avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/include/pca953x.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2008 Extreme Engineering Solutions, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#ifndef __PCA953X_H_
+#define __PCA953X_H_
+
+#define PCA953X_IN		0x00
+#define PCA953X_OUT		0x01
+#define PCA953X_POL		0x02
+#define PCA953X_CONF		0x03
+
+#define PCA953X_OUT_LOW		0
+#define PCA953X_OUT_HIGH	1
+#define PCA953X_POL_NORMAL	0
+#define PCA953X_POL_INVERT	1
+#define PCA953X_DIR_OUT		0
+#define PCA953X_DIR_IN		1
+
+int pca953x_set_val(u8 chip, uint mask, uint data);
+int pca953x_set_pol(u8 chip, uint mask, uint data);
+int pca953x_set_dir(u8 chip, uint mask, uint data);
+int pca953x_get_val(u8 chip);
+
+#endif /* __PCA953X_H_ */