| <!-- |
| Documentation/_templates/layout.html |
| |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. The |
| ASF licenses this file to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance with the |
| License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| License for the specific language governing permissions and limitations |
| under the License. |
| --> |
| |
| <!DOCTYPE html> |
| <html class="writer-html5" lang="en" > |
| <head> |
| <meta charset="utf-8" /><meta name="generator" content="Docutils 0.18.1: http://docutils.sourceforge.net/" /> |
| |
| <meta name="viewport" content="width=device-width, initial-scale=1.0" /> |
| <title>Device Drivers — NuttX latest documentation</title> |
| <link rel="stylesheet" href="../../_static/pygments.css" type="text/css" /> |
| <link rel="stylesheet" href="../../_static/css/theme.css" type="text/css" /> |
| <link rel="stylesheet" href="../../_static/copybutton.css" type="text/css" /> |
| <link rel="stylesheet" href="../../_static/tabs.css" type="text/css" /> |
| <link rel="stylesheet" href="../../_static/custom.css" type="text/css" /> |
| <link rel="shortcut icon" href="../../_static/favicon.ico"/> |
| <!--[if lt IE 9]> |
| <script src="../../_static/js/html5shiv.min.js"></script> |
| <![endif]--> |
| |
| <script src="../../_static/jquery.js"></script> |
| <script src="../../_static/_sphinx_javascript_frameworks_compat.js"></script> |
| <script data-url_root="../../" id="documentation_options" src="../../_static/documentation_options.js"></script> |
| <script src="../../_static/doctools.js"></script> |
| <script src="../../_static/sphinx_highlight.js"></script> |
| <script src="../../_static/clipboard.min.js"></script> |
| <script src="../../_static/copybutton.js"></script> |
| <script src="../../_static/js/theme.js"></script> |
| <link rel="index" title="Index" href="../../genindex.html" /> |
| <link rel="search" title="Search" href="../../search.html" /> |
| <link rel="next" title="Character Device Drivers" href="character/index.html" /> |
| <link rel="prev" title="Binary Loader" href="../binfmt.html" /> |
| </head> |
| |
| <body class="wy-body-for-nav"> |
| <div class="wy-grid-for-nav"> |
| <nav data-toggle="wy-nav-shift" class="wy-nav-side"> |
| <div class="wy-side-scroll"> |
| <div class="wy-side-nav-search" > |
| |
| <a href="../../index.html" class="icon icon-home"> NuttX |
| |
| |
| |
| </a> |
| |
| <!-- this version selector is quite ugly, should be probably replaced by something |
| more modern --> |
| |
| <div class="version-selector"> |
| <select onchange="javascript:location.href = this.value;"> |
| |
| <option value="../../../latest" selected="selected">latest</option> |
| |
| <option value="../../../10.0.0" >10.0.0</option> |
| |
| <option value="../../../10.0.1" >10.0.1</option> |
| |
| <option value="../../../10.1.0" >10.1.0</option> |
| |
| <option value="../../../10.2.0" >10.2.0</option> |
| |
| <option value="../../../10.3.0" >10.3.0</option> |
| |
| <option value="../../../11.0.0" >11.0.0</option> |
| |
| <option value="../../../12.0.0" >12.0.0</option> |
| |
| <option value="../../../12.1.0" >12.1.0</option> |
| |
| <option value="../../../12.2.0" >12.2.0</option> |
| |
| <option value="../../../12.2.1" >12.2.1</option> |
| |
| <option value="../../../12.3.0" >12.3.0</option> |
| |
| <option value="../../../12.4.0" >12.4.0</option> |
| |
| <option value="../../../12.5.0" >12.5.0</option> |
| |
| <option value="../../../12.5.1" >12.5.1</option> |
| |
| <option value="../../../12.6.0" >12.6.0</option> |
| |
| <option value="../../../12.7.0" >12.7.0</option> |
| |
| <option value="../../../12.8.0" >12.8.0</option> |
| |
| <option value="../../../12.9.0" >12.9.0</option> |
| |
| <option value="../../../12.10.0" >12.10.0</option> |
| |
| <option value="../../../12.11.0" >12.11.0</option> |
| |
| </select> |
| </div> |
| |
| |
| <div role="search"> |
| <form id="rtd-search-form" class="wy-form" action="../../search.html" method="get"> |
| <input type="text" name="q" placeholder="Search docs" aria-label="Search docs" /> |
| <input type="hidden" name="check_keywords" value="yes" /> |
| <input type="hidden" name="area" value="default" /> |
| </form> |
| </div> |
| |
| </div><div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="Navigation menu"> |
| <p class="caption" role="heading"><span class="caption-text">Table of Contents</span></p> |
| <ul class="current"> |
| <li class="toctree-l1"><a class="reference internal" href="../../index.html">Home</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../introduction/index.html">Introduction</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../quickstart/index.html">Getting Started</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../contributing/index.html">Contributing</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../introduction/inviolables.html">The Inviolable Principles of NuttX</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../platforms/index.html">Supported Platforms</a></li> |
| <li class="toctree-l1 current"><a class="reference internal" href="../index.html">OS Components</a><ul class="current"> |
| <li class="toctree-l2"><a class="reference internal" href="../power.html">Power Management</a></li> |
