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/clk/clk_sandbox.c

@@ -0,0 +1,107 @@
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <errno.h>
+#include <asm/clk.h>
+
+struct sandbox_clk_priv {
+	ulong rate[SANDBOX_CLK_ID_COUNT];
+	bool enabled[SANDBOX_CLK_ID_COUNT];
+};
+
+static ulong sandbox_clk_get_rate(struct clk *clk)
+{
+	struct sandbox_clk_priv *priv = dev_get_priv(clk->dev);
+
+	if (clk->id >= SANDBOX_CLK_ID_COUNT)
+		return -EINVAL;
+
+	return priv->rate[clk->id];
+}
+
+static ulong sandbox_clk_set_rate(struct clk *clk, ulong rate)
+{
+	struct sandbox_clk_priv *priv = dev_get_priv(clk->dev);
+	ulong old_rate;
+
+	if (clk->id >= SANDBOX_CLK_ID_COUNT)
+		return -EINVAL;
+
+	if (!rate)
+		return -EINVAL;
+
+	old_rate = priv->rate[clk->id];
+	priv->rate[clk->id] = rate;
+
+	return old_rate;
+}
+
+static int sandbox_clk_enable(struct clk *clk)
+{
+	struct sandbox_clk_priv *priv = dev_get_priv(clk->dev);
+
+	if (clk->id >= SANDBOX_CLK_ID_COUNT)
+		return -EINVAL;
+
+	priv->enabled[clk->id] = true;
+
+	return 0;
+}
+
+static int sandbox_clk_disable(struct clk *clk)
+{
+	struct sandbox_clk_priv *priv = dev_get_priv(clk->dev);
+
+	if (clk->id >= SANDBOX_CLK_ID_COUNT)
+		return -EINVAL;
+
+	priv->enabled[clk->id] = false;
+
+	return 0;
+}
+
+static struct clk_ops sandbox_clk_ops = {
+	.get_rate	= sandbox_clk_get_rate,
+	.set_rate	= sandbox_clk_set_rate,
+	.enable		= sandbox_clk_enable,
+	.disable	= sandbox_clk_disable,
+};
+
+static const struct udevice_id sandbox_clk_ids[] = {
+	{ .compatible = "sandbox,clk" },
+	{ }
+};
+
+U_BOOT_DRIVER(clk_sandbox) = {
+	.name		= "clk_sandbox",
+	.id		= UCLASS_CLK,
+	.of_match	= sandbox_clk_ids,
+	.ops		= &sandbox_clk_ops,
+	.priv_auto_alloc_size = sizeof(struct sandbox_clk_priv),
+};
+
+ulong sandbox_clk_query_rate(struct udevice *dev, int id)
+{
+	struct sandbox_clk_priv *priv = dev_get_priv(dev);
+
+	if (id < 0 || id >= SANDBOX_CLK_ID_COUNT)
+		return -EINVAL;
+
+	return priv->rate[id];
+}
+
+int sandbox_clk_query_enable(struct udevice *dev, int id)
+{
+	struct sandbox_clk_priv *priv = dev_get_priv(dev);
+
+	if (id < 0 || id >= SANDBOX_CLK_ID_COUNT)
+		return -EINVAL;
+
+	return priv->enabled[id];
+}