// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Power management for audio on multifunction CS5535 companion device
 * Copyright (C) Jaya Kumar
 */

#include <linux/init.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/initval.h>
#include <sound/asoundef.h>
#include <sound/pcm.h>
#include <sound/ac97_codec.h>
#include "cs5535audio.h"

static void snd_cs5535audio_stop_hardware(struct cs5535audio *cs5535au)
{
        /* 
        we depend on snd_ac97_suspend to tell the
        AC97 codec to shutdown. the amd spec suggests
        that the LNK_SHUTDOWN be done at the same time
        that the codec power-down is issued. instead,
        we do it just after rather than at the same 
        time. excluding codec specific build_ops->suspend
        ac97 powerdown hits:
        0x8000 EAPD 
        0x4000 Headphone amplifier 
        0x0300 ADC & DAC 
        0x0400 Analog Mixer powerdown (Vref on) 
        I am not sure if this is the best that we can do.
        The remainder to be investigated are:
        - analog mixer (vref off) 0x0800
        - AC-link powerdown 0x1000
        - codec internal clock 0x2000
        */

        /* set LNK_SHUTDOWN to shutdown AC link */
        cs_writel(cs5535au, ACC_CODEC_CNTL, ACC_CODEC_CNTL_LNK_SHUTDOWN);

}

static int __maybe_unused snd_cs5535audio_suspend(struct device *dev)
{
        struct snd_card *card = dev_get_drvdata(dev);
        struct cs5535audio *cs5535au = card->private_data;
        int i;

        snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
        snd_ac97_suspend(cs5535au->ac97);
        for (i = 0; i < NUM_CS5535AUDIO_DMAS; i++) {
                struct cs5535audio_dma *dma = &cs5535au->dmas[i];
                if (dma && dma->substream)
                        dma->saved_prd = dma->ops->read_prd(cs5535au);
        }
        /* save important regs, then disable aclink in hw */
        snd_cs5535audio_stop_hardware(cs5535au);
        return 0;
}

static int __maybe_unused snd_cs5535audio_resume(struct device *dev)
{
        struct snd_card *card = dev_get_drvdata(dev);
        struct cs5535audio *cs5535au = card->private_data;
        u32 tmp;
        int timeout;
        int i;

        /* set LNK_WRM_RST to reset AC link */
        cs_writel(cs5535au, ACC_CODEC_CNTL, ACC_CODEC_CNTL_LNK_WRM_RST);

        timeout = 50;
        do {
                tmp = cs_readl(cs5535au, ACC_CODEC_STATUS);
                if (tmp & PRM_RDY_STS)
                        break;
                udelay(1);
        } while (--timeout);

        if (!timeout)
                dev_err(cs5535au->card->dev, "Failure getting AC Link ready\n");

        /* set up rate regs, dma. actual initiation is done in trig */
        for (i = 0; i < NUM_CS5535AUDIO_DMAS; i++) {
                struct cs5535audio_dma *dma = &cs5535au->dmas[i];
                if (dma && dma->substream) {
                        dma->substream->ops->prepare(dma->substream);
                        dma->ops->setup_prd(cs5535au, dma->saved_prd);
                }
        }

        /* we depend on ac97 to perform the codec power up */
        snd_ac97_resume(cs5535au->ac97);
        snd_power_change_state(card, SNDRV_CTL_POWER_D0);

        return 0;
}

SIMPLE_DEV_PM_OPS(snd_cs5535audio_pm, snd_cs5535audio_suspend, snd_cs5535audio_resume);