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 81E7CC88CB2 for ; Mon, 12 Jun 2023 17:36:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232462AbjFLRgc (ORCPT ); Mon, 12 Jun 2023 13:36:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230165AbjFLRgF (ORCPT ); Mon, 12 Jun 2023 13:36:05 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75A163AA5; Mon, 12 Jun 2023 10:35:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686591307; x=1718127307; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=5WMQQbOARw55yzbpOK/Pk6hobT1SHUO/FQ3x65ntFcQ=; b=j2RxsKNG1eZMS+lULufT1KUkd+JB+Uy804emRn+Mai3nJF4P+C/GQVzm x42GpnMir6nrEGEVfV4dpqYLyi4FQHC4NcV+4bp5MAsuvm8sESupq0GAD vH971/LPpRHL2CACtX4N0fMO9rxa6hJAfM8a0CCBe/BvMMWY+QWwhfFCG h/0nhjsBWoGhyWCJUC6TkO4r4NobyRZ9C9ZLEzg185I4sHnzlVCAgxwml oXXY845CNhlFfYl9N1J6noXWVpJGLhzm/23Q0Mgv+CpUC3ayxEM+Nel4A xKzxWumlnOggIkfWxJJfJmpdUak3EyYlu4+5PkdwYMq9sJQek/xWMGe4+ w==; X-IronPort-AV: E=McAfee;i="6600,9927,10739"; a="337749672" X-IronPort-AV: E=Sophos;i="6.00,236,1681196400"; d="scan'208";a="337749672" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2023 10:32:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10739"; a="776474295" X-IronPort-AV: E=Sophos;i="6.00,236,1681196400"; d="scan'208";a="776474295" Received: from smile.fi.intel.com ([10.237.72.54]) by fmsmga008.fm.intel.com with ESMTP; 12 Jun 2023 10:32:38 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.96) (envelope-from ) id 1q8lPB-003GXT-0L; Mon, 12 Jun 2023 20:32:37 +0300 Date: Mon, 12 Jun 2023 20:32:36 +0300 From: Andy Shevchenko To: Geert Uytterhoeven Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Walleij , Bartosz Golaszewski , Alexander Stein Subject: Re: [rfc, rft, PATCH v1 1/1] gpio: aggregator: Introduce delay support for individual output pins Message-ID: References: <20230608162130.55015-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 09, 2023 at 09:11:04AM +0200, Geert Uytterhoeven wrote: > On Thu, Jun 8, 2023 at 6:23 PM Andy Shevchenko > wrote: > > The aggregator mode can also handle properties of the platform, that > > do not belong to the GPIO controller itself. One of such a property > > is signal delay line. Intdoduce support of it. > > > > Signed-off-by: Andy Shevchenko > > --- > > > > I don't like the idea of gpio-delay or similar. We have already GPIO > > aggregator that incorporates the GPIO proxy / forwarder functionality. > > I think this makes sense. Thank you for the support of the idea. ... > I hope no one ever needs to use the values from the example in the > bindings > > enable-gpios = <&enable_delay 0 130000 30000>; > > on a non-sleepable GPIO. Not only is a looping delay of 130 ms very bad > for system responsiveness, such large delays may not even be supported > on all systems (e.g. ARM implementation says < 2 ms). > So for large values, this should use mdelay(). > > This also applies to gpio-delay, of course. Thank you for pointing this out. I will think about better approach. Shan't we add a comment into DT bindings to warn users about this? -- With Best Regards, Andy Shevchenko