Merge pull request #6962 from dhalbert/espressif-deep-sleep-hold-pins

Espressif: do not hold pins during deep sleep if not necessary

Author: dhalbert

ports/espressif/boards/adafruit_feather_esp32s2_tft/board.c

@@ -88,9 +88,6 @@ void board_init(void) {
     displayio_display_obj_t *display = &displays[0].display;
     display->base.type = &displayio_display_type;
 
-    // workaround as board_init() is called before reset_port() in main.c
-///    pwmout_reset();
-
     common_hal_displayio_display_construct(
         display,
         bus,
@@ -127,8 +124,8 @@ bool espressif_board_reset_pin_number(gpio_num_t pin_number) {
     // Override the I2C/TFT power pin reset to prevent resetting the display.
     if (pin_number == 21) {
         // Turn on TFT and I2C
-        gpio_set_direction(21, GPIO_MODE_DEF_OUTPUT);
-        gpio_set_level(21, true);
+        gpio_set_direction(pin_number, GPIO_MODE_DEF_OUTPUT);
+        gpio_set_level(pin_number, true);
         return true;
     }
     return false;

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

@@ -173,9 +173,6 @@ void NORETURN common_hal_alarm_enter_deep_sleep(void) {
     // We no longer need to remember the pin preservations, since any pin resets are all done.
     clear_pin_preservations();
 
-    // Allow pin holds to work during deep sleep.
-    gpio_deep_sleep_hold_en();
-
     // 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.
     esp_deep_sleep_start();

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

@@ -173,6 +173,12 @@ void preserve_pin_number(gpio_num_t pin_number) {
         gpio_hold_en(pin_number);
         _preserved_pin_mask |= PIN_BIT(pin_number);
     }
+    if (_preserved_pin_mask) {
+        // Allow pin holds to work during deep sleep. This increases power consumption noticeably
+        // during deep sleep, so enable holds only if we actually are holding some pins.
+        // 270uA or so extra current is consumed even with no pins held.
+        gpio_deep_sleep_hold_en();
+    }
 }
 
 void clear_pin_preservations(void) {

shared-bindings/alarm/__init__.c

@@ -144,6 +144,12 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(alarm_light_sleep_until_alarms_obj, 1, MP_OB
 //|
 //|     On some microcontrollers, some pins cannot remain in their original state for hardware reasons.
 //|
+//|     .. note::
+//|       On Espressif chips, preserving pin settings during deep sleep may consume extra current.
+//|       On ESP32, this was measured to be 250 uA or more.
+//|       Consider not preserving pins unless you need to.
+//|       Measure power consumption carefully both with no pins preserved and with the pins you might want to
+//|       preserve to achieve the lowest consumption.
 //|
 //|     **If CircuitPython is connected to a host computer via USB or BLE
 //|     the first time a deep sleep is requested,