From: Markus Pargmann <mpa@pengutronix.de>
To: Shengjiu Wang <shengjiu.wang@freescale.com>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>,
timur@tabi.org, Li.Xiubo@freescale.com, lgirdwood@gmail.com,
broonie@kernel.org, perex@perex.cz, tiwai@suse.de,
alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V1] ASoC: fsl_ssi: refine ipg clock usage in this module
Date: Wed, 10 Sep 2014 12:53:59 +0200 [thread overview]
Message-ID: <20140910105359.GA16489@pengutronix.de> (raw)
In-Reply-To: <20140910103005.GB17326@audiosh1>
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Hi,
On Wed, Sep 10, 2014 at 06:30:06PM +0800, Shengjiu Wang wrote:
> On Wed, Sep 10, 2014 at 08:21:18AM +0200, Markus Pargmann wrote:
> > On Tue, Sep 09, 2014 at 11:38:05AM -0700, Nicolin Chen wrote:
> > > On Tue, Sep 09, 2014 at 05:18:07PM +0800, Shengjiu Wang wrote:
> > > > @@ -1321,7 +1333,11 @@ static int fsl_ssi_probe(struct platform_device *pdev)
> > > > return -ENOMEM;
> > > > }
> > > >
> > > > - ssi_private->regs = devm_regmap_init_mmio(&pdev->dev, iomem,
> > > > + if (ssi_private->soc->imx)
> > > > + ssi_private->regs = devm_regmap_init_mmio_clk(&pdev->dev,
> > > > + "ipg", iomem, &fsl_ssi_regconfig);
> > > > + else
> > > > + ssi_private->regs = devm_regmap_init_mmio(&pdev->dev, iomem,
> > >
> > > As Markus mentioned, the key point here is to be compatible with those
> > > non-clock-name platforms.
> > >
> > > I think it would be safer to keep the current code while adding an extra
> > > clk_disable_unprepare() at the end of probe() as a common routine. And
> > > meantime, make sure to have the call for imx only because it seems that
> > > the other platforms do not depend on the clock. //a bit guessing here :)
> > >
> > > Then we can get a patch like:
> > > open() {
> > > + clk_prepare_enable();
> > > ....
> > > }
> > >
> > > close() {
> > > ....
> > > + clk_disable_unprepare()
> > > }
> > >
> > > probe() {
> > > clk_get();
> > > clk_prepare_enable();
> > > ....
> > > if (xxx)
> > > - goto err_xx;
> > > + return ret;
> > > ....
> > > + clk_disable_unprepare();
> > > return 0;
> > > -err_xx:
> > > - clk_disable_unprepare()
> > > }
> > >
> > > remove() {
> > > ....
> > > - clk_disable_unprepare()
> > > }
> >
> > If I remember correctly, there may be AC97 communication with the codec
> > before any substream is created. That's why we enable the SSI unit right
> > at the beginning for AC97 in fsl_ssi_setup_reg_vals(). So we need to
> > check for AC97 before disabling clocks.
> >
> > Best regards,
> >
> > Markus
>
> hi Markus
>
> I think if clk_prepare_enable() in startup(), and clk_disable_unprepare()
> in shutdown can meet this requirement, right?
Yes that could work.
>
> done:
> if (ssi_private->dai_fmt)
> _fsl_ssi_set_dai_fmt(ssi_private, ssi_private->dai_fmt);
>
> I find that in end of probe, there is setting of dai_fmt. Can we remove this?
> because this setting need to enable ipg clock, and if ac97, ipg clock can't be
> disabled.
No you can't remove it. It is necessary for the DT property "fsl,mode".
Most dts do not have this property anymore because the sound cards are
setting the dai-fmt. But there are still some powerpc dts files that
contain that property.
Best regards,
Markus
--
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next prev parent reply other threads:[~2014-09-10 10:54 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-09 9:18 [PATCH V1] ASoC: fsl_ssi: refine ipg clock usage in this module Shengjiu Wang
2014-09-09 9:49 ` [alsa-devel] " Markus Pargmann
2014-09-09 9:55 ` Li.Xiubo
2014-09-09 11:27 ` Mark Brown
2014-09-09 18:03 ` Nicolin Chen
2014-09-09 18:15 ` Mark Brown
2014-09-09 18:41 ` Nicolin Chen
2014-09-09 13:17 ` Timur Tabi
2014-09-09 15:21 ` Mark Brown
2014-09-09 15:24 ` Timur Tabi
2014-09-09 18:38 ` Nicolin Chen
2014-09-09 19:37 ` Timur Tabi
2014-09-09 19:59 ` Nicolin Chen
2014-09-09 20:03 ` Timur Tabi
2014-09-09 20:27 ` Nicolin Chen
2014-09-09 20:37 ` Timur Tabi
2014-09-09 21:09 ` Nicolin Chen
2014-09-10 10:01 ` Shengjiu Wang
2014-09-10 6:21 ` Markus Pargmann
2014-09-10 6:42 ` [alsa-devel] " Nicolin Chen
2014-09-10 10:30 ` Shengjiu Wang
2014-09-10 10:53 ` Markus Pargmann [this message]
2014-09-10 8:12 ` Shengjiu Wang
2014-09-10 17:42 ` Nicolin Chen
2014-09-11 6:36 ` Markus Pargmann
2014-09-11 7:07 ` Shengjiu Wang
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