diff --git a/mcp6x_spi.c b/mcp6x_spi.c
index dd76e60..bf09628 100644
--- a/mcp6x_spi.c
+++ b/mcp6x_spi.c
@@ -150,7 +150,7 @@
 		 (status >> MCP6X_SPI_GRANT) & 0x1);
 	mcp_gpiostate = status & 0xff;
 
-	if (register_spi_bitbang_master(&bitbang_spi_master_mcp6x)) {
+	if (register_spi_bitbang_master(&bitbang_spi_master_mcp6x, NULL)) {
 		/* This should never happen. */
 		msg_perr("MCP6X bitbang SPI master init failed!\n");
 		return 1;