From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752517AbdIFJW7 (ORCPT ); Wed, 6 Sep 2017 05:22:59 -0400 Received: from mail-out.m-online.net ([212.18.0.9]:49317 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752167AbdIFJWz (ORCPT ); Wed, 6 Sep 2017 05:22:55 -0400 X-Auth-Info: jSvD4mFyhcNe4aPzEQsEw2DRVhwXjqoMNw6zin+Nz/w= Subject: Re: [PATCH] sound: soc: fsl: Do not set DAI sysclk when it is equal to system freq To: Nicolin Chen Cc: Fabio Estevam , Timur Tabi , Xiubo Li , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , "festevam@gmail.com" , "alsa-devel@alsa-project.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" References: <1504436701-20700-1-git-send-email-lukma@denx.de> <07e54d28-3bbc-aad2-146b-30867c0bc337@denx.de> <20170905052031.GB2774@Asurada-CZ80> <819784e1-910b-6833-997a-2097e147bd0c@denx.de> <20170905181108.GB23906@Asurada-Nvidia> <20170905225225.GA14132@Asurada-Nvidia> From: =?UTF-8?Q?=c5=81ukasz_Majewski?= Organization: DENX Message-ID: Date: Wed, 6 Sep 2017 11:22:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170905225225.GA14132@Asurada-Nvidia> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Nicolin, > On Tue, Sep 05, 2017 at 11:13:40PM +0200, Łukasz Majewski wrote: > >> They key point here is the asoc_simple_card_parse_clk() function >> from simple-card-utils.c >> >> Please look how the clock is assigned; It first checks for cpu >> clock, then for "system-clock-frequency" DTS node and _finally_ >> looks for another "child" clock [1], which is the codec attached to >> I2C. > > Here is the routine that I understood from the code: > 1) asoc_simple_card_parse_clk_cpu(dev, cpu, dai_link, cpu_dai); > => asoc_simple_card_parse_clk(dev, cpu, // cpu node in sound{} [1] > dai_link->cpu_of_node, // node ssi2 [2] > cpu_dai, dai_link->cpu_dai_name); > ==> 1.1) devm_get_clk_from_child(dev, node, NULL); // [1] > ==> 1.2) of_property_read_u32(node, "system-clock-frequency", &val)// [1] > ==> 1.3) devm_get_clk_from_child(dev, dai_of_node, NULL); // [2] > > 2) asoc_simple_card_parse_clk_codec(dev, codec, dai_link, codec_dai); > => asoc_simple_card_parse_clk(dev, codec, // codec node in sound{} [3] > dai_link->codec_of_node,// node tfa9879 [4] > codec_dai, dai_link->codec_dai_name); > ==> 2.1) devm_get_clk_from_child(dev, node, NULL); // [3] > ==> 2.2) of_property_read_u32(node, "system-clock-frequency", &val)// [3] > ==> 2.3) devm_get_clk_from_child(dev, dai_of_node, NULL); // [4] > > For the cpu routine, it first checks for clock property under cpu > node of simple-card, then for "system-clock-frequency" in the cpu > node of simple-card, and finally looks for clock property in ssi2 > node. I've double checked this and the simple_dai->sysclk is assigned in the asoc_simple_card_parse_clk() -----> dev: sound -----> clk node: /soc/aips-bus@02000000/spba-bus@02000000/ssi@0202c000 -----> Clk asignment And this clock is taken from this node. It looks like ipg clock for ssi... > > For codec routine, it first checks for clock property under codec > node of simple-card, then for "system-clock-frequency" in codec > node of simple-card, and finally looks for clock property in the > tfa9879 node. > > The cpu and codec are totally separate, aren't they? And I don't > think it's right if not. Yes, they should be separated. > >>>> which has clock from I2C (66 MHz). >>> >>> You mean I2C scl or I2S sclk? >> >> I2C scl. > > A couple of things here..... > 1) I don't think I2C scl can run at 66MHz...The 66MHz is probably > the ipg clock of I2C controller. I agree. I2C scl runs with 400 kHz (as recommended by I2C high speed spec). And considering above, the 66 MHz clock seems to be from ssi IP block. > 2) Even if the scl does run at 66MHz, there is no point in passing > the clock of I2C scl into an I2S dai-link. Yes. > > So I feel something must be wrong. I suggest you to add some printk > to check the names of those nodes and x_of_node in the simple card > driver. The problem is with the "lack" of clock nodes/properties at dailink_master: cpu { sound-dai = <&ssi2>; clock = <&SSSS>; system-clock-frequency = ; }; and as a result we take some "default" clock. > >> My DTS [1] (it is different than other in-tree supported codecs - at >> least I did not find similar setup in DTSes): >> >> sound { >> compatible = "simple-audio-card"; >> label = "tfa9879-mono"; >> >> simple-audio-card,dai-link { >> /* DAC */ >> format = "i2s"; >> bitclock-master = <&dailink_master>; >> frame-master = <&dailink_master>; >> >> dailink_master: cpu { >> sound-dai = <&ssi2>; >> }; >> codec { >> sound-dai = <&codec>; >> }; >> }; > > I remember there is another style for a single dai-link. Could you > please try that one? There is an example in: > Documentation/devicetree/bindings/sound/simple-card.txt Yes, the simple-audio-card,cpu simple-audio-card,format, .... etc. I've omitted it since in the code it is regarded as "old": (simple-card.c line 384). > I think that the proper solution would be to add check for: freq < sysclk/5 in fsl_ssi_set_dai_sysclk() and return -ENOTSUPP to make the simple-audo-card driver happy (and not introducing regressions). -- Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de