From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolin Chen Subject: Re: [PATCH] ASoC: cs42888: Add codec driver support Date: Tue, 25 Feb 2014 00:06:49 +0800 Message-ID: <20140224160648.GC6132@MrMyself> References: <1393224929-7555-1-git-send-email-Guangyu.Chen@freescale.com> <20140224113011.GE25940@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from tx2outboundpool.messaging.microsoft.com (tx2ehsobe003.messaging.microsoft.com [65.55.88.13]) by alsa0.perex.cz (Postfix) with ESMTP id 59145261A22 for ; Mon, 24 Feb 2014 17:18:41 +0100 (CET) Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: "Austin, Brian" Cc: "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "alsa-devel@alsa-project.org" , "pawel.moll@arm.com" , "ijc+devicetree@hellion.org.uk" , Mark Brown , "linux-doc@vger.kernel.org" , Liam Girdwood , "Handrigan, Paul" , "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" , "rob@landley.net" , "galak@codeaurora.org" , "grant.likely@linaro.org" List-Id: alsa-devel@alsa-project.org T24gTW9uLCBGZWIgMjQsIDIwMTQgYXQgMDM6NTI6MjRQTSArMDAwMCwgQXVzdGluLCBCcmlhbiB3 cm90ZToKPiA+PiArCWlmICghSVNfRVJSKGNzNDI4ODgtPmNsaykpCj4gPj4gKwkJY2xrX2Rpc2Fi bGVfdW5wcmVwYXJlKGNzNDI4ODgtPmNsayk7Cj4gPiAKPiA+IERvZXMgdGhlIGRldmljZSB3b3Jr IHdpdGhvdXQgTUNMSz8KPiBZZXMsIE1DTEsgaXMgcmVxdWlyZWQuIElmIHlvdSBjYW7igJl0IGdl dCB0aGUgY2xvY2sgeW91IHNob3VsZCBlcnJvciBvdXQuCgpXYWl0Li4uUmVnYXJkaW5nIHRoaXMg Y2xvY2sgcGFydCwgSSBqdXN0IGZvcmdvdCB0aGUgcmVhc29uIEkgcHV0IHRoZSBjb2RlOgoKMzg1 ICAgICAgICAgY3M0Mjg4OC0+Y2xrID0gZGV2bV9jbGtfZ2V0KCZpMmMtPmRldiwgIm1jbGsiKTsK Mzg2ICAgICAgICAgaWYgKElTX0VSUihjczQyODg4LT5jbGspKQozODcgICAgICAgICAgICAgICAg IGRldl93YXJuKCZpMmMtPmRldiwgImZhaWxlZCB0byBnZXQgdGhlIGNsb2NrOiAlbGRcbiIsCjM4 OCAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgIFBUUl9FUlIoY3M0Mjg4OC0+Y2xrKSk7 Cgp3YXMgYmVjYXVzZSB0aGUgTUNMSyBtaWdodCBiZSBwcm92aWRlZCBmcm9tIFNvQyAoREFJIG1h c3Rlcikgc28gaXQgY291bGQKYmUgdG90YWxseSBjb250cm9sbGVkIGJ5IENQVSBEQUkgZHJpdmVy LCBFU0FJIGZvciBleGFtcGxlIGhhcyBpdHMgb3duCmRpdmlkZXJzIHRvIGRlcml2ZSB0aGUgSENL VCBjbG9jayAoTUNMSyBmb3IgVHgpIGZyb20gYWhiIGNsb2NrIGluIFNvQwpjbG9jayB0cmVlLCBp biB3aGljaCBjYXNlIHdlIG1pZ2h0IG5vdCBlYXNpbHkgcGFzcyBhIHZhbGlkIGNsb2NrIHBoYW5k bGUKdmlhIERULiAoUkZDIHRvIHRoaXMgdGhvdWdodC4pCgpUaGFuayB5b3UsCk5pY29saW4gQ2hl bgoKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCkFsc2Et ZGV2ZWwgbWFpbGluZyBsaXN0CkFsc2EtZGV2ZWxAYWxzYS1wcm9qZWN0Lm9yZwpodHRwOi8vbWFp bG1hbi5hbHNhLXByb2plY3Qub3JnL21haWxtYW4vbGlzdGluZm8vYWxzYS1kZXZlbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752941AbaBXQTv (ORCPT ); Mon, 24 Feb 2014 11:19:51 -0500 Received: from [65.55.88.14] ([65.55.88.14]:53393 "EHLO tx2outboundpool.messaging.microsoft.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751867AbaBXQTs convert rfc822-to-8bit (ORCPT ); Mon, 24 Feb 2014 11:19:48 -0500 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: -2 X-BigFish: VS-2(zz98dIc89bh1432Izz1f42h2148h208ch1ee6h1de0h1fdah2073h2146h1202h1e76h2189h1d1ah1d2ah21bch1fc6hzzz2dh2a8h839h93fhd25hd2bhf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h1ad9h1b0ah1b2fh2222h224fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1fe8h1ff5h209eh2216h22d0h2336h2438h2461h2487h24d7h2516h2545h255eh1155h) Date: Tue, 25 Feb 2014 00:06:49 +0800 From: Nicolin Chen To: "Austin, Brian" CC: Mark Brown , "Handrigan, Paul" , "robh+dt@kernel.org" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "rob@landley.net" , Liam Girdwood , "grant.likely@linaro.org" , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "alsa-devel@alsa-project.org" Subject: Re: [PATCH] ASoC: cs42888: Add codec driver support Message-ID: <20140224160648.GC6132@MrMyself> References: <1393224929-7555-1-git-send-email-Guangyu.Chen@freescale.com> <20140224113011.GE25940@sirena.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Content-Transfer-Encoding: 8BIT X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 24, 2014 at 03:52:24PM +0000, Austin, Brian wrote: > >> + if (!IS_ERR(cs42888->clk)) > >> + clk_disable_unprepare(cs42888->clk); > > > > Does the device work without MCLK? > Yes, MCLK is required. If you can’t get the clock you should error out. Wait...Regarding this clock part, I just forgot the reason I put the code: 385 cs42888->clk = devm_clk_get(&i2c->dev, "mclk"); 386 if (IS_ERR(cs42888->clk)) 387 dev_warn(&i2c->dev, "failed to get the clock: %ld\n", 388 PTR_ERR(cs42888->clk)); was because the MCLK might be provided from SoC (DAI master) so it could be totally controlled by CPU DAI driver, ESAI for example has its own dividers to derive the HCKT clock (MCLK for Tx) from ahb clock in SoC clock tree, in which case we might not easily pass a valid clock phandle via DT. (RFC to this thought.) Thank you, Nicolin Chen