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/drivers/i2c/muxes/pca954x.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2015 - 2016 Xilinx, Inc.
+ * Written by Michal Simek
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <i2c.h>
+#include <asm/gpio.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct pca954x_priv {
+	u32 addr; /* I2C mux address */
+	u32 width; /* I2C mux width - number of busses */
+};
+
+static int pca954x_deselect(struct udevice *mux, struct udevice *bus,
+			    uint channel)
+{
+	struct pca954x_priv *priv = dev_get_priv(mux);
+	uchar byte = 0;
+
+	return dm_i2c_write(mux, priv->addr, &byte, 1);
+}
+
+static int pca954x_select(struct udevice *mux, struct udevice *bus,
+			  uint channel)
+{
+	struct pca954x_priv *priv = dev_get_priv(mux);
+	uchar byte = 1 << channel;
+
+	return dm_i2c_write(mux, priv->addr, &byte, 1);
+}
+
+static const struct i2c_mux_ops pca954x_ops = {
+	.select = pca954x_select,
+	.deselect = pca954x_deselect,
+};
+
+static const struct udevice_id pca954x_ids[] = {
+	{ .compatible = "nxp,pca9548", .data = (ulong)8 },
+	{ .compatible = "nxp,pca9544", .data = (ulong)4 },
+	{ }
+};
+
+static int pca954x_ofdata_to_platdata(struct udevice *dev)
+{
+	struct pca954x_priv *priv = dev_get_priv(dev);
+
+	priv->addr = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "reg", 0);
+	if (!priv->addr) {
+		debug("MUX not found\n");
+		return -ENODEV;
+	}
+	priv->width = dev_get_driver_data(dev);
+
+	if (!priv->width) {
+		debug("No I2C MUX width specified\n");
+		return -EINVAL;
+	}
+
+	debug("Device %s at 0x%x with width %d\n",
+	      dev->name, priv->addr, priv->width);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(pca954x) = {
+	.name = "pca954x",
+	.id = UCLASS_I2C_MUX,
+	.of_match = pca954x_ids,
+	.ops = &pca954x_ops,
+	.ofdata_to_platdata = pca954x_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct pca954x_priv),
+};