Qurt platform custom icm42688p IMU driver (#20753)

- first version of IMU driver for the VOXL 2 platform (Qurt)
 - this is a customized version of the Invensense ICM42688P driver, it is currently in the VOXL 2 board directory

platforms/common/work_queue/hrt_queue.c

@@ -126,15 +126,10 @@ int hrt_work_queue(struct work_s *work, worker_t worker, void *arg, uint32_t del
 	dq_addlast(&work->dq, &wqueue->q);
 
 	if (px4_getpid() != wqueue->pid) { /* only need to wake up if called from a different thread */
-#ifdef __PX4_QURT
-		px4_task_kill(wqueue->pid, SIGALRM);      /* Wake up the worker thread */
-#else
 		//wqueue->pid == own task? -> don't signal
 		px4_task_kill(wqueue->pid, SIGCONT);      /* Wake up the worker thread */
-#endif
 	}
 
 	hrt_work_unlock();
 	return PX4_OK;
 }
-

platforms/common/work_queue/hrt_thread.c

@@ -138,6 +138,16 @@ static void hrt_work_process()
 	/* Default to sleeping for 1 sec */
 	next  = 1000000;
 
+#ifdef __PX4_QURT
+	// In Posix certain signals wake up a sleeping thread but it isn't the case
+	// with the Qurt POSIX implementation. So rather than assume we can come out
+	// of the sleep early by a signal we just wake up more often. The best way to
+	// fix this would be to move to a px4_sem_timedwait. But the current implementation
+	// of that function on Qurt uses this hrt_thread! So, it would all have to be
+	// re-written to use Qurt semaphores which do have timed waits.
+	next = 1000;
+#endif
+
 	hrt_work_lock();
 
 	work  = (struct work_s *)wqueue->q.head;
@@ -287,9 +297,5 @@ void hrt_work_queue_init(void)
 					    (char *const *)NULL);
 
 
-#ifdef __PX4_QURT
-	signal(SIGALRM, _sighandler);
-#else
 	signal(SIGCONT, _sighandler);
-#endif
 }

platforms/common/work_queue/work_queue.c

@@ -41,6 +41,7 @@
 #include <px4_platform_common/defines.h>
 #include <px4_platform_common/workqueue.h>
 #include <px4_platform_common/tasks.h>
+#include <px4_platform_common/posix.h>
 
 #include <signal.h>
 #include <stdint.h>
@@ -125,11 +126,7 @@ int work_queue(int qid, struct work_s *work, worker_t worker, void *arg, uint32_
 	work->qtime  = clock_systimer(); /* Time work queued */
 
 	dq_addlast((dq_entry_t *)work, &wqueue->q);
-#ifdef __PX4_QURT
-	px4_task_kill(wqueue->pid, SIGALRM);      /* Wake up the worker thread */
-#else
 	px4_task_kill(wqueue->pid, SIGCONT);      /* Wake up the worker thread */
-#endif
 
 	work_unlock(qid);
 	return PX4_OK;