gpio: detect esp8285 chip to allow the use of GPIO9 and GPIO10 (#1964)

* gpio: detect esp8285 chip to allow the use of GPIO9 and GPIO10

* add another reference to the current rtos headers (but not used anywhere in the sdk code)

* fix typo in register order

* fixup! fix typo in register order

code/espurna/espurna.ino

@@ -74,6 +74,9 @@ void setup() {
         debugSetup();
     #endif
 
+    // Init GPIO functions
+    gpioSetup();
+
     // Init RTCMEM
     rtcmemSetup();
 

code/espurna/gpio.ino

@@ -6,19 +6,21 @@ Copyright (C) 2017-2019 by Xose Pérez <xose dot perez at gmail dot com>
 
 */
 
-unsigned int _gpio_locked = 0;
+#include <bitset>
+
+constexpr const size_t GPIO_PINS = 16;
+
+std::bitset<GPIO_PINS> _gpio_locked;
+std::bitset<GPIO_PINS> _gpio_available;
 
 bool gpioValid(unsigned char gpio) {
-    if (gpio <= 5) return true;
-    if (12 <= gpio && gpio <= 15) return true;
-    return false;
+    return _gpio_available.test(gpio);
 }
 
 bool gpioGetLock(unsigned char gpio) {
     if (gpioValid(gpio)) {
-        unsigned int mask = 1 << gpio;
-        if ((_gpio_locked & mask) == 0) {
-            _gpio_locked |= mask;
+        if (!_gpio_locked.test(gpio)) {
+            _gpio_locked.set(gpio);
             DEBUG_MSG_P(PSTR("[GPIO] GPIO%u locked\n"), gpio);
             return true;
         }
@@ -29,11 +31,36 @@ bool gpioGetLock(unsigned char gpio) {
 
 bool gpioReleaseLock(unsigned char gpio) {
     if (gpioValid(gpio)) {
-        unsigned int mask = 1 << gpio;
-        _gpio_locked &= ~mask;
+        _gpio_locked.reset(gpio);
         DEBUG_MSG_P(PSTR("[GPIO] GPIO%u lock released\n"), gpio);
         return true;
     }
     DEBUG_MSG_P(PSTR("[GPIO] Failed releasing lock for GPIO%u\n"), gpio);
     return false;
 }
+
+void gpioSetup() {
+
+    // https://github.com/espressif/esptool/blob/f04d34bcab29ace798d2d3800ba87020cccbbfdd/esptool.py#L1060-L1070
+    // "One or the other efuse bit is set for ESP8285"
+    // https://github.com/espressif/ESP8266_RTOS_SDK/blob/3c055779e9793e5f082afff63a011d6615e73639/components/esp8266/include/esp8266/efuse_register.h#L20-L21
+    // "define EFUSE_IS_ESP8285    (1 << 4)"
+    const uint32_t efuse_blocks[4] {
+        READ_PERI_REG(0x3ff00050),
+        READ_PERI_REG(0x3ff00054),
+        READ_PERI_REG(0x3ff00058),
+        READ_PERI_REG(0x3ff0005c)
+    };
+
+    const bool esp8285 = (
+        (efuse_blocks[0] & (1 << 4))
+        || (efuse_blocks[2] & (1 << 16))
+    );
+
+    for (unsigned char pin=0; pin < GPIO_PINS; ++pin) {
+        if (pin <= 5) _gpio_available.set(pin);
+        if (((pin == 9) || (pin == 10)) && (esp8285)) _gpio_available.set(pin);
+        if (12 <= pin && pin <= 15) _gpio_available.set(pin);
+    }
+
+}