Open drain output option for IO expander interrupt

Author: James Wilson

hal/inc/hal_platform.h

@@ -354,6 +354,9 @@
 # ifndef HAL_PLATFORM_MCP23S17_MIRROR_INTERRUPTS
 #  define HAL_PLATFORM_MCP23S17_MIRROR_INTERRUPTS (0)
 # endif // HAL_PLATFORM_MCP23S17_MIRROR_INTERRUPTS
+# ifndef HAL_PLATFORM_MCP23S17_OPEN_DRAIN_INT
+#  define HAL_PLATFORM_MCP23S17_OPEN_DRAIN_INT (0)
+# endif // HAL_PLATFORM_MCP23S17_OPEN_DRAIN_INT
 #endif /* HAL_PLATFORM_MCP23S17 */
 
 #ifndef HAL_PLATFORM_DEMUX

hal/shared/mcp23s17.cpp

@@ -135,9 +135,19 @@ int Mcp23s17::reset(bool verify) {
     hal_gpio_write(IOE_RST, 1);
     HAL_Delay_Milliseconds(10);
 
+#if HAL_PLATFORM_MCP23S17_MIRROR_INTERRUPTS || HAL_PLATFORM_MCP23S17_OPEN_DRAIN_INT
+    uint8_t iocon {};
+
 #if HAL_PLATFORM_MCP23S17_MIRROR_INTERRUPTS
-    CHECK(writeRegister(IOCON_ADDR[0], 1u << 6));
+    iocon |= 1u << 6;
+#endif
+#if HAL_PLATFORM_MCP23S17_OPEN_DRAIN_INT
+    iocon |= 1u << 2;
 #endif
+
+    CHECK(writeRegister(IOCON_ADDR[0], iocon));
+#endif
+
     if (verify) {
         uint8_t tmp[22] = {0x00};
         CHECK(readContinuousRegisters(IODIR_ADDR[0], tmp, sizeof(tmp)));

hal/src/trackerm/hal_platform_config.h

@@ -34,6 +34,7 @@
 #define HAL_PLATFORM_MCP23S17_SPI (HAL_SPI_INTERFACE1)
 #define HAL_PLATFORM_MCP23S17_SPI_CLOCK (16000000)
 #define HAL_PLATFORM_MCP23S17_MIRROR_INTERRUPTS (1)
+#define HAL_PLATFORM_MCP23S17_OPEN_DRAIN_INT (1)
 #define HAL_PLATFORM_DEMUX (1)
 
 #if defined(MODULE_FUNCTION) && MODULE_FUNCTION != 2 // MOD_FUNC_BOOTLOADER