Fix preserve_dios during fake deep sleep

main.c

@@ -789,6 +789,12 @@ static bool __attribute__((noinline)) run_code_py(safe_mode_t safe_mode, bool *s
         #if CIRCUITPY_DISPLAYIO
         common_hal_displayio_auto_primary_display();
         #endif
+        // Undo any preserve_dios.
+        #if CIRCUITPY_ALARM_PRESERVE_DIOS
+        common_hal_alarm_clear_pin_preservations();
+        #endif
+        // Reset pins, as if there was a hard reset.
+        reset_all_pins();
         // Pretend that the next run is the first run, as if we were reset.
         *simulate_reset = true;
     }

ports/atmel-samd/common-hal/alarm/__init__.c

@@ -127,9 +127,6 @@ mp_obj_t common_hal_alarm_light_sleep_until_alarms(size_t n_alarms, const mp_obj
 }
 
 void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms, size_t n_dios, digitalio_digitalinout_obj_t **preserve_dios) {
-    if (n_dios > 0) {
-        mp_raise_NotImplementedError_varg(MP_ERROR_TEXT("%q"), MP_QSTR_preserve_dios);
-    }
     _setup_sleep_alarms(true, n_alarms, alarms);
 }
 

ports/espressif/common-hal/alarm/__init__.c

@@ -182,7 +182,7 @@ void MP_NORETURN common_hal_alarm_enter_deep_sleep(void) {
     #endif
 
     // We no longer need to remember the pin preservations, since any pin resets are all done.
-    clear_pin_preservations();
+    common_hal_alarm_clear_pin_preservations();
 
     // The ESP-IDF caches the deep sleep settings and applies them before sleep.
     // We don't need to worry about resetting them in the interim.

ports/espressif/common-hal/microcontroller/Pin.c

@@ -7,6 +7,7 @@
 
 #include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-bindings/alarm/__init__.h"
 
 #include "py/mphal.h"
 
@@ -368,7 +369,7 @@ void preserve_pin_number(gpio_num_t pin_number) {
     }
 }
 
-void clear_pin_preservations(void) {
+void common_hal_alarm_clear_pin_preservations(void) {
     _preserved_pin_mask = 0;
 }
 

ports/espressif/common-hal/microcontroller/Pin.h

@@ -29,7 +29,6 @@ extern bool pin_number_is_free(gpio_num_t pin_number);
 extern void never_reset_pin_number(gpio_num_t pin_number);
 
 extern void preserve_pin_number(gpio_num_t pin_number);
-extern void clear_pin_preservations(void);
 
 // Allow the board to reset a pin in a board-specific way. This can be used
 // for LEDs or enable pins to put them in a state beside the default pull-up.

ports/espressif/mpconfigport.mk

@@ -64,6 +64,7 @@ CIRCUITPY_LIBC_STRING0 = 0
 # These modules are implemented in ports/<port>/common-hal:
 CIRCUITPY__EVE ?= 1
 CIRCUITPY_ALARM ?= 1
+CIRCUITPY_ALARM_PRESERVE_DIOS ?= 1
 CIRCUITPY_ALARM_TOUCH ?= 1
 CIRCUITPY_ANALOGBUFIO ?= 1
 CIRCUITPY_AUDIOBUSIO ?= 1

ports/nordic/common-hal/alarm/__init__.c

@@ -232,9 +232,6 @@ mp_obj_t common_hal_alarm_light_sleep_until_alarms(size_t n_alarms, const mp_obj
 }
 
 void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms, size_t n_dios, digitalio_digitalinout_obj_t **preserve_dios) {
-    if (n_dios > 0) {
-        mp_raise_NotImplementedError_varg(MP_ERROR_TEXT("%q"), MP_QSTR_preserve_dios);
-    }
     _setup_sleep_alarms(true, n_alarms, alarms);
 }
 

ports/raspberrypi/common-hal/alarm/__init__.c

@@ -191,9 +191,6 @@ mp_obj_t common_hal_alarm_light_sleep_until_alarms(size_t n_alarms, const mp_obj
 }
 
