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 69952C44512 for ; Thu, 16 Jul 2026 17:56:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=toxy2jG5k8rsmVjBC6umRfCjIF/9rl6IYwmcJggg3gc=; b=ANw1KJ0vv67PvlqghQsnDKIrbQ UN+vgdHFhqwvOk9zhMUpNik5rO84x0YSjbnvhD447Me0bIYRbKOSkWre4ZyLyZCraGwXcFt99EVMR WhV0pHeYtyLhvjMJWBY9tTdAkDOtdKhaV51KaITsjTBP+DkZ38KX913FLDXl9KS7eXj6FAdRytZZF JNJk37i3oi+eIHVuYeX+faFYBOCu/dZYBgtEmcm43PJjIgshsL3md7hEAwoya6vdZNw7VOBgXyTzl Okri62hXn4RLhYyAO/zImN3FZc1Mu+4rz+ZH9bnH0KDyEgFl17tS/zVw9bdCYOwFwKr4aRoRpgmC2 jWTPONtw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wkQKH-00000000KG9-3WX0; Thu, 16 Jul 2026 17:56:49 +0000 Received: from mgamail.intel.com ([198.175.65.13]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wkQKF-00000000KFY-1Piy; Thu, 16 Jul 2026 17:56:48 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1784224608; x=1815760608; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=JOhrs1OFvboDcLOeh8gPY/kmKk14v0E8LAeuat6Eybc=; b=N4XXRmqaeMNBUYUpyup/U/uYwhgjmDYWtA8kJGbF/irR7oBsdx4olCLr IXTgpI9wAhf5OpptkxAvPUIZnGkB8GTxwDLFwbWyrB6vYsl3q2ZEEFqlH WPNp5tC5p/pBkecJmdVwqDhERuObN4KTBePOdZzksnv/XKSLDCld8lmFo ZdusP1BRvBv4JyxLjASA72vUmYq4gy0Dl2W1LgVgIfkeN628iNjj/DNuA d70VATMJBOB1DpqufEcmjGdgTJmGDImJJ3wBFM4QoFNR4TdvpKYrqhwpW SuiF4BKo1c93vU2WzkaPF+FO/+QSPDJyu/JALaBETp+AAZH2+AwrzxeDf g==; X-CSE-ConnectionGUID: bV/Xezj3RYyChRatmuKahA== X-CSE-MsgGUID: uwMXjpKZQRaHhLZBsAHfMg== X-IronPort-AV: E=McAfee;i="6800,10657,11848"; a="96029972" X-IronPort-AV: E=Sophos;i="6.25,167,1779174000"; d="scan'208";a="96029972" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2026 10:56:47 -0700 X-CSE-ConnectionGUID: o44G+L4dSBaDIU9Jshoh0g== X-CSE-MsgGUID: dUnJTDUlRJ2uULcA2u/yFw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,167,1779174000"; d="scan'208";a="260160330" Received: from conormcd-mobl2.ger.corp.intel.com (HELO localhost) ([10.245.245.26]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2026 10:56:40 -0700 Date: Thu, 16 Jul 2026 20:56:38 +0300 From: Andy Shevchenko To: Michael Walle Cc: Yu-Chun Lin , Michael.Hennerich@analog.com, afaerber@suse.com, andy@kernel.org, brgl@kernel.org, conor+dt@kernel.org, cy.huang@realtek.com, devicetree@vger.kernel.org, dlechner@baylibre.com, james.tai@realtek.com, jic23@kernel.org, krzk+dt@kernel.org, lars@metafoo.de, linus.walleij@linaro.org, linusw@kernel.org, linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-realtek-soc@lists.infradead.org, mathieu.dubois-briand@bootlin.com, nuno.sa@analog.com, robh@kernel.org, stanley_chang@realtek.com, tychang@realtek.com, wbg@kernel.org Subject: Re: [PATCH v3 3/7] gpio: regmap: Add gpio_regmap_operation and write-enable support Message-ID: References: <20260716062614.1507243-1-eleanor.lin@realtek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260716_105647_439799_3EF349C6 X-CRM114-Status: GOOD ( 33.17 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jul 16, 2026 at 12:55:37PM +0200, Michael Walle wrote: > On Thu Jul 16, 2026 at 11:40 AM CEST, Andy Shevchenko wrote: > > On Thu, Jul 16, 2026 at 11:08:55AM +0200, Michael Walle wrote: > >> On Thu Jul 16, 2026 at 10:27 AM CEST, Andy Shevchenko wrote: > >> > On Thu, Jul 16, 2026 at 02:26:14PM +0800, Yu-Chun Lin wrote: ... > >> > From the above list I tend to the approach 2, but this might require to have > >> > GPIO regmap level of locking. I'm a bit lost in the context, though. I assume > >> > we need a fresh start, id est issue a v6 with approach 2 or 3 in place and > >> > summarize the choices in the cover letter, so we can understand what has been > >> > considered. > >> > >> I don't really like approach 3. You'd need to check if the regs of > >> both xlate calls are the same. With the sample code above, you > >> silently drop the first xlate'd reg. > > > > If I rank the proposals, the worst is #1, the best is #2. > > > >> And honestly, it really seems like a one-off. What controllers, are > >> there that need a write enable bit. The real problem seems to be > >> the assumption that we operate on just one bit. IOW we either set > >> mask or don't set mask in gpio_regmap_set(). > > > > Yes, we should KISS. > > But IMHO #2 and #3 are not KISS. Approach 2 is just a way of adding > some kind of pre op to a gpio set. Just tying it to a write enable > feature. That kinda bothers me. It might also be useful for other > things, too. So don't tie it to just write enable. And who is doing > a write disable if it's not self clearing for example. Probably Some > kind of post op :) > > Approach 3 is a way to change the value of the written value - in > a restricted way, as is is just doing a OR with both values. > > Also approach 2 might not even work if the hardware requires the > write enable bit set in the *same* write as the gpio set bit. Thus, > we might need both anyway in the future. > > >> For a more generic solution, we should be able to control the > >> written value. We could add another .value_xlate(). > > > > Maybe not now? > > But if not now, then when? I wouldn't add the write enable feature > and later a more generic solution which also covers the write enable > feature. Taking into account how it's done in HW, I think the whole approach can be folded to just a boolean flag (or a simply bit shift) in the config. Wouldn't it work? > > As per IPs, Synopsys IPs (not exactly GPIO) likes to > > have that kind of "protection". So, from HW perspective it's kinda > > pattern, and it might be possible to see more IPs (including GPIO) > > that follow it in some cases. -- With Best Regards, Andy Shevchenko