// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Cobalt button interface driver.
 *
 *  Copyright (C) 2007-2008  Yoichi Yuasa <yuasa@linux-mips.org>
 */
#include <linux/input.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define BUTTONS_POLL_INTERVAL   30      /* msec */
#define BUTTONS_COUNT_THRESHOLD 3
#define BUTTONS_STATUS_MASK     0xfe000000

static const unsigned short cobalt_map[] = {
        KEY_RESERVED,
        KEY_RESTART,
        KEY_LEFT,
        KEY_UP,
        KEY_DOWN,
        KEY_RIGHT,
        KEY_ENTER,
        KEY_SELECT
};

struct buttons_dev {
        unsigned short keymap[ARRAY_SIZE(cobalt_map)];
        int count[ARRAY_SIZE(cobalt_map)];
        void __iomem *reg;
};

static void handle_buttons(struct input_dev *input)
{
        struct buttons_dev *bdev = input_get_drvdata(input);
        uint32_t status;
        int i;

        status = ~readl(bdev->reg) >> 24;

        for (i = 0; i < ARRAY_SIZE(bdev->keymap); i++) {
                if (status & (1U << i)) {
                        if (++bdev->count[i] == BUTTONS_COUNT_THRESHOLD) {
                                input_event(input, EV_MSC, MSC_SCAN, i);
                                input_report_key(input, bdev->keymap[i], 1);
                                input_sync(input);
                        }
                } else {
                        if (bdev->count[i] >= BUTTONS_COUNT_THRESHOLD) {
                                input_event(input, EV_MSC, MSC_SCAN, i);
                                input_report_key(input, bdev->keymap[i], 0);
                                input_sync(input);
                        }
                        bdev->count[i] = 0;
                }
        }
}

static int cobalt_buttons_probe(struct platform_device *pdev)
{
        struct buttons_dev *bdev;
        struct input_dev *input;
        struct resource *res;
        int error, i;

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

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res)
                return -EBUSY;

        bdev->reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
        if (!bdev->reg)
                return -ENOMEM;

        memcpy(bdev->keymap, cobalt_map, sizeof(bdev->keymap));

        input = devm_input_allocate_device(&pdev->dev);
        if (!input)
                return -ENOMEM;

        input_set_drvdata(input, bdev);

        input->name = "Cobalt buttons";
        input->phys = "cobalt/input0";
        input->id.bustype = BUS_HOST;

        input->keycode = bdev->keymap;
        input->keycodemax = ARRAY_SIZE(bdev->keymap);
        input->keycodesize = sizeof(unsigned short);

        input_set_capability(input, EV_MSC, MSC_SCAN);
        __set_bit(EV_KEY, input->evbit);
        for (i = 0; i < ARRAY_SIZE(cobalt_map); i++)
                __set_bit(bdev->keymap[i], input->keybit);
        __clear_bit(KEY_RESERVED, input->keybit);


        error = input_setup_polling(input, handle_buttons);
        if (error)
                return error;

        input_set_poll_interval(input, BUTTONS_POLL_INTERVAL);

        error = input_register_device(input);
        if (error)
                return error;

        return 0;
}

MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");
MODULE_DESCRIPTION("Cobalt button interface driver");
MODULE_LICENSE("GPL");
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:Cobalt buttons");

static struct platform_driver cobalt_buttons_driver = {
        .probe  = cobalt_buttons_probe,
        .driver = {
                .name   = "Cobalt buttons",
        },
};
module_platform_driver(cobalt_buttons_driver);