Allow ESP boards to customize how a pin is reset

ports/espressif/boards/adafruit_feather_esp32s2_tft/board.c

@@ -71,14 +71,6 @@ uint8_t display_init_sequence[] = {
 
 
 void board_init(void) {
-    // Never reset the I2C/TFT power pin because doing so will reset the display.
-    // Instead, on reset set the default value and free the pin for user use.
-    // Relying on the normal pin reset would briefly float/pull the pin that
-    // could lead to a power brownout.
-    common_hal_never_reset_pin(&pin_GPIO21);
-
-    reset_board();
-
     busio_spi_obj_t *spi = common_hal_board_create_spi(0);
     displayio_fourwire_obj_t *bus = &displays[0].fourwire_bus;
     bus->base.type = &displayio_fourwire_type;
@@ -99,7 +91,6 @@ void board_init(void) {
     // workaround as board_init() is called before reset_port() in main.c
     pwmout_reset();
 
-
     common_hal_displayio_display_construct(
         display,
         bus,
@@ -138,12 +129,18 @@ bool board_requests_safe_mode(void) {
     return false;
 }
 
-void reset_board(void) {
-    // Turn on TFT and I2C
-    gpio_set_direction(21, GPIO_MODE_DEF_OUTPUT);
-    gpio_set_level(21, true);
+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);
+        return true;
+    }
+    return false;
+}
 
-    free_pin_number(21);
+void reset_board(void) {
 }
 
 void board_deinit(void) {

ports/espressif/boards/adafruit_magtag_2.9_grayscale/board.c

@@ -172,6 +172,25 @@ void reset_board(void) {
 
 }
 
+bool espressif_board_reset_pin_number(gpio_num_t pin_number) {
+    // Pin 16 is speaker enable and it's pulled down on the board. We don't want
+    // to pull it high because then we'll compete with the external pull down.
+    // So, reset without any pulls internally.
+    if (pin_number == 16) {
+        gpio_config_t cfg = {
+            .pin_bit_mask = BIT64(16),
+            .mode = GPIO_MODE_DISABLE,
+            // The pin is externally pulled down, so we don't need to pull it.
+            .pull_up_en = false,
+            .pull_down_en = false,
+            .intr_type = GPIO_INTR_DISABLE,
+        };
+        gpio_config(&cfg);
+        return true;
+    }
+    return false;
+}
+
 void board_deinit(void) {
     displayio_epaperdisplay_obj_t *display = &displays[0].epaper_display;
     if (display->base.type == &displayio_epaperdisplay_type) {

ports/espressif/boards/microdev_micro_s2/board.c

@@ -28,6 +28,8 @@
 #include "mpconfigboard.h"
 #include "shared-bindings/microcontroller/Pin.h"
 
+#include "components/driver/include/driver/gpio.h"
+
 void board_init(void) {
     // Debug UART
     #ifdef DEBUG
@@ -40,6 +42,17 @@ bool board_requests_safe_mode(void) {
     return false;
 }
 
+bool espressif_board_reset_pin_number(gpio_num_t pin_number) {
+    // Pin 21 is a high side LED so pull it down to prevent lighting the LED.
+    if (pin_number == 21) {
+        gpio_reset_pin(21);
+        gpio_pullup_dis(21);
+        gpio_pulldown_en(21);
+        return true;
+    }
+    return false;
+}
+
 void reset_board(void) {
 }
 

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

@@ -50,6 +50,10 @@ void common_hal_never_reset_pin(const mcu_pin_obj_t *pin) {
     never_reset_pin_number(pin->number);
 }
 
+MP_WEAK bool espressif_board_reset_pin_number(gpio_num_t pin_number) {
+    return false;
+}
+
 STATIC void _reset_pin(gpio_num_t pin_number) {
     #if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32S3)
     // Never ever reset pins used for flash and RAM.
@@ -76,6 +80,11 @@ STATIC void _reset_pin(gpio_num_t pin_number) {
     }
     #endif
 
+    // Give the board a chance to reset the pin in a particular way.
+    if (espressif_board_reset_pin_number(pin_number)) {
+        return;
+    }
+
     gpio_reset_pin(pin_number);
 
     #ifdef DOUBLE_TAP_PIN
@@ -133,10 +142,6 @@ void claim_pin(const mcu_pin_obj_t *pin) {
     in_use[pin->number / 32] |= (1 << (pin->number % 32));
 }
 
-void free_pin_number(gpio_num_t pin_number) {
-    in_use[pin_number / 32] &= ~(1 << (pin_number % 32));
-}
-
 void common_hal_mcu_pin_claim(const mcu_pin_obj_t *pin) {
     claim_pin(pin);
 }

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

@@ -39,9 +39,13 @@ void common_hal_reset_pin(const mcu_pin_obj_t *pin);
 void common_hal_never_reset_pin(const mcu_pin_obj_t *pin);
 void claim_pin(const mcu_pin_obj_t *pin);
 void claim_pin_number(gpio_num_t pin_number);
-// Free the pin without resetting it.
-void free_pin_number(gpio_num_t pin_number);
 bool pin_number_is_free(gpio_num_t pin_number);
 void never_reset_pin_number(gpio_num_t pin_number);
 
+// 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.
+// Return true to indicate that the pin was reset. Returning false will lead to
+// the port-default reset behavior.
+bool espressif_board_reset_pin_number(gpio_num_t pin_number);
+
 #endif // MICROPY_INCLUDED_ESPRESSIF_COMMON_HAL_MICROCONTROLLER_PIN_H