linux-kernel - [PATCH] mfd: ti_am335x_tscadc: avoid possible deadlock of reg

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Date:	Tue, 22 Oct 2013 16:12:39 +0200
From:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:	Lee Jones <lee.jones@...aro.org>
Cc:	Samuel Ortiz <sameo@...ux.intel.com>, linux-kernel@...r.kernel.org,
	Zubair Lutfullah <zubair.lutfullah@...il.com>,
	Felipe Balbi <balbi@...com>, kishon@...com,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH] mfd: ti_am335x_tscadc: avoid possible deadlock of reg_lock

Since the addition of continuous sampling mode and shared irq support,
the reg_lock lock can be taken with and without interrupts. This patch
uses the *_irq* variant which should be used in order to avaoid a deadlock.

Cc: Zubair Lutfullah <zubair.lutfullah@...il.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 drivers/mfd/ti_am335x_tscadc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index baaf5a8..912a41f 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -56,21 +56,25 @@ EXPORT_SYMBOL_GPL(am335x_tsc_se_update);
 
 void am335x_tsc_se_set(struct ti_tscadc_dev *tsadc, u32 val)
 {
-	spin_lock(&tsadc->reg_lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsadc->reg_lock, flags);
 	tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
 	tsadc->reg_se_cache |= val;
 	am335x_tsc_se_update(tsadc);
-	spin_unlock(&tsadc->reg_lock);
+	spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 }
 EXPORT_SYMBOL_GPL(am335x_tsc_se_set);
 
 void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
 {
-	spin_lock(&tsadc->reg_lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsadc->reg_lock, flags);
 	tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
 	tsadc->reg_se_cache &= ~val;
 	am335x_tsc_se_update(tsadc);
-	spin_unlock(&tsadc->reg_lock);
+	spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 }
 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
 
-- 
1.8.4.rc3

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