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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/sound/pci/cs5535audio/cs5535audio_pm.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 * Power management for audio on multifunction CS5535 companion device

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 * Copyright (C) Jaya Kumar

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 */

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#include <linux/init.h>

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#include <linux/pci.h>

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#include <linux/delay.h>

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#include <sound/core.h>

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#include <sound/control.h>

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#include <sound/initval.h>

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#include <sound/asoundef.h>

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#include <sound/pcm.h>

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#include <sound/ac97_codec.h>

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#include "cs5535audio.h"

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static void snd_cs5535audio_stop_hardware(struct cs5535audio *cs5535au)

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{

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	/* 

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	we depend on snd_ac97_suspend to tell the

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	AC97 codec to shutdown. the amd spec suggests

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	that the LNK_SHUTDOWN be done at the same time

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	that the codec power-down is issued. instead,

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	we do it just after rather than at the same 

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	time. excluding codec specific build_ops->suspend

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	ac97 powerdown hits:

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	0x8000 EAPD 

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	0x4000 Headphone amplifier 

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	0x0300 ADC & DAC 

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	0x0400 Analog Mixer powerdown (Vref on) 

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	I am not sure if this is the best that we can do.

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	The remainder to be investigated are:

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	- analog mixer (vref off) 0x0800

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	- AC-link powerdown 0x1000

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	- codec internal clock 0x2000

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	*/

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	/* set LNK_SHUTDOWN to shutdown AC link */

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	cs_writel(cs5535au, ACC_CODEC_CNTL, ACC_CODEC_CNTL_LNK_SHUTDOWN);

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}

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static int __maybe_unused snd_cs5535audio_suspend(struct device *dev)

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{

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	struct snd_card *card = dev_get_drvdata(dev);

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	struct cs5535audio *cs5535au = card->private_data;

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	int i;

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	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);

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	snd_ac97_suspend(cs5535au->ac97);

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	for (i = 0; i < NUM_CS5535AUDIO_DMAS; i++) {

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		struct cs5535audio_dma *dma = &cs5535au->dmas[i];

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		if (dma && dma->substream)

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			dma->saved_prd = dma->ops->read_prd(cs5535au);

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	}

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	/* save important regs, then disable aclink in hw */

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	snd_cs5535audio_stop_hardware(cs5535au);

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	return 0;

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}

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static int __maybe_unused snd_cs5535audio_resume(struct device *dev)

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{

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	struct snd_card *card = dev_get_drvdata(dev);

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	struct cs5535audio *cs5535au = card->private_data;

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	u32 tmp;

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	int timeout;

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	int i;

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	/* set LNK_WRM_RST to reset AC link */

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	cs_writel(cs5535au, ACC_CODEC_CNTL, ACC_CODEC_CNTL_LNK_WRM_RST);

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	timeout = 50;

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	do {

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		tmp = cs_readl(cs5535au, ACC_CODEC_STATUS);

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		if (tmp & PRM_RDY_STS)

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			break;

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		udelay(1);

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	} while (--timeout);

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	if (!timeout)

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

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	/* set up rate regs, dma. actual initiation is done in trig */

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	for (i = 0; i < NUM_CS5535AUDIO_DMAS; i++) {

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		struct cs5535audio_dma *dma = &cs5535au->dmas[i];

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		if (dma && dma->substream) {

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			dma->substream->ops->prepare(dma->substream);

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			dma->ops->setup_prd(cs5535au, dma->saved_prd);

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		}

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	}

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	/* we depend on ac97 to perform the codec power up */

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	snd_ac97_resume(cs5535au->ac97);

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	snd_power_change_state(card, SNDRV_CTL_POWER_D0);

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	return 0;

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}

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SIMPLE_DEV_PM_OPS(snd_cs5535audio_pm, snd_cs5535audio_suspend, snd_cs5535audio_resume);

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