Add a timeout to busio_i2c_scan

Author: prplz

shared-bindings/busio/I2C.c

@@ -33,7 +33,9 @@
 
 #include "shared/runtime/buffer_helper.h"
 #include "shared/runtime/context_manager_helpers.h"
+#include "py/mperrno.h"
 #include "py/runtime.h"
+#include "supervisor/port.h"
 #include "supervisor/shared/translate.h"
 
 //| class I2C:
@@ -138,9 +140,14 @@ STATIC mp_obj_t busio_i2c_scan(mp_obj_t self_in) {
     busio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
     check_for_deinit(self);
     check_lock(self);
+    // 5 seconds
+    uint64_t deadline = port_get_raw_ticks(NULL) + 5 * 1024;
     mp_obj_t list = mp_obj_new_list(0, NULL);
     // 7-bit addresses 0b0000xxx and 0b1111xxx are reserved
     for (int addr = 0x08; addr < 0x78; ++addr) {
+        if (port_get_raw_ticks(NULL) > deadline) {
+            mp_raise_OSError(MP_ETIMEDOUT);
+        }
         bool success = common_hal_busio_i2c_probe(self, addr);
         if (success) {
             mp_obj_list_append(list, MP_OBJ_NEW_SMALL_INT(addr));