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Subject[PATCH 4/4] clk: Add simple gated clock
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Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>

---
drivers/clk/Kconfig | 4 ++++
drivers/clk/Makefile | 1 +
drivers/clk/clk-gate.c | 41 +++++++++++++++++++++++++++++++++++++++++
include/linux/clk.h | 13 +++++++++++++
4 files changed, 59 insertions(+)

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 0a27963..75d2902 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -9,3 +9,7 @@ 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..833e0da
--- /dev/null
+++ b/drivers/clk/clk-gate.c
@@ -0,0 +1,41 @@
+
+#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 int clk_gate_enable(struct clk_hw *clk)
+{
+ struct clk_gate *gate = to_clk_gate(clk);
+ u32 reg;
+
+ reg = __raw_readl(gate->reg);
+ reg |= 1 << gate->bit_idx;
+ __raw_writel(reg, gate->reg);
+
+ return 0;
+}
+
+static void clk_gate_disable(struct clk_hw *clk)
+{
+ struct clk_gate *gate = to_clk_gate(clk);
+ u32 reg;
+
+ reg = __raw_readl(gate->reg);
+ reg &= ~(1 << gate->bit_idx);
+ __raw_writel(reg, gate->reg);
+}
+
+struct clk_hw_ops clk_gate_ops = {
+ .recalc_rate = clk_gate_get_rate,
+ .enable = clk_gate_enable,
+ .disable = clk_gate_disable,
+};
+EXPORT_SYMBOL_GPL(clk_gate_ops);
+
diff --git a/include/linux/clk.h b/include/linux/clk.h
index fd62e86..7c26135 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_ops;
+
+#endif /* CONFIG_GENERIC_CLK_GATE */
+
+
#else /* !CONFIG_GENERIC_CLK */

/*

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