[PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context

[PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context

[Kwangwoo Lee]

>From d5de0d22109de7564f9bf1df688acbe6b18f41db Mon Sep 17 00:00:00 2001
From: Kwangwoo Lee <kwangwoo.lee@gmail.com>
Date: Mon, 11 May 2009 20:05:50 +0900
Subject: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context.

This patch enhances pointer movements much smoother.
The original patch is written by Thierry.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Kwangwoo Lee <kwangwoo.lee@gmail.com>
---
 drivers/input/touchscreen/tsc2007.c |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/tsc2007.c
b/drivers/input/touchscreen/tsc2007.c
index 948e167..03bbe58 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -70,6 +70,7 @@ struct ts_event {
 struct tsc2007 {
 	struct input_dev	*input;
 	char			phys[32];
+	struct work_struct	work;
 	struct hrtimer		timer;
 	struct ts_event		tc;

@@ -173,6 +174,9 @@ static void tsc2007_send_event(void *tsc)

 		dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
 			x, y, rt);
+	} else {
+		if (!ts->pendown)
+			ts->pendown = 1;
 	}

 	hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
@@ -197,6 +201,13 @@ static int tsc2007_read_values(struct tsc2007 *tsc)
 	return 0;
 }

+static void tsc2007_work(struct work_struct *work)
+{
+	struct tsc2007 *ts = container_of(work, struct tsc2007, work);
+	tsc2007_read_values(ts);
+	tsc2007_send_event(ts);
+}
+
 static enum hrtimer_restart tsc2007_timer(struct hrtimer *handle)
 {
 	struct tsc2007 *ts = container_of(handle, struct tsc2007, timer);
@@ -218,9 +229,7 @@ static enum hrtimer_restart tsc2007_timer(struct
hrtimer *handle)
 	} else {
 		/* pen is still down, continue with the measurement */
 		dev_dbg(&ts->client->dev, "pen is still down\n");
-
-		tsc2007_read_values(ts);
-		tsc2007_send_event(ts);
+		schedule_work(&ts->work);
 	}

 	spin_unlock_irqrestore(&ts->lock, flags);
@@ -253,7 +262,7 @@ static int tsc2007_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct tsc2007 *ts;
-	struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data;
+	struct tsc2007_platform_data *pdata = client->dev.platform_data;
 	struct input_dev *input_dev;
 	int err;

@@ -280,6 +289,7 @@ static int tsc2007_probe(struct i2c_client *client,

 	hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	ts->timer.function = tsc2007_timer;
+	INIT_WORK(&ts->work, tsc2007_work);

 	spin_lock_init(&ts->lock);

-- 
1.5.6.5

Re: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context

[Dmitry Torokhov]

Hi,

On Mon, May 11, 2009 at 08:44:00PM +0900, Kwangwoo Lee wrote:
> From d5de0d22109de7564f9bf1df688acbe6b18f41db Mon Sep 17 00:00:00 2001
> From: Kwangwoo Lee <kwangwoo.lee@gmail.com>
> Date: Mon, 11 May 2009 20:05:50 +0900
> Subject: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context.
> 
> This patch enhances pointer movements much smoother.
> The original patch is written by Thierry.
> 
> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
> Signed-off-by: Kwangwoo Lee <kwangwoo.lee@gmail.com>
> ---
>  drivers/input/touchscreen/tsc2007.c |   18 ++++++++++++++----
>  1 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/tsc2007.c
> b/drivers/input/touchscreen/tsc2007.c
> index 948e167..03bbe58 100644
> --- a/drivers/input/touchscreen/tsc2007.c
> +++ b/drivers/input/touchscreen/tsc2007.c
> @@ -70,6 +70,7 @@ struct ts_event {
>  struct tsc2007 {
>  	struct input_dev	*input;
>  	char			phys[32];
> +	struct work_struct	work;

Every time I see a work_struct in a driver and don't see
cancel_work_sync() anywhere I know there are issues...

-- 
Dmitry

Re: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context

[Dmitry Torokhov]

On Mon, May 11, 2009 at 08:38:09AM -0700, Dmitry Torokhov wrote:
> Hi,
> 
> On Mon, May 11, 2009 at 08:44:00PM +0900, Kwangwoo Lee wrote:
> > From d5de0d22109de7564f9bf1df688acbe6b18f41db Mon Sep 17 00:00:00 2001
> > From: Kwangwoo Lee <kwangwoo.lee@gmail.com>
> > Date: Mon, 11 May 2009 20:05:50 +0900
> > Subject: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context.
> > 
> > This patch enhances pointer movements much smoother.
> > The original patch is written by Thierry.
> > 
> > Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
> > Signed-off-by: Kwangwoo Lee <kwangwoo.lee@gmail.com>
> > ---
> >  drivers/input/touchscreen/tsc2007.c |   18 ++++++++++++++----
> >  1 files changed, 14 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/input/touchscreen/tsc2007.c
> > b/drivers/input/touchscreen/tsc2007.c
> > index 948e167..03bbe58 100644
> > --- a/drivers/input/touchscreen/tsc2007.c
> > +++ b/drivers/input/touchscreen/tsc2007.c
> > @@ -70,6 +70,7 @@ struct ts_event {
> >  struct tsc2007 {
> >  	struct input_dev	*input;
> >  	char			phys[32];
> > +	struct work_struct	work;
> 
> Every time I see a work_struct in a driver and don't see
> cancel_work_sync() anywhere I know there are issues...
> 

Also, why do we need to chain irq->timer->work now? Surely we can bypass
the timer if we have to read in process context.

-- 
Dmitry

Re: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context

[Kwangwoo Lee]

Hi,

On Tue, May 12, 2009 at 12:41 AM, Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
> On Mon, May 11, 2009 at 08:38:09AM -0700, Dmitry Torokhov wrote:
>> Hi,
>> On Mon, May 11, 2009 at 08:44:00PM +0900, Kwangwoo Lee wrote:
>> > From d5de0d22109de7564f9bf1df688acbe6b18f41db Mon Sep 17 00:00:00 2001
>> > From: Kwangwoo Lee <kwangwoo.lee@gmail.com>
>> > Date: Mon, 11 May 2009 20:05:50 +0900
>> > Subject: [PATCH 2/2] Input: tsc2007: do I2C transfers in non-interrupt context.
>> >
>> > This patch enhances pointer movements much smoother.
>> > The original patch is written by Thierry.
>> >
>> > --- a/drivers/input/touchscreen/tsc2007.c
>> > +++ b/drivers/input/touchscreen/tsc2007.c
>> > @@ -70,6 +70,7 @@ struct ts_event {
>> >  struct tsc2007 {
>> >     struct input_dev        *input;
>> >     char                    phys[32];
>> > +   struct work_struct      work;
>>
>> Every time I see a work_struct in a driver and don't see
>> cancel_work_sync() anywhere I know there are issues...
>>

Thanks for your comment. I also missed that thing, sorry.

> Also, why do we need to chain irq->timer->work now? Surely we can bypass
> the timer if we have to read in process context.

It's good point. I'll check again.
Thanks.

-- 
Kwangwoo Lee <kwangwoo.lee@gmail.com>
--
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