Merge pull request #4234 from jflyper/bfdev-max7456-preinit-output-hi

Preinit for MAX7456 on Kakute F4 requires output hi.

src/main/drivers/bus_spi.h

@@ -87,6 +87,8 @@ typedef enum SPIDevice {
 #define SPI_DEV_TO_CFG(x)   ((x) + 1)
 
 void spiPreInitCs(ioTag_t iotag);
+void spiPreInitCsOutPU(ioTag_t iotag);
+
 bool spiInit(SPIDevice device);
 void spiSetDivisor(SPI_TypeDef *instance, uint16_t divisor);
 uint8_t spiTransferByte(SPI_TypeDef *instance, uint8_t data);

src/main/drivers/bus_spi_config.c

@@ -25,7 +25,14 @@
 
 // Bring a pin for possible CS line to pull-up state in preparation for
 // sequential initialization by relevant drivers.
-// Note that the pin is set to input for safety at this point.
+
+// There are two versions:
+// spiPreInitCs set the pin to input with pullup (IOCFG_IPU) for safety at this point.
+// spiPreInitCsOutPU which actually drive the pin for digital hi.
+//
+// The later is required for SPI slave devices on some targets, interfaced through level shifters, such as Kakute F4.
+// Note that with this handling, a pin declared as CS pin for MAX7456 needs special care when re-purposing the pin for other, especially, input uses.
+// This will/should be fixed when we go fully reconfigurable.
 
 void spiPreInitCs(ioTag_t iotag)
 {
@@ -35,3 +42,13 @@ void spiPreInitCs(ioTag_t iotag)
         IOConfigGPIO(io, IOCFG_IPU);
     }
 }
+
+void spiPreInitCsOutPU(ioTag_t iotag)
+{
+    IO_t io = IOGetByTag(iotag);
+    if (io) {
+        IOInit(io, OWNER_SPI_PREINIT, 0);
+        IOConfigGPIO(io, IOCFG_OUT_PP);
+        IOHi(io);
+    }
+}

src/main/fc/fc_init.c

@@ -213,7 +213,7 @@ void spiPreInit(void)
     spiPreInitCs(IO_TAG(L3GD20_CS_PIN));
 #endif
 #ifdef USE_MAX7456
-    spiPreInitCs(IO_TAG(MAX7456_SPI_CS_PIN));
+    spiPreInitCsOutPU(IO_TAG(MAX7456_SPI_CS_PIN)); // XXX 3.2 workaround for Kakute F4. See comment for spiPreInitCSOutPU.
 #endif
 #ifdef USE_SDCARD
     spiPreInitCs(IO_TAG(SDCARD_SPI_CS_PIN));