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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D76DC433F5 for ; Thu, 10 Mar 2022 20:10:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244608AbiCJULK (ORCPT ); Thu, 10 Mar 2022 15:11:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240295AbiCJULH (ORCPT ); Thu, 10 Mar 2022 15:11:07 -0500 Received: from metanate.com (unknown [IPv6:2001:8b0:1628:5005::111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D912B9BBAA for ; Thu, 10 Mar 2022 12:10:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=metanate.com; s=stronger; h=In-Reply-To:Content-Type:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description; bh=EudowKxfuxNie/ZjDfg6vUBWXj6aFVtwbByn8cDt7u0=; b=KLfK5 LOPvlCEY+dbh4fbpastBX+zfJn5iFUDHcdp+MUaGJd5qE9DZWpDNYguBfD7VQtiWoXPch/2af1BPo 9N/bXphDDYVXm7QWcFOWTlx/wAohslHDHNewkmh+dq/7vIUGvISsGltk3Bi8/k7z8Saf+n51heS+k +QImFLyPlJ3vlXVX2wlVKWauAClsOHiGF1hRHuxuwaN5BvgKiPrh1yyKLVUD+uHMMt83ZCO80Pa6T yQt9ZYB056GPJz7MgCafSaTxvWm0Fu4n3WlaZXFnKYmsm+ShpX1KrOeStWLL9HTWvRSFOKztcaHPr jHrlLpTaAwL5rAEaRIML00ecOT8JQ==; Received: from [81.174.171.191] (helo=donbot) by email.metanate.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nSP6Z-0001lX-L2; Thu, 10 Mar 2022 20:09:47 +0000 Date: Thu, 10 Mar 2022 20:09:42 +0000 From: John Keeping To: Mark Brown Cc: alsa-devel@alsa-project.org, Liam Girdwood , Jaroslav Kysela , Takashi Iwai , Daniel Beer , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] ASoC: tas5805m: fix pdn polarity Message-ID: References: <20220309135649.195277-1-john@metanate.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Authenticated: YES Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 09, 2022 at 09:55:40PM +0000, Mark Brown wrote: > On Wed, Mar 09, 2022 at 08:16:07PM +0000, John Keeping wrote: > > On Wed, Mar 09, 2022 at 04:28:30PM +0000, Mark Brown wrote: > > > > I think the device tree binding needs to be clarified here to be > > > explicit about this since there's obviously some room for user confusion > > > here. We can probably get away with a change at this point since it's > > > not hit a release but we do need to try to avoid the situation where any > > > other implementations use active high polarity for the bindings. > > > Taking a quick survey of the other devices that have a pdn-gpios > > property: > > > - tvp5150 is correct with the driver setting 0 to make the device active > > > - tas571x also sets 0 to make the device active > > > - ak4375 uses the opposite sense setting PDN = 1 to make the device > > active; this has no in-tree users and was merged as part of v5.17-rc1 > > so it's not in a released kernel yet > > Sure, I still think it would be good to update the binding document to > clarify things as part of your patch - the binding currently just has it > as the "pdn" pin not the /pdn pin or anything. I've been thinking about this but I can't really think what to say. tas571x's binding says: GPIO specifier for the TAS571x's active low powerdown line Is that the sort of wording you have in mind? To me it seems like a general principle that the GPIO_ACTIVE_{HIGH,LOW} flags should be used to indicate how the pin works so that the driver consistently uses logical levels regardless of how the hardware is wired. >From the driver point of view pdn-gpios is effectively reset-gpios by another name and it's pretty consistent that setting a reset GPIO to 1 means the device is inaccessible. Maybe this just means I'm approaching this "down" from the software abstraction more than "up" from the hardware.