Add docs

Author: multiplemonomials

targets/TARGET_Ambiq_Micro/TARGET_Apollo3/device/gpio_api.c

@@ -25,8 +25,6 @@
 #include "gpio_api.h"
 #include "PeripheralPins.h"
 
-#include <string.h>
-
 /** Set the given pin as GPIO
  *
  * @param pin The pin to be set as GPIO

targets/TARGET_Ambiq_Micro/TARGET_Apollo3/device/objects_gpio.h

@@ -64,8 +64,8 @@ typedef enum {
 typedef struct _gpio_t {
     ap3_gpio_pad_t pad;
     am_hal_gpio_pincfg_t cfg;
-    bool openDrain;
-    bool isOutput;
+    bool openDrain; ///< Whether the pin is configured open drain as of the last gpio_mode() call
+    bool isOutput; ///< Whether the pin is configured as an output as of the last gpio_dir() call
 } gpio_t;
 
 typedef struct ap3_gpio_irq_control_t {