// SPDX-License-Identifier: GPL-2.0
/*
 * arch/sh/boards/mach-x3proto/gpio.c
 *
 * Renesas SH-X3 Prototype Baseboard GPIO Support.
 *
 * Copyright (C) 2010 - 2012  Paul Mundt
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gpio/driver.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/irqdomain.h>
#include <linux/io.h>
#include <mach/ilsel.h>
#include <mach/hardware.h>

#define KEYCTLR 0xb81c0000
#define KEYOUTR 0xb81c0002
#define KEYDETR 0xb81c0004

static DEFINE_SPINLOCK(x3proto_gpio_lock);
static struct irq_domain *x3proto_irq_domain;

static int x3proto_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
        unsigned long flags;
        unsigned int data;

        spin_lock_irqsave(&x3proto_gpio_lock, flags);
        data = __raw_readw(KEYCTLR);
        data |= (1 << gpio);
        __raw_writew(data, KEYCTLR);
        spin_unlock_irqrestore(&x3proto_gpio_lock, flags);

        return 0;
}

static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
{
        return !!(__raw_readw(KEYDETR) & (1 << gpio));
}

static int x3proto_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
{
        int virq;

        if (gpio < chip->ngpio)
                virq = irq_create_mapping(x3proto_irq_domain, gpio);
        else
                virq = -ENXIO;

        return virq;
}

static void x3proto_gpio_irq_handler(struct irq_desc *desc)
{
        struct irq_data *data = irq_desc_get_irq_data(desc);
        struct irq_chip *chip = irq_data_get_irq_chip(data);
        unsigned long mask;
        int pin;

        chip->irq_mask_ack(data);

        mask = __raw_readw(KEYDETR);
        for_each_set_bit(pin, &mask, NR_BASEBOARD_GPIOS)
                generic_handle_domain_irq(x3proto_irq_domain, pin);

        chip->irq_unmask(data);
}

struct gpio_chip x3proto_gpio_chip = {
        .label                  = "x3proto-gpio",
        .direction_input        = x3proto_gpio_direction_input,
        .get                    = x3proto_gpio_get,
        .to_irq                 = x3proto_gpio_to_irq,
        .base                   = -1,
        .ngpio                  = NR_BASEBOARD_GPIOS,
};

static int x3proto_gpio_irq_map(struct irq_domain *domain, unsigned int virq,
                                irq_hw_number_t hwirq)
{
        irq_set_chip_and_handler_name(virq, &dummy_irq_chip, handle_simple_irq,
                                      "gpio");

        return 0;
}

static struct irq_domain_ops x3proto_gpio_irq_ops = {
        .map    = x3proto_gpio_irq_map,
        .xlate  = irq_domain_xlate_twocell,
};

int __init x3proto_gpio_setup(void)
{
        int ilsel, ret;

        ilsel = ilsel_enable(ILSEL_KEY);
        if (unlikely(ilsel < 0))
                return ilsel;

        ret = gpiochip_add_data(&x3proto_gpio_chip, NULL);
        if (unlikely(ret))
                goto err_gpio;

        x3proto_irq_domain = irq_domain_create_linear(NULL, NR_BASEBOARD_GPIOS,
                                                   &x3proto_gpio_irq_ops, NULL);
        if (unlikely(!x3proto_irq_domain))
                goto err_irq;

        pr_info("registering '%s' support, handling GPIOs %u -> %u, "
                "bound to IRQ %u\n",
                x3proto_gpio_chip.label, x3proto_gpio_chip.base,
                x3proto_gpio_chip.base + x3proto_gpio_chip.ngpio,
                ilsel);

        irq_set_chained_handler(ilsel, x3proto_gpio_irq_handler);
        irq_set_irq_wake(ilsel, 1);

        return 0;

err_irq:
        gpiochip_remove(&x3proto_gpio_chip);
        ret = 0;
err_gpio:
        synchronize_irq(ilsel);

        ilsel_disable(ILSEL_KEY);

        return ret;
}