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From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>, Mark Brown <broonie@kernel.org>
Cc: <thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
	<lgirdwood@gmail.com>, <perex@perex.cz>, <tiwai@suse.com>,
	<mperttunen@nvidia.com>, <gregkh@linuxfoundation.org>,
	<sboyd@kernel.org>, <robh+dt@kernel.org>, <mark.rutland@arm.com>,
	<pdeschrijver@nvidia.com>, <pgaikwad@nvidia.com>,
	<spujar@nvidia.com>, <josephl@nvidia.com>,
	<daniel.lezcano@linaro.org>, <mmaddireddy@nvidia.com>,
	<markz@nvidia.com>, <devicetree@vger.kernel.org>,
	<linux-clk@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 12/19] ASoC: tegra: Add initial parent configuration for audio mclk
Date: Fri, 27 Dec 2019 13:19:59 -0800
Message-ID: <dbbce994-27f5-d949-078d-05646100e6be@nvidia.com> (raw)
In-Reply-To: <856d8a92-0c24-6722-952c-06b86c706e97@gmail.com>


On 12/27/19 6:56 AM, Dmitry Osipenko wrote:
> 25.12.2019 20:57, Mark Brown пишет:
>> On Mon, Dec 23, 2019 at 12:14:34AM +0300, Dmitry Osipenko wrote:
>>> 21.12.2019 01:26, Sowjanya Komatineni пишет:
>>>> Tegra PMC clock clk_out_1 is dedicated for audio mclk from Tegra30
>>>> through Tegra210 and currently Tegra clock driver does initial parent
>>>> configuration for audio mclk "clk_out_1" and enables them by default.
>> Please delete unneeded context from mails when replying.  Doing this
>> makes it much easier to find your reply in the message, helping ensure
>> it won't be missed by people scrolling through the irrelevant quoted
>> material.
> Ok
>
>>>> -	clk_disable_unprepare(data->clk_cdev1);
>>>> -	clk_disable_unprepare(data->clk_pll_a_out0);
>>>> -	clk_disable_unprepare(data->clk_pll_a);
>>>> +	if (__clk_is_enabled(data->clk_cdev1))
>>>> +		clk_disable_unprepare(data->clk_cdev1);
>>> The root of the problem is that you removed clocks enabling from
>>> tegra_asoc_utils_init().
currently, audio mclk and its parent clocks enabling are from clock 
driver init and not from tegra_asoc_utils_init.
>>> I'm not sure why clocks should be disabled during the rate-changing,
>>> probably this action is not really needed.
>> I know nothing about this particular device but this is not that
>> unusual a restriction for audio hardware, you often can't
>> robustly reconfigure the clocking for a device while it's active
>> due to issues in the hardware.  You often see issues with FIFOs
>> glitching or state machines getting stuck.  This may not be an
>> issue here but if it's something that's documented as a
>> requirement it's probably good to pay attention.
> I don't know details about that hardware either, maybe it is simply not
> safe to change PLL_A rate dynamically and then CLK_SET_RATE_GATE could
> be used.
>
> If nobody knows for sure, then will be better to keep
> tegra_asoc_utils_set_rate() unchanged.
plla rate change through tegra_asoc_utils_set_rate() happens only when 
there is not active playback or record corresponding to this sound device.

So, I don't see reason for disabling clock during rate change and not 
sure why we had this from the beginning.

Thierry/Sameer,

Can you please comment?

