// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 74xx MMIO GPIO driver
 *
 *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
 */

#include <linux/bits.h>
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/gpio/generic.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>

#define MMIO_74XX_DIR_IN        BIT(8)
#define MMIO_74XX_DIR_OUT       BIT(9)
#define MMIO_74XX_BIT_CNT(x)    ((x) & GENMASK(7, 0))

struct mmio_74xx_gpio_priv {
        struct gpio_generic_chip gen_gc;
        unsigned int flags;
};

static const struct of_device_id mmio_74xx_gpio_ids[] = {
        {
                .compatible     = "ti,741g125",
                .data           = (const void *)(MMIO_74XX_DIR_IN | 1),
        },
        {
                .compatible     = "ti,742g125",
                .data           = (const void *)(MMIO_74XX_DIR_IN | 2),
        },
        {
                .compatible     = "ti,74125",
                .data           = (const void *)(MMIO_74XX_DIR_IN | 4),
        },
        {
                .compatible     = "ti,74365",
                .data           = (const void *)(MMIO_74XX_DIR_IN | 6),
        },
        {
                .compatible     = "ti,74244",
                .data           = (const void *)(MMIO_74XX_DIR_IN | 8),
        },
        {
                .compatible     = "ti,741624",
                .data           = (const void *)(MMIO_74XX_DIR_IN | 16),
        },
        {
                .compatible     = "ti,741g74",
                .data           = (const void *)(MMIO_74XX_DIR_OUT | 1),
        },
        {
                .compatible     = "ti,7474",
                .data           = (const void *)(MMIO_74XX_DIR_OUT | 2),
        },
        {
                .compatible     = "ti,74175",
                .data           = (const void *)(MMIO_74XX_DIR_OUT | 4),
        },
        {
                .compatible     = "ti,74174",
                .data           = (const void *)(MMIO_74XX_DIR_OUT | 6),
        },
        {
                .compatible     = "ti,74273",
                .data           = (const void *)(MMIO_74XX_DIR_OUT | 8),
        },
        {
                .compatible     = "ti,7416374",
                .data           = (const void *)(MMIO_74XX_DIR_OUT | 16),
        },
        { }
};
MODULE_DEVICE_TABLE(of, mmio_74xx_gpio_ids);

static int mmio_74xx_get_direction(struct gpio_chip *gc, unsigned offset)
{
        struct mmio_74xx_gpio_priv *priv = gpiochip_get_data(gc);

        if (priv->flags & MMIO_74XX_DIR_OUT)
                return GPIO_LINE_DIRECTION_OUT;

        return  GPIO_LINE_DIRECTION_IN;
}

static int mmio_74xx_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
        struct mmio_74xx_gpio_priv *priv = gpiochip_get_data(gc);

        if (priv->flags & MMIO_74XX_DIR_IN)
                return 0;

        return -ENOTSUPP;
}

static int mmio_74xx_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
        struct mmio_74xx_gpio_priv *priv = gpiochip_get_data(gc);

        if (priv->flags & MMIO_74XX_DIR_OUT)
                return gpio_generic_chip_set(&priv->gen_gc, gpio, val);

        return -ENOTSUPP;
}

static int mmio_74xx_gpio_probe(struct platform_device *pdev)
{
        struct gpio_generic_chip_config config = { };
        struct mmio_74xx_gpio_priv *priv;
        void __iomem *dat;
        int err;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->flags = (uintptr_t)device_get_match_data(&pdev->dev);

        dat = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(dat))
                return PTR_ERR(dat);

        config.dev = &pdev->dev;
        config.sz = DIV_ROUND_UP(MMIO_74XX_BIT_CNT(priv->flags), 8);
        config.dat = dat;

        err = gpio_generic_chip_init(&priv->gen_gc, &config);
        if (err)
                return err;

        priv->gen_gc.gc.direction_input = mmio_74xx_dir_in;
        priv->gen_gc.gc.direction_output = mmio_74xx_dir_out;
        priv->gen_gc.gc.get_direction = mmio_74xx_get_direction;
        priv->gen_gc.gc.ngpio = MMIO_74XX_BIT_CNT(priv->flags);
        priv->gen_gc.gc.owner = THIS_MODULE;

        return devm_gpiochip_add_data(&pdev->dev, &priv->gen_gc.gc, priv);
}

static struct platform_driver mmio_74xx_gpio_driver = {
        .driver = {
                .name           = "74xx-mmio-gpio",
                .of_match_table = mmio_74xx_gpio_ids,
        },
        .probe  = mmio_74xx_gpio_probe,
};
module_platform_driver(mmio_74xx_gpio_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("74xx MMIO GPIO driver");