[alsa-devel] [PATCH] ASoC: davinci-mcasp: add support for suspend and resume

[Gururaja Hebbar]

On Tuesday 01 October 2013 06:20 PM, Daniel Mack wrote:
> When the system returns from suspend, it looses its configuration. Most
> of it is restored by running a normal audio stream startup, but the DAI
> format is left unset as that's configured on the audio device creation.
> 
> Hence, it suffices here to care for the registers which are touched by
> davinci_mcasp_set_dai_fmt() and restore them when the system is resumed.


I believe you have confirmed below are the only registers/fields which
will lose context across suspend/resume.

Regards
Gururaja


> 
> Signed-off-by: Daniel Mack <zonque at gmail.com>
> ---
>  sound/soc/davinci/davinci-mcasp.c | 39 +++++++++++++++++++++++++++++++++++++++
>  sound/soc/davinci/davinci-mcasp.h | 12 ++++++++++++
>  2 files changed, 51 insertions(+)
> 
> diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
> index 591f853..5023da7 100644
> --- a/sound/soc/davinci/davinci-mcasp.c
> +++ b/sound/soc/davinci/davinci-mcasp.c
> @@ -1272,12 +1272,51 @@ static int davinci_mcasp_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int davinci_mcasp_suspend(struct device *dev)
> +{
> +	struct davinci_audio_dev *a = dev_get_drvdata(dev);
> +	void __iomem *base = a->base;
> +
> +	a->context.txfmtctl = mcasp_get_reg(base + DAVINCI_MCASP_TXFMCTL_REG);
> +	a->context.rxfmtctl = mcasp_get_reg(base + DAVINCI_MCASP_RXFMCTL_REG);
> +	a->context.txfmt = mcasp_get_reg(base + DAVINCI_MCASP_TXFMT_REG);
> +	a->context.rxfmt = mcasp_get_reg(base + DAVINCI_MCASP_RXFMT_REG);
> +	a->context.aclkxctl = mcasp_get_reg(base + DAVINCI_MCASP_ACLKXCTL_REG);
> +	a->context.aclkrctl = mcasp_get_reg(base + DAVINCI_MCASP_ACLKRCTL_REG);
> +	a->context.pdir = mcasp_get_reg(base + DAVINCI_MCASP_PDIR_REG);
> +
> +	return 0;
> +}
> +
> +static int davinci_mcasp_resume(struct device *dev)
> +{
> +	struct davinci_audio_dev *a = dev_get_drvdata(dev);
> +	void __iomem *base = a->base;
> +
> +	mcasp_set_reg(base + DAVINCI_MCASP_TXFMCTL_REG, a->context.txfmtctl);
> +	mcasp_set_reg(base + DAVINCI_MCASP_RXFMCTL_REG, a->context.rxfmtctl);
> +	mcasp_set_reg(base + DAVINCI_MCASP_TXFMT_REG, a->context.txfmt);
> +	mcasp_set_reg(base + DAVINCI_MCASP_RXFMT_REG, a->context.rxfmt);
> +	mcasp_set_reg(base + DAVINCI_MCASP_ACLKXCTL_REG, a->context.aclkxctl);
> +	mcasp_set_reg(base + DAVINCI_MCASP_ACLKRCTL_REG, a->context.aclkrctl);
> +	mcasp_set_reg(base + DAVINCI_MCASP_PDIR_REG, a->context.pdir);
> +
> +	return 0;
> +}
> +#endif
> +
> +SIMPLE_DEV_PM_OPS(davinci_mcasp_pm_ops,
> +		  davinci_mcasp_suspend,
> +		  davinci_mcasp_resume);
> +
>  static struct platform_driver davinci_mcasp_driver = {
>  	.probe		= davinci_mcasp_probe,
>  	.remove		= davinci_mcasp_remove,
>  	.driver		= {
>  		.name	= "davinci-mcasp",
>  		.owner	= THIS_MODULE,
> +		.pm	= &davinci_mcasp_pm_ops,
>  		.of_match_table = mcasp_dt_ids,
>  	},
>  };
> diff --git a/sound/soc/davinci/davinci-mcasp.h b/sound/soc/davinci/davinci-mcasp.h
> index a9ac0c1..a2e27e1 100644
> --- a/sound/soc/davinci/davinci-mcasp.h
> +++ b/sound/soc/davinci/davinci-mcasp.h
> @@ -43,6 +43,18 @@ struct davinci_audio_dev {
>  	/* McASP FIFO related */
>  	u8	txnumevt;
>  	u8	rxnumevt;
> +
> +#ifdef CONFIG_PM_SLEEP
> +	struct {
> +		u32	txfmtctl;
> +		u32	rxfmtctl;
> +		u32	txfmt;
> +		u32	rxfmt;
> +		u32	aclkxctl;
> +		u32	aclkrctl;
> +		u32	pdir;
> +	} context;
> +#endif
>  };
>  
>  #endif	/* DAVINCI_MCASP_H */
>