Refactor Rust drivers for strict idiomatic documentation and 8-line enforcement

drivers/0x0d_timer/0x0d_timer.c

@@ -0,0 +1,58 @@
+/**
+ * @file 0x0d_timer.c
+ * @brief Repeating timer demo using timer.c/timer.h
+ * @author Kevin Thomas
+ * @date 2025
+ *
+ * MIT License
+ *
+ * Copyright (c) 2025 Kevin Thomas
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Demonstrates repeating timer callbacks using the timer driver
+ * (timer.h / timer.c). A one-second heartbeat timer prints a message
+ * over UART to confirm the timer is firing.
+ *
+ * Wiring:
+ *   No external wiring required
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "timer.h"
+
+/**
+ * @brief Heartbeat timer callback that prints a message over UART
+ *
+ * @return bool true to keep the repeating timer active
+ */
+static bool heartbeat_callback(void) {
+    printf("Timer heartbeat\r\n");
+    return true;
+}
+
+int main(void) {
+    stdio_init_all();
+    timer_driver_start(1000, heartbeat_callback);
+    while (true)
+        tight_loop_contents();
+}