From bcff0549fc9084d6d3eeaf190cf7cc2471fef19e Mon Sep 17 00:00:00 2001
From: William Vinnicombe <william.vinnicombe@raspberrypi.com>
Date: Fri, 5 Sep 2025 15:56:01 +0100
Subject: [PATCH] Implement low_power_sleep_until_irq

Add to hello_sleep_gpio test using chars_available_callback
---
 src/rp2_common/pico_low_power/low_power.c | 20 ++++++++++++++++++++
 test/hello_sleep/hello_sleep_gpio.c       | 16 ++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/src/rp2_common/pico_low_power/low_power.c b/src/rp2_common/pico_low_power/low_power.c
index db684c2a..d12e02fe 100644
--- a/src/rp2_common/pico_low_power/low_power.c
+++ b/src/rp2_common/pico_low_power/low_power.c
@@ -182,6 +182,26 @@ static void restore_other_interrupts(void) {
     }
 }
 
+int low_power_sleep_until_irq(const clock_dest_set_t *keep_enabled) {
+    clock_dest_set_t local_keep_enabled;
+    replace_null_enable_values(keep_enabled, &local_keep_enabled);
+
+    add_stdio_clocks(&local_keep_enabled);
+
+    prepare_for_clock_gating();
+    // gate clocks
+    clock_gate_sleep_en(&local_keep_enabled);
+
+    low_power_enable_processor_deep_sleep();
+    // Go to sleep until any event happens
+    __wfi();
+    low_power_disable_processor_deep_sleep();
+
+    post_clock_gating();
+
+    return 0;
+}
+
 // only the deep_sleep variant of this, as DORMANT cannot wake from TIMER
 int low_power_sleep_until_timer(timer_hw_t *timer, absolute_time_t until,
                                 const clock_dest_set_t *keep_enabled, bool exclusive) {
diff --git a/test/hello_sleep/hello_sleep_gpio.c b/test/hello_sleep/hello_sleep_gpio.c
index 0a925cee..f2789f61 100644
--- a/test/hello_sleep/hello_sleep_gpio.c
+++ b/test/hello_sleep/hello_sleep_gpio.c
@@ -24,6 +24,13 @@ bool repeater(repeating_timer_t *timer) {
     return true;
 }
 
+void chars_available_callback(__unused void *param) {
+    char buf[16] = {0};
+    while (stdio_get_until(buf, sizeof(buf), make_timeout_time_us(10)) > 0) {
+        printf("Chars available callback: %s\n", buf);
+    }
+}
+
 #if HAS_POWMAN_TIMER
 static bool came_from_pstate = false;
 static char powman_last_pwrup[100];
@@ -61,6 +68,9 @@ int main() {
     repeating_timer_t repeat;
     add_repeating_timer_ms(500, repeater, NULL, &repeat);
 
+    // test stdio_set_chars_available_callback
+    stdio_set_chars_available_callback(chars_available_callback, NULL);
+
 #if HAS_POWMAN_TIMER
     if (came_from_pstate) {
         printf("Came from powerup %s with (%s) memory kept on - skipping to end\n", powman_last_pwrup, powman_last_pstate);
@@ -96,6 +106,12 @@ int main() {
     printf("Doing %d second pause to prove timer running\n", SLEEP_TIME_S);
     busy_wait_ms(SLEEP_TIME_MS);
 
+    printf("Going to sleep until any wakeup (expecting stdin characters)\n");
+
+    low_power_sleep_until_irq(NULL);
+    printf("Doing %d second pause to prove timer running\n", SLEEP_TIME_S);
+    busy_wait_ms(SLEEP_TIME_MS);
+
     // todo, ah; we should start the aon timer; still have to decide what to do about keeping them in sync
     start_time = get_absolute_time();
     us_to_timespec(start_time, &ts);