root/sound/drivers/pcsp/pcsp_input.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  PC Speaker beeper driver for Linux
 *
 *  Copyright (c) 2002 Vojtech Pavlik
 *  Copyright (c) 1992 Orest Zborowski
 */


#include <linux/init.h>
#include <linux/input.h>
#include <linux/io.h>
#include "pcsp.h"
#include "pcsp_input.h"

static void pcspkr_do_sound(unsigned int count)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&i8253_lock, flags);

        if (count) {
                /* set command for counter 2, 2 byte write */
                outb_p(0xB6, 0x43);
                /* select desired HZ */
                outb_p(count & 0xff, 0x42);
                outb((count >> 8) & 0xff, 0x42);
                /* enable counter 2 */
                outb_p(inb_p(0x61) | 3, 0x61);
        } else {
                /* disable counter 2 */
                outb(inb_p(0x61) & 0xFC, 0x61);
        }

        raw_spin_unlock_irqrestore(&i8253_lock, flags);
}

void pcspkr_stop_sound(void)
{
        pcspkr_do_sound(0);
}

static int pcspkr_input_event(struct input_dev *dev, unsigned int type,
                              unsigned int code, int value)
{
        unsigned int count = 0;

        if (atomic_read(&pcsp_chip.timer_active) || !pcsp_chip.pcspkr)
                return 0;

        switch (type) {
        case EV_SND:
                switch (code) {
                case SND_BELL:
                        if (value)
                                value = 1000;
                        break;
                case SND_TONE:
                        break;
                default:
                        return -1;
                }
                break;

        default:
                return -1;
        }

        if (value > 20 && value < 32767)
                count = PIT_TICK_RATE / value;

        pcspkr_do_sound(count);

        return 0;
}

int pcspkr_input_init(struct input_dev **rdev, struct device *dev)
{
        int err;

        struct input_dev *input_dev = devm_input_allocate_device(dev);
        if (!input_dev)
                return -ENOMEM;

        input_dev->name = "PC Speaker";
        input_dev->phys = "isa0061/input0";
        input_dev->id.bustype = BUS_ISA;
        input_dev->id.vendor = 0x001f;
        input_dev->id.product = 0x0001;
        input_dev->id.version = 0x0100;
        input_dev->dev.parent = dev;

        input_dev->evbit[0] = BIT(EV_SND);
        input_dev->sndbit[0] = BIT(SND_BELL) | BIT(SND_TONE);
        input_dev->event = pcspkr_input_event;

        err = input_register_device(input_dev);
        if (err)
                return err;

        *rdev = input_dev;
        return 0;
}