Provide initialization and cleanup callback functions

Implement initialization callback function

mtouch_driver_init() performs the following:

1. Sets the default values of the driver.
2. Parses any options specified in graphics.conf using input_parseopts(). For details, see the “Touch configuration file” section in the Screen documentation.
3. Performs any necessary hardware initialization.
4. Configure callback functions using mtouch_driver_funcs_t as described in Connect to the Input Events library.
5. Specify driver parameters using mtouch_driver_params_t as described in Connect to the Input Events library.
6. Connect to Input Events library as described in Connect to the Input Events library.
7. Create a separate thread to communicate directly with the hardware via the hardware interface (e.g., I2C, SPI, USB, etc.) and trigger the Input Events library API function mtouch_driver_process_packet() to start processing the touch-related event data.

void* (*init)(const char* options);
      

An example implementation of mtouch_driver_init():

void * mtouch_driver_init(const char* options)
{
	pthread_attr_t pattr;
	sched_param_t param;
	
	/* touch_dev_t is the structure which contains information specific to
	 * your touch device along with other NTO and thread information.
	 */
	touch_dev_t *td = (touch_dev_t *)calloc(1,sizeof(touch_dev_t));
    memset(td,0,sizeof(touch_dev_t));
	if(td==NULL){
		mtouch_error("touch_device", "Failed to allocate memory for device structure");
		return NULL;
	}
	
	/* Initialize any defaults for your touch device here */
	td->thread_priority = 21; /* Thread priority for communicating directly with the hardware */

   /* Parse the mtouch options from graphics.conf */
	input_parseopts(options, set_options, td);

   /* Connect to device */
	td->chid = ChannelCreate(0);
	if(td->chid == -1) {
		mtouch_error("touch_device","%s: ChannelCreate: %s",__FUNCTION__,strerror(errno));
		goto failChannelCreate;
	}

	td->coid = ConnectAttach(0,0,td->chid,_NTO_SIDE_CHANNEL,0);
	if(td->coid==-1) {
		mtouch_error("touch_device","%s: ConnectAttach: %s",__FUNCTION__,strerror(errno));
		goto failConnectAttach;
	}
	
	/* Utility function attach_drier() to configure your callback function and
	 *  connect to the Input Events library
	 */
	if(attach_driver(td)!=EOK) {
		goto failAttachLibInputEvents;
	}

	pthread_attr_init(&pattr);
	param.sched_priority = td->thread_priority;
	pthread_attr_setschedparam(&pattr, &param);
	pthread_attr_setinheritsched(&pattr, PTHREAD_EXPLICIT_SCHED);
	
	/* Create a thread for communicating directly with the hardware and to
	 * trigger mtouch_driver_process_packet() */
	int ret = pthread_create(&td->recv_thread, &pattr, tp_recv_thread, td);
	if (EOK != ret) {
		mtouch_error("touch_device", "Failed to create the intr thread (%s - %i)",strerror(errno),ret);
		goto failCreateThread;
	}
	pthread_setname_np(td->recv_thread, "touch_device");
	
	return td;

failCreateThread:
	InterruptDetach(td->tp_iid);
	td->tp_iid = -1;

failAttachLibInputEvents:
	mtouch_driver_detach(td->inputevents_hdl);
	td->inputevents_hdl = NULL;

failInitialize:
	ChannelDestroy(td->chid);
	td->chid = -1;

failConnectAttach:
	ConnectDetach(td->chid);
	td->chid = -1;

failChannelCreate:
	free(td);
	return NULL;
}
   

Implement cleanup callback function

mtouch_driver_fini() performs any necessary device cleanup and disconnects from the Input Events library.

void (*fini)(void* dev);

An example implementation of mtouch_driver_fini():

void mtouch_driver_fini(void* dev)
{
	touch_dev_t *td = dev;

	pthread_cancel(td->tp_recv_thread);
	pthread_join(td->tp_recv_thread, NULL);

	if (td->inputevents_hdl) {
		mtouch_driver_detach(td->inputevents_hdl);
		td->inputevents_hdl = NULL;
	}

	free(td);
}