From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id E3BB57D2F0 for ; Fri, 29 Mar 2019 00:14:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728690AbfC2AMr (ORCPT ); Thu, 28 Mar 2019 20:12:47 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:40702 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728684AbfC2AMr (ORCPT ); Thu, 28 Mar 2019 20:12:47 -0400 Received: by mail-pf1-f194.google.com with SMTP id c207so146824pfc.7; Thu, 28 Mar 2019 17:12:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9UpI7O5lQwSfUmmY+yeBJ3QKa1u/yRDi0jCHPskrx3o=; b=NJfntTxOCdeBHU8NGBtBiikIJ+97XCZlI71cbPKdrb2auAtErjwSrwVosYuCEatY4O 7cZGL8fEV4Kvur126FcT2Qb8KNORIPHMUTt6odEmxysesy9JoLOoi3wnjs/kBjbZwKyU 2+H7tFvIvNMMDZOMHOq8YkoxDa50E31nbWFfj8CRXHzARt5BEStK5IU+7qbjgKa90Dey YImTzp4bcEqWtH5wZhl463/c0ecLwVPtcOwJB7mHqc+EZetaXj8jON7s0nwCy4JcAHWI icGcXo9GRFUCddBgq1JvJoM5R02QajMvEoqjS/d9zjVot/oyxaXZvokHcLjo7iUMl6D7 xyhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9UpI7O5lQwSfUmmY+yeBJ3QKa1u/yRDi0jCHPskrx3o=; b=s4hvqPk50oCDhlOIvdpxD6ylZ18YrdbY3Aff5pOzagMGD66KU6xTKBZWn+Z6A1NcXc tvvfvvG3q2VGJkQuSFYdqLEo3H7Qt7Gn60aqvc7S6sHJRwJSju+tAcemPXVru243sTen M8e0wa/ZuzCbCNcziN8YKsLOdUwgWR97XvQUfEuYtTBTgbjxHbdhgI9/yXLJtIiw0i9/ n6ENAq0g8shGj+ar9ridQK1V1kdN/9ptlk4j/WMmFUYIemM97m0LNBZZPry1kE7nJunF upDfVi2DsJ3G9VWgEhfl8kZ1S5eZq6T2KV0OBHMAAVf3YquBRjfEdA3L2RqYydiNzpOf tsbA== X-Gm-Message-State: APjAAAX+eDjBnxwiqACvxeUcaLlc3nOvGfUAhqveeR/eYurE4I3Hp6oQ 6r+8GG9TzPeDctUH2Uu5fHc= X-Google-Smtp-Source: APXvYqwnQS2Eg9fTwvfqCPsys3GRnHqqqi9Z/WVcpl3mi4YerBKWIVRY048SX+ltG+p9LTP/JitMxQ== X-Received: by 2002:a65:5941:: with SMTP id g1mr13390379pgu.51.1553818366177; Thu, 28 Mar 2019 17:12:46 -0700 (PDT) Received: from localhost.localdomain ([104.238.181.70]) by smtp.gmail.com with ESMTPSA id f125sm432488pfc.91.2019.03.28.17.12.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Mar 2019 17:12:44 -0700 (PDT) From: Changbin Du To: Jonathan Corbet Cc: rjw@rjwysocki.net, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Changbin Du Subject: [PATCH v2 08/24] acpi doc: convert acpi/gpio-properties.txt to rst format Date: Fri, 29 Mar 2019 08:11:19 +0800 Message-Id: <20190329001135.15847-9-changbin.du@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190329001135.15847-1-changbin.du@gmail.com> References: <20190329001135.15847-1-changbin.du@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du --- ...pio-properties.txt => gpio-properties.rst} | 78 +++++++++++-------- Documentation/acpi/index.rst | 1 + MAINTAINERS | 2 +- 3 files changed, 46 insertions(+), 35 deletions(-) rename Documentation/acpi/{gpio-properties.txt => gpio-properties.rst} (81%) diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.rst similarity index 81% rename from Documentation/acpi/gpio-properties.txt rename to Documentation/acpi/gpio-properties.rst index 88c65cb5bf0a..89c636963544 100644 --- a/Documentation/acpi/gpio-properties.txt +++ b/Documentation/acpi/gpio-properties.rst @@ -1,5 +1,8 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== _DSD Device Properties Related to GPIO --------------------------------------- +====================================== With the release of ACPI 5.1, the _DSD configuration object finally allows names to be given to GPIOs (and other things as well) returned @@ -8,7 +11,7 @@ the corresponding GPIO, which is pretty error prone (it depends on the _CRS output ordering, for example). With _DSD we can now query GPIOs using a name instead of an integer -index, like the ASL example below shows: +index, like the ASL example below shows:: // Bluetooth device with reset and shutdown GPIOs Device (BTH) @@ -34,15 +37,19 @@ index, like the ASL example below shows: }) } -The format of the supported GPIO property is: +The format of the supported GPIO property is:: Package () { "name", Package () { ref, index, pin, active_low }} - ref - The device that has _CRS containing GpioIo()/GpioInt() resources, - typically this is the device itself (BTH in our case). - index - Index of the GpioIo()/GpioInt() resource in _CRS starting from zero. - pin - Pin in the GpioIo()/GpioInt() resource. Typically this is zero. - active_low - If 1 the GPIO is marked as active_low. +ref + The device that has _CRS containing GpioIo()/GpioInt() resources, + typically this is the device itself (BTH in our case). +index + Index of the GpioIo()/GpioInt() resource in _CRS starting from zero. +pin + Pin in the GpioIo()/GpioInt() resource. Typically this is zero. +active_low + If 1 the GPIO is marked as active_low. Since ACPI GpioIo() resource does not have a field saying whether it is active low or high, the "active_low" argument can be used here. Setting @@ -55,7 +62,7 @@ It is possible to leave holes in the array of GPIOs. This is useful in cases like with SPI host controllers where some chip selects may be implemented as GPIOs