rockbox/firmware/target/arm/ipod/piezo.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2006-2007 Robert Keevil
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include "thread.h"
#include "system.h"
#include "kernel.h"
#include "usb.h"
#include "logf.h"
#include "piezo.h"

static long piezo_stack[DEFAULT_STACK_SIZE/sizeof(long)];
static const char piezo_thread_name[] = "piezo";
static struct event_queue piezo_queue;
static unsigned int duration;
static bool beeping;

enum {
    Q_PIEZO_BEEP = 1,
    Q_PIEZO_BEEP_FOR_TICK,
    Q_PIEZO_BEEP_FOR_USEC,
    Q_PIEZO_STOP
};

static inline void piezo_hw_init(void)
{
#ifndef SIMULATOR
    /*logf("PIEZO: hw_init");*/
    outl(inl(0x70000010) & ~0xc, 0x70000010);
    outl(inl(0x6000600c) | 0x20000, 0x6000600c);    /* enable device */
#endif
}

static void piezo_hw_tick(unsigned int form_and_period)
{
#ifndef SIMULATOR
    outl(0x80000000 | form_and_period, 0x7000a000); /* set pitch */
#endif
}

static inline void piezo_hw_stop(void)
{
#ifndef SIMULATOR
    outl(0x0, 0x7000a000);    /* piezo off */
#endif
}

static void piezo_thread(void)
{
    struct queue_event ev;
    long piezo_usec_off;

    while(1)
    {
        queue_wait(&piezo_queue, &ev);
        switch(ev.id)
        {
            case Q_PIEZO_BEEP:
                piezo_hw_tick((unsigned int)ev.data);
                beeping = true;
                break;
            case Q_PIEZO_BEEP_FOR_TICK:
                piezo_hw_tick((unsigned int)ev.data);
                beeping = true;
                sleep(duration);
                if (beeping)
                    piezo_hw_stop();
                beeping = false;
                /* remove anything that appeared while sleeping */
                queue_clear(&piezo_queue);
                break;
            case Q_PIEZO_BEEP_FOR_USEC:
                piezo_usec_off = USEC_TIMER + duration;
                piezo_hw_tick((unsigned int)ev.data);
                beeping = true;
                while (TIME_BEFORE(USEC_TIMER, piezo_usec_off))
                    if (duration >= 5000) yield();
                if (beeping)
                    piezo_hw_stop();
                beeping = false;
                /* remove anything that appeared while sleeping */
                queue_clear(&piezo_queue);
                break;
            case Q_PIEZO_STOP:
                if (beeping)
                    piezo_hw_stop();
                beeping = false;
                break;
#ifndef SIMULATOR
            case SYS_USB_CONNECTED:
                /*logf("USB: Piezo core");*/
                piezo_hw_stop();
                queue_clear(&piezo_queue);
                usb_acknowledge(SYS_USB_CONNECTED_ACK);
                usb_wait_for_disconnect(&piezo_queue);
                break ;
#endif
            case SYS_TIMEOUT:
                break;
        }
        yield();
    }
}


void piezo_play(unsigned short inv_freq, unsigned char form)
{
    queue_post(&piezo_queue, Q_PIEZO_BEEP,
        (intptr_t)((unsigned int)form << 16 | inv_freq));
}

void piezo_play_for_tick(unsigned short inv_freq,
                    unsigned char form, unsigned int dur)
{
    duration = dur;
    queue_post(&piezo_queue, Q_PIEZO_BEEP_FOR_TICK,
        (intptr_t)((unsigned int)form << 16 | inv_freq));
}

void piezo_play_for_usec(unsigned short inv_freq,
                    unsigned char form, unsigned int dur)
{
    duration = dur;
    queue_post(&piezo_queue, Q_PIEZO_BEEP_FOR_USEC,
        (intptr_t)((unsigned int)form << 16 | inv_freq));
}

void piezo_stop(void)
{
    queue_post(&piezo_queue, Q_PIEZO_STOP, 0);
}

void piezo_clear(void)
{
    queue_clear(&piezo_queue);
    piezo_stop();
}

bool piezo_busy(void)
{
    return !queue_empty(&piezo_queue);
}

/*  conversion factor used to based on the following data

        period          Hz
        10              8547
        20              4465
        30              3024
        40              2286
        50              1846
        60              1537
        70              1320
        80              1165
        90              1030
        100             928

    someone with better recording/analysing equipment should be able
    to get more accurate figures


    Above measurements are not measuring fundamental frequency,
    but rather a subharmonic frequency

    Given a 192khz frequency with a divisor of 1,
    these following values should be measurable

        Divisor         Hz
        10              19200
        20              9600
        30              6400
        40              4800
        50              3840
        60              3200
        70              2743
        80              2400
        90              2133
        100             1920

*/

unsigned int piezo_hz(unsigned int hz)
{
    if (hz > 0)
        // Calculated by measuring frequency cycle time on ipodvideo
        return 192000/hz;
    else
        return 0;
}

void piezo_init(void)
{
    /*logf("PIEZO: init");*/
    piezo_hw_init();
    queue_init(&piezo_queue, true);
    create_thread(piezo_thread, piezo_stack, sizeof(piezo_stack), 0,
            piezo_thread_name IF_PRIO(, PRIORITY_REALTIME)
            IF_COP(, CPU));
}

void piezo_button_beep(unsigned short hz, unsigned short dur, bool force)
{
    /* old on clickwheel action - piezo_play_for_usec(50, 0x80, 400);
       old on button action - piezo_play_for_usec(50, 0x80, 3000); */

    if (force) {
        piezo_clear();
        piezo_play_for_usec(piezo_hz(hz), 0x80, dur * 1000);
    } else if (queue_empty(&piezo_queue))
    {
        piezo_play_for_usec(piezo_hz(hz), 0x80, dur * 1000);
    }
}