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

[Feng Tang]

The TSC2007 data sheet say in some case the HW may fire some false
interrrupt, which I also met during integrating one TSC2007 device.
Most of the tsc2007 platforms including ours are using a gpio line as
tsc2007's irq line, so calling disable_irq_nosync() to actually
prevent the gpio controller from firing IRQ for tsc2007 in such case.

Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
---
 drivers/input/touchscreen/tsc2007.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 1f674cb..03c1961 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -171,6 +171,18 @@ 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.
+	 *
+	 * Most of the tsc2007 platforms are using a gpio line as
+	 * tsc2007's irq line, so calling disable_irq_nosync() will
+	 * actually prevent the gpio controller from firing IRQ for
+	 * this tsc2007 line in such case.
+	 */
+	disable_irq_nosync(irq);
+
 	while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 
 		/* pen is down, continue with the measurement */
@@ -221,6 +233,7 @@ 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
> 
> Thanks.
> 
> > 
> > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
> > ---
> >  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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