From patchwork Mon Feb 13 20:40:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Shevchenko X-Patchwork-Id: 653242 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 CA819C6379F for ; Mon, 13 Feb 2023 20:39:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229607AbjBMUjb (ORCPT ); Mon, 13 Feb 2023 15:39:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbjBMUja (ORCPT ); Mon, 13 Feb 2023 15:39:30 -0500 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 622671284B; Mon, 13 Feb 2023 12:39:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676320769; x=1707856769; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=89B8F9htL6Qei6aB89FjZiKtmN09XvKCxECHkIfzD7U=; b=IVaapr+CmWP5I+LrvCa71OigVxsAwRzBW9xsu3+x3IUhIW/U/zGCpcat PSYSPDvB7n5m4xMlurj9Ut8vEbv9THrQgONulA/zUiJ5fGcKR4sO2UrIU 7YC9sGBBprrVFnmgK/3kXgMhvvILqBhXa7OVLc2FzxbjiwtcmRISUVzuR ZYvUeRmj7Ykv8eU14QlL+/XRz2H9q5QGfLaM2ZejnXtrYSdQnElwcaQOD gRP6lAZ+jMngfbaL301cwbfS373usDHSEMytc4aERmXyr1yk7MlJ1XRYf m9ysHqYhJVvD5ztZmJwt/vlyrsxa/6VPrraIu0qkSDlaWcBdbhF0c1rRV g==; X-IronPort-AV: E=McAfee;i="6500,9779,10620"; a="358401414" X-IronPort-AV: E=Sophos;i="5.97,294,1669104000"; d="scan'208";a="358401414" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Feb 2023 12:39:29 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10620"; a="914470130" X-IronPort-AV: E=Sophos;i="5.97,294,1669104000"; d="scan'208";a="914470130" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga006.fm.intel.com with ESMTP; 13 Feb 2023 12:39:27 -0800 Received: by black.fi.intel.com (Postfix, from userid 1003) id D92F51A6; Mon, 13 Feb 2023 22:40:06 +0200 (EET) From: Andy Shevchenko To: Andy Shevchenko , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Mika Westerberg , "Rafael J. Wysocki" , Len Brown Subject: [PATCH v2 1/1] Documentation: firmware-guide: gpio-properties: Clarify Explicit and Implicit Date: Mon, 13 Feb 2023 22:40:05 +0200 Message-Id: <20230213204005.55483-1-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.39.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Clarify the Explicit and Implicit meanings in the table of Pull Bias. While at it, distinguish pull bias keywords used in ACPI by using bold font in the table of the respective terms. Signed-off-by: Andy Shevchenko --- v2: fixed formatting issues .../firmware-guide/acpi/gpio-properties.rst | 35 +++++++++++++------ 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/Documentation/firmware-guide/acpi/gpio-properties.rst b/Documentation/firmware-guide/acpi/gpio-properties.rst index eaec732cc77c..db0c0b1f3700 100644 --- a/Documentation/firmware-guide/acpi/gpio-properties.rst +++ b/Documentation/firmware-guide/acpi/gpio-properties.rst @@ -67,17 +67,30 @@ state of the output pin which driver should use during its initialization. Linux tries to use common sense here and derives the state from the bias and polarity settings. The table below shows the expectations: -========= ============= ============== -Pull Bias Polarity Requested... -========= ============= ============== -Implicit x AS IS (assumed firmware configured for us) -Explicit x (no _DSD) as Pull Bias (Up == High, Down == Low), - assuming non-active (Polarity = !Pull Bias) -Down Low as low, assuming active -Down High as low, assuming non-active -Up Low as high, assuming non-active -Up High as high, assuming active -========= ============= ============== ++-------------+-------------+-----------------------------------------------+ +| Pull Bias | Polarity | Requested... | ++=============+=============+===============================================+ +| Implicit | ++-------------+-------------+-----------------------------------------------+ +| **Default** | x | AS IS (assumed firmware configured it for us) | ++-------------+-------------+-----------------------------------------------+ +| Explicit | ++-------------+-------------+-----------------------------------------------+ +| **None** | x | AS IS (assumed firmware configured it for us) | +| | | with no Pull Bias | ++-------------+-------------+-----------------------------------------------+ +| **Up** | x (no _DSD) | | +| +-------------+ as high, assuming non-active | +| | Low | | +| +-------------+-----------------------------------------------+ +| | High | as high, assuming active | ++-------------+-------------+-----------------------------------------------+ +| **Down** | x (no _DSD) | | +| +-------------+ as low, assuming non-active | +| | High | | +| +-------------+-----------------------------------------------+ +| | Low | as low, assuming active | ++-------------+-------------+-----------------------------------------------+ That said, for our above example the both GPIOs, since the bias setting is explicit and _DSD is present, will be treated as active with a high