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

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Date:   Thu, 11 Jul 2019 06:09:53 +0000
From:   "S.j. Wang" <shengjiu.wang@....com>
To:     Nicolin Chen <nicoleotsuka@...il.com>
CC:     "timur@...nel.org" <timur@...nel.org>,
        "Xiubo.Lee@...il.com" <Xiubo.Lee@...il.com>,
        "festevam@...il.com" <festevam@...il.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-kernel@...r.kernel.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.

This line can be removed. 

Best regards
Wang Shengjiu