nrf: Feed the watchdog from the RTC interrupt

Feeding a watchdog from a periodic interrupt isn't the smartest thing
to do (unless you have setup multi-channels) so we also allow us to
express to the WDT driver whether we've arrived from an ISR or not.

ports/nrf/drivers/bluetooth/ble_uart.c

@@ -94,15 +94,14 @@ static ubluepy_advertise_data_t m_adv_data_eddystone_url;
 #endif // BLUETOOTH_WEBBLUETOOTH_REPL
 
 int mp_hal_stdin_rx_chr(void) {
-    wdt_feed();
+    wdt_feed(false);
 
     while (!ble_uart_enabled()) {
         // wait for connection
-	wdt_feed();
+	wdt_feed(false);
     }
     while (isBufferEmpty(mp_rx_ring_buffer)) {
-	wdt_feed();
-        ;
+	wdt_feed(false);
     }
 
     uint8_t byte;

ports/nrf/drivers/wdt.c

@@ -76,7 +76,7 @@ void wdt_init(void)
     }
 }
 
-void wdt_feed(void)
+void wdt_feed(bool isr)
 {
     /*
      * A WDT button allows us to feed the dog from somewhere that would
@@ -86,6 +86,8 @@ void wdt_feed(void)
      */
 #if MICROPY_HW_HAS_WDT_BUTTON
     if (!button_pressed())
+#else
+    if (!isr)
 #endif
         nrf_wdt_reload_request_set(0);
 }

ports/nrf/drivers/wdt.h

@@ -26,6 +26,6 @@
 #define __MICROPY_INCLUDED_LIB_WDT_H__
 
 void wdt_init(void);
-void wdt_feed(void);
+void wdt_feed(bool isr);
 
 #endif // __MICROPY_INCLUDED_LIB_WDT_H__

ports/nrf/modules/machine/rtcounter.c

@@ -28,6 +28,7 @@
 #include "py/nlr.h"
 #include "py/runtime.h"
 #include "rtcounter.h"
+#include "wdt.h"
 #include "nrfx_rtc.h"
 #include "nrf_clock.h"
 
@@ -106,6 +107,7 @@ STATIC void interrupt_handler(size_t instance_id) {
         uint32_t val = nrfx_rtc_counter_get(self->p_rtc) + config->period;
         nrfx_rtc_cc_set(self->p_rtc, 0, val, true);
     }
+    wdt_feed(true);
 }
 
 #if !defined(BLUETOOTH_SD)