From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-x244.google.com (mail-pg0-x244.google.com [IPv6:2607:f8b0:400e:c05::244]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3xmZS33DxMzDqZ9 for ; Tue, 5 Sep 2017 15:06:11 +1000 (AEST) Received: by mail-pg0-x244.google.com with SMTP id m9so1340256pgd.0 for ; Mon, 04 Sep 2017 22:06:10 -0700 (PDT) Date: Mon, 4 Sep 2017 22:06:03 -0700 From: Nicolin Chen To: Lukasz Majewski Cc: Timur Tabi , Xiubo Li , Fabio Estevam , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , 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 Message-ID: <20170905050602.GA2774@Asurada-CZ80> References: <1504436701-20700-1-git-send-email-lukma@denx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1504436701-20700-1-git-send-email-lukma@denx.de> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 > --- > 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 >