feat(spi): Add return values to SPI begin + comments on SPI buses

cores/esp32/esp32-hal-spi.h

@@ -38,8 +38,8 @@ extern "C" {
 #define HSPI 2  //SPI 2 bus normally mapped to pins 12 - 15, but can be matrixed to any pins
 #define VSPI 3  //SPI 3 bus normally attached to pins 5, 18, 19 and 23, but can be matrixed to any pins
 #else
-#define FSPI 0
-#define HSPI 1
+#define FSPI 0  // ESP32C2, C3, C6, H2, S3, P4 - SPI 2 bus
+#define HSPI 1  // ESP32S3, P4 - SPI 3 bus
 #endif
 
 // This defines are not representing the real Divider of the ESP32

libraries/SPI/src/SPI.cpp

@@ -63,9 +63,9 @@ SPIClass::~SPIClass() {
 #endif
 }
 
-void SPIClass::begin(int8_t sck, int8_t miso, int8_t mosi, int8_t ss) {
+bool SPIClass::begin(int8_t sck, int8_t miso, int8_t mosi, int8_t ss) {
   if (_spi) {
-    return;
+    return true;
   }
 
   if (!_div) {
@@ -74,7 +74,7 @@ void SPIClass::begin(int8_t sck, int8_t miso, int8_t mosi, int8_t ss) {
 
   _spi = spiStartBus(_spi_num, _div, SPI_MODE0, SPI_MSBFIRST);
   if (!_spi) {
-    return;
+    return false;
   }
 
   if (sck == -1 && miso == -1 && mosi == -1 && ss == -1) {
@@ -110,10 +110,11 @@ void SPIClass::begin(int8_t sck, int8_t miso, int8_t mosi, int8_t ss) {
   if (_mosi >= 0 && !spiAttachMOSI(_spi, _mosi)) {
     goto err;
   }
-  return;
+  return true;
 
 err:
   log_e("Attaching pins to SPI failed.");
+  return false;
 }
 
 void SPIClass::end() {

libraries/SPI/src/SPI.h

@@ -61,7 +61,7 @@ class SPIClass {
 public:
   SPIClass(uint8_t spi_bus = HSPI);
   ~SPIClass();
-  void begin(int8_t sck = -1, int8_t miso = -1, int8_t mosi = -1, int8_t ss = -1);
+  bool begin(int8_t sck = -1, int8_t miso = -1, int8_t mosi = -1, int8_t ss = -1);
   void end();
 
   void setHwCs(bool use);