1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>request_threaded_irq</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="The Linux Kernel API"><link rel="up" href="hardware.html#idp1125715868" title="Interrupt Handling"><link rel="prev" href="API-free-irq.html" title="free_irq"><link rel="next" href="API-request-any-context-irq.html" title="request_any_context_irq"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">request_threaded_irq</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-free-irq.html">Prev</a> </td><th width="60%" align="center">Interrupt Handling</th><td width="20%" align="right"> <a accesskey="n" href="API-request-any-context-irq.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-request-threaded-irq"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>request_threaded_irq — 2 allocate an interrupt line 3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">request_threaded_irq </b>(</code></td><td>unsigned int <var class="pdparam">irq</var>, </td></tr><tr><td> </td><td>irq_handler_t <var class="pdparam">handler</var>, </td></tr><tr><td> </td><td>irq_handler_t <var class="pdparam">thread_fn</var>, </td></tr><tr><td> </td><td>unsigned long <var class="pdparam">irqflags</var>, </td></tr><tr><td> </td><td>const char * <var class="pdparam">devname</var>, </td></tr><tr><td> </td><td>void * <var class="pdparam">dev_id</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idp1125822116"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>irq</code></em></span></dt><dd><p> 4 Interrupt line to allocate 5 </p></dd><dt><span class="term"><em class="parameter"><code>handler</code></em></span></dt><dd><p> 6 Function to be called when the IRQ occurs. 7 Primary handler for threaded interrupts 8 If NULL and thread_fn != NULL the default 9 primary handler is installed 10 </p></dd><dt><span class="term"><em class="parameter"><code>thread_fn</code></em></span></dt><dd><p> 11 Function called from the irq handler thread 12 If NULL, no irq thread is created 13 </p></dd><dt><span class="term"><em class="parameter"><code>irqflags</code></em></span></dt><dd><p> 14 Interrupt type flags 15 </p></dd><dt><span class="term"><em class="parameter"><code>devname</code></em></span></dt><dd><p> 16 An ascii name for the claiming device 17 </p></dd><dt><span class="term"><em class="parameter"><code>dev_id</code></em></span></dt><dd><p> 18 A cookie passed back to the handler function 19 </p></dd></dl></div></div><div class="refsect1"><a name="idp1125829092"></a><h2>Description</h2><p> 20 This call allocates interrupt resources and enables the 21 interrupt line and IRQ handling. From the point this 22 call is made your handler function may be invoked. Since 23 your handler function must clear any interrupt the board 24 raises, you must take care both to initialise your hardware 25 and to set up the interrupt handler in the right order. 26 </p><p> 27 28 If you want to set up a threaded irq handler for your device 29 then you need to supply <em class="parameter"><code>handler</code></em> and <em class="parameter"><code>thread_fn</code></em>. <em class="parameter"><code>handler</code></em> is 30 still called in hard interrupt context and has to check 31 whether the interrupt originates from the device. If yes it 32 needs to disable the interrupt on the device and return 33 IRQ_WAKE_THREAD which will wake up the handler thread and run 34 <em class="parameter"><code>thread_fn</code></em>. This split handler design is necessary to support 35 shared interrupts. 36 </p><p> 37 38 Dev_id must be globally unique. Normally the address of the 39 device data structure is used as the cookie. Since the handler 40 receives this value it makes sense to use it. 41 </p><p> 42 43 If your interrupt is shared you must pass a non NULL dev_id 44 as this is required when freeing the interrupt. 45</p></div><div class="refsect1"><a name="idp1125832604"></a><h2>Flags</h2><p> 46 </p><p> 47 48 IRQF_SHARED Interrupt is shared 49 IRQF_TRIGGER_* Specify active edge(s) or level 50</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-free-irq.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="hardware.html#idp1125715868">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-request-any-context-irq.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">free_irq</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span class="phrase">request_any_context_irq</span></td></tr></table></div></body></html> 51