                .decimation_factor = 8,
        },
        [ID_AD7766_1] = {
                .decimation_factor = 16,
        },
        [ID_AD7766_2] = {
                .decimation_factor = 32,
        },
};

static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
        .preenable = &ad7766_preenable,
        .postdisable = &ad7766_postdisable,
};

static const struct iio_info ad7766_info = {
        .read_raw = &ad7766_read_raw,
};

static irqreturn_t ad7766_irq(int irq, void *private)
{
        iio_trigger_poll(private);
        return IRQ_HANDLED;
}

static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
{
        struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);

        if (enable)
                enable_irq(ad7766->spi->irq);
        else
                disable_irq(ad7766->spi->irq);

        return 0;
}

static const struct iio_trigger_ops ad7766_trigger_ops = {
        .set_trigger_state = ad7766_set_trigger_state,
        .validate_device = iio_trigger_validate_own_device,
};

static int ad7766_probe(struct spi_device *spi)
{
        const struct spi_device_id *id = spi_get_device_id(spi);
        struct iio_dev *indio_dev;
        struct ad7766 *ad7766;
        int ret;

        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
        if (!indio_dev)
                return -ENOMEM;

        ad7766 = iio_priv(indio_dev);
        ad7766->chip_info = &ad7766_chip_info[id->driver_data];

        ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
        if (IS_ERR(ad7766->mclk))
                return PTR_ERR(ad7766->mclk);

        ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
        ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
        ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";

        ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
                ad7766->reg);
        if (ret)
                return ret;

        ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
                GPIOD_OUT_HIGH);
        if (IS_ERR(ad7766->pd_gpio))
                return PTR_ERR(ad7766->pd_gpio);

        indio_dev->name = spi_get_device_id(spi)->name;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = ad7766_channels;
        indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
        indio_dev->info = &ad7766_info;

        if (spi->irq > 0) {
                ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
                        indio_dev->name, indio_dev->id);
                if (!ad7766->trig)
                        return -ENOMEM;

                ad7766->trig->ops = &ad7766_trigger_ops;
                ad7766->trig->dev.parent = &spi->dev;
                iio_trigger_set_drvdata(ad7766->trig, ad7766);

                ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
                        IRQF_TRIGGER_FALLING, dev_name(&spi->dev),
                        ad7766->trig);
                if (ret < 0)
                        return ret;

                /*
                 * The device generates interrupts as long as it is powered up.
                 * Some platforms might not allow the option to power it down so
                 * disable the interrupt to avoid extra load on the system
                 */
                disable_irq(spi->irq);

                ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
                if (ret)
                        return ret;
        }

        spi_set_drvdata(spi, indio_dev);

        ad7766->spi = spi;

        /* First byte always 0 */
        ad7766->xfer.rx_buf = &ad7766->data[1];
        ad7766->xfer.len = 3;

        spi_message_init(&ad7766->msg);
        spi_message_add_tail(&ad7766->xfer, &ad7766->msg);

        ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
                &iio_pollfunc_store_time, &ad7766_trigger_handler,
                &ad7766_buffer_setup_ops);
        if (ret)
                return ret;

        ret = devm_iio_device_register(&spi->dev, indio_dev);
        if (ret)
                return ret;
        return 0;
}

static const struct spi_device_id ad7766_id[] = {
        {"ad7766", ID_AD7766},
        {"ad7766-1", ID_AD7766_1},
        {"ad7766-2", ID_AD7766_2},
        {"ad7767", ID_AD7766},
        {"ad7767-1", ID_AD7766_1},
        {"ad7767-2", ID_AD7766_2},
        {}
};
MODULE_DEVICE_TABLE(spi, ad7766_id);

static struct spi_driver ad7766_driver = {
        .driver = {
                .name   = "ad7766",
        },
        .probe          = ad7766_probe,
        .id_table       = ad7766_id,
};
module_spi_driver(ad7766_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
MODULE_LICENSE("GPL v2");