// SPDX-License-Identifier: GPL-2.0-only
/*
 * MEN 16z188 Analog to Digial Converter
 *
 * Copyright (C) 2014 MEN Mikroelektronik GmbH (www.men.de)
 * Author: Johannes Thumshirn <johannes.thumshirn@men.de>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mcb.h>
#include <linux/io.h>
#include <linux/iio/iio.h>

#define Z188_ADC_MAX_CHAN       8
#define Z188_ADC_GAIN           0x0700000
#define Z188_MODE_VOLTAGE       BIT(27)
#define Z188_CFG_AUTO           0x1
#define Z188_CTRL_REG           0x40

#define ADC_DATA(x) (((x) >> 2) & 0x7ffffc)
#define ADC_OVR(x) ((x) & 0x1)

struct z188_adc {
        struct resource *mem;
        void __iomem *base;
};

#define Z188_ADC_CHANNEL(idx) {                                 \
                .type = IIO_VOLTAGE,                            \
                .indexed = 1,                                   \
                .channel = (idx),                               \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
}

static const struct iio_chan_spec z188_adc_iio_channels[] = {
        Z188_ADC_CHANNEL(0),
        Z188_ADC_CHANNEL(1),
        Z188_ADC_CHANNEL(2),
        Z188_ADC_CHANNEL(3),
        Z188_ADC_CHANNEL(4),
        Z188_ADC_CHANNEL(5),
        Z188_ADC_CHANNEL(6),
        Z188_ADC_CHANNEL(7),
};

static int z188_iio_read_raw(struct iio_dev *iio_dev,
                        struct iio_chan_spec const *chan,
                        int *val,
                        int *val2,
                        long info)
{
        struct z188_adc *adc = iio_priv(iio_dev);
        int ret;
        u16 tmp;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                tmp = readw(adc->base + chan->channel * 4);

                if (ADC_OVR(tmp)) {
                        dev_info(&iio_dev->dev,
                                "Oversampling error on ADC channel %d\n",
                                chan->channel);
                        return -EIO;
                }
                *val = ADC_DATA(tmp);
                ret = IIO_VAL_INT;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static const struct iio_info z188_adc_info = {
        .read_raw = &z188_iio_read_raw,
};

static void men_z188_config_channels(void __iomem *addr)
{
        int i;
        u32 cfg;
        u32 ctl;

        ctl = readl(addr + Z188_CTRL_REG);
        ctl |= Z188_CFG_AUTO;
        writel(ctl, addr + Z188_CTRL_REG);

        for (i = 0; i < Z188_ADC_MAX_CHAN; i++) {
                cfg = readl(addr + i);
                cfg &= ~Z188_ADC_GAIN;
                cfg |= Z188_MODE_VOLTAGE;
                writel(cfg, addr + i);
        }
}

static int men_z188_probe(struct mcb_device *dev,
                        const struct mcb_device_id *id)
{
        struct z188_adc *adc;
        struct iio_dev *indio_dev;
        struct resource *mem;
        int ret;

        indio_dev = devm_iio_device_alloc(&dev->dev, sizeof(struct z188_adc));
        if (!indio_dev)
                return -ENOMEM;

        adc = iio_priv(indio_dev);
        indio_dev->name = "z188-adc";
        indio_dev->info = &z188_adc_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = z188_adc_iio_channels;
        indio_dev->num_channels = ARRAY_SIZE(z188_adc_iio_channels);

        mem = mcb_request_mem(dev, "z188-adc");
        if (IS_ERR(mem))
                return PTR_ERR(mem);

        adc->base = ioremap(mem->start, resource_size(mem));
        if (adc->base == NULL)
                goto err;

        men_z188_config_channels(adc->base);

        adc->mem = mem;
        mcb_set_drvdata(dev, indio_dev);

        ret = iio_device_register(indio_dev);
        if (ret)
                goto err_unmap;

        return 0;

err_unmap:
        iounmap(adc->base);
err:
        mcb_release_mem(mem);
        return -ENXIO;
}

static void men_z188_remove(struct mcb_device *dev)
{
        struct iio_dev *indio_dev  = mcb_get_drvdata(dev);
        struct z188_adc *adc = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);
        iounmap(adc->base);
        mcb_release_mem(adc->mem);
}

static const struct mcb_device_id men_z188_ids[] = {
        { .device = 0xbc },
        { }
};
MODULE_DEVICE_TABLE(mcb, men_z188_ids);

static struct mcb_driver men_z188_driver = {
        .driver = {
                .name = "z188-adc",
        },
        .probe = men_z188_probe,
        .remove = men_z188_remove,
        .id_table = men_z188_ids,
};
module_mcb_driver(men_z188_driver);

MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core");
MODULE_IMPORT_NS("MCB");