Subject: Re: [PATCH 1/2] ASoC: fsl_sai: Add clock control for SAI

From: Nicolin Chen <[email-masked]>
Date: Fri, 4 Apr 2014 17:28:05 +0800

Hi Xiubo,

On Fri, Apr 04, 2014 at 05:24:39PM +0800, Xiubo Li-B47053 wrote:
> Hi,
> 
> I have test this series on my Vybrid-TWR board and it works happily.

You just checked the wrong version. I've sent a mail to let people disregard
this version and a newer v2.

> 
> [...]
> > diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
> > index 3847d2a..2d749df 100644
> > --- a/sound/soc/fsl/fsl_sai.c
> > +++ b/sound/soc/fsl/fsl_sai.c
> > @@ -428,5 +428,18 @@ static int fsl_sai_startup(struct snd_pcm_substream
> > *substream,
> >  {
> >  	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
> > -	u32 reg;
> > +	struct device *dev = &sai->pdev->dev;
> > +	u32 reg, ret;
> > +
> 
> I'd prefer:
>   +	int ret;

Just like last time I said, it would be converted to 'int' any way. There's
no much difference between them.

> 
> > +	ret = clk_prepare_enable(sai->ipg_clk);
> > +	if (ret) {
> > +		dev_err(dev, "failed to prepare and enable ipg clock\n");
> > +		return ret;
> > +	}
> > +
> 
> [...]
> 
> > @@ -609,5 +630,5 @@ static int fsl_sai_probe(struct platform_device *pdev)
> > 
> >  	sai->regmap = devm_regmap_init_mmio_clk(&pdev->dev,
> > -			"sai", base, &fsl_sai_regmap_config);
> > +			"ipg", base, &fsl_sai_regmap_config);
> >  	if (IS_ERR(sai->regmap)) {
> >  		dev_err(&pdev->dev, "regmap init failed\n");
> > @@ -615,4 +636,16 @@ static int fsl_sai_probe(struct platform_device *pdev)
> >  	}
> > 
> > +	sai->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
> > +	if (IS_ERR(sai->ipg_clk)) {
> > +		dev_err(&pdev->dev, "failed to get ipg clock\n");
> > +		return PTR_ERR(sai->ipg_clk);
> > +	}
> > +
> 
> Since the 'ipg' clock is just intend to be used for registers accessing and
> We are using the regmap_init_mmio_clk(), so we can just drop it here and
> Let the regmap APIs to do the clock options properly.

This 'ipg' clock, which I renamed in v2 to 'bus clock', is not just used
in the way you said but also able to drive bit clock as your own code in
the fsl_sai_set_dai_sysclk_tr(), and as reference manual describes:

52.3.1.3 Bus clock
The bus clock is used by the control and configuration registers and to
generate synchronous interrupts and DMA requests.

Thanks,
Nicolin

> 
> Otherwise it look good to me.
> 
> After this:
> Acked-by: Xiubo Li <[email-masked]>
> 
> 
> 
> Thanks,
> 
> Brs,
> Xiubo
> 
> 
> 
> 
> > +	sai->sai_clk = devm_clk_get(&pdev->dev, "sai");
> > +	if (IS_ERR(sai->sai_clk)) {
> > +		dev_err(&pdev->dev, "failed to get sai clock\n");
> > +		return PTR_ERR(sai->sai_clk);
> > +	}
> > +
> >  	irq = platform_get_irq(pdev, 0);
> >  	if (irq < 0) {
> > diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h
> > index 677670d..cbaf114 100644
> > --- a/sound/soc/fsl/fsl_sai.h
> > +++ b/sound/soc/fsl/fsl_sai.h
> > @@ -127,4 +127,6 @@ struct fsl_sai {
> >  	struct platform_device *pdev;
> >  	struct regmap *regmap;
> > +	struct clk *ipg_clk;
> > +	struct clk *sai_clk;
> > 
> >  	bool big_endian_regs;
> > --
> > 1.8.4
> > 
>