// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Nano River Technologies viperboard IIO ADC driver
 *
 *  (C) 2012 by Lemonage GmbH
 *  Author: Lars Poeschel <poeschel@lemonage.de>
 *  All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>

#include <linux/usb.h>
#include <linux/iio/iio.h>

#include <linux/mfd/viperboard.h>

#define VPRBRD_ADC_CMD_GET              0x00

struct vprbrd_adc_msg {
        u8 cmd;
        u8 chan;
        u8 val;
} __packed;

struct vprbrd_adc {
        struct vprbrd *vb;
};

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

static struct iio_chan_spec const vprbrd_adc_iio_channels[] = {
        VPRBRD_ADC_CHANNEL(0),
        VPRBRD_ADC_CHANNEL(1),
        VPRBRD_ADC_CHANNEL(2),
        VPRBRD_ADC_CHANNEL(3),
};

static int vprbrd_iio_read_raw(struct iio_dev *iio_dev,
                                struct iio_chan_spec const *chan,
                                int *val,
                                int *val2,
                                long info)
{
        int ret, error = 0;
        struct vprbrd_adc *adc = iio_priv(iio_dev);
        struct vprbrd *vb = adc->vb;
        struct vprbrd_adc_msg *admsg = (struct vprbrd_adc_msg *)vb->buf;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                mutex_lock(&vb->lock);

                admsg->cmd = VPRBRD_ADC_CMD_GET;
                admsg->chan = chan->channel;
                admsg->val = 0x00;

                ret = usb_control_msg(vb->usb_dev,
                        usb_sndctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
                        VPRBRD_USB_TYPE_OUT, 0x0000, 0x0000, admsg,
                        sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);
                if (ret != sizeof(struct vprbrd_adc_msg)) {
                        dev_err(&iio_dev->dev, "usb send error on adc read\n");
                        error = -EREMOTEIO;
                }

                ret = usb_control_msg(vb->usb_dev,
                        usb_rcvctrlpipe(vb->usb_dev, 0), VPRBRD_USB_REQUEST_ADC,
                        VPRBRD_USB_TYPE_IN, 0x0000, 0x0000, admsg,
                        sizeof(struct vprbrd_adc_msg), VPRBRD_USB_TIMEOUT_MS);

                *val = admsg->val;

                mutex_unlock(&vb->lock);

                if (ret != sizeof(struct vprbrd_adc_msg)) {
                        dev_err(&iio_dev->dev, "usb recv error on adc read\n");
                        error = -EREMOTEIO;
                }

                if (error)
                        goto error;

                return IIO_VAL_INT;
        default:
                error = -EINVAL;
                break;
        }
error:
        return error;
}

static const struct iio_info vprbrd_adc_iio_info = {
        .read_raw = &vprbrd_iio_read_raw,
};

static int vprbrd_adc_probe(struct platform_device *pdev)
{
        struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
        struct vprbrd_adc *adc;
        struct iio_dev *indio_dev;
        int ret;

        /* registering iio */
        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
        if (!indio_dev)
                return -ENOMEM;

        adc = iio_priv(indio_dev);
        adc->vb = vb;
        indio_dev->name = "viperboard adc";
        indio_dev->info = &vprbrd_adc_iio_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = vprbrd_adc_iio_channels;
        indio_dev->num_channels = ARRAY_SIZE(vprbrd_adc_iio_channels);

        ret = devm_iio_device_register(&pdev->dev, indio_dev);
        if (ret) {
                dev_err(&pdev->dev, "could not register iio (adc)");
                return ret;
        }

        return 0;
}

static struct platform_driver vprbrd_adc_driver = {
        .driver = {
                .name   = "viperboard-adc",
        },
        .probe          = vprbrd_adc_probe,
};

module_platform_driver(vprbrd_adc_driver);

MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
MODULE_DESCRIPTION("IIO ADC driver for Nano River Techs Viperboard");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:viperboard-adc");