1.1.4.4.4 DRV_WM8904_CommandEventHandlerSet Function
void DRV_WM8904_CommandEventHandlerSet ( DRV_HANDLE handle, const DRV_WM8904_COMMAND_EVENT_HANDLER eventHandler, const uintptr_t contextHandle )
Summary
This function allows a client to identify a command event handling function for the driver to call back when the last submitted command have finished.
Description
This function allows a client to identify a command event handling function for the driver to call back when the last submitted command have finished.
The event handler should be set before the client performs any "WM8904 Codec Specific Client Routines" operations that could generate events. The event handler once set, persists until the client closes the driver or sets another event handler (which could be a "NULL" pointer to indicate no callback).
Preconditions
The DRV_WM8904_Initialize routine must have been called for the specified WM8904 driver instance.
DRV_WM8904_Open must have been called to obtain a valid opened device handle.
Parameters
| Parameters | Description |
|---|---|
| handle | A valid open-instance handle, returned from the driver's open routine |
| eventHandler | Pointer to the event handler function. |
| context | The value of parameter will be passed back to the client unchanged, when the eventHandler function is called. It can be used to identify any client specific data object that identifies the instance of the client module (for example, it may be a pointer to the client module's state structure). |
Returns
None.
Remarks
If the client does not want to be notified when the command has completed, it does not need to register a callback.
Example
MY_APP_OBJ myAppObj; uint8_t mybuffer[MY_BUFFER_SIZE]; DRV_WM8904_BUFFER_HANDLE bufferHandle; _// myWM8904Handle is the handle returned // by the DRV_WM8904_Open function._ _// Client registers an event handler with driver_ DRV_WM8904_CommandEventHandlerSet(myWM8904Handle, APP_WM8904CommandEventHandler, (uintptr_t)&myAppObj); DRV_WM8904_DeEmphasisFilterSet(myWM8904Handle, DRV_WM8904_DEEMPHASIS_FILTER_44_1KHZ) _// Event is received when // the buffer is processed._ void APP_WM8904CommandEventHandler(uintptr_t contextHandle) { _// contextHandle points to myAppObj._ switch(event) { _// Last Submitted command is completed._ _// Perform further processing here_} }
C
void DRV_WM8904_CommandEventHandlerSet(DRV_HANDLE handle, const
DRV_WM8904_COMMAND_EVENT_HANDLER eventHandler, const uintptr_t contextHandle);