linux-kernel - [PATCH v2 2/2] clk: fractional-divider: fix sparse warnings

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Message-Id: <1427741869-239562-3-git-send-email-andriy.shevchenko@linux.intel.com>
Date:	Mon, 30 Mar 2015 21:57:49 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Stephen Boyd <sboyd@...eaurora.org>, linux-kernel@...r.kernel.org,
	heikki.krogerus@...ux.intel.com
Cc:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v2 2/2] clk: fractional-divider: fix sparse warnings

Sparse complains about possible imbalance in locking.

drivers/clk/clk-fractional-divider.c:37:9: warning: context imbalance in 'clk_fd_recalc_rate' - different lock contexts for basic block
drivers/clk/clk-fractional-divider.c:61:12: warning: context imbalance in 'clk_fd_set_rate' - different lock contexts for basic block

Let's rewrite code to fix this and make it more straight.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/clk/clk-fractional-divider.c | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c
index 9c53704..3766da8 100644
--- a/drivers/clk/clk-fractional-divider.c
+++ b/drivers/clk/clk-fractional-divider.c
@@ -26,13 +26,13 @@ static unsigned long clk_fd_recalc_rate(struct clk_hw *hw,
 	unsigned long flags = 0;
 	u32 val;
 
-	if (fd->lock)
+	if (fd->lock) {
 		spin_lock_irqsave(fd->lock, flags);
-
-	val = clk_readl(fd->reg);
-
-	if (fd->lock)
+		val = clk_readl(fd->reg);
 		spin_unlock_irqrestore(fd->lock, flags);
+	} else {
+		val = clk_readl(fd->reg);
+	}
 
 	m = (val & fd->mmask) >> fd->mshift;
 	n = (val & fd->nmask) >> fd->nshift;
@@ -58,27 +58,34 @@ static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate,
 	return mult_frac(rate, m, n);
 }
 
+static void clk_fd_update(struct clk_fractional_divider *fd,
+			  unsigned long m, unsigned long n)
+{
+	u32 val;
+
+	val = clk_readl(fd->reg);
+	val &= ~(fd->mmask | fd->nmask);
+	val |= (m << fd->mshift) | (n << fd->nshift);
+	clk_writel(val, fd->reg);
+}
+
 static int clk_fd_set_rate(struct clk_hw *hw, unsigned long rate,
 			   unsigned long parent_rate)
 {
 	struct clk_fractional_divider *fd = to_clk_fd(hw);
 	unsigned long flags = 0;
 	unsigned long n, m;
-	u32 val;
 
 	rational_best_approximation(rate, parent_rate,
 			fd->mmask >> fd->mshift, fd->nmask >> fd->nshift, &m, &n);
 
-	if (fd->lock)
+	if (fd->lock) {
 		spin_lock_irqsave(fd->lock, flags);
-
-	val = clk_readl(fd->reg);
-	val &= ~(fd->mmask | fd->nmask);
-	val |= (m << fd->mshift) | (n << fd->nshift);
-	clk_writel(val, fd->reg);
-
-	if (fd->lock)
+		clk_fd_update(fd, m, n);
 		spin_unlock_irqrestore(fd->lock, flags);
+	} else {
+		clk_fd_update(fd, m, n);
+	}
 
 	return 0;
 }
-- 
2.1.4

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