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Message-ID: <20140915102224.GA23877@audiosh1>
Date: Mon, 15 Sep 2014 18:22:27 +0800
From: Shengjiu Wang <shengjiu.wang@...escale.com>
To: Markus Pargmann <mpa@...gutronix.de>
CC: <timur@...i.org>, <nicoleotsuka@...il.com>,
<Li.Xiubo@...escale.com>, <lgirdwood@...il.com>,
<broonie@...nel.org>, <perex@...ex.cz>, <tiwai@...e.de>,
<alsa-devel@...a-project.org>, <linuxppc-dev@...ts.ozlabs.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3] ASoC: fsl_ssi: refine ipg clock usage in this module
On Mon, Sep 15, 2014 at 12:05:41PM +0200, Markus Pargmann wrote:
> On Fri, Sep 12, 2014 at 06:35:15PM +0800, Shengjiu Wang wrote:
> > Check if ipg clock is in clock-names property, then we can move the
> > ipg clock enable and disable operation to startup and shutdown, that
> > is only enable ipg clock when ssi is working and keep clock is disabled
> > when ssi is in idle.
> > But when the checking is failed, remain the clock control as before.
> >
> > Signed-off-by: Shengjiu Wang <shengjiu.wang@...escale.com>
> > ---
> > V3 change log:
> > update patch according Nicolin and markus's comments
> >
> >
> > sound/soc/fsl/fsl_ssi.c | 53 ++++++++++++++++++++++++++++++++++++++++-------
> > 1 file changed, 45 insertions(+), 8 deletions(-)
> >
> > diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
> > index 2fc3e66..6d1dfd5 100644
> > --- a/sound/soc/fsl/fsl_ssi.c
> > +++ b/sound/soc/fsl/fsl_ssi.c
> > @@ -169,6 +169,7 @@ struct fsl_ssi_private {
> > u8 i2s_mode;
> > bool use_dma;
> > bool use_dual_fifo;
> > + bool has_ipg_clk_name;
> > unsigned int fifo_depth;
> > struct fsl_ssi_rxtx_reg_val rxtx_reg_val;
> >
> > @@ -530,6 +531,11 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
> > struct snd_soc_pcm_runtime *rtd = substream->private_data;
> > struct fsl_ssi_private *ssi_private =
> > snd_soc_dai_get_drvdata(rtd->cpu_dai);
> > + int ret;
> > +
> > + ret = clk_prepare_enable(ssi_private->clk);
> > + if (ret)
> > + return ret;
> >
> > /* When using dual fifo mode, it is safer to ensure an even period
> > * size. If appearing to an odd number while DMA always starts its
> > @@ -544,6 +550,21 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
> > }
> >
> > /**
> > + * fsl_ssi_shutdown: shutdown the SSI
> > + *
> > + */
> > +static void fsl_ssi_shutdown(struct snd_pcm_substream *substream,
> > + struct snd_soc_dai *dai)
> > +{
> > + struct snd_soc_pcm_runtime *rtd = substream->private_data;
> > + struct fsl_ssi_private *ssi_private =
> > + snd_soc_dai_get_drvdata(rtd->cpu_dai);
> > +
> > + clk_disable_unprepare(ssi_private->clk);
> > +
> > +}
> > +
> > +/**
> > * fsl_ssi_set_bclk - configure Digital Audio Interface bit clock
> > *
> > * Note: This function can be only called when using SSI as DAI master
> > @@ -1043,6 +1064,7 @@ static int fsl_ssi_dai_probe(struct snd_soc_dai *dai)
> >
> > static const struct snd_soc_dai_ops fsl_ssi_dai_ops = {
> > .startup = fsl_ssi_startup,
> > + .shutdown = fsl_ssi_shutdown,
> > .hw_params = fsl_ssi_hw_params,
> > .hw_free = fsl_ssi_hw_free,
> > .set_fmt = fsl_ssi_set_dai_fmt,
> > @@ -1168,17 +1190,22 @@ static int fsl_ssi_imx_probe(struct platform_device *pdev,
> > u32 dmas[4];
> > int ret;
> >
> > - ssi_private->clk = devm_clk_get(&pdev->dev, NULL);
> > + if (ssi_private->has_ipg_clk_name)
