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From: Chris Leech <christopher.leech@linux.intel.com>
To: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: linux-input@vger.kernel.org
Subject: Re: [PATCH 2/5] qt602240_ts: move clearing of pending interrupt closer to request_threaded_irq
Date: Thu, 18 Nov 2010 11:29:02 -0800	[thread overview]
Message-ID: <20101118192902.GE1273@cleech-lnx.jf.intel.com> (raw)
In-Reply-To: <4CE521B9.9070509@samsung.com>

On Thu, Nov 18, 2010 at 09:53:13PM +0900, Joonyoung Shim wrote:
> Hi, Chris.
>
> On 2010-11-17 오전 5:41, Chris Leech wrote:
>> I've seen interrupts asserted on the CHG pin between the call to make_highcgh()
>> during initialization and registering the interrupt handler, leaving CHG low
>> and no events get passed up.
>>
>
> The CHG pin can be affected by control of gpios connected to touch
> chip. Could you check it? I think it doesn't matter where
> make_highchg() exists actually.

My understanding is that CHG is to be used to trigger interrupts, and
the attached gpio should be set as an input.  I'm not sure trying to set
the value from the gpio side is going to work.

The problem I was seeing was the attached gpio configured as a
falling-edge-triggered interrupt stuck in the low state, and
qt602240_interrupt is never called.  What that says to me is that CHG
transitioned low before the interrupt handler was registered.  From what
I can see, the only way to reset CHG is to clear the queue of pending
messages, which is what make_highchg does.

- Chris

> Thanks.
>
>> This moves the clearing of pending messages to right before the call to
>> request_threaded_irq().  I still think there's a race here that could leave CHG
>> stuck low, but worry about clearing the message queue while the interrupt
>> handler is registered without some sort of additional locking.
>>
>> Signed-off-by: Chris Leech<christopher.leech@linux.intel.com>
>> ---
>>   drivers/input/touchscreen/qt602240_ts.c |    8 ++++----
>>   1 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/input/touchscreen/qt602240_ts.c b/drivers/input/touchscreen/qt602240_ts.c
>> index 0b92c9d..95496ec 100644
>> --- a/drivers/input/touchscreen/qt602240_ts.c
>> +++ b/drivers/input/touchscreen/qt602240_ts.c
>> @@ -991,10 +991,6 @@ static int qt602240_initialize(struct qt602240_data *data)
>>   	if (error)
>>   		return error;
>>
>> -	error = qt602240_make_highchg(data);
>> -	if (error)
>> -		return error;
>> -
>>   	qt602240_handle_pdata(data);
>>
>>   	/* Backup to memory */
>> @@ -1280,6 +1276,10 @@ static int __devinit qt602240_probe(struct i2c_client *client,
>>   	if (error)
>>   		goto err_free_object;
>>
>> +	error = qt602240_make_highchg(data);
>> +	if (error)
>> +		goto err_free_object;
>> +
>>   	error = request_threaded_irq(client->irq, NULL, qt602240_interrupt,
>>   			IRQF_TRIGGER_FALLING, client->dev.driver->name, data);
>>   	if (error) {
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-input" in
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>>
>
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  reply	other threads:[~2010-11-18 19:29 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-16 20:41 [PATCH 0/4] qt602240_ts changes for Intel mid platform Chris Leech
2010-11-16 20:41 ` [PATCH 1/5] qt602240_ts: fix wrong sizeof in object table allocation Chris Leech
2010-11-18 11:16   ` Joonyoung Shim
2010-11-18 11:30     ` Joonyoung Shim
2010-11-16 20:41 ` [PATCH 2/5] qt602240_ts: move clearing of pending interrupt closer to request_threaded_irq Chris Leech
2010-11-18 12:53   ` Joonyoung Shim
2010-11-18 19:29     ` Chris Leech [this message]
2010-11-18 22:54       ` Dmitry Torokhov
2010-11-16 20:42 ` [PATCH 3/5] qt602240_ts: Trust factory configuration of touchscreen Chris Leech
2010-11-18 13:09   ` Joonyoung Shim
2010-11-18 19:41     ` Chris Leech
2010-11-16 20:42 ` [PATCH 4/5] qt602240_ts: add optional hooks for board specific reset logic Chris Leech
2010-11-18 11:32   ` Joonyoung Shim
2010-11-18 19:46     ` Chris Leech
2010-11-16 20:42 ` [PATCH 5/5] qt602240_ts: add mXT224 identifier to id_table, to match Intel mid firmware identifier Chris Leech
2010-11-18 11:34   ` Joonyoung Shim

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