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Subject[RFC,PATCH 2/2] clk: Generic support for fixed-rate clocks
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Since most platforms will need a fixed-rate clock, add one. This will
also serve as a basic example of an implementation of struct clk.

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>

---
include/linux/clk.h | 13 +++++++++++++
kernel/Makefile | 1 +
kernel/clk.c | 25 +++++++++++++++++++++++++
3 files changed, 39 insertions(+)
diff --git a/include/linux/clk.h b/include/linux/clk.h
index bb6957a..6269b44 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -123,6 +123,19 @@ static inline struct clk *clk_get_parent(struct clk *clk)
return ERR_PTR(-ENOSYS);
}

+/* Simple fixed-rate clock */
+struct clk_fixed {
+ struct clk clk;
+ unsigned long rate;
+};
+
+extern struct clk_ops clk_fixed_ops;
+
+#define INIT_CLK_FIXED(name, r) { \
+ .clk = INIT_CLK(name.clk, clk_fixed_ops), \
+ .rate = (r) \
+}
+
#else /* !CONFIG_USE_COMMON_STRUCT_CLK */

/*
diff --git a/kernel/Makefile b/kernel/Makefile
index 057472f..1ae15aa 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -105,6 +105,7 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
obj-$(CONFIG_PADATA) += padata.o
+obj-$(CONFIG_USE_COMMON_STRUCT_CLK) += clk.o

ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
diff --git a/kernel/clk.c b/kernel/clk.c
new file mode 100644
index 0000000..85c0670
--- /dev/null
+++ b/kernel/clk.c
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2010 Canonical Ltd <jeremy.kerr@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Standard functionality for the common clock API.
+ */
+
+#include <linux/module.h>
+#include <linux/clk.h>
+
+#define to_clk_fixed(clk) (container_of(clk, struct clk_fixed, clk))
+
+static unsigned long clk_fixed_get_rate(struct clk *clk)
+{
+ return to_clk_fixed(clk)->rate;
+}
+
+struct clk_ops clk_fixed_ops = {
+ .get_rate = clk_fixed_get_rate,
+};
+
+EXPORT_SYMBOL_GPL(clk_fixed_ops);

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