linux-kernel - [PATCH V3 2/3] ARM: clk-gate2: Add API imx_clk_gate2_exclusive for clk

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Date:	Fri, 8 Aug 2014 15:02:48 +0800
From:	Shengjiu Wang <shengjiu.wang@...escale.com>
To:	<shawn.guo@...escale.com>, <kernel@...gutronix.de>,
	<linux@....linux.org.uk>, <robh+dt@...nel.org>,
	<pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>
CC:	<shengjiu.wang@...escale.com>, <Guangyu.Chen@...escale.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH V3 2/3] ARM: clk-gate2: Add API imx_clk_gate2_exclusive for clk_gate2

As some clocks are mutually exlcusive, they can't be enabled simultaneously,
So add this new API for registering exclusive clock, the enable function will
check if there is exclusive clock and it is not enabled, then this clock can
be enabled, otherwise, it will return error.

Signed-off-by: Shengjiu Wang <shengjiu.wang@...escale.com>
---
 arch/arm/mach-imx/clk-gate2.c |   18 +++++++++++++++++-
 arch/arm/mach-imx/clk.h       |    2 ++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/clk-gate2.c b/arch/arm/mach-imx/clk-gate2.c
index 84acdfd..df64c4d 100644
--- a/arch/arm/mach-imx/clk-gate2.c
+++ b/arch/arm/mach-imx/clk-gate2.c
@@ -8,7 +8,7 @@
  *
  * Gated clock implementation
  */
-
+#include <linux/clk-private.h>
 #include <linux/clk-provider.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -34,6 +34,7 @@ struct clk_gate2 {
 	u8		flags;
 	spinlock_t	*lock;
 	unsigned int	*share_count;
+	struct clk	*clk_exclusive;
 };
 
 #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
@@ -46,6 +47,11 @@ static int clk_gate2_enable(struct clk_hw *hw)
 
 	spin_lock_irqsave(gate->lock, flags);
 
+	if (gate->clk_exclusive && __clk_is_enabled(gate->clk_exclusive)) {
+		spin_unlock_irqrestore(gate->lock, flags);
+		return -EBUSY;
+	}
+
 	if (gate->share_count && (*gate->share_count)++ > 0)
 		goto out;
 
@@ -147,3 +153,13 @@ struct clk *clk_register_gate2(struct device *dev, const char *name,
 
 	return clk;
 }
+
+int imx_clk_gate2_exclusive(struct clk *clk1, struct clk *clk2)
+{
+	struct clk_gate2 *gate1 = to_clk_gate2(clk1->hw);
+	struct clk_gate2 *gate2 = to_clk_gate2(clk2->hw);
+
+	gate1->clk_exclusive = clk2;
+	gate2->clk_exclusive = clk1;
+	return 0;
+}
diff --git a/arch/arm/mach-imx/clk.h b/arch/arm/mach-imx/clk.h
index d5ba76f..2b07376 100644
--- a/arch/arm/mach-imx/clk.h
+++ b/arch/arm/mach-imx/clk.h
@@ -36,6 +36,8 @@ struct clk *clk_register_gate2(struct device *dev, const char *name,
 struct clk * imx_obtain_fixed_clock(
 			const char *name, unsigned long rate);
 
+int imx_clk_gate2_exclusive(struct clk *clk1, struct clk *clk2);
+
 static inline struct clk *imx_clk_gate2(const char *name, const char *parent,
 		void __iomem *reg, u8 shift)
 {
-- 
1.7.9.5

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