linux-kernel - Re: [PATCH V2 2/2] ASoC: fsl_esai: recover the channel swap after xrun

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Date:   Wed, 3 Jul 2019 22:56:19 +0200
From:   Cezary Rojewski <cezary.rojewski@...el.com>
To:     shengjiu.wang@....com
Cc:     timur@...nel.org, nicoleotsuka@...il.com, Xiubo.Lee@...il.com,
        festevam@...il.com, broonie@...nel.org,
        alsa-devel@...a-project.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 2/2] ASoC: fsl_esai: recover the channel swap after
 xrun

On 2019-07-03 08:42, shengjiu.wang@....com wrote:
> +static void fsl_esai_reset(unsigned long arg)
> +{
> +	struct fsl_esai *esai_priv = (struct fsl_esai *)arg;
> +	u32 saisr, tfcr, rfcr;
> +
> +	/* save the registers */
> +	regmap_read(esai_priv->regmap, REG_ESAI_TFCR, &tfcr);
> +	regmap_read(esai_priv->regmap, REG_ESAI_RFCR, &rfcr);
> +
> +	/* stop the tx & rx */
> +	fsl_esai_trigger_stop(esai_priv, 1);
> +	fsl_esai_trigger_stop(esai_priv, 0);
> +
> +	/* reset the esai, and restore the registers */
> +	fsl_esai_init(esai_priv);

<comment below applies>

> +
> +	regmap_update_bits(esai_priv->regmap, REG_ESAI_TCR,
> +			   ESAI_xCR_xPR_MASK,
> +			   ESAI_xCR_xPR);
> +	regmap_update_bits(esai_priv->regmap, REG_ESAI_RCR,
> +			   ESAI_xCR_xPR_MASK,
> +			   ESAI_xCR_xPR);
> +
> +	/* restore registers by regcache_sync */
> +	fsl_esai_register_restore(esai_priv);
> +

Both _init and _restore may fail given their declaration in 1/2 "ASoC: 
fsl_esai: Wrap some operations to be functions" yet here you simply 
ignore the return values.

If failure of said functions is permissive, it might be a good place for 
a comment.

Czarek