> > + ssi_private->clk = devm_clk_get(&pdev->dev, "ipg");
> > + else
> > + ssi_private->clk = devm_clk_get(&pdev->dev, NULL);
> > if (IS_ERR(ssi_private->clk)) {
> > ret = PTR_ERR(ssi_private->clk);
> > dev_err(&pdev->dev, "could not get clock: %d\n", ret);
> > return ret;
> > }
> >
> > - ret = clk_prepare_enable(ssi_private->clk);
> > - if (ret) {
> > - dev_err(&pdev->dev, "clk_prepare_enable failed: %d\n", ret);
> > - return ret;
> > + if (!ssi_private->has_ipg_clk_name) {
> > + ret = clk_prepare_enable(ssi_private->clk);
> > + if (ret) {
> > + dev_err(&pdev->dev, "clk_prepare_enable failed: %d\n", ret);
> > + return ret;
> > + }
> > }
> >
> > /* For those SLAVE implementations, we ingore non-baudclk cases
> > @@ -1236,8 +1263,9 @@ static int fsl_ssi_imx_probe(struct platform_device *pdev,
> > return 0;
> >
> > error_pcm:
> > - clk_disable_unprepare(ssi_private->clk);
> >
> > + if (!ssi_private->has_ipg_clk_name)
> > + clk_disable_unprepare(ssi_private->clk);
> > return ret;
> > }
> >
> > @@ -1246,7 +1274,8 @@ static void fsl_ssi_imx_clean(struct platform_device *pdev,
> > {
> > if (!ssi_private->use_dma)
> > imx_pcm_fiq_exit(pdev);
> > - clk_disable_unprepare(ssi_private->clk);
> > + if (!ssi_private->has_ipg_clk_name)
> > + clk_disable_unprepare(ssi_private->clk);
> > }
> >
> > static int fsl_ssi_probe(struct platform_device *pdev)
> > @@ -1321,8 +1350,16 @@ static int fsl_ssi_probe(struct platform_device *pdev)
> > return -ENOMEM;
> > }
> >
> > - ssi_private->regs = devm_regmap_init_mmio(&pdev->dev, iomem,
> > + ret = of_property_match_string(np, "clock-names", "ipg");
> > + if (ret < 0) {
> > + ssi_private->has_ipg_clk_name = false;
> > + ssi_private->regs = devm_regmap_init_mmio(&pdev->dev, iomem,
> > &fsl_ssi_regconfig);
>
> Sorry if I was unclear about that. My suggestion was to enable the clock
> right here:
> clk_prepare_enable(ssi_private->clk);
>
> Then you can remove ssi_private->has_ipg_clk_name and all
> clk_prepare_enable() and clk_disable_unprepare() from above. Also you
> can move the devm_clk_get() into this block.
>
ipg clock not only need to be enabled when accessing register, but also
need to be enabled when ssi is working. So I add clk_enable in startup.
> It seems you really want to implement this for devicetrees where the
> "ipg" clock-name is missing, but I don't understand why? I really can't
> see any benefit of adding all these clk_prepare_enable() calls for all
> cornercases that may occure. For example the clocks for AC97 are still
> missing in this version.
When ipg clock-name is missing, I just remain the code logic as before.
So AC97 case is same as before too.
When have ipg clock-name, register it to regmap for accessing register,
and enabling ipg clock in startup also is useful for AC97.
I don't understand why you think clock for AC97 is still missing?
wang shengjiu
>
> Best regards,
>
> Markus
>
> > + } else {
> > + ssi_private->has_ipg_clk_name = true;
> > + ssi_private->regs = devm_regmap_init_mmio_clk(&pdev->dev,
> > + "ipg", iomem, &fsl_ssi_regconfig);
> > + }
> > if (IS_ERR(ssi_private->regs)) {
> > dev_err(&pdev->dev, "Failed to init register map\n");
> > return PTR_ERR(ssi_private->regs);
> > --
> > 1.7.9.5
> >
> >
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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