clk: Add a bypass clock for K210

This is a small driver to do a software bypass of a clock if hardware
bypass is not working. I have tried to write this in a generic fashion, so
that it could be potentially broken out of the kendryte code at some future
date. For the K210, it is used to have aclk bypass pll0 and use in0 instead
so that the CPU keeps on working.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
CC: Lukasz Majewski <lukma@denx.de>

1 files changed, 31 insertions, 0 deletions

diff --git a/include/kendryte/bypass.h b/include/kendryte/bypass.h
new file mode 100644
index 0000000000..a081cbd12f
--- /dev/null
+++ b/include/kendryte/bypass.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
+ */
+#ifndef K210_BYPASS_H
+#define K210_BYPASS_H
+
+#include <clk.h>
+
+struct k210_bypass {
+	struct clk clk;
+	struct clk **children; /* Clocks to reparent */
+	struct clk **saved_parents; /* Parents saved over en-/dis-able */
+	struct clk *bypassee; /* Clock to bypass */
+	const struct clk_ops *bypassee_ops; /* Ops of the bypass clock */
+	struct clk *alt; /* Clock to set children to when bypassing */
+	size_t child_count;
+};
+
+#define to_k210_bypass(_clk) container_of(_clk, struct k210_bypass, clk)
+
+int k210_bypass_set_children(struct clk *clk, struct clk **children,
+			     size_t child_count);
+struct clk *k210_register_bypass_struct(const char *name,
+					const char *parent_name,
+					struct k210_bypass *bypass);
+struct clk *k210_register_bypass(const char *name, const char *parent_name,
+				 struct clk *bypassee,
+				 const struct clk_ops *bypassee_ops,
+				 struct clk *alt);
+#endif /* K210_BYPASS_H */