From c52890eed7680f9249909977e3bd26785aa3bd5a Mon Sep 17 00:00:00 2001
From: ourairquality <info@ourairquality.org>
Date: Tue, 30 Aug 2016 21:22:05 +1000
Subject: [PATCH] GPIO16 support.

---
 core/esp_gpio.c         | 17 +++++++++++++++++
 core/include/esp/gpio.h | 14 ++++++++++----
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/core/esp_gpio.c b/core/esp_gpio.c
index 8d12be1..f6db1ef 100644
--- a/core/esp_gpio.c
+++ b/core/esp_gpio.c
@@ -5,9 +5,26 @@
  * BSD Licensed as described in the file LICENSE
  */
 #include <esp/gpio.h>
+#include <esp/rtc_regs.h>
 
 void gpio_enable(const uint8_t gpio_num, const gpio_direction_t direction)
 {
+    if (gpio_num == 16) {
+        RTC.GPIO_CFG[3] = (RTC.GPIO_CFG[3] & 0xffffffbc) | 1;
+        RTC.GPIO_CONF = (RTC.GPIO_CONF & 0xfffffffe) | 0;
+        switch (direction) {
+        case GPIO_INPUT:
+            RTC.GPIO_ENABLE = (RTC.GPIO_OUT & 0xfffffffe);
+            break;
+        case GPIO_OUTPUT:
+        case GPIO_OUT_OPEN_DRAIN:
+            /* TODO open drain? */
+            RTC.GPIO_ENABLE = (RTC.GPIO_OUT & 0xfffffffe) | 1;
+            break;
+        }
+        return;
+    }
+
     switch (direction) {
     case GPIO_INPUT:
         GPIO.ENABLE_OUT_CLEAR = BIT(gpio_num);
diff --git a/core/include/esp/gpio.h b/core/include/esp/gpio.h
index 80fd43f..f3f6308 100644
--- a/core/include/esp/gpio.h
+++ b/core/include/esp/gpio.h
@@ -10,6 +10,7 @@
 #define _ESP_GPIO_H
 #include <stdbool.h>
 #include "esp/gpio_regs.h"
+#include "esp/rtc_regs.h"
 #include "esp/iomux.h"
 #include "esp/interrupts.h"
 
@@ -23,7 +24,7 @@ typedef enum {
     GPIO_OUT_OPEN_DRAIN, /* Open drain output */
 } gpio_direction_t;
 
-/* Enable GPIO on the specified pin, and set it to input or output mode
+/* Enable GPIO on the specified pin, and set it to input or output mode.
  */
 void gpio_enable(const uint8_t gpio_num, const gpio_direction_t direction);
 
@@ -80,7 +81,9 @@ static inline void gpio_set_output_on_sleep(const uint8_t gpio_num, bool enabled
  */
 static inline void gpio_write(const uint8_t gpio_num, const bool set)
 {
-    if (set)
+    if (gpio_num == 16) {
+        RTC.GPIO_OUT = (RTC.GPIO_OUT & 0xfffffffe) | (set ? 1 : 0);
+    } else if (set)
         GPIO.OUT_SET = BIT(gpio_num) & GPIO_OUT_PIN_MASK;
     else
         GPIO.OUT_CLEAR = BIT(gpio_num) & GPIO_OUT_PIN_MASK;
@@ -101,7 +104,7 @@ static inline void gpio_toggle(const uint8_t gpio_num)
        get an invalid value. Prevents one task from clobbering another
        task's pins, without needing to disable/enable interrupts.
     */
-    if(GPIO.OUT & BIT(gpio_num))
+    if (GPIO.OUT & BIT(gpio_num))
         GPIO.OUT_CLEAR = BIT(gpio_num) & GPIO_OUT_PIN_MASK;
     else
         GPIO.OUT_SET = BIT(gpio_num) & GPIO_OUT_PIN_MASK;
@@ -118,7 +121,10 @@ static inline void gpio_toggle(const uint8_t gpio_num)
  */
 static inline bool gpio_read(const uint8_t gpio_num)
 {
-    return GPIO.IN & BIT(gpio_num);
+    if (gpio_num == 16)
+        return RTC.GPIO_IN & 1;
+    else
+        return GPIO.IN & BIT(gpio_num);
 }
 
 extern void gpio_interrupt_handler(void);