From b45b2722d842c9ae4c2f7800a3b767bfd82bd4b9 Mon Sep 17 00:00:00 2001
From: Laurens Valk <laurens@pybricks.com>
Date: Mon, 6 Oct 2025 14:11:47 +0200
Subject: [PATCH] pbio/drv/button_gpio: Wait for release and delay on power
 down.

Fixes https://github.com/pybricks/support/issues/2176
---
 lib/pbio/drv/button/button.h                 |  6 ++++++
 lib/pbio/drv/button/button_gpio.c            | 19 ++++++++++++++++---
 lib/pbio/drv/button/button_nxt.c             |  3 +++
 lib/pbio/drv/button/button_resistor_ladder.c |  3 +++
 lib/pbio/drv/button/button_test.c            |  3 +++
 lib/pbio/drv/core.c                          |  1 +
 6 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/lib/pbio/drv/button/button.h b/lib/pbio/drv/button/button.h
index cbdea165b..1b11a4045 100644
--- a/lib/pbio/drv/button/button.h
+++ b/lib/pbio/drv/button/button.h
@@ -15,9 +15,15 @@
  */
 void pbdrv_button_init(void);
 
+/**
+ * De-initializes the low level button driver.
+ */
+void pbdrv_button_deinit(void);
+
 #else
 
 #define pbdrv_button_init()
+#define pbdrv_button_deinit()
 
 #endif
 
diff --git a/lib/pbio/drv/button/button_gpio.c b/lib/pbio/drv/button/button_gpio.c
index 3df64a93a..4248dfabd 100644
--- a/lib/pbio/drv/button/button_gpio.c
+++ b/lib/pbio/drv/button/button_gpio.c
@@ -9,6 +9,7 @@
 
 #include <pbdrv/gpio.h>
 #include <pbio/button.h>
+#include <pbio/busy_count.h>
 #include <pbio/config.h>
 #include <pbio/error.h>
 #include <pbio/os.h>
@@ -49,7 +50,9 @@ pbio_error_t pbdrv_button_process_thread(pbio_os_state_t *state, void *context)
 
     pbio_os_timer_set(&timer, 10);
 
-    for (;;) {
+    // Loop until cancellation is requested on power off and buttons are released.
+    while (!pbdrv_button_process.request || pbdrv_button_state) {
+
         PBIO_OS_AWAIT_UNTIL(state, pbio_os_timer_is_expired(&timer));
 
         next = pbdrv_button_gpio_read();
@@ -64,8 +67,11 @@ pbio_error_t pbdrv_button_process_thread(pbio_os_state_t *state, void *context)
         pbio_os_timer_extend(&timer);
     }
 
-    // Unreachable
-    PBIO_OS_ASYNC_END(PBIO_ERROR_FAILED);
+    // Wait a while after release to prevent accidental power on.
+    PBIO_OS_AWAIT_MS(state, &timer, 200);
+    pbio_busy_count_down();
+
+    PBIO_OS_ASYNC_END(PBIO_ERROR_CANCELED);
 }
 
 #endif // PBDRV_CONFIG_BUTTON_GPIO_DEBOUNCE
@@ -90,4 +96,11 @@ void pbdrv_button_init(void) {
     #endif
 }
 
+void pbdrv_button_deinit(void) {
+    #if PBDRV_CONFIG_BUTTON_GPIO_DEBOUNCE
+    pbio_busy_count_up();
+    pbio_os_process_make_request(&pbdrv_button_process, PBIO_OS_PROCESS_REQUEST_TYPE_CANCEL);
+    #endif
+}
+
 #endif // PBDRV_CONFIG_BUTTON_GPIO
diff --git a/lib/pbio/drv/button/button_nxt.c b/lib/pbio/drv/button/button_nxt.c
index ccad088f1..bb16f5c68 100644
--- a/lib/pbio/drv/button/button_nxt.c
+++ b/lib/pbio/drv/button/button_nxt.c
@@ -14,6 +14,9 @@
 void pbdrv_button_init(void) {
 }
 
+void pbdrv_button_deinit(void) {
+}
+
 pbio_button_flags_t pbdrv_button_get_pressed(void) {
 
     nx_avr_button_t button = nx_avr_get_button();
diff --git a/lib/pbio/drv/button/button_resistor_ladder.c b/lib/pbio/drv/button/button_resistor_ladder.c
index cc7e00b3f..8c09d62d7 100644
--- a/lib/pbio/drv/button/button_resistor_ladder.c
+++ b/lib/pbio/drv/button/button_resistor_ladder.c
@@ -48,6 +48,9 @@ void pbdrv_button_init(void) {
     pbio_os_process_start(&pbdrv_button_init_process, pbdrv_button_init_process_thread, NULL);
 }
 
+void pbdrv_button_deinit(void) {
+}
+
 pbio_button_flags_t pbdrv_button_get_pressed(void) {
     pbdrv_resistor_ladder_ch_flags_t flags;
     pbio_error_t err;
diff --git a/lib/pbio/drv/button/button_test.c b/lib/pbio/drv/button/button_test.c
index b365a6848..d82d1c118 100644
--- a/lib/pbio/drv/button/button_test.c
+++ b/lib/pbio/drv/button/button_test.c
@@ -19,6 +19,9 @@ void pbio_test_button_set_pressed(pbio_button_flags_t flags) {
 void pbdrv_button_init(void) {
 }
 
+void pbdrv_button_deinit(void) {
+}
+
 pbio_button_flags_t pbdrv_button_get_pressed(void) {
     return pbio_test_button_flags;
 }
diff --git a/lib/pbio/drv/core.c b/lib/pbio/drv/core.c
index 4017fc93c..b485ac0c9 100644
--- a/lib/pbio/drv/core.c
+++ b/lib/pbio/drv/core.c
@@ -89,6 +89,7 @@ void pbdrv_deinit(void) {
 
     pbdrv_imu_deinit();
     pbdrv_bluetooth_deinit();
+    pbdrv_button_deinit();
 
     while (pbio_busy_count_busy()) {
         pbio_os_run_processes_and_wait_for_event();