/*
 * Digital Beep Input Interface for HD-audio codec
 *
 * Author: Matthew Ranostay <mranostay@embeddedalley.com>
 * Copyright (c) 2008 Embedded Alley Solutions Inc
 *
 *  This driver 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 driver is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/input.h>
#include <linux/pci.h>
#include <linux/workqueue.h>
#include <sound/core.h>
#include "hda_beep.h"
#include "hda_local.h"

enum {
        DIGBEEP_HZ_STEP = 46875,        /* 46.875 Hz */
        DIGBEEP_HZ_MIN = 93750,         /* 93.750 Hz */
        DIGBEEP_HZ_MAX = 12000000,      /* 12 KHz */
};

static void snd_hda_generate_beep(struct work_struct *work)
{
        struct hda_beep *beep =
                container_of(work, struct hda_beep, beep_work);
        struct hda_codec *codec = beep->codec;

        if (!beep->enabled)
                return;

        /* generate tone */
        snd_hda_codec_write_cache(codec, beep->nid, 0,
                        AC_VERB_SET_BEEP_CONTROL, beep->tone);
}

/* (non-standard) Linear beep tone calculation for IDT/STAC codecs 
 *
 * The tone frequency of beep generator on IDT/STAC codecs is
 * defined from the 8bit tone parameter, in Hz,
 *    freq = 48000 * (257 - tone) / 1024
 * that is from 12kHz to 93.75Hz in steps of 46.875 Hz
 */
static int beep_linear_tone(struct hda_beep *beep, int hz)
{
        if (hz <= 0)
                return 0;
        hz *= 1000; /* fixed point */
        hz = hz - DIGBEEP_HZ_MIN
                + DIGBEEP_HZ_STEP / 2; /* round to nearest step */
        if (hz < 0)
                hz = 0; /* turn off PC beep*/
        else if (hz >= (DIGBEEP_HZ_MAX - DIGBEEP_HZ_MIN))
                hz = 1; /* max frequency */
        else {
                hz /= DIGBEEP_HZ_STEP;
                hz = 255 - hz;
        }
        return hz;
}

/* HD-audio standard beep tone parameter calculation
 *
 * The tone frequency in Hz is calculated as
 *   freq = 48000 / (tone * 4)
 * from 47Hz to 12kHz
 */
static int beep_standard_tone(struct hda_beep *beep, int hz)
{
        if (hz <= 0)
                return 0; /* disabled */
        hz = 12000 / hz;
        if (hz > 0xff)
                return 0xff;
        if (hz <= 0)
                return 1;
        return hz;
}

static int snd_hda_beep_event(struct input_dev *dev, unsigned int type,
                                unsigned int code, int hz)
{
        struct hda_beep *beep = input_get_drvdata(dev);

        switch (code) {
        case SND_BELL:
                if (hz)
                        hz = 1000;
        case SND_TONE:
                if (beep->linear_tone)
                        beep->tone = beep_linear_tone(beep, hz);
                else
                        beep->tone = beep_standard_tone(beep, hz);
                break;
        default:
                return -1;
        }

        /* schedule beep event */
        schedule_work(&beep->beep_work);
        return 0;
}

int snd_hda_attach_beep_device(struct hda_codec *codec, int nid)
{
        struct input_dev *input_dev;
        struct hda_beep *beep;
        int err;

        if (!snd_hda_get_bool_hint(codec, "beep"))
                return 0; /* disabled explicitly */

        beep = kzalloc(sizeof(*beep), GFP_KERNEL);
        if (beep == NULL)
                return -ENOMEM;
        snprintf(beep->phys, sizeof(beep->phys),
                "card%d/codec#%d/beep0", codec->bus->card->number, codec->addr);
        input_dev = input_allocate_device();
        if (!input_dev) {
                kfree(beep);
                return -ENOMEM;
        }

        /* setup digital beep device */
        input_dev->name = "HDA Digital PCBeep";
        input_dev->phys = beep->phys;
        input_dev->id.bustype = BUS_PCI;

        input_dev->id.vendor = codec->vendor_id >> 16;
        input_dev->id.product = codec->vendor_id & 0xffff;
        input_dev->id.version = 0x01;

        input_dev->evbit[0] = BIT_MASK(EV_SND);
        input_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE);
        input_dev->event = snd_hda_beep_event;
        input_dev->dev.parent = &codec->bus->pci->dev;
        input_set_drvdata(input_dev, beep);

        err = input_register_device(input_dev);
        if (err < 0) {
                input_free_device(input_dev);
                kfree(beep);
                return err;
        }

        /* enable linear scale */
        snd_hda_codec_write(codec, nid, 0,
                AC_VERB_SET_DIGI_CONVERT_2, 0x01);

        beep->nid = nid;
        beep->dev = input_dev;
        beep->codec = codec;
        beep->enabled = 1;
        codec->beep = beep;

        INIT_WORK(&beep->beep_work, &snd_hda_generate_beep);
        return 0;
}
EXPORT_SYMBOL_HDA(snd_hda_attach_beep_device);

void snd_hda_detach_beep_device(struct hda_codec *codec)
{
        struct hda_beep *beep = codec->beep;
        if (beep) {
                cancel_work_sync(&beep->beep_work);

                input_unregister_device(beep->dev);
                kfree(beep);
                codec->beep = NULL;
        }
}
EXPORT_SYMBOL_HDA(snd_hda_detach_beep_device);