On Tue, Oct 11, 2011 at 11:46 PM, Richard Zhao
[off-list ref] wrote:

On Thu, Sep 22, 2011 at 03:26:59PM -0700, Mike Turquette wrote:

quoted

From: Jeremy Kerr <redacted>

Signed-off-by: Jeremy Kerr <redacted>
Signed-off-by: Mark Brown <redacted>
Signed-off-by: Jamie Iles <redacted>
Signed-off-by: Mike Turquette <redacted>
---
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

I feel hard to tell the tree the clk parent, at register/init time. For the
simple gate clk, the only way is to set .get_parent. But normally, for clk
without any divider we set .get_parent to NULL. Maybe we can put .parent to
struct clk_hw?

For non-mux clocks, whose parent is *always* going to be the same, you
should create a duplicate .parent in the clk_hw_* structure and then
have .get_parent return clk_hw_*->parent.

This is analogous to the way clk_hw_fixed returns clk_hw_fixed->rate
when .recalc is called on it.

Regards,
Mike

Thanks
Richard

quoted

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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