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Subject[PATCH v2 4/7] clk: Add simple gated clock
Date
From: Jeremy Kerr <jeremy.kerr@canonical.com>

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Mike Turquette <mturquette@ti.com>
---
Changes since v1:
Add copyright header
Fold in Jamie's patch for set-to-disable clks
Use BIT macro instead of shift

drivers/clk/Kconfig | 4 ++
drivers/clk/Makefile | 1 +
drivers/clk/clk-gate.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/clk.h | 13 ++++++++
4 files changed, 96 insertions(+), 0 deletions(-)
create mode 100644 drivers/clk/clk-gate.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index d8313d7..a78967c 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -12,3 +12,7 @@ config GENERIC_CLK
config GENERIC_CLK_FIXED
bool
depends on GENERIC_CLK
+
+config GENERIC_CLK_GATE
+ bool
+ depends on GENERIC_CLK
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 9a3325a..d186446 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -2,3 +2,4 @@
obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o
obj-$(CONFIG_GENERIC_CLK) += clk.o
obj-$(CONFIG_GENERIC_CLK_FIXED) += clk-fixed.o
+obj-$(CONFIG_GENERIC_CLK_GATE) += clk-gate.o
diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
new file mode 100644
index 0000000..a1d8e79
--- /dev/null
+++ b/drivers/clk/clk-gate.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2010-2011 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.
+ *
+ * Simple clk gate implementation
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <asm/io.h>
+
+#define to_clk_gate(clk) container_of(clk, struct clk_gate, hw)
+
+static unsigned long clk_gate_get_rate(struct clk_hw *clk)
+{
+ return clk_get_rate(clk_get_parent(clk->clk));
+}
+
+static void clk_gate_set_bit(struct clk_hw *clk)
+{
+ struct clk_gate *gate = to_clk_gate(clk);
+ u32 reg;
+
+ reg = __raw_readl(gate->reg);
+ reg |= BIT(gate->bit_idx);
+ __raw_writel(reg, gate->reg);
+}
+
+static void clk_gate_clear_bit(struct clk_hw *clk)
+{
+ struct clk_gate *gate = to_clk_gate(clk);
+ u32 reg;
+
+ reg = __raw_readl(gate->reg);
+ reg &= ~BIT(gate->bit_idx);
+ __raw_writel(reg, gate->reg);
+}
+
+static int clk_gate_enable_set(struct clk_hw *clk)
+{
+ clk_gate_set_bit(clk);
+
+ return 0;
+}
+
+static void clk_gate_disable_clear(struct clk_hw *clk)
+{
+ clk_gate_clear_bit(clk);
+}
+
+struct clk_hw_ops clk_gate_set_enable_ops = {
+ .recalc_rate = clk_gate_get_rate,
+ .enable = clk_gate_enable_set,
+ .disable = clk_gate_disable_clear,
+};
+EXPORT_SYMBOL_GPL(clk_gate_set_enable_ops);
+
+static int clk_gate_enable_clear(struct clk_hw *clk)
+{
+ clk_gate_clear_bit(clk);
+
+ return 0;
+}
+
+static void clk_gate_disable_set(struct clk_hw *clk)
+{
+ clk_gate_set_bit(clk);
+}
+
+struct clk_hw_ops clk_gate_set_disable_ops = {
+ .recalc_rate = clk_gate_get_rate,
+ .enable = clk_gate_enable_clear,
+ .disable = clk_gate_disable_set,
+};
+EXPORT_SYMBOL_GPL(clk_gate_set_disable_ops);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 1903dd8..626fd0d 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -124,6 +124,19 @@ extern struct clk_hw_ops clk_fixed_ops;

#endif /* CONFIG_GENERIC_CLK_FIXED */

+#ifdef CONFIG_GENERIC_CLK_GATE
+
+struct clk_gate {
+ struct clk_hw hw;
+ void __iomem *reg;
+ u8 bit_idx;
+};
+
+extern struct clk_hw_ops clk_gate_set_enable_ops;
+extern struct clk_hw_ops clk_gate_set_disable_ops;
+
+#endif /* CONFIG_GENERIC_CLK_GATE */
+
/**
* clk_register - register and initialize a new clock
*
--
1.7.4.1


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