From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CFCEC433F5 for ; Tue, 4 Sep 2018 16:02:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DDF3520645 for ; Tue, 4 Sep 2018 16:02:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="h+3XiWyu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDF3520645 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=ti.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727836AbeIDU2M (ORCPT ); Tue, 4 Sep 2018 16:28:12 -0400 Received: from lelv0142.ext.ti.com ([198.47.23.249]:36304 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726259AbeIDU2M (ORCPT ); Tue, 4 Sep 2018 16:28:12 -0400 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id w84G2Frq102234; Tue, 4 Sep 2018 11:02:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1536076935; bh=cbApl1W+nnVWF5fbiUL2sXm91NjJQQVYdmsVKNChgYE=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=h+3XiWyu1A6nh+aCJFlaosbV6O9QI6MbSavAQ2cIyT/f1tz6Ldu8nk4ia2KjIY9Wt 27Taxl217htccDQO1PnRXmgUFZHEdqMEHLJ0Goy3Ezh0geps+9rTvjpmXFoyZKlFJs NdBd9fkpBfv9r5TLMggOBju1UY9lLhQaMgWBj3jw= Received: from DLEE109.ent.ti.com (dlee109.ent.ti.com [157.170.170.41]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id w84G2Fdx000842; Tue, 4 Sep 2018 11:02:15 -0500 Received: from DLEE113.ent.ti.com (157.170.170.24) by DLEE109.ent.ti.com (157.170.170.41) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1466.3; Tue, 4 Sep 2018 11:02:15 -0500 Received: from dflp33.itg.ti.com (10.64.6.16) by DLEE113.ent.ti.com (157.170.170.24) with Microsoft SMTP Server (version=TLS1_0, cipher=TLS_RSA_WITH_AES_256_CBC_SHA) id 15.1.1466.3 via Frontend Transport; Tue, 4 Sep 2018 11:02:14 -0500 Received: from [172.22.184.106] (ileax41-snat.itg.ti.com [10.172.224.153]) by dflp33.itg.ti.com (8.14.3/8.13.8) with ESMTP id w84G2EOC023236; Tue, 4 Sep 2018 11:02:14 -0500 Subject: Re: [PATCH] ASoC: tlv320aic31xx: Add MICBIAS off setting To: Mark Brown CC: Liam Girdwood , Rob Herring , Mark Rutland , , , References: <20180831180507.28867-1-afd@ti.com> <20180903112656.GF10302@sirena.org.uk> <701a066c-33e1-4476-7403-fdb9a3c366d8@ti.com> <20180904144159.GC12993@sirena.org.uk> <7163381a-ae09-ad3b-064d-990c98f13ccb@ti.com> <20180904145503.GD12993@sirena.org.uk> <85973bf4-1acb-1731-d93e-29c8141a3c53@ti.com> <20180904155655.GJ12993@sirena.org.uk> From: "Andrew F. Davis" Message-ID: <5e7fdb87-651d-6056-9323-7a29573b6300@ti.com> Date: Tue, 4 Sep 2018 11:02:14 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180904155655.GJ12993@sirena.org.uk> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/04/2018 10:56 AM, Mark Brown wrote: > On Tue, Sep 04, 2018 at 10:10:24AM -0500, Andrew F. Davis wrote: >> On 09/04/2018 09:55 AM, Mark Brown wrote: > >>> you get to keep the pieces" territory. If we really want to have a way >>> of explicitly specifying that some widgets should never be turned on >>> then it feels like rather than have something device and widget specific >>> like this we should instead have a higher level way of doing that which >>> can be applied to any widget, that is something that could be useful >>> especially with things like speaker drivers where there's real potential >>> for physical damage to the system. > >> Not sure how that could even look, it would need to be in DT as only >> that layer knows the connections, but then the it would also have to >> have internal knowledge of the widgets used in the driver.. > > We already have a bunch of DT code that knows about and uses the > external widgets the device has (which are I'd guess the only ones where > this is an issue)? I was thinking just have a property that lists the > widgets that should never be turned on. > >>> Like I said in my original reply I'm also worried that this will break >>> existing boards by causing them to change to a voltage of 0 when they >>> had managed to end up with the default of 2V which happened to work for >>> them. > >> Then only time this could happen is if they specified MICBIAS_OFF in DT >> but got the default 2v instead. In which case, yes, the behavior would >> change, but it would also be changing to the correct behavior. We can't >> avoid fixing code on the off chance someone depended on the broken >> behavior, no progress could ever be made. > > I'm really having a lot of trouble seeing MICBIAS_OFF as a useful > voltage to specify in DT in the first place. > I don't see the usefulness in specifying any bias voltage in DT at all, it is a configuration and can be made at runtime, it has no place in DT. But it is already here, so lets allow all available voltages a board may need and the CODEC can supply, even 0.