From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C5FDDC140 for ; Thu, 19 Oct 2023 21:29:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none X-Greylist: delayed 62 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 19 Oct 2023 14:29:04 PDT Received: from fgw22-7.mail.saunalahti.fi (fgw22-7.mail.saunalahti.fi [62.142.5.83]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C64A8106 for ; Thu, 19 Oct 2023 14:29:04 -0700 (PDT) Received: from localhost (88-113-24-34.elisa-laajakaista.fi [88.113.24.34]) by fgw22.mail.saunalahti.fi (Halon) with ESMTP id 5fac9ca2-6ec6-11ee-a9de-005056bdf889; Fri, 20 Oct 2023 00:27:58 +0300 (EEST) From: andy.shevchenko@gmail.com Date: Fri, 20 Oct 2023 00:27:58 +0300 To: AKASHI Takahiro Cc: sudeep.holla@arm.com, cristian.marussi@arm.com, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, linus.walleij@linaro.org, Oleksii_Moisieiev@epam.com, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org Subject: Re: [RFC v2 0/5] gpio: add pinctrl based generic gpio driver Message-ID: References: <20231005025843.508689-1-takahiro.akashi@linaro.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231005025843.508689-1-takahiro.akashi@linaro.org> Thu, Oct 05, 2023 at 11:58:38AM +0900, AKASHI Takahiro kirjoitti: > This is a revised version of my previous RFC[1]. Although I modified > the commits to make them look SCMI-independent, they are still posted > as RFC because I have never tested them on real hardware. > > (background) > I'm currently working on implementing SCMI pinctrl/gpio drivers > on U-Boot[2]. Although the pinctrl driver for the kernel[3] was submitted > by EPAM, it doesn't contain the gpio driver and I believe that we should > discuss a couple of points on the kernel side to finalize my design for > U-Boot. > > So this RFC is intended for reviews, especially to raise some issues. > > 1) how to obtain a value on an input pin > All the existing gpio drivers are set to obtain a value on an input > pin by accessing the hardware directly. In SCMI case, however, this is > just impossible in its nature and must be supported via a protocol > using "Input-value" configuration type. (See the spec[4], table-23.) > > The current pinconf framework is missing the feature (the pinconf > parameter and a helper function). See patch#1, #2 and #3. > > Please note that there is an issue around the pin configuration in > EPAM's current pinctrl driver as I commented[5]. > > 2) DT bindings > I would like to propose a generic binding for pinctrl based gpio driver. > This allows a "consumer" driver to handle gpio pins like as other > normal gpio controllers support. (patch#5) > > 3) generic GPIO driver > Based on (2), I tried to prototype a generic driver in patch#4. > Thanks to a set of existing pinctrl_gpio helper functions, except (1), > It seems that the driver can be implemented not relying on pin controller > specific code, at least for SCMI pinctrl. > > I will appreciate any comments. Any comment here: I'm listed as a designated reviewer of GPIO patches, why am I not Cc'ed on this? I definitely have some comments against the code (no DT, though). Please, use (up-to-date) MAINTAINERS in your v3. -- With Best Regards, Andy Shevchenko