// SPDX-License-Identifier: GPL-2.0-only
/*
 * AppliedMicro X-Gene SoC GPIO Driver
 *
 * Copyright (c) 2014, Applied Micro Circuits Corporation
 * Author: Feng Kan <fkan@apm.com>.
 */

#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/gpio/driver.h>
#include <linux/types.h>
#include <linux/bitops.h>

#define GPIO_SET_DR_OFFSET      0x0C
#define GPIO_DATA_OFFSET        0x14
#define GPIO_BANK_STRIDE        0x0C

#define XGENE_GPIOS_PER_BANK    16
#define XGENE_MAX_GPIO_BANKS    3
#define XGENE_MAX_GPIOS         (XGENE_GPIOS_PER_BANK * XGENE_MAX_GPIO_BANKS)

#define GPIO_BIT_OFFSET(x)      (x % XGENE_GPIOS_PER_BANK)
#define GPIO_BANK_OFFSET(x)     ((x / XGENE_GPIOS_PER_BANK) * GPIO_BANK_STRIDE)

struct xgene_gpio {
        struct gpio_chip        chip;
        void __iomem            *base;
        spinlock_t              lock;
        u32                     set_dr_val[XGENE_MAX_GPIO_BANKS];
};

static int xgene_gpio_get(struct gpio_chip *gc, unsigned int offset)
{
        struct xgene_gpio *chip = gpiochip_get_data(gc);
        unsigned long bank_offset;
        u32 bit_offset;

        bank_offset = GPIO_DATA_OFFSET + GPIO_BANK_OFFSET(offset);
        bit_offset = GPIO_BIT_OFFSET(offset);
        return !!(ioread32(chip->base + bank_offset) & BIT(bit_offset));
}

static void __xgene_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
{
        struct xgene_gpio *chip = gpiochip_get_data(gc);
        unsigned long bank_offset;
        u32 setval, bit_offset;

        bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
        bit_offset = GPIO_BIT_OFFSET(offset) + XGENE_GPIOS_PER_BANK;

        setval = ioread32(chip->base + bank_offset);
        if (val)
                setval |= BIT(bit_offset);
        else
                setval &= ~BIT(bit_offset);
        iowrite32(setval, chip->base + bank_offset);
}

static int xgene_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
{
        struct xgene_gpio *chip = gpiochip_get_data(gc);
        unsigned long flags;

        spin_lock_irqsave(&chip->lock, flags);
        __xgene_gpio_set(gc, offset, val);
        spin_unlock_irqrestore(&chip->lock, flags);

        return 0;
}

static int xgene_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
{
        struct xgene_gpio *chip = gpiochip_get_data(gc);
        unsigned long bank_offset, bit_offset;

        bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
        bit_offset = GPIO_BIT_OFFSET(offset);

        if (ioread32(chip->base + bank_offset) & BIT(bit_offset))
                return GPIO_LINE_DIRECTION_IN;

        return GPIO_LINE_DIRECTION_OUT;
}

static int xgene_gpio_dir_in(struct gpio_chip *gc, unsigned int offset)
{
        struct xgene_gpio *chip = gpiochip_get_data(gc);
        unsigned long flags, bank_offset;
        u32 dirval, bit_offset;

        bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
        bit_offset = GPIO_BIT_OFFSET(offset);

        spin_lock_irqsave(&chip->lock, flags);

        dirval = ioread32(chip->base + bank_offset);
        dirval |= BIT(bit_offset);
        iowrite32(dirval, chip->base + bank_offset);

        spin_unlock_irqrestore(&chip->lock, flags);

        return 0;
}

static int xgene_gpio_dir_out(struct gpio_chip *gc,
                                        unsigned int offset, int val)
{
        struct xgene_gpio *chip = gpiochip_get_data(gc);
        unsigned long flags, bank_offset;
        u32 dirval, bit_offset;

        bank_offset = GPIO_SET_DR_OFFSET + GPIO_BANK_OFFSET(offset);
        bit_offset = GPIO_BIT_OFFSET(offset);

        spin_lock_irqsave(&chip->lock, flags);

        dirval = ioread32(chip->base + bank_offset);
        dirval &= ~BIT(bit_offset);
        iowrite32(dirval, chip->base + bank_offset);
        __xgene_gpio_set(gc, offset, val);

        spin_unlock_irqrestore(&chip->lock, flags);

        return 0;
}

static int xgene_gpio_suspend(struct device *dev)
{
        struct xgene_gpio *gpio = dev_get_drvdata(dev);
        unsigned long bank_offset;
        unsigned int bank;

        for (bank = 0; bank < XGENE_MAX_GPIO_BANKS; bank++) {
                bank_offset = GPIO_SET_DR_OFFSET + bank * GPIO_BANK_STRIDE;
                gpio->set_dr_val[bank] = ioread32(gpio->base + bank_offset);
        }
        return 0;
}

static int xgene_gpio_resume(struct device *dev)
{
        struct xgene_gpio *gpio = dev_get_drvdata(dev);
        unsigned long bank_offset;
        unsigned int bank;

        for (bank = 0; bank < XGENE_MAX_GPIO_BANKS; bank++) {
                bank_offset = GPIO_SET_DR_OFFSET + bank * GPIO_BANK_STRIDE;
                iowrite32(gpio->set_dr_val[bank], gpio->base + bank_offset);
        }
        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(xgene_gpio_pm, xgene_gpio_suspend, xgene_gpio_resume);

static int xgene_gpio_probe(struct platform_device *pdev)
{
        struct xgene_gpio *gpio;

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

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

        gpio->chip.ngpio = XGENE_MAX_GPIOS;

        spin_lock_init(&gpio->lock);
        gpio->chip.parent = &pdev->dev;
        gpio->chip.get_direction = xgene_gpio_get_direction;
        gpio->chip.direction_input = xgene_gpio_dir_in;
        gpio->chip.direction_output = xgene_gpio_dir_out;
        gpio->chip.get = xgene_gpio_get;
        gpio->chip.set = xgene_gpio_set;
        gpio->chip.label = dev_name(&pdev->dev);
        gpio->chip.base = -1;

        platform_set_drvdata(pdev, gpio);

        return devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
}

static const struct of_device_id xgene_gpio_of_match[] = {
        { .compatible = "apm,xgene-gpio", },
        {},
};

#ifdef CONFIG_ACPI
static const struct acpi_device_id xgene_gpio_acpi_match[] = {
        { "APMC0D14", 0 },
        { },
};
#endif

static struct platform_driver xgene_gpio_driver = {
        .driver = {
                .name = "xgene-gpio",
                .of_match_table = xgene_gpio_of_match,
                .acpi_match_table = ACPI_PTR(xgene_gpio_acpi_match),
                .pm     = pm_sleep_ptr(&xgene_gpio_pm),
        },
        .probe = xgene_gpio_probe,
};
builtin_platform_driver(xgene_gpio_driver);