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From: Nicolin Chen <nicoleotsuka@gmail•com>
To: "Łukasz Majewski" <lukma@denx•de>
Cc: Fabio Estevam <fabio.estevam@nxp•com>,
	Timur Tabi <timur@tabi•org>, Xiubo Li <Xiubo.Lee@gmail•com>,
	Liam Girdwood <lgirdwood@gmail•com>,
	Mark Brown <broonie@kernel•org>, Jaroslav Kysela <perex@perex•cz>,
	Takashi Iwai <tiwai@suse•com>,
	"festevam@gmail•com" <festevam@gmail•com>,
	"alsa-devel@alsa-project•org" <alsa-devel@alsa-project•org>,
	"linuxppc-dev@lists•ozlabs.org" <linuxppc-dev@lists•ozlabs.org>,
	"linux-kernel@vger•kernel.org" <linux-kernel@vger•kernel.org>
Subject: Re: [PATCH] sound: soc: fsl: Do not set DAI sysclk when it is equal to system freq
Date: Tue, 5 Sep 2017 11:11:09 -0700	[thread overview]
Message-ID: <20170905181108.GB23906@Asurada-Nvidia> (raw)
In-Reply-To: <819784e1-910b-6833-997a-2097e147bd0c@denx.de>

On Tue, Sep 05, 2017 at 10:35:34AM +0200, Łukasz Majewski wrote:

> >And apparently, we shouldn't set bitclk to 66MHz either. Can
> >you help to find where this 66MHz comes from?

> 2. int asoc_simple_card_init_dai() @ simple-card-utils.c

Oh, I just searched in the simple-card.c but missed this file.

> In this function (point 2.) the
> simple_dai->sysclk is set and:
> snd_soc_dai_set_sysclk(dai, 0, simple_dai->sysclk, 0)
> which sets frequency to 66 MHz [*].
> 
> The asoc_simple_card_init_dai() is called in
> asoc_simple_card_dai_init() @ simple-card.c
> which is assigned to dai_link->init
> dai_link->init		= asoc_simple_card_dai_init; @ simple_card.c
> 
> And the sysclk itself is defined at:
> -------------------------------------
> dai_props->codec_dai->sysclk, which is used at:a

Why codec_dai? Why not dai_props->cpu_dai->sysclk since we are talking
about SSI?

> asoc_simple_card_startup(), asoc_simple_card_shutdown() and others
> functions at simple-card.c
> It is setup at:
> asoc_simple_card_parse_clk() @ simple-card-utils.c from macro:
> #define asoc_simple_card_parse_clk_cpu()
> And the problem is:
> -------------------
> 
> At the
> asoc_simple_card_parse_clk()
> we finally go to dts node:
> /soc/aips-bus@02100000/i2c@021a0000/tfa9879@6C

This tfa9879 should be the CODEC right?

> which has clock from I2C (66 MHz).

You mean I2C scl or I2S sclk?

-----------------------------------------------------------------

But anyway, I feel very confused here as you have 66MHz clock rate
(regardless of it purpose) for a codec dai but it's been passed to
a cpu dai (SSI).

> [*] - I could workaround this problem by setting:
> 
> system-clock-frequency = <0> in
> 
> 			dailink_master: cpu {
> 			    sound-dai = <&ssi2>;
> 			};
> 
> but this is IMHO even worse hack.... than this patch.

I haven't used simple-card for a while so I forgot how to define
its DT bindings specifically. But you should assign ssi2 as the
CPU dai and assign tfa9879 as a CODEC dai.

  reply	other threads:[~2017-09-05 18:10 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-03 11:05 [PATCH] sound: soc: fsl: Do not set DAI sysclk when it is equal to system freq Lukasz Majewski
2017-09-03 12:44 ` Fabio Estevam
2017-09-03 14:40   ` Łukasz Majewski
2017-09-03 15:29     ` Fabio Estevam
2017-09-05  5:20     ` Nicolin Chen
2017-09-05  8:35       ` Łukasz Majewski
2017-09-05 18:11         ` Nicolin Chen [this message]
2017-09-05 21:13           ` Łukasz Majewski
2017-09-05 22:52             ` Nicolin Chen
2017-09-06  9:22               ` Łukasz Majewski
2017-09-06 17:33                 ` Nicolin Chen
2017-09-06 18:35                   ` Łukasz Majewski
2017-09-06 19:47                     ` Nicolin Chen
2017-09-06 21:18                       ` Łukasz Majewski
2017-09-07 23:10                       ` Łukasz Majewski
2017-09-08  0:39                         ` Nicolin Chen
2017-09-05 23:20             ` Fabio Estevam
2017-09-06  8:44               ` Łukasz Majewski
2017-09-05 20:14         ` Fabio Estevam
2017-09-05 21:14           ` Łukasz Majewski
2017-09-05  5:06 ` Nicolin Chen
2017-09-05  7:37   ` Łukasz Majewski
2017-09-05  7:52     ` Nicolin Chen
2017-09-05  8:19       ` Łukasz Majewski
2017-09-05 15:15         ` Mark Brown
2017-09-05 17:45           ` Nicolin Chen
2017-09-07 13:44             ` Mark Brown
2017-09-07 23:03               ` Nicolin Chen

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