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From: Shawn Guo <shawn.guo@freescale.com>
To: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: Shengjiu Wang <shengjiu.wang@freescale.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] ASoC: fsl_spdif: don't change the root clock rate of spdif in driver
Date: Wed, 17 Sep 2014 09:32:52 +0800	[thread overview]
Message-ID: <20140917013251.GA4796@dragon> (raw)
In-Reply-To: <20140916180028.GA6784@Asurada>

On Tue, Sep 16, 2014 at 11:19:28AM -0700, Nicolin Chen wrote:
> On Tue, Sep 16, 2014 at 07:46:34PM +0800, Shengjiu Wang wrote:
> > The spdif root clock may be used by other module or defined with
> > CLK_SET_RATE_GATE, so we can't change the clock rate in driver.
> > In this patch remove the clk_set_rate and clk_round_rate to protect the
> > clock.
> 
> It's a quite convenient and conservative way to remove the clock
> dealing code in the driver, however, it may result less flexible
> functionalities.
> 
> The reason why I left the clk_set_rate() in the driver is to hope
> we may find a better way to tackle those tough situations. For IP
> itself, it doesn't matter if the clock the SoC provides to it is
> being shared by other modules or not.
> 
> So I think, if it's a shared clock, we should not define it as a
> rate-changeable one in the SoC level, as we might still have some
> SoCs provide a dedicated clock to S/PDIF so as to get the maximum
> range of clock support for users.
> 
> @Shawn
> Sorry to involve you in this topic. I'm not so sure if we can do
> this in the clock driver so that the clock rate would be fixed
> even if the driver is trying to change it. If we can, I think we
> may use a better solution here instead.

No, we do not have anything like that today.

Shawn

WARNING: multiple messages have this Message-ID (diff)
From: Shawn Guo <shawn.guo@freescale.com>
To: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: Shengjiu Wang <shengjiu.wang@freescale.com>,
	alsa-devel@alsa-project.org, lgirdwood@gmail.com, tiwai@suse.de,
	linux-kernel@vger.kernel.org, broonie@kernel.org, timur@tabi.org,
	perex@perex.cz, Li.Xiubo@freescale.com,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] ASoC: fsl_spdif: don't change the root clock rate of spdif in driver
Date: Wed, 17 Sep 2014 09:32:52 +0800	[thread overview]
Message-ID: <20140917013251.GA4796@dragon> (raw)
In-Reply-To: <20140916180028.GA6784@Asurada>

On Tue, Sep 16, 2014 at 11:19:28AM -0700, Nicolin Chen wrote:
> On Tue, Sep 16, 2014 at 07:46:34PM +0800, Shengjiu Wang wrote:
> > The spdif root clock may be used by other module or defined with
> > CLK_SET_RATE_GATE, so we can't change the clock rate in driver.
> > In this patch remove the clk_set_rate and clk_round_rate to protect the
> > clock.
> 
> It's a quite convenient and conservative way to remove the clock
> dealing code in the driver, however, it may result less flexible
> functionalities.
> 
> The reason why I left the clk_set_rate() in the driver is to hope
> we may find a better way to tackle those tough situations. For IP
> itself, it doesn't matter if the clock the SoC provides to it is
> being shared by other modules or not.
> 
> So I think, if it's a shared clock, we should not define it as a
> rate-changeable one in the SoC level, as we might still have some
> SoCs provide a dedicated clock to S/PDIF so as to get the maximum
> range of clock support for users.
> 
> @Shawn
> Sorry to involve you in this topic. I'm not so sure if we can do
> this in the clock driver so that the clock rate would be fixed
> even if the driver is trying to change it. If we can, I think we
> may use a better solution here instead.

No, we do not have anything like that today.

Shawn

WARNING: multiple messages have this Message-ID (diff)
From: Shawn Guo <shawn.guo@freescale.com>
To: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: Shengjiu Wang <shengjiu.wang@freescale.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] ASoC: fsl_spdif: don't change the root clock rate of spdif in driver
Date: Wed, 17 Sep 2014 09:32:52 +0800	[thread overview]
Message-ID: <20140917013251.GA4796@dragon> (raw)
In-Reply-To: <20140916180028.GA6784@Asurada>

On Tue, Sep 16, 2014 at 11:19:28AM -0700, Nicolin Chen wrote:
> On Tue, Sep 16, 2014 at 07:46:34PM +0800, Shengjiu Wang wrote:
> > The spdif root clock may be used by other module or defined with
> > CLK_SET_RATE_GATE, so we can't change the clock rate in driver.
> > In this patch remove the clk_set_rate and clk_round_rate to protect the
> > clock.
> 
> It's a quite convenient and conservative way to remove the clock
> dealing code in the driver, however, it may result less flexible
> functionalities.
> 
> The reason why I left the clk_set_rate() in the driver is to hope
> we may find a better way to tackle those tough situations. For IP
> itself, it doesn't matter if the clock the SoC provides to it is
> being shared by other modules or not.
> 
> So I think, if it's a shared clock, we should not define it as a
> rate-changeable one in the SoC level, as we might still have some
> SoCs provide a dedicated clock to S/PDIF so as to get the maximum
> range of clock support for users.
> 
> @Shawn
> Sorry to involve you in this topic. I'm not so sure if we can do
> this in the clock driver so that the clock rate would be fixed
> even if the driver is trying to change it. If we can, I think we
> may use a better solution here instead.

No, we do not have anything like that today.

Shawn

  parent reply	other threads:[~2014-09-17  1:32 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-16 11:46 [PATCH] ASoC: fsl_spdif: don't change the root clock rate of spdif in driver Shengjiu Wang
2014-09-16 11:46 ` Shengjiu Wang
2014-09-16 11:46 ` Shengjiu Wang
2014-09-16 18:19 ` Nicolin Chen
2014-09-16 18:19   ` Nicolin Chen
2014-09-16 18:19   ` Nicolin Chen
2014-09-16 18:32   ` Mark Brown
2014-09-16 18:32     ` Mark Brown
2014-09-17  1:32   ` Shawn Guo [this message]
2014-09-17  1:32     ` Shawn Guo
2014-09-17  1:32     ` Shawn Guo
2014-09-17  2:24     ` Nicolin Chen
2014-09-17  2:24       ` Nicolin Chen
2014-09-17  2:24       ` Nicolin Chen
2014-09-17  2:31       ` Shawn Guo
2014-09-17  2:31         ` Shawn Guo
2014-09-17  2:31         ` Shawn Guo
2014-09-17  2:50         ` Nicolin Chen
2014-09-17  2:50           ` Nicolin Chen
2014-09-17  2:50           ` Nicolin Chen

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