On Thu, Nov 18, 2010 at 09:53:13PM +0900, Joonyoung Shim wrote:
> Hi, Chris.
>
> On 2010-11-17 ìì 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@xxxxxxxxxxxxxxx>
>> ---
>> 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) {
>>
>> --
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>
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