linux-kernel - [PATCH 1/2] Input: tsc2007 - Disable irq when the irq thread is handling data

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Date:	Tue, 29 Nov 2011 16:12:57 +0800
From:	Feng Tang <feng.tang@...el.com>
To:	dtor@...l.ru, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org, kwlee@...kvision.com
Cc:	joel.clark@...el.com, Feng Tang <feng.tang@...el.com>
Subject: [PATCH 1/2] Input: tsc2007 - Disable irq when the irq thread is handling data

The TSC2007 data sheet say in some case the HW may fire some false
interrrupt, which I also met during integrating one TSC2007 device.
So add the disable_irq/enable_irq protection around data handling.

Signed-off-by: Feng Tang <feng.tang@...el.com>
---
 drivers/input/touchscreen/tsc2007.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 1f674cb..789f216 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -171,6 +171,13 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 	struct ts_event tc;
 	u32 rt;
 
+	/*
+	 * Disable the irq, as it may fire several other IRQs during
+	 * this thread is handling data, as suggested by the TSC2007
+	 * datasheet, p19, "Touch Detect" chapter
+	 */
+	disable_irq_nosync(irq);
+
 	while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 
 		/* pen is down, continue with the measurement */
@@ -221,6 +228,7 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 	if (ts->clear_penirq)
 		ts->clear_penirq();
 
+	enable_irq(irq);
 	return IRQ_HANDLED;
 }
 
-- 
1.7.1

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