| <li class="toctree-l2"><a class="reference internal" href="../binfmt.html">Binary Loader</a></li> |
| <li class="toctree-l2 current"><a class="current reference internal" href="#">Device Drivers</a><ul> |
| <li class="toctree-l3"><a class="reference internal" href="character/index.html">Character Device Drivers</a></li> |
| <li class="toctree-l3"><a class="reference internal" href="block/index.html">Block Device Drivers</a></li> |
| <li class="toctree-l3"><a class="reference internal" href="special/index.html">Specialized Device Drivers</a></li> |
| <li class="toctree-l3"><a class="reference internal" href="#lower-half-and-upper-half">Lower-half and upper-half</a></li> |
| </ul> |
| </li> |
| <li class="toctree-l2"><a class="reference internal" href="../filesystem.html">NuttX File System</a></li> |
| <li class="toctree-l2"><a class="reference internal" href="../nxflat.html">NXFLAT</a></li> |
| <li class="toctree-l2"><a class="reference internal" href="../nxgraphics/index.html">NX Graphics Subsystem</a></li> |
| <li class="toctree-l2"><a class="reference internal" href="../nxwidgets.html">NxWidgets</a></li> |
| <li class="toctree-l2"><a class="reference internal" href="../paging.html">On-Demand Paging</a></li> |
| </ul> |
| </li> |
| <li class="toctree-l1"><a class="reference internal" href="../../applications/index.html">Applications</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../reference/index.html">API Reference</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../faq/index.html">FAQ</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../guides/index.html">Guides</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../glossary.html">Glossary</a></li> |
| </ul> |
| |
| </div> |
| </div> |
| </nav> |
| |
| <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap"><nav class="wy-nav-top" aria-label="Mobile navigation menu" > |
| <i data-toggle="wy-nav-top" class="fa fa-bars"></i> |
| <a href="../../index.html">NuttX</a> |
| </nav> |
| |
| <div class="wy-nav-content"> |
| <div class="rst-content"> |
| <div role="navigation" aria-label="Page navigation"> |
| <ul class="wy-breadcrumbs"> |
| <li><a href="../../index.html" class="icon icon-home" aria-label="Home"></a></li> |
| <li class="breadcrumb-item"><a href="../index.html">OS Components</a></li> |
| <li class="breadcrumb-item active">Device Drivers</li> |
| <li class="wy-breadcrumbs-aside"> |
| <a href="../../_sources/components/drivers/index.rst.txt" rel="nofollow"> View page source</a> |
| </li> |
| </ul> |
| <hr/> |
| </div> |
| <div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article"> |
| <div itemprop="articleBody"> |
| |
| <section id="device-drivers"> |
| <h1>Device Drivers<a class="headerlink" href="#device-drivers" title="Permalink to this heading"></a></h1> |
| <p>NuttX supports a variety of device drivers, which can be broadly |
| divided in three classes:</p> |
| <div class="toctree-wrapper compound"> |
| <ul> |
| <li class="toctree-l1"><a class="reference internal" href="character/index.html">Character Device Drivers</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="block/index.html">Block Device Drivers</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="special/index.html">Specialized Device Drivers</a></li> |
| </ul> |
| </div> |
| <div class="admonition note"> |
| <p class="admonition-title">Note</p> |
| <p>Device driver support depends on the <em>in-memory</em>, <em>pseudo</em> |
| file system that is enabled by default.</p> |
| </div> |
| <section id="lower-half-and-upper-half"> |
| <h2>Lower-half and upper-half<a class="headerlink" href="#lower-half-and-upper-half" title="Permalink to this heading"></a></h2> |
| <p>Drivers in NuttX generally work in two distinct layers:</p> |
| <blockquote> |
| <div><ul class="simple"> |
| <li><p>An <em>upper half</em> which registers itself to NuttX using |
| a call such as <code class="xref c c-func docutils literal notranslate"><span class="pre">register_driver()</span></code> or |
| <code class="xref c c-func docutils literal notranslate"><span class="pre">register_blockdriver()</span></code> and implements the corresponding |
| high-level interface (<cite>read</cite>, <cite>write</cite>, <cite>close</cite>, etc.). |
| implements the interface. This <em>upper half</em> calls into |
| the <em>lower half</em> via callbacks.</p></li> |
| <li><p>A “lower half” which is typically hardware-specific. This is |
| usually implemented at the architecture or board level.</p></li> |
| </ul> |
| </div></blockquote> |
| </section> |
| </section> |
| |
| |
| </div> |
| </div> |
| <footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer"> |
| <a href="../binfmt.html" class="btn btn-neutral float-left" title="Binary Loader" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left" aria-hidden="true"></span> Previous</a> |
| <a href="character/index.html" class="btn btn-neutral float-right" title="Character Device Drivers" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a> |
| </div> |
| |
| <hr/> |
| |
| <div role="contentinfo"> |
| <p>© Copyright 2020, The Apache Software Foundation.</p> |
| </div> |
| |
| |
| |
| </footer> |
| </div> |
| </div> |
| </section> |
| </div> |
| <script> |
| jQuery(function () { |
| SphinxRtdTheme.Navigation.enable(true); |
| }); |
| </script> |
| |
| </body> |
| </html> |