 void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms, size_t n_dios, digitalio_digitalinout_obj_t **preserve_dios) {
-    if (n_dios > 0) {
-        mp_raise_NotImplementedError_varg(MP_ERROR_TEXT("%q"), MP_QSTR_preserve_dios);
-    }
     _setup_sleep_alarms(true, n_alarms, alarms);
 }
 

ports/stm/common-hal/alarm/__init__.c

@@ -129,9 +129,6 @@ mp_obj_t common_hal_alarm_light_sleep_until_alarms(size_t n_alarms, const mp_obj
 }
 
 void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms, size_t n_dios, digitalio_digitalinout_obj_t **preserve_dios) {
-    if (n_dios > 0) {
-        mp_raise_NotImplementedError_varg(MP_ERROR_TEXT("%q"), MP_QSTR_preserve_dios);
-    }
     _setup_sleep_alarms(true, n_alarms, alarms);
 }
 

py/circuitpy_mpconfig.mk

@@ -104,6 +104,10 @@ CFLAGS += -DCIRCUITPY_AESIO=$(CIRCUITPY_AESIO)
 CIRCUITPY_ALARM ?= 0
 CFLAGS += -DCIRCUITPY_ALARM=$(CIRCUITPY_ALARM)
 
+# Whether `alarm.exit_and_deep_sleep_until_alarms()` supports `preserve_dios`.
+CIRCUITPY_ALARM_PRESERVE_DIOS ?= 0
+CFLAGS += -DCIRCUITPY_ALARM_PRESERVE_DIOS=$(CIRCUITPY_ALARM_PRESERVE_DIOS)
+
 CIRCUITPY_ALARM_TOUCH ?= $(CIRCUITPY_ALARM)
 CFLAGS += -DCIRCUITPY_ALARM_TOUCH=$(CIRCUITPY_ALARM_TOUCH)
 

shared-bindings/alarm/__init__.c

@@ -137,6 +137,8 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(alarm_light_sleep_until_alarms_obj, 1, MP_OB
 //|
 //|     Preserving `DigitalInOut` states during deep sleep can be used to ensure that
 //|     external or on-board devices are powered or unpowered during sleep, among other purposes.
+//|     Once the board wakes up from deep sleep, the `DigitalInOut` states are no longer preserved
+//|     and must be restored by your code.
 //|
 //|     On some microcontrollers, some pins cannot remain in their original state for hardware reasons.
 //|
@@ -193,6 +195,11 @@ static mp_obj_t alarm_exit_and_deep_sleep_until_alarms(size_t n_args, const mp_o
 
     mp_obj_t preserve_dios = args[ARG_preserve_dios].u_obj;
     const size_t num_dios = (size_t)MP_OBJ_SMALL_INT_VALUE(mp_obj_len(preserve_dios));
+    #if !CIRCUITPY_ALARM_PRESERVE_DIOS
+    if (num_dios > 0) {
+        mp_raise_NotImplementedError_varg(MP_ERROR_TEXT("%q"), MP_QSTR_preserve_dios);
+    }
+    #endif
     digitalio_digitalinout_obj_t *dios_array[num_dios];
 
     for (mp_uint_t i = 0; i < num_dios; i++) {

shared-bindings/alarm/__init__.h

@@ -26,6 +26,13 @@ extern void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj
 
 extern MP_NORETURN void common_hal_alarm_enter_deep_sleep(void);
 
+#if CIRCUITPY_ALARM_PRESERVE_DIOS
+// Clear any pin preservations set up for deep sleep (real or fake), releasing
+// held pins so they can be reset. Only declared on ports that implement
+// `preserve_dios`.
+extern void common_hal_alarm_clear_pin_preservations(void);
+#endif
+
 // May be used to re-initialize peripherals like GPIO, if the VM reset returned
 // them to a default state
 extern void common_hal_alarm_pretending_deep_sleep(void);