// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/gpio/gpio-mb86s7x.c
 *
 *  Copyright (C) 2015 Fujitsu Semiconductor Limited
 *  Copyright (C) 2015 Linaro Ltd.
 */

#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/gpio/driver.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/slab.h>

#include "gpiolib-acpi.h"

/*
 * Only first 8bits of a register correspond to each pin,
 * so there are 4 registers for 32 pins.
 */
#define PDR(x)  (0x0 + x / 8 * 4)
#define DDR(x)  (0x10 + x / 8 * 4)
#define PFR(x)  (0x20 + x / 8 * 4)

#define OFFSET(x)       BIT((x) % 8)

struct mb86s70_gpio_chip {
        struct gpio_chip gc;
        void __iomem *base;
        spinlock_t lock;
};

static int mb86s70_gpio_request(struct gpio_chip *gc, unsigned gpio)
{
        struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(&gchip->lock, flags);

        val = readl(gchip->base + PFR(gpio));
        val &= ~OFFSET(gpio);
        writel(val, gchip->base + PFR(gpio));

        spin_unlock_irqrestore(&gchip->lock, flags);

        return 0;
}

static void mb86s70_gpio_free(struct gpio_chip *gc, unsigned gpio)
{
        struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
        unsigned long flags;
        u32 val;

        spin_lock_irqsave(&gchip->lock, flags);

        val = readl(gchip->base + PFR(gpio));
        val |= OFFSET(gpio);
        writel(val, gchip->base + PFR(gpio));

        spin_unlock_irqrestore(&gchip->lock, flags);
}

static int mb86s70_gpio_direction_input(struct gpio_chip *gc, unsigned gpio)
{
        struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
        unsigned long flags;
        unsigned char val;

        spin_lock_irqsave(&gchip->lock, flags);

        val = readl(gchip->base + DDR(gpio));
        val &= ~OFFSET(gpio);
        writel(val, gchip->base + DDR(gpio));

        spin_unlock_irqrestore(&gchip->lock, flags);

        return 0;
}

static int mb86s70_gpio_direction_output(struct gpio_chip *gc,
                                         unsigned gpio, int value)
{
        struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
        unsigned long flags;
        unsigned char val;

        spin_lock_irqsave(&gchip->lock, flags);

        val = readl(gchip->base + PDR(gpio));
        if (value)
                val |= OFFSET(gpio);
        else
                val &= ~OFFSET(gpio);
        writel(val, gchip->base + PDR(gpio));

        val = readl(gchip->base + DDR(gpio));
        val |= OFFSET(gpio);
        writel(val, gchip->base + DDR(gpio));

        spin_unlock_irqrestore(&gchip->lock, flags);

        return 0;
}

static int mb86s70_gpio_get(struct gpio_chip *gc, unsigned gpio)
{
        struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);

        return !!(readl(gchip->base + PDR(gpio)) & OFFSET(gpio));
}

static int mb86s70_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
{
        struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
        unsigned long flags;
        unsigned char val;

        spin_lock_irqsave(&gchip->lock, flags);

        val = readl(gchip->base + PDR(gpio));
        if (value)
                val |= OFFSET(gpio);
        else
                val &= ~OFFSET(gpio);
        writel(val, gchip->base + PDR(gpio));

        spin_unlock_irqrestore(&gchip->lock, flags);

        return 0;
}

static int mb86s70_gpio_to_irq(struct gpio_chip *gc, unsigned int offset)
{
        int irq, index;

        for (index = 0;; index++) {
                irq = platform_get_irq(to_platform_device(gc->parent), index);
                if (irq < 0)
                        return irq;
                if (irq_get_irq_data(irq)->hwirq == offset)
                        return irq;
        }
        return -EINVAL;
}

static int mb86s70_gpio_probe(struct platform_device *pdev)
{
        struct mb86s70_gpio_chip *gchip;
        struct clk *clk;
        int ret;

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

        platform_set_drvdata(pdev, gchip);

        gchip->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(gchip->base))
                return PTR_ERR(gchip->base);

        clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
        if (IS_ERR(clk))
                return PTR_ERR(clk);

        spin_lock_init(&gchip->lock);

        gchip->gc.direction_output = mb86s70_gpio_direction_output;
        gchip->gc.direction_input = mb86s70_gpio_direction_input;
        gchip->gc.request = mb86s70_gpio_request;
        gchip->gc.free = mb86s70_gpio_free;
        gchip->gc.get = mb86s70_gpio_get;
        gchip->gc.set = mb86s70_gpio_set;
        gchip->gc.to_irq = mb86s70_gpio_to_irq;
        gchip->gc.label = dev_name(&pdev->dev);
        gchip->gc.ngpio = 32;
        gchip->gc.owner = THIS_MODULE;
        gchip->gc.parent = &pdev->dev;
        gchip->gc.base = -1;

        ret = gpiochip_add_data(&gchip->gc, gchip);
        if (ret)
                return dev_err_probe(&pdev->dev, ret,
                                     "couldn't register gpio driver\n");

        acpi_gpiochip_request_interrupts(&gchip->gc);

        return 0;
}

static void mb86s70_gpio_remove(struct platform_device *pdev)
{
        struct mb86s70_gpio_chip *gchip = platform_get_drvdata(pdev);

        acpi_gpiochip_free_interrupts(&gchip->gc);
        gpiochip_remove(&gchip->gc);
}

static const struct of_device_id mb86s70_gpio_dt_ids[] = {
        { .compatible = "fujitsu,mb86s70-gpio" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mb86s70_gpio_dt_ids);

#ifdef CONFIG_ACPI
static const struct acpi_device_id mb86s70_gpio_acpi_ids[] = {
        { "SCX0007" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(acpi, mb86s70_gpio_acpi_ids);
#endif

static struct platform_driver mb86s70_gpio_driver = {
        .driver = {
                .name = "mb86s70-gpio",
                .of_match_table = mb86s70_gpio_dt_ids,
                .acpi_match_table = ACPI_PTR(mb86s70_gpio_acpi_ids),
        },
        .probe = mb86s70_gpio_probe,
        .remove = mb86s70_gpio_remove,
};
module_platform_driver(mb86s70_gpio_driver);

MODULE_DESCRIPTION("MB86S7x GPIO Driver");
MODULE_ALIAS("platform:mb86s70-gpio");
MODULE_LICENSE("GPL");