// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OpenCores Keyboard Controller Driver
 * http://www.opencores.org/project,keyboardcontroller
 *
 * Copyright 2007-2009 HV Sistemas S.L.
 */

#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

struct opencores_kbd {
        struct input_dev *input;
        void __iomem *addr;
        int irq;
        unsigned short keycodes[128];
};

static irqreturn_t opencores_kbd_isr(int irq, void *dev_id)
{
        struct opencores_kbd *opencores_kbd = dev_id;
        struct input_dev *input = opencores_kbd->input;
        unsigned char c;

        c = readb(opencores_kbd->addr);
        input_report_key(input, c & 0x7f, c & 0x80 ? 0 : 1);
        input_sync(input);

        return IRQ_HANDLED;
}

static int opencores_kbd_probe(struct platform_device *pdev)
{
        struct input_dev *input;
        struct opencores_kbd *opencores_kbd;
        int irq, i, error;

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

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

        input = devm_input_allocate_device(&pdev->dev);
        if (!input) {
                dev_err(&pdev->dev, "failed to allocate input device\n");
                return -ENOMEM;
        }

        opencores_kbd->input = input;

        opencores_kbd->addr = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(opencores_kbd->addr))
                return PTR_ERR(opencores_kbd->addr);

        input->name = pdev->name;
        input->phys = "opencores-kbd/input0";

        input->id.bustype = BUS_HOST;
        input->id.vendor = 0x0001;
        input->id.product = 0x0001;
        input->id.version = 0x0100;

        input->keycode = opencores_kbd->keycodes;
        input->keycodesize = sizeof(opencores_kbd->keycodes[0]);
        input->keycodemax = ARRAY_SIZE(opencores_kbd->keycodes);

        __set_bit(EV_KEY, input->evbit);

        for (i = 0; i < ARRAY_SIZE(opencores_kbd->keycodes); i++) {
                /*
                 * OpenCores controller happens to have scancodes match
                 * our KEY_* definitions.
                 */
                opencores_kbd->keycodes[i] = i;
                __set_bit(opencores_kbd->keycodes[i], input->keybit);
        }
        __clear_bit(KEY_RESERVED, input->keybit);

        error = devm_request_irq(&pdev->dev, irq, &opencores_kbd_isr,
                                 IRQF_TRIGGER_RISING,
                                 pdev->name, opencores_kbd);
        if (error) {
                dev_err(&pdev->dev, "unable to claim irq %d\n", irq);
                return error;
        }

        error = input_register_device(input);
        if (error) {
                dev_err(&pdev->dev, "unable to register input device\n");
                return error;
        }

        return 0;
}

static struct platform_driver opencores_kbd_device_driver = {
        .probe    = opencores_kbd_probe,
        .driver   = {
                .name = "opencores-kbd",
        },
};
module_platform_driver(opencores_kbd_device_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Javier Herrero <jherrero@hvsistemas.es>");
MODULE_DESCRIPTION("Keyboard driver for OpenCores Keyboard Controller");