New SPI invert hardware SS function in hall-spi and SPI library

cores/esp32/esp32-hal-spi.c

@@ -74,6 +74,7 @@ struct spi_struct_t {
   int8_t miso;
   int8_t mosi;
   int8_t ss;
+  bool ss_invert;
 };
 
 #if CONFIG_IDF_TARGET_ESP32S2
@@ -365,7 +366,7 @@ bool spiAttachSS(spi_t *spi, uint8_t ss_num, int8_t ss) {
     return false;
   }
   pinMode(ss, OUTPUT);
-  pinMatrixOutAttach(ss, SPI_SS_IDX(spi->num, ss_num), false, false);
+  pinMatrixOutAttach(ss, SPI_SS_IDX(spi->num, ss_num), spi->ss_invert, false);
   spiEnableSSPins(spi, (1 << ss_num));
   spi->ss = ss;
   if (!perimanSetPinBus(ss, ESP32_BUS_TYPE_SPI_MASTER_SS, (void *)(spi->num + 1), spi->num, -1)) {
@@ -435,6 +436,12 @@ void spiSSDisable(spi_t *spi) {
   SPI_MUTEX_UNLOCK();
 }
 
+void spiSSInvert(spi_t *spi, bool invert) {
+  if (spi) {
+    spi->ss_invert = invert;
+  }
+}
+
 void spiSSSet(spi_t *spi) {
   if (!spi) {
     return;

cores/esp32/esp32-hal-spi.h

@@ -97,6 +97,8 @@ void spiSSSet(spi_t *spi);
 void spiSSClear(spi_t *spi);
 
 void spiWaitReady(spi_t *spi);
+//invert hardware SS
+void spiSSInvert(spi_t *spi, bool invert);
 
 uint32_t spiGetClockDiv(spi_t *spi);
 uint8_t spiGetDataMode(spi_t *spi);

libraries/SPI/src/SPI.cpp

@@ -144,6 +144,12 @@ void SPIClass::setHwCs(bool use) {
   _use_hw_ss = use;
 }
 
+void SPIClass::setSSInvert(bool invert) {
+  if (_spi) {
+    spiSSInvert(_spi, invert);
+  }
+}
+
 void SPIClass::setFrequency(uint32_t freq) {
   SPI_PARAM_LOCK();
   //check if last freq changed

libraries/SPI/src/SPI.h

@@ -65,6 +65,7 @@ class SPIClass {
   void end();
 
   void setHwCs(bool use);
+  void setSSInvert(bool invert);  //use before setHwCS for change to be used by setHwCs
   void setBitOrder(uint8_t bitOrder);
   void setDataMode(uint8_t dataMode);
   void setFrequency(uint32_t freq);