1 files changed, 33 insertions, 0 deletions
diff --git a/libhw/rp2040_gpioirq.h b/libhw/rp2040_gpioirq.h
new file mode 100644
index 0000000..06041c9
--- /dev/null
+++ b/libhw/rp2040_gpioirq.h
@@ -0,0 +1,33 @@
+/* libhw/rp2040_gpioirq.h - Utilities for sharing the GPIO IRQ (IO_IRQ_BANK0)
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _LIBHW_RP2040_GPIOIRQ_H_
+#define _LIBHW_RP2040_GPIOIRQ_H_
+
+#include <hardware/gpio.h> /* for enum gpio_irq_level */
+
+typedef void (*gpioirq_handler_t)(void *arg, uint gpio, enum gpio_irq_level event);
+
+/**
+ * Register `fn(arg, ...)` to be called when `event` fires on GPIO pin
+ * `gpio`.
+ *
+ * If multiple events happen close together, the handlers will not
+ * necessarily be called in-order.
+ *
+ * Your handler does not need to acknowledge the IRQ; that will be
+ * done for you after your handler is called.
+ *
+ * It is illegal to call gpioirq_set_and_enable_exclusive_handler()
+ * on multiple cores.
+ *
+ * This is better than the Pico-SDK <hardware/gpio.h> IRQ functions
+ * because their functions call the handlers for every event, and it
+ * is up to you to de-mux them in your handler.
+ */
+void gpioirq_set_and_enable_exclusive_handler(uint gpio, enum gpio_irq_level event, gpioirq_handler_t fn, void *arg);
+
+#endif /* _LIBHW_RP2040_GPIOIRQ_H_ */