From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Lukasz Majewski <lukma@denx.de>
Cc: Timur Tabi <timur@tabi.org>, Xiubo Li <Xiubo.Lee@gmail.com>,
Fabio Estevam <fabio.estevam@nxp.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>,
alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.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: Mon, 4 Sep 2017 22:06:03 -0700 [thread overview]
Message-ID: <20170905050602.GA2774@Asurada-CZ80> (raw)
In-Reply-To: <1504436701-20700-1-git-send-email-lukma@denx.de>
On Sun, Sep 03, 2017 at 01:05:01PM +0200, Lukasz Majewski wrote:
> The problem is visible in the following setup (on the imx6q):
> "simple-audio-card" -> ssi2 -> I2S + I2C -> codec
>
> The function call log (simple-card probe -> CONFIG_SND_SIMPLE_CARD):
>
> asoc_simple_card_init_dai() @ sound/soc/generic/simple-card-utils.c
> snd_soc_dai_set_sysclk()
> fsl_ssi_set_dai_sysclk() @ sound/soc/fsl/fsl_ssi.c
>
> The last call is changing the bit clock (BCLK) frequency to SSI's IP
> block clock (ipg = 66 MHz) [1].
I think a bigger question here is why the routine sets BCLK to 66MHz.
> This is wrong, since IMX SSI block requires the I2S BCLK to be less
> than 1/5 of [1].
>
> As a result the driver initialization passes without any errors, but the
> speaker-test test case breaks.
>
> This commit checks if the fsl_ssi_set_dai_sysclk() frequency passed is
> not equal to [1].
I don't feel it's quite comprehensive...what if it's being set to 67MHz.
Thanks
Nicolin
> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> ---
> sound/soc/fsl/fsl_ssi.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
> index 173cb84..1186fa9 100644
> --- a/sound/soc/fsl/fsl_ssi.c
> +++ b/sound/soc/fsl/fsl_ssi.c
> @@ -809,6 +809,8 @@ static int fsl_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
> int clk_id, unsigned int freq, int dir)
> {
> struct fsl_ssi_private *ssi_private = snd_soc_dai_get_drvdata(cpu_dai);
> + if (clk_get_rate(ssi_private->clk) == freq)
> + return 0;
>
> ssi_private->bitclk_freq = freq;
>
> --
> 2.1.4
>
next prev parent reply other threads:[~2017-09-05 5:06 UTC|newest]
Thread overview: 27+ 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
[not found] ` <AM5PR0401MB262706674539BFE651706CC6E3900@AM5PR0401MB2627.eurprd04.prod.outlook.com>
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
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 [this message]
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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