Yes, we can use CLK_SET_RATE_GATE for PLLA and remove clock disabling 
before rate change.


  reply index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-20 22:26 [PATCH v5 00/19] Move PMC clocks into Tegra PMC driver Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 01/19] dt-bindings: clock: tegra: Change CLK_M_DIV to OSC_DIV clocks Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 02/19] clk: tegra: Change CLK_M_DIV clocks " Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 03/19] clk: tegra: Fix Tegra PMC clock out parents Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 04/19] dt-bindings: tegra: Convert Tegra PMC bindings to YAML Sowjanya Komatineni
2019-12-26 23:23   ` Rob Herring
2019-12-20 22:26 ` [PATCH v5 05/19] dt-bindings: soc: tegra-pmc: Add Tegra PMC clock bindings Sowjanya Komatineni
2019-12-26 23:24   ` Rob Herring
2019-12-20 22:26 ` [PATCH v5 06/19] soc: tegra: Add Tegra PMC clocks registration into PMC driver Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 07/19] dt-bindings: soc: tegra-pmc: Add id for Tegra PMC 32KHz blink clock Sowjanya Komatineni
2019-12-22 21:55   ` Dmitry Osipenko
2019-12-27 21:30     ` Sowjanya Komatineni
2019-12-30 19:39       ` Dmitry Osipenko
2019-12-26 18:17   ` Rob Herring
2019-12-27 21:35     ` Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 08/19] soc: tegra: Add support for " Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 09/19] clk: tegra: Remove tegra_pmc_clk_init along with clk ids Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 10/19] dt-bindings: clock: tegra: Remove pmc clock ids from clock dt-bindings Sowjanya Komatineni
2019-12-20 22:26 ` [PATCH v5 11/19] ASoC: tegra: Use device managed resource APIs to get the clock Sowjanya Komatineni
2019-12-22 21:14   ` Dmitry Osipenko
2019-12-20 22:26 ` [PATCH v5 12/19] ASoC: tegra: Add initial parent configuration for audio mclk Sowjanya Komatineni
2019-12-22 21:14   ` Dmitry Osipenko
2019-12-22 21:18     ` Dmitry Osipenko
2019-12-27 21:25       ` Sowjanya Komatineni
2019-12-28 14:28         ` Dmitry Osipenko
2019-12-25 17:57     ` Mark Brown
2019-12-27 14:56       ` Dmitry Osipenko
2019-12-27 21:19         ` Sowjanya Komatineni [this message]
     [not found]           ` <b6ec6cfd-d883-ea28-00f8-884fa80cfee1@nvidia.com>
2020-01-02 16:12             ` Dmitry Osipenko
     [not found]               ` <fb252096-e101-7d21-9717-c23607ae6edd@nvidia.com>
2020-01-05  1:05                 ` Dmitry Osipenko
2020-01-05  5:03                   ` Sowjanya Komatineni
2020-01-06  4:21                     ` Sameer Pujar
2020-01-06 16:09                       ` Sowjanya Komatineni
     [not found]                         ` <33eb0b3e-5605-3dfd-a6ea-a50ae1348c86@nvidia.com>
2020-01-06 22:59                           ` Dmitry Osipenko
2019-12-27 22:48         ` Mark Brown
2019-12-20 22:26 ` [PATCH v5 13/19] ASoC: tegra: Add fallback implementation " Sowjanya Komatineni
2019-12-20 22:27 ` [PATCH v5 14/19] clk: tegra: Remove audio related clock enables from init_table Sowjanya Komatineni
2019-12-20 22:27 ` [PATCH v5 15/19] ARM: dts: tegra: Add clock-cells property to pmc Sowjanya Komatineni
2019-12-20 22:27 ` [PATCH v5 16/19] arm64: tegra: Add clock-cells property to Tegra PMC node Sowjanya Komatineni
2019-12-20 22:27 ` [PATCH v5 17/19] ARM: tegra: Update sound node clocks in device tree Sowjanya Komatineni
2019-12-20 22:27 ` [PATCH v5 18/19] arm64: tegra: smaug: Change clk_out_2 provider to pmc Sowjanya Komatineni
2019-12-22 22:00   ` Dmitry Osipenko
2019-12-27 21:32     ` Sowjanya Komatineni
2019-12-20 22:27 ` [PATCH v5 19/19] ASoC: nau8825: change Tegra clk_out_2 provider from tegra_car " Sowjanya Komatineni

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