and some as native signals. For example a SPI host controller can have chip selects 0 and 2 implemented as GPIOs and 1 as -native: +native:: Package () { "cs-gpios", @@ -67,7 +74,7 @@ native: } Other supported properties --------------------------- +========================== Following Device Tree compatible device properties are also supported by _DSD device properties for GPIO controllers: @@ -78,7 +85,7 @@ _DSD device properties for GPIO controllers: - input - line-name -Example: +Example:: Name (_DSD, Package () { // _DSD Hierarchical Properties Extension UUID @@ -100,7 +107,7 @@ Example: - gpio-line-names -Example: +Example:: Package () { "gpio-line-names", @@ -114,7 +121,7 @@ See Documentation/devicetree/bindings/gpio/gpio.txt for more information about these properties. ACPI GPIO Mappings Provided by Drivers --------------------------------------- +====================================== There are systems in which the ACPI tables do not contain _DSD but provide _CRS with GpioIo()/GpioInt() resources and device drivers still need to work with @@ -139,16 +146,16 @@ line in that resource starting from zero, and the active-low flag for that line, respectively, in analogy with the _DSD GPIO property format specified above. For the example Bluetooth device discussed previously the data structures in -question would look like this: +question would look like this:: -static const struct acpi_gpio_params reset_gpio = { 1, 1, false }; -static const struct acpi_gpio_params shutdown_gpio = { 0, 0, false }; + static const struct acpi_gpio_params reset_gpio = { 1, 1, false }; + static const struct acpi_gpio_params shutdown_gpio = { 0, 0, false }; -static const struct acpi_gpio_mapping bluetooth_acpi_gpios[] = { - { "reset-gpios", &reset_gpio, 1 }, - { "shutdown-gpios", &shutdown_gpio, 1 }, - { }, -}; + static const struct acpi_gpio_mapping bluetooth_acpi_gpios[] = { + { "reset-gpios", &reset_gpio, 1 }, + { "shutdown-gpios", &shutdown_gpio, 1 }, + { }, + }; Next, the mapping table needs to be passed as the second argument to acpi_dev_add_driver_gpios() that will register it with the ACPI device object @@ -158,12 +165,12 @@ calling acpi_dev_remove_driver_gpios() on the ACPI device object where that table was previously registered. Using the _CRS fallback ------------------------ +======================= If a device does not have _DSD or the driver does not create ACPI GPIO mapping, the Linux GPIO framework refuses to return any GPIOs. This is because the driver does not know what it actually gets. For example if we -have a device like below: +have a device like below:: Device (BTH) { @@ -177,7 +184,7 @@ have a device like below: }) } -The driver might expect to get the right GPIO when it does: +The driver might expect to get the right GPIO when it does:： desc = gpiod_get(dev, "reset", GPIOD_OUT_LOW); @@ -193,22 +200,25 @@ the ACPI GPIO mapping tables are hardly linked to ACPI ID and certain objects, as listed in the above chapter, of the device in question. Getting GPIO descriptor ------------------------ +======================= + +There are two main approaches to get GPIO resource from ACPI:: -There are two main approaches to get GPIO resource from ACPI: - desc = gpiod_get(dev, connection_id, flags); - desc = gpiod_get_index(dev, connection_id, index, flags); + desc = gpiod_get(dev, connection_id, flags); + desc = gpiod_get_index(dev, connection_id, index, flags); We may consider two different cases here, i.e. when connection ID is provided and otherwise. -Case 1: - desc = gpiod_get(dev, "non-null-connection-id", flags); - desc = gpiod_get_index(dev, "non-null-connection-id", index, flags); +Case 1:: + + desc = gpiod_get(dev, "non-null-connection-id", flags); + desc = gpiod_get_index(dev, "non-null-connection-id", index, flags); + +Case 2:: -Case 2: - desc = gpiod_get(dev, NULL, flags); - desc = gpiod_get_index(dev, NULL, index, flags); + desc = gpiod_get(dev, NULL, flags); + desc = gpiod_get_index(dev, NULL, index, flags); Case 1 assumes that corresponding ACPI device description must have defined device properties and will prevent to getting any GPIO resources diff --git a/Documentation/acpi/index.rst b/Documentation/acpi/index.rst index d10170942e13..0fae18cc1eea 100644 --- a/Documentation/acpi/index.rst +++ b/Documentation/acpi/index.rst @@ -12,4 +12,5 @@ Linux ACPI (Advanced Configuration and Power Interface) enumeration osi DSD-properties-rules + gpio-properties scan_handlers diff --git a/MAINTAINERS b/MAINTAINERS index 3e5a5d263f29..718890f348d4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6593,7 +6593,7 @@ M: Andy Shevchenko L: linux-gpio@vger.kernel.org L: linux-acpi@vger.kernel.org S: Maintained -F: Documentation/acpi/gpio-properties.txt +F: Documentation/acpi/gpio-properties.rst F: drivers/gpio/gpiolib-acpi.c GPIO IR Transmitter -- 2.20.1