clk: initial common clk support

This adds barebox common clk support loosely based on the Kernel common
clk support. differences are:

- barebox does not need prepare/unprepare
- no parent rate propagation for set_rate
- struct clk is not really encapsulated from the drivers

Along with the clk support we have support for some basic clk building
blocks:

- clk-fixed
- clk-fixed-factor
- clk-mux
- clk-divider

clk-fixed and clk-fixed-factor are completely generic, clk-mux and clk-divider
are currently the way i.MX muxes/dividers are implemented.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/clk/clk-fixed.c b/drivers/clk/clk-fixed.c
new file mode 100644
index 0000000000..fa89cb2840
--- /dev/null
+++ b/drivers/clk/clk-fixed.c
@@ -0,0 +1,55 @@
+/*
+ * clk-fixed.c - generic barebox clock support. Based on Linux clk support
+ *
+ * Copyright (c) 2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <common.h>
+#include <malloc.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+struct clk_fixed {
+	struct clk clk;
+	unsigned long rate;
+};
+
+static unsigned long clk_fixed_recalc_rate(struct clk *clk,
+		unsigned long parent_rate)
+{
+	struct clk_fixed *fix = container_of(clk, struct clk_fixed, clk);
+
+	return fix->rate;
+}
+
+struct clk_ops clk_fixed_ops = {
+	.recalc_rate = clk_fixed_recalc_rate,
+};
+
+struct clk *clk_fixed(const char *name, int rate)
+{
+	struct clk_fixed *fix = xzalloc(sizeof *fix);
+	int ret;
+
+	fix->rate = rate;
+	fix->clk.ops = &clk_fixed_ops;
+	fix->clk.name = name;
+
+	ret = clk_register(&fix->clk);
+	if (ret) {
+		free(fix);
+		return ERR_PTR(ret);
+	}
+
+	return &fix->clk;
+}