linux-kernel - Re: [PATCH V3 2/2] ASoC: fsl_esai: recover the channel swap after xrun

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Message-ID: <20190710233605.GA9886@Asurada-Nvidia.nvidia.com>
Date:   Wed, 10 Jul 2019 16:36:06 -0700
From:   Nicolin Chen <nicoleotsuka@...il.com>
To:     shengjiu.wang@....com
Cc:     timur@...nel.org, 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 V3 2/2] ASoC: fsl_esai: recover the channel swap after
 xrun

Hi Shengjiu,

Mostly looks good to me, just some small comments.

On Mon, Jul 08, 2019 at 02:38:52PM +0800, shengjiu.wang@....com wrote:
  
> +static void fsl_esai_hw_reset(unsigned long arg)
> +{
> +	struct fsl_esai *esai_priv = (struct fsl_esai *)arg;
> +	u32 saisr, tfcr, rfcr;
> +	bool tx = true, rx = false, enabled[2];

Could we swap the lines of u32 and bool? It'd look better.

> +	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);

Let's add a line of comments for these two:
	/* Enforce ESAI personal resets for both TX and RX */

> +	/*
> +	 * Restore registers by regcache_sync, and ignore
> +	 * return value
> +	 */

Could fit into single-line?

> +	regmap_update_bits(esai_priv->regmap, REG_ESAI_TCR,
> +			   ESAI_xCR_xPR_MASK, 0);
> +	regmap_update_bits(esai_priv->regmap, REG_ESAI_RCR,
> +			   ESAI_xCR_xPR_MASK, 0);
> +
> +	regmap_update_bits(esai_priv->regmap, REG_ESAI_PRRC,
> +			   ESAI_PRRC_PDC_MASK, ESAI_PRRC_PDC(ESAI_GPIO));
> +	regmap_update_bits(esai_priv->regmap, REG_ESAI_PCRC,
> +			   ESAI_PCRC_PC_MASK, ESAI_PCRC_PC(ESAI_GPIO));

Could remove the blank line and add a line of comments:
	/* Remove ESAI personal resets by configuring PCRC and PRRC also */

Btw, I still feel this personal reset can be stuffed into one
of the wrapper functions. But let's keep this simple for now.

> +	regmap_read(esai_priv->regmap, REG_ESAI_SAISR, &saisr);

Why do we read saisr here? All its bits would get cleared by
the hardware reset. If it's a must to clear again, we should
add a line of comments to emphasize it.

Thank you