[mynewt-core] 02/03: hw/mcu/nordic: Waiting for HFCLK to settle

[jerzy]

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commit e7742ececb8c0ff35d684d484519686588a6d179
Author: Niklas Casaril <nik...@casaril.com>
AuthorDate: Fri Dec 18 07:45:30 2020 +1000

    hw/mcu/nordic: Waiting for HFCLK to settle
    
    Checking both STATE and SRC of HFCLK if refcount is 0
---
 hw/mcu/nordic/nrf52xxx/src/nrf52_clock.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/hw/mcu/nordic/nrf52xxx/src/nrf52_clock.c 
b/hw/mcu/nordic/nrf52xxx/src/nrf52_clock.c
index 210c583..3151db6 100644
--- a/hw/mcu/nordic/nrf52xxx/src/nrf52_clock.c
+++ b/hw/mcu/nordic/nrf52xxx/src/nrf52_clock.c
@@ -44,7 +44,16 @@ nrf52_clock_hfxo_request(void)
     __HAL_DISABLE_INTERRUPTS(ctx);
     assert(nrf52_clock_hfxo_refcnt < 0xff);
     if (nrf52_clock_hfxo_refcnt == 0) {
-        NRF_CLOCK->TASKS_HFCLKSTART = 1;
+        /* Check the current STATE and SRC of HFCLK */
+        if ((NRF_CLOCK->HFCLKSTAT &
+             (CLOCK_HFCLKSTAT_SRC_Msk | CLOCK_HFCLKSTAT_STATE_Msk)) !=
+            (CLOCK_HFCLKSTAT_SRC_Xtal << CLOCK_HFCLKSTAT_SRC_Pos |
+             CLOCK_HFCLKSTAT_STATE_Running << CLOCK_HFCLKSTAT_STATE_Pos)) {
+            NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
+            NRF_CLOCK->TASKS_HFCLKSTART = 1;
+            while (!NRF_CLOCK->EVENTS_HFCLKSTARTED) {
+            }
+        }
         started = 1;
     }
     ++nrf52_clock_hfxo_refcnt;