1 <?xml version="1.0" encoding="utf-8"?>

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     7     Nokia Corporation - initial contribution.

     8 Contributors: 

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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-6E208C69-AC2C-4A7A-8203-2C4C3F2E54F5" xml:lang="en"><title>Binding

    13 and Unbinding</title><shortdesc>This document describes how device drivers bind and unbind interrupts.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <p>To handle events, the interrupt source and the ISR have to be registered

    15 with the OS: this is called binding the interrupt. An interrupt

    16 has to be unbound when its use is complete.</p>

    17 <section id="GUID-36710685-0B8C-4D78-A453-B8772F1D6492"><title>Binding</title> <p> An

    18 interrupt source ID is bound with the driver's interrupt service routine.

    19 This is done using the function <xref href="GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3.dita#GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3/GUID-4E3CB472-3525-32F8-9BC4-8ECFEE931E7B"><apiname>Interrupt::Bind()</apiname></xref> in the <i>second

    20 stage constructor</i> of the physical channel. Interrupt binding can fail

    21 if the source has been already used or bound. </p> <codeblock id="GUID-0743023B-86D7-5F76-B58F-A1A2159EFAE4" xml:space="preserve">TInt DExUartPhysicalChannelH4::DoCreate(TInt aUnit, const TDesC8* aInfo, const TVersion&amp; aVer)

    22     {

    23     ...

    24     // Bind the interrupt service routine (ISR) to a specific 

    25     // interrupt ID. When the ISR is called, the value aPtr,

    26     // (here this object) is passed as the argument. The ISR 

    27     // must be a static void function, taking a single TAny* 

    28     // parameter: void Isr(TAny* aParam). Interrupt::Enable() 

    29     // must be called to start receiving interrupts. Bind() 

    30     // returns KErrInUse if the ISR is already bound.

    31     //

    32     TInt r = Interrupt::Bind(iIrqId,UartIsr,this);

    33     if (r!=KErrNone)

    34         {

    35         KDBG(Kern::Printf("DExUartPhysicalChannel::Interrupt Binding 

    36                 for UART failed"));

    37         return r;

    38         }

    39 

    40     return KErrNone;

    41     }</codeblock></section>

    42 <section id="GUID-B68C33DD-AC9D-4211-8ADF-0A2D5F02B721"><title>Unbinding</title> <p> An

    43 interrupt is unbound by calling <xref href="GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3.dita#GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3/GUID-DF98A40B-453C-3BC0-B538-D9A6943732E0"><apiname>Interrupt::UnBind()</apiname></xref>, which

    44 de-registers the interrupt source and routine. This must be done before or

    45 during physical channel destruction. Unbinding an interrupt does not disable

    46 its source. Interrupts have to be disabled explicitly before unbinding to

    47 avoid spurious interrupts. </p> <codeblock id="GUID-7F959F0F-E295-5310-8296-7BBF36D408FB" xml:space="preserve">/**

    48  Physical channel destructor. Delete and free any objects created and

    49  allocated by the physical channel. This is called by the    

    50  framework while unloading the driver (PDD).

    51  */

    52 DExUartPhysicalChannelH4::~DExUartPhysicalChannelH4()

    53     {

    54     // Unbind the UART interrupt. Interrupt::Unbind() frees the  

    55     // interrupt service routine (ISR) function from the specified

    56     // interrupt ID.

    57     // 

    58     Interrupt::Unbind (iIrqId);

    59     }</codeblock></section>

    60 </conbody></concept>