linux-kernel - [PATCH v4 1/7] clk: kona: allow nested ccu_write

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Message-Id: <1401483188-5395-2-git-send-email-elder@linaro.org>
Date:	Fri, 30 May 2014 15:53:02 -0500
From:	Alex Elder <elder@...aro.org>
To:	mturquette@...aro.org, mporter@...aro.org, bcm@...thebug.org
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v4 1/7] clk: kona: allow nested ccu_write_enable() requests

Use a counter rather than a Boolean to track whether write access to
a CCU has been enabled or not.  This will allow more than one of
these requests to be nested.

Note that __ccu_write_enable() and __ccu_write_disable() calls all
come in pairs, and they are always surrounded immediately by calls
to ccu_lock() and ccu_unlock().

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/clk/bcm/clk-kona.c | 14 ++++----------
 drivers/clk/bcm/clk-kona.h |  2 +-
 2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c
index 95af2e6..ee8e988 100644
--- a/drivers/clk/bcm/clk-kona.c
+++ b/drivers/clk/bcm/clk-kona.c
@@ -170,13 +170,8 @@ static inline void ccu_unlock(struct ccu_data *ccu, unsigned long flags)
  */
 static inline void __ccu_write_enable(struct ccu_data *ccu)
 {
-	if (ccu->write_enabled) {
-		pr_err("%s: access already enabled for %s\n", __func__,
-			ccu->name);
-		return;
-	}
-	ccu->write_enabled = true;
-	__ccu_write(ccu, 0, CCU_ACCESS_PASSWORD | 1);
+	if (!ccu->write_enabled++)
+		__ccu_write(ccu, 0, CCU_ACCESS_PASSWORD | 1);
 }
 
 static inline void __ccu_write_disable(struct ccu_data *ccu)
@@ -186,9 +181,8 @@ static inline void __ccu_write_disable(struct ccu_data *ccu)
 			ccu->name);
 		return;
 	}
-
-	__ccu_write(ccu, 0, CCU_ACCESS_PASSWORD);
-	ccu->write_enabled = false;
+	if (!--ccu->write_enabled)
+		__ccu_write(ccu, 0, CCU_ACCESS_PASSWORD);
 }
 
 /*
diff --git a/drivers/clk/bcm/clk-kona.h b/drivers/clk/bcm/clk-kona.h
index 2537b30..e9a8466 100644
--- a/drivers/clk/bcm/clk-kona.h
+++ b/drivers/clk/bcm/clk-kona.h
@@ -478,7 +478,7 @@ struct ccu_policy {
 struct ccu_data {
 	void __iomem *base;	/* base of mapped address space */
 	spinlock_t lock;	/* serialization lock */
-	bool write_enabled;	/* write access is currently enabled */
+	u32 write_enabled;	/* write access enable count */
 	struct ccu_policy policy;
 	struct list_head links;	/* for ccu_list */
 	struct device_node *node;
-- 
1.9.1

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