rp2: Add mp_hal_is_pin_reserved.

As cyw43 pins might be dynamic, add a function that returns if a pin is
reserved. This is used by MICROPY_HW_PIN_RESERVED

Signed-off-by: Peter Harper <peter.harper@raspberrypi.com>

Author: peterharperuk

ports/rp2/boards/RPI_PICO_W/mpconfigboard.h

@@ -20,4 +20,6 @@
 
 #define MICROPY_HW_PIN_EXT_COUNT    CYW43_WL_GPIO_COUNT
 
-#define MICROPY_HW_PIN_RESERVED(i) ((i) == CYW43_PIN_WL_HOST_WAKE || (i) == CYW43_PIN_WL_REG_ON)
+// If this returns true for a pin then its irq will not be disabled on a soft reboot
+int mp_hal_is_pin_reserved(int n);
+#define MICROPY_HW_PIN_RESERVED(i) mp_hal_is_pin_reserved(i)

ports/rp2/mphalport.c

@@ -268,3 +268,11 @@ void soft_timer_init(void) {
 void mp_wfe_or_timeout(uint32_t timeout_ms) {
     best_effort_wfe_or_timeout(delayed_by_ms(get_absolute_time(), timeout_ms));
 }
+
+int mp_hal_is_pin_reserved(int n) {
+    #if MICROPY_PY_NETWORK_CYW43
+    return n == CYW43_PIN_WL_HOST_WAKE;
+    #else
+    return false;
+    #endif
+}

ports/rp2/mphalport.h

@@ -210,5 +210,6 @@ enum {
 void mp_hal_get_mac(int idx, uint8_t buf[6]);
 void mp_hal_get_mac_ascii(int idx, size_t chr_off, size_t chr_len, char *dest);
 void mp_hal_generate_laa_mac(int idx, uint8_t buf[6]);
+int mp_hal_is_pin_reserved(int n);
 
 #endif // MICROPY_INCLUDED_RP2_MPHALPORT_H