// SPDX-License-Identifier: GPL-2.0
/*
 * AD7606 Parallel Interface ADC driver
 *
 * Copyright 2011 - 2024 Analog Devices Inc.
 * Copyright 2024 BayLibre SAS.
 */

#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/types.h>

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

#include "ad7606.h"
#include "ad7606_bus_iface.h"

static int ad7606_par_bus_update_scan_mode(struct iio_dev *indio_dev,
                                           const unsigned long *scan_mask)
{
        struct ad7606_state *st = iio_priv(indio_dev);
        unsigned int c, ret;

        for (c = 0; c < indio_dev->num_channels; c++) {
                if (test_bit(c, scan_mask))
                        ret = iio_backend_chan_enable(st->back, c);
                else
                        ret = iio_backend_chan_disable(st->back, c);
                if (ret)
                        return ret;
        }

        return 0;
}

static int ad7606_par_bus_setup_iio_backend(struct device *dev,
                                            struct iio_dev *indio_dev)
{
        struct ad7606_state *st = iio_priv(indio_dev);
        unsigned int c;
        int ret;
        struct iio_backend_data_fmt data = {
                .sign_extend = true,
                .enable = true,
        };

        st->back = devm_iio_backend_get(dev, NULL);
        if (IS_ERR(st->back))
                return PTR_ERR(st->back);

        /* If the device is iio_backend powered the PWM is mandatory */
        if (!st->cnvst_pwm)
                return dev_err_probe(st->dev, -EINVAL,
                                     "A PWM is mandatory when using backend.\n");

        ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev);
        if (ret)
                return ret;

        ret = devm_iio_backend_enable(dev, st->back);
        if (ret)
                return ret;

        for (c = 0; c < indio_dev->num_channels; c++) {
                ret = iio_backend_data_format_set(st->back, c, &data);
                if (ret)
                        return ret;
        }

        return 0;
}

static int ad7606_par_bus_reg_read(struct ad7606_state *st, unsigned int addr)
{
        struct ad7606_platform_data *pdata = st->dev->platform_data;
        int val, ret;

        ret = pdata->bus_reg_read(st->back, addr, &val);
        if (ret)
                return ret;

        return val;
}

static int ad7606_par_bus_reg_write(struct ad7606_state *st, unsigned int addr,
                                    unsigned int val)
{
        struct ad7606_platform_data *pdata = st->dev->platform_data;

        return pdata->bus_reg_write(st->back, addr, val);
}

static const struct ad7606_bus_ops ad7606_bi_bops = {
        .iio_backend_config = ad7606_par_bus_setup_iio_backend,
        .update_scan_mode = ad7606_par_bus_update_scan_mode,
        .reg_read = ad7606_par_bus_reg_read,
        .reg_write = ad7606_par_bus_reg_write,
};

static int ad7606_par16_read_block(struct device *dev,
                                   int count, void *buf)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct ad7606_state *st = iio_priv(indio_dev);


        /*
         * On the parallel interface, the frstdata signal is set to high while
         * and after reading the sample of the first channel and low for all
         * other channels.  This can be used to check that the incoming data is
         * correctly aligned.  During normal operation the data should never
         * become unaligned, but some glitch or electrostatic discharge might
         * cause an extra read or clock cycle.  Monitoring the frstdata signal
         * allows to recover from such failure situations.
         */
        int num = count;
        u16 *_buf = buf;

        if (st->gpio_frstdata) {
                insw((unsigned long)st->base_address, _buf, 1);
                if (!gpiod_get_value(st->gpio_frstdata)) {
                        ad7606_reset(st);
                        return -EIO;
                }
                _buf++;
                num--;
        }
        insw((unsigned long)st->base_address, _buf, num);
        return 0;
}

static const struct ad7606_bus_ops ad7606_par16_bops = {
        .read_block = ad7606_par16_read_block,
};

static int ad7606_par8_read_block(struct device *dev,
                                  int count, void *buf)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct ad7606_state *st = iio_priv(indio_dev);
        /*
         * On the parallel interface, the frstdata signal is set to high while
         * and after reading the sample of the first channel and low for all
         * other channels.  This can be used to check that the incoming data is
         * correctly aligned.  During normal operation the data should never
         * become unaligned, but some glitch or electrostatic discharge might
         * cause an extra read or clock cycle.  Monitoring the frstdata signal
         * allows to recover from such failure situations.
         */
        int num = count;
        u16 *_buf = buf;

