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

drivers/0x03_button/button.h

@@ -0,0 +1,80 @@
+/**
+ * @file button.h
+ * @brief Header for push-button GPIO input driver with debounce
+ * @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.
+ */
+
+#ifndef BUTTON_H
+#define BUTTON_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * @brief Initialize a GPIO pin as an active-low button input with pull-up
+ *
+ * Configures the pin as an input and enables the internal pull-up resistor.
+ * The pin reads logic high when the button is open and logic low when the
+ * button connects the pin to GND.
+ *
+ * @param pin         GPIO pin number to configure as a button input
+ * @param debounce_ms Debounce settling time in milliseconds (e.g. 20)
+ */
+void button_init(uint32_t pin, uint32_t debounce_ms);
+
+/**
+ * @brief Read the debounced state of the button
+ *
+ * Returns true only when the pin reads low continuously for the debounce
+ * period configured in button_init(). This prevents mechanical contact
+ * bounce from registering as multiple rapid presses.
+ *
+ * @param pin GPIO pin number previously initialized with button_init()
+ * @return bool true if the button is firmly pressed, false if released
+ */
+bool button_is_pressed(uint32_t pin);
+
+/**
+ * @brief Initialize a GPIO pin as a push-pull digital output for an indicator LED
+ *
+ * Configures the pin as a digital output and drives it low (LED off). Use
+ * together with button_led_set() to mirror button state visually.
+ *
+ * @param pin GPIO pin number to configure as an LED output
+ */
+void button_led_init(uint32_t pin);
+
+/**
+ * @brief Set the indicator LED state
+ *
+ * Drives the output pin high (LED on) or low (LED off).
+ *
+ * @param pin GPIO pin number previously initialized with button_led_init()
+ * @param on  true to turn the LED on, false to turn it off
+ */
+void button_led_set(uint32_t pin, bool on);
+
+#endif // BUTTON_H