Linux中gpio接口的使用方法示例
<p><span><strong>前言</strong></span></p>
<p>
Linux内核中gpio是最简单，最常用的资源(和 interrupt ,dma,timer一样)驱动程序，应用程序都能够通过相应的接口使用gpio，gpio使用0～MAX_INT之间的整数标识，不能使用负数,gpio与硬件体系密切相关的,不过linux有一个框架处理gpio，能够使用统一的接口来操作gpio.在讲gpio核心(gpiolib.c)之前先来看看gpio是怎么使用的</p>
<p>
<span><strong>使用gpio</strong></span></p>
<p>
使用gpio接口需要包含<code>#include <linux/gpio.h></code> ，在驱动中使用延时函数mdelay，需要包含<code>#include <linux/delay.h></code>文件，Documentation/gpio.txt文件有作详细说明。</p>
<p>
判断一个IO是否合法：</p>
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<code class="bash plain">int gpio_is_valid(int number);</code>
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设置GPIO的方向，如果是输出同时设置电平：</p>
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<code class="bash plain">/* </code><code class="bash functions">set</code> <code class="bash plain">as input or output, returning 0 or negative errno */</code>
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<code class="bash plain">int gpio_direction_input(unsigned gpio);</code>
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<code class="bash plain">int gpio_direction_output(unsigned gpio, int value);</code>
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获取输入引脚的电平：</p>
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<code class="bash plain">/* GPIO INPUT: </code><code class="bash keyword">return</code> <code class="bash plain">zero or nonzero */</code>
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<code class="bash plain">int gpio_get_value(unsigned gpio);</code>
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<code class="bash plain">/* GPIO OUTPUT */</code>
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<code class="bash plain">void gpio_set_value(unsigned gpio, int value);</code>
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<code class="bash plain">int gpio_cansleep(unsigned gpio);</code>
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<code class="bash plain">/* GPIO INPUT: </code><code class="bash keyword">return</code> <code class="bash plain">zero or nonzero, might </code><code class="bash functions">sleep</code> <code class="bash plain">*/</code>
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<code class="bash plain">int gpio_get_value_cansleep(unsigned gpio);</code>
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<code class="bash plain">/* GPIO OUTPUT, might </code><code class="bash functions">sleep</code> <code class="bash plain">*/</code>
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<code class="bash plain">void gpio_set_value_cansleep(unsigned gpio, int value);</code>
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获取一个GPIO并声明标签：</p>
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<code class="bash plain">/* request GPIO, returning 0 or negative errno.</code>
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<code class="bash plain">* non-null labels may be useful </code><code class="bash keyword">for</code> <code class="bash plain">diagnostics.</code>
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<code class="bash plain">*/</code>
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<code class="bash plain">int gpio_request(unsigned gpio, const char *label);</code>
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<code class="bash plain">/* release previously-claimed GPIO */</code>
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<code class="bash plain">void gpio_free(unsigned gpio);</code>
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将GPIO映射为IRQ中断：</p>
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<code class="bash plain">/* map GPIO numbers to IRQ numbers */</code>
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<code class="bash plain">int gpio_to_irq(unsigned gpio);</code>
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<code class="bash plain">/* map IRQ numbers to GPIO numbers (avoid using this) */</code>
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<code class="bash plain">int irq_to_gpio(unsigned irq);</code>
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设置GPIO的IRQ中断类型：</p>
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<code class="bash keyword">if</code> <code class="bash plain">(!sw->both_edges) {</code>
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<code class="bash spaces"> </code><code class="bash keyword">if</code> <code class="bash plain">(gpio_get_value(sw->gpio)) {</code>
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<code class="bash spaces"> </code><code class="bash plain">set_irq_type(gpio_to_irq(sw->gpio), IRQ_TYPE_EDGE_FALLING);</code>
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<code class="bash spaces"> </code><code class="bash plain">} </code><code class="bash keyword">else</code> <code class="bash plain">{</code>
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<code class="bash spaces"> </code><code class="bash plain">set_irq_type(gpio_to_irq(sw->gpio), IRQ_TYPE_EDGE_RISING);</code>
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<code class="bash spaces"> </code><code class="bash plain">}</code>
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<code class="bash plain">}</code>
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<p>
参考文章</p>
<p>
Linux中的gpio口使用方法</p>
<p>
<span><strong>总结</strong></span></p>
<p>
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，如果有疑问大家可以留言交流，谢谢大家对的支持。</p>
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原文链接：https://segmentfault.com/a/1190000011838979</p>
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