        if (st->gpio_frstdata) {
                insb((unsigned long)st->base_address, _buf, 2);
                if (!gpiod_get_value(st->gpio_frstdata)) {
                        ad7606_reset(st);
                        return -EIO;
                }
                _buf++;
                num--;
        }
        insb((unsigned long)st->base_address, _buf, num * 2);

        return 0;
}

static const struct ad7606_bus_ops ad7606_par8_bops = {
        .read_block = ad7606_par8_read_block,
};

static int ad7606_par_probe(struct platform_device *pdev)
{
        const struct ad7606_chip_info *chip_info;
        const struct platform_device_id *id;
        struct resource *res;
        void __iomem *addr;
        resource_size_t remap_size;
        int irq;

        /*
         * If a firmware node is available (ACPI or DT), platform_device_id is null
         * and we must use get_match_data.
         */
        if (dev_fwnode(&pdev->dev)) {
                chip_info = device_get_match_data(&pdev->dev);
                if (device_property_present(&pdev->dev, "io-backends"))
                        /*
                         * If a backend is available ,call the core probe with backend
                         * bops, otherwise use the former bops.
                         */
                        return ad7606_probe(&pdev->dev, 0, NULL,
                                            chip_info,
                                            &ad7606_bi_bops);
        } else {
                id = platform_get_device_id(pdev);
                chip_info = (const struct ad7606_chip_info *)id->driver_data;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        addr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(addr))
                return PTR_ERR(addr);

        remap_size = resource_size(res);

        return ad7606_probe(&pdev->dev, irq, addr, chip_info,
                            remap_size > 1 ? &ad7606_par16_bops :
                            &ad7606_par8_bops);
}

static const struct platform_device_id ad7606_driver_ids[] = {
        { .name = "ad7605-4", .driver_data = (kernel_ulong_t)&ad7605_4_info, },
        { .name = "ad7606-4", .driver_data = (kernel_ulong_t)&ad7606_4_info, },
        { .name = "ad7606-6", .driver_data = (kernel_ulong_t)&ad7606_6_info, },
        { .name = "ad7606-8", .driver_data = (kernel_ulong_t)&ad7606_8_info, },
        { .name = "ad7606b", .driver_data = (kernel_ulong_t)&ad7606b_info, },
        { .name = "ad7606c-16", .driver_data = (kernel_ulong_t)&ad7606c_16_info },
        { .name = "ad7606c-18", .driver_data = (kernel_ulong_t)&ad7606c_18_info },
        { .name = "ad7607", .driver_data = (kernel_ulong_t)&ad7607_info, },
        { .name = "ad7608", .driver_data = (kernel_ulong_t)&ad7608_info, },
        { .name = "ad7609", .driver_data = (kernel_ulong_t)&ad7609_info, },
        { }
};
MODULE_DEVICE_TABLE(platform, ad7606_driver_ids);

static const struct of_device_id ad7606_of_match[] = {
        { .compatible = "adi,ad7605-4", .data = &ad7605_4_info },
        { .compatible = "adi,ad7606-4", .data = &ad7606_4_info },
        { .compatible = "adi,ad7606-6", .data = &ad7606_6_info },
        { .compatible = "adi,ad7606-8", .data = &ad7606_8_info },
        { .compatible = "adi,ad7606b", .data = &ad7606b_info },
        { .compatible = "adi,ad7606c-16", .data = &ad7606c_16_info },
        { .compatible = "adi,ad7606c-18", .data = &ad7606c_18_info },
        { .compatible = "adi,ad7607", .data = &ad7607_info },
        { .compatible = "adi,ad7608", .data = &ad7608_info },
        { .compatible = "adi,ad7609", .data = &ad7609_info },
        { }
};
MODULE_DEVICE_TABLE(of, ad7606_of_match);

static struct platform_driver ad7606_driver = {
        .probe = ad7606_par_probe,
        .id_table = ad7606_driver_ids,
        .driver = {
                .name = "ad7606",
                .pm = AD7606_PM_OPS,
                .of_match_table = ad7606_of_match,
        },
};
module_platform_driver(ad7606_driver);

MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS("IIO_AD7606");
MODULE_IMPORT_NS("IIO_BACKEND");