From patchwork Mon Oct 2 02:15:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AKASHI Takahiro X-Patchwork-Id: 729092 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 A104DE784A6 for ; Mon, 2 Oct 2023 02:17:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235059AbjJBCRM (ORCPT ); Sun, 1 Oct 2023 22:17:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234505AbjJBCRM (ORCPT ); Sun, 1 Oct 2023 22:17:12 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7F5BCE for ; Sun, 1 Oct 2023 19:17:08 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id 98e67ed59e1d1-273e3d8b57aso3507266a91.0 for ; Sun, 01 Oct 2023 19:17:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1696213028; x=1696817828; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=6b76Ych1HnNWX1i2+SMCurFq8JmPkRVbgEKvHul6Y6M=; b=HOzAakugpT5jH49+zsnPAoGSrzC4RQyW/9VDM64hsVYCKqErk5vj91prWqv4SNRaKJ 5+FTn+BahMoYmBzhLezqiIKWLSb7H/caYdDYpoOv1CMyO5OXnc9iVuKmoQA0IGjtm2GT iXvc6meL4x0AxeRFVNWsmyfEvp99k/T8QCA9wilnwLQ6LgoI7RWSQ1/Q6/l1orzeZVV9 SeQxYOnwFlOF37n3nG65k8ZZY6pnCVFWfpBfGjpeI/nPkILxYQDHjuhW8WmAvX/65mAu 5JuSP3JWhWahRncrRMmbxi2100BIvGWYRep7oGmMrPSKJhPPjWiAl6sYi3RiaEv73ajE h9QA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696213028; x=1696817828; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=6b76Ych1HnNWX1i2+SMCurFq8JmPkRVbgEKvHul6Y6M=; b=v6hXtcOsMCVPlWAhGhomYedc9OqBe1FAFtyBYiFK5ANKKdkFbKkD7CHGNuakUusosO S9W77Zps9+iqzMPHG/hhw47V3Yu2EczU43n7KUdqjvpd+H2e/ylkawKMeyYL5+a2Za0v 4+mdzRetDnv7UocvYsEekx39sM0zJ4Glv00OUzaCeAn7QjAO8Y2bsp119gzLmg8xamFx +W0sJU3YrtFdsmXm4Fi+qsS7Gg9A7hWyoMKu3ht4xbS615ZVexA5sJsj7L6jBv1riEeC iv9tPLb6RprwsFl6Wfq8aD2zHbmk8R8G809bM7ig+zod5QVNujBguvcid7I0KJH3V9Rb zasA== X-Gm-Message-State: AOJu0YzpDWm8AM9DG7mulT5gOOwosMJi5E7xq1aX4m6tvjo9S+968uji yIWs1g5pfs6+DgZyho3+jRGfTA== X-Google-Smtp-Source: AGHT+IG7F7GjhJnFomtH628B6eLxLuj4n7S9f0mGkASawyhxSQzyDo06i0YtDgv7Hzddo0DyTk9qvw== X-Received: by 2002:a17:90a:242:b0:263:730b:f568 with SMTP id t2-20020a17090a024200b00263730bf568mr9141074pje.3.1696213028338; Sun, 01 Oct 2023 19:17:08 -0700 (PDT) Received: from octopus.. ([2400:4050:c3e1:100:7ab1:199:d138:f054]) by smtp.gmail.com with ESMTPSA id mg11-20020a17090b370b00b002609cadc56esm5278319pjb.11.2023.10.01.19.17.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Oct 2023 19:17:08 -0700 (PDT) From: AKASHI Takahiro To: 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 Cc: Oleksii_Moisieiev@epam.com, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, AKASHI Takahiro Subject: [RFC 0/4] gpio: add SCMI pinctrl based driver Date: Mon, 2 Oct 2023 11:15:58 +0900 Message-Id: <20231002021602.260100-1-takahiro.akashi@linaro.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org I'm currently working on implementing SCMI pinctrl/gpio drivers on U-Boot[1]. Although the pinctrl driver for the kernel[2] 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. (Please note that I have *never* tested the code because I don't have any real hardware to test SCMI on it.) 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[3], table-23.) The current pinconf framework is missing the feature (the pinconf parameter and a helper function). See patch#1 and #2. Please note that there is an issue around the pin configuration in EPAM's current pinctrl driver as I commented[4]. 2) DT bindings I would like to propose a generic binding for SCMI pinctrl based gpio driver. This allows a "consumer" driver to handle gpio input pins like as other normal gpio controllers provide. (patch#4) 3) generic GPIO driver Based on (2), I tried to prototype a generic driver in patch#3. As you can see, there is no SCMI-specific line of code as a set of existing helper functions, except (1), seem to be enough to implement required interfaces. So I'm not sure whether the driver should has a "compatibles" property of "arm,scmi-gpio-generic". I will appreciate any comments. -Takahiro Akashi [1] https://lists.denx.de/pipermail/u-boot/2023-September/529765.html [2] https://lkml.iu.edu/hypermail/linux/kernel/2308.1/01082.html [3] https://developer.arm.com/documentation/den0056/ [4] https://lkml.iu.edu/hypermail/linux/kernel/2308.2/07483.html AKASHI Takahiro (4): pinctrl: define PIN_CONFIG_INPUT pinctrl: add pinctrl_gpio_get_config() gpio: scmi: add SCMI pinctrl based gpio driver dt-bindings: gpio: Add bindings for SCMI pinctrl based gpio .../bindings/gpio/arm,scmi-gpio.yaml | 71 ++++++++ drivers/gpio/Kconfig | 8 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-scmi.c | 154 ++++++++++++++++++ drivers/pinctrl/core.c | 19 +++ include/linux/pinctrl/consumer.h | 8 + include/linux/pinctrl/pinconf-generic.h | 3 + 7 files changed, 264 insertions(+) create mode 100644 Documentation/devicetree/bindings/gpio/arm,scmi-gpio.yaml create mode 100644 drivers/gpio/gpio-scmi.c