K64F lp ticker driver - calculation bug fix.

Delta calculation from lp_ticker_set_interrupt() function:
delta_us = timestamp > now_us ? timestamp - now_us : (uint32_t)((uint64_t)timestamp + 0xFFFFFFFF - now_us);

Lets assume that timestam == now_us.
Expected delta value should be 0 and in this current version is 0xFFFFFFFF.

The following condition:
timestamp > now_us
should have the following form:
timestamp >= now_us

Additionally modified us ticker driver to provide the same logic.

Author: mprse

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/TARGET_MCU_K64F/us_ticker.c

@@ -83,10 +83,15 @@ void us_ticker_clear_interrupt(void)
 
 void us_ticker_set_interrupt(timestamp_t timestamp)
 {
+    uint32_t now_us, delta_us;
+
+    now_us = us_ticker_read();
+    delta_us = timestamp >= now_us ? timestamp - now_us : (uint32_t)((uint64_t)timestamp + 0xFFFFFFFF - now_us);
+
     uint32_t delta = timestamp - us_ticker_read();
     PIT_StopTimer(PIT, kPIT_Chnl_3);
     PIT_StopTimer(PIT, kPIT_Chnl_2);
-    PIT_SetTimerPeriod(PIT, kPIT_Chnl_3, (uint32_t)delta);
+    PIT_SetTimerPeriod(PIT, kPIT_Chnl_3, (uint32_t)delta_us);
     PIT_EnableInterrupts(PIT, kPIT_Chnl_3, kPIT_TimerInterruptEnable);
     PIT_StartTimer(PIT, kPIT_Chnl_3);
     PIT_StartTimer(PIT, kPIT_Chnl_2);

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/api/lp_ticker.c

@@ -135,7 +135,7 @@ void lp_ticker_set_interrupt(timestamp_t timestamp)
 
     lptmr_schedule = 0;
     now_us = lp_ticker_read();
-    delta_us = timestamp > now_us ? timestamp - now_us : (uint32_t)((uint64_t)timestamp + 0xFFFFFFFF - now_us);
+    delta_us = timestamp >= now_us ? timestamp - now_us : (uint32_t)((uint64_t)timestamp + 0xFFFFFFFF - now_us);
 
     /* Checking if LPTRM can handle this sleep */
     delta_ticks = USEC_TO_COUNT(delta_us, CLOCK_GetFreq(kCLOCK_Er32kClk));