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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 70C05E784AF for ; Mon, 2 Oct 2023 09:33:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Io9MbsmKKqFmOx5TB8eoE2uIlqU6LQ5Zhs3z5T9Nyj8=; b=LLT/ZcGYanRYb2 u1ILQL6vg9yZcNG/UyCuGey9UTxjSs+Gy7nRsjxOtLFd88rpitk5IP1jF/2StzUWATrNvGwqpEQXS 464yPZgdO0U3VVpx+i9WAhHAGIrKCywVY5Bg/UiEdbAE4WK/wlAnLKk+pVnquMXeZGXBMKuSZNsme Cb7i5yCRzCwUffRC20+LqZs4KfZuFwEqS6pm1pIEsK2vfO1PigvmdUrhdxkuaJupUitwpe0nDM/mk dEole7SaoxU4Dr/7KjobtqkxzKjT+WEzQ7RKQVLN5bZVGRun9c7mkPfrbIorhhjE9rpJKreGeuCtc E47EmJd1WJ7QdC9SPq4Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qnFI3-00CEmA-0k; Mon, 02 Oct 2023 09:32:35 +0000 Received: from mgamail.intel.com ([192.55.52.115]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qnFI0-00CElH-0U for linux-arm-kernel@lists.infradead.org; Mon, 02 Oct 2023 09:32:34 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1696239152; x=1727775152; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=6GmsFUuqnSQcHUaemY2k1EPSCoudlb/4q0uxHkXHGLg=; b=dkf50AiPLPHlFSRjx8ih7Pt2PUbvcFb8GG8fBFlijAV6i9Tdd/9VopZ8 BhRJr3hedZRMYxNxSB2rZEBmFYYCjTLwMIPuMlm43nMBq7Hh8SdbIIgWu k+pNQmgNrtXFj5x7fF0pNI40zkiNK2sDB2SxtXMZMgzpnyIiRpUSDAlU1 BzNyivlOVXA/TTsOB5kPpEunkWyJtuN+qwSyEtpaeXySW9csZBexNPPdM yHNTpozNEX9cSB8sp3mhIN/78S8hc6BJmz0YaulIVJr0zToyaYcEc9a6Y nqBkNpCsNcWQD7kBkkoYAayu51LFDX5ZDauhnsDia6kQlCufH8UqWcPGi g==; X-IronPort-AV: E=McAfee;i="6600,9927,10850"; a="382515681" X-IronPort-AV: E=Sophos;i="6.03,194,1694761200"; d="scan'208";a="382515681" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2023 02:32:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10850"; a="1081591076" X-IronPort-AV: E=Sophos;i="6.03,194,1694761200"; d="scan'208";a="1081591076" Received: from smile.fi.intel.com ([10.237.72.54]) by fmsmga005.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2023 02:32:25 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.97-RC0) (envelope-from ) id 1qnFHq-000000027Vr-1phY; Mon, 02 Oct 2023 12:32:22 +0300 Date: Mon, 2 Oct 2023 12:32:22 +0300 From: Andy Shevchenko To: Kent Gibson Cc: Linus Walleij , Bartosz Golaszewski , Yury Norov , linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Shubhrajyoti Datta , Srinivas Neeli , Michal Simek , Bartosz Golaszewski , Rasmus Villemoes , Marek =?iso-8859-1?Q?Beh=FAn?= Subject: Re: [PATCH v1 5/5] gpiolib: cdev: Utilize more bitmap APIs Message-ID: References: <20230926052007.3917389-1-andriy.shevchenko@linux.intel.com> <20230926052007.3917389-6-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231002_023232_240090_B2508899 X-CRM114-Status: GOOD ( 27.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 02, 2023 at 05:25:05PM +0800, Kent Gibson wrote: > On Mon, Oct 02, 2023 at 12:05:11PM +0300, Andy Shevchenko wrote: > > On Wed, Sep 27, 2023 at 10:23:12PM +0800, Kent Gibson wrote: > > > On Wed, Sep 27, 2023 at 04:59:34PM +0300, Andy Shevchenko wrote: > > > > On Wed, Sep 27, 2023 at 09:49:35PM +0800, Kent Gibson wrote: > > > > > On Wed, Sep 27, 2023 at 03:17:06PM +0300, Andy Shevchenko wrote: > > > > > > On Wed, Sep 27, 2023 at 09:32:11AM +0800, Kent Gibson wrote: ... > > > > > > Yet, it opens a way to scale this in case we might have v3 ABI that let's say > > > > > > allows to work with 512 GPIOs at a time. With your code it will be much harder > > > > > > to achieve and see what you wrote about maintenance (in that case). > > > > > > > > > > v3 ABI?? libgpiod v2 is barely out the door! > > > > > Do you have any cases where 64 lines per request is limiting? > > > > > > > > IIRC it was SO question where the OP asks exactly about breaking the 64 lines > > > > limitation in the current ABI. > > > > > > > > > If that sort of speculation isn't premature optimisation then I don't know > > > > > what is. > > > > > > > > No, based on the real question / discussion, just have no link at hand. > > > > But it's quite a niche, I can agree. > > > > > > Let me know if you find a ref to that discussion - I'm curious. > > > > Here it is (read comments as well): > > https://stackoverflow.com/questions/76307370/control-gpio-from-linux-userspace-with-linux-gpio-h > > > > That question looks to me to be confusing how many GPIOs can be > requested per request (64) and in total (effectively unlimited) - thinking > they are the same. > That could be due to their desire to use the gpiod_chip_get_all_lines() > convenience function with a chip with more than 64 lines, rather than > because they have an actual need for the lines to be managed in a single > request. > > So that doesn't look like a genuine use case to me - just a "what if I > want to do X" question. Certainly not something that would warrant a v3 > ABI. Sure, and I'm not talking about v3 ABI to go for, see the word "might" in my reply in the first paragraph of this message. -- With Best Regards, Andy Shevchenko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel