TWL4030 keypad timeout interrupt

TWL4030 keypad timeout interrupt

[Felipe Balbi]

Hi all,

I noted whenever we release a key in omap-twl4030.c driver it generates
two interrupts: one for release event and one for a timeout event.

Is that expected or is that a bug somewhere in the driver ?

It's easily noted by cat /proc/interrupts ;-)

-- 
	- Balbi

Re: TWL4030 keypad timeout interrupt

[Felipe Balbi]

On Tue, 13 May 2008 16:54:17 +0300, Felipe Balbi <felipe.balbi@nokia.com>
wrote:
> Hi all,
> 
> I noted whenever we release a key in omap-twl4030.c driver it generates
> two interrupts: one for release event and one for a timeout event.
> 
> Is that expected or is that a bug somewhere in the driver ?
> 
> It's easily noted by cat /proc/interrupts ;-)

Replying to myself as I found some more clues.

By checking the code I could see that only rising edge of
timeout interrupt is being enabled. Also timeout register
is at 0xd6, but code is writing 0x04...

So if i read it correctly, we might have 0 set as our timeout.

which might explain why we only see the timeout interrupt
when releasing the key.

Am I right ?

I might be completely wrong here, but that extra interrupt
happening all the time is just bugging me :-p

-- 
Best Regards,

Felipe Balbi
http://felipebalbi.com
me@felipebalbi.com

RE: TWL4030 keypad timeout interrupt

[Girish]

 
>
>
>On Tue, 13 May 2008 16:54:17 +0300, Felipe Balbi 
><felipe.balbi@nokia.com>
>wrote:
>> Hi all,
>> 
>> I noted whenever we release a key in omap-twl4030.c driver it 
>> generates two interrupts: one for release event and one for 
>a timeout event.
>> 
>> Is that expected or is that a bug somewhere in the driver ?
>> 
>> It's easily noted by cat /proc/interrupts ;-)
>
>Replying to myself as I found some more clues.
>
>By checking the code I could see that only rising edge of 
>timeout interrupt is being enabled. Also timeout register is 
>at 0xd6, but code is writing 0x04...
>

No, the code is writing to 0x00D2 + 0x04 (the t2keypad base address: 0x00D2). 

>So if i read it correctly, we might have 0 set as our timeout.
>
>which might explain why we only see the timeout interrupt when 
>releasing the key.
>
>Am I right ?

Well, the timeout is here to help the controller come out of hangs, if any. 

>
>I might be completely wrong here, but that extra interrupt 
>happening all the time is just bugging me :-p




Regards,
Girish

Re: TWL4030 keypad timeout interrupt

[Felipe Balbi]

On Wed, May 14, 2008 at 10:38:09AM +0530, ext Girish wrote:
> 
>  
> >
> >
> >On Tue, 13 May 2008 16:54:17 +0300, Felipe Balbi 
> ><felipe.balbi@nokia.com>
> >wrote:
> >> Hi all,
> >> 
> >> I noted whenever we release a key in omap-twl4030.c driver it 
> >> generates two interrupts: one for release event and one for 
> >a timeout event.
> >> 
> >> Is that expected or is that a bug somewhere in the driver ?
> >> 
> >> It's easily noted by cat /proc/interrupts ;-)
> >
> >Replying to myself as I found some more clues.
> >
> >By checking the code I could see that only rising edge of 
> >timeout interrupt is being enabled. Also timeout register is 
> >at 0xd6, but code is writing 0x04...
> >
> 
> No, the code is writing to 0x00D2 + 0x04 (the t2keypad base address: 0x00D2). 

Ok, good :-)
thanks

> 
> >So if i read it correctly, we might have 0 set as our timeout.
> >
> >which might explain why we only see the timeout interrupt when 
> >releasing the key.
> >
> >Am I right ?
> 
> Well, the timeout is here to help the controller come out of hangs, if any. 

But is it possible that whenever we release a key we get a timeout? I
think something is wrong there.

-- 
	- Balbi

RE: TWL4030 keypad timeout interrupt

[Girish]

 

>-----Original Message-----
>From: Felipe Balbi [mailto:felipe.balbi@nokia.com] 
>Sent: Wednesday, May 14, 2008 1:46 PM
>To: ext Girish
>Cc: 'Felipe Balbi'; felipe.balbi@nokia.com; 'Linux OMAP Mailing List'
>Subject: Re: TWL4030 keypad timeout interrupt
>
>Ok, good :-)
>thanks
>
>> 
>> >So if i read it correctly, we might have 0 set as our timeout.
>> >
>> >which might explain why we only see the timeout interrupt when 
>> >releasing the key.
>> >
>> >Am I right ?
>> 
>> Well, the timeout is here to help the controller come out of 
>hangs, if any. 
>
>But is it possible that whenever we release a key we get a 
>timeout? I think something is wrong there.

No, it's an empty timeout feature, an interrupt is generated if no key is pressed
during that period of time.


Regards,
Girish

RE: TWL4030 keypad timeout interrupt

[Gopinath, Thara]

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org
> [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Girish
> Sent: Wednesday, May 14, 2008 2:27 PM
> To: felipe.balbi@nokia.com
> Cc: 'Felipe Balbi'; 'Linux OMAP Mailing List'
> Subject: RE: TWL4030 keypad timeout interrupt
>
>
>
> >-----Original Message-----
> >From: Felipe Balbi [mailto:felipe.balbi@nokia.com]
> >Sent: Wednesday, May 14, 2008 1:46 PM
> >To: ext Girish
> >Cc: 'Felipe Balbi'; felipe.balbi@nokia.com; 'Linux OMAP Mailing List'
> >Subject: Re: TWL4030 keypad timeout interrupt
> >
> >Ok, good :-)
> >thanks
> >
> >>
> >> >So if i read it correctly, we might have 0 set as our timeout.
> >> >
> >> >which might explain why we only see the timeout interrupt when
> >> >releasing the key.
> >> >
> >> >Am I right ?
> >>
> >> Well, the timeout is here to help the controller come out of
> >hangs, if any.
> >
> >But is it possible that whenever we release a key we get a
> timeout? I
> >think something is wrong there.
>
> No, it's an empty timeout feature, an interrupt is generated
> if no key is pressed during that period of time.
>
>
> Regards,
> Girish

This feature allows the TWL4030 keypad internal sequencer to go to idle state if no keypresses are made for the period of time programmed in the timeout register.The reason why you are seeing this only after a release is because this timeout feature is activated only after a release event.Thus when a key is release you see a keyreleased event interrupt and after the programmed timeout interval is over a timeout event interrupt.This timeout interrupt does nothing but tell you that the keypad internal sequencer is going to idle state.
This is not a must to have feature but there is nothing wrong with having it also.

Regards
Thara

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Re: TWL4030 keypad timeout interrupt

[Felipe Balbi]

On Wed, May 14, 2008 at 03:22:56PM +0530, ext Gopinath, Thara wrote:
> 
> 
> > -----Original Message-----
> > From: linux-omap-owner@vger.kernel.org
> > [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Girish
> > Sent: Wednesday, May 14, 2008 2:27 PM
> > To: felipe.balbi@nokia.com
> > Cc: 'Felipe Balbi'; 'Linux OMAP Mailing List'
> > Subject: RE: TWL4030 keypad timeout interrupt
> >
> >
> >
> > >-----Original Message-----
> > >From: Felipe Balbi [mailto:felipe.balbi@nokia.com]
> > >Sent: Wednesday, May 14, 2008 1:46 PM
> > >To: ext Girish
> > >Cc: 'Felipe Balbi'; felipe.balbi@nokia.com; 'Linux OMAP Mailing List'
> > >Subject: Re: TWL4030 keypad timeout interrupt
> > >
> > >Ok, good :-)
> > >thanks
> > >
> > >>
> > >> >So if i read it correctly, we might have 0 set as our timeout.
> > >> >
> > >> >which might explain why we only see the timeout interrupt when
> > >> >releasing the key.
> > >> >
> > >> >Am I right ?
> > >>
> > >> Well, the timeout is here to help the controller come out of
> > >hangs, if any.
> > >
> > >But is it possible that whenever we release a key we get a
> > timeout? I
> > >think something is wrong there.
> >
> > No, it's an empty timeout feature, an interrupt is generated
> > if no key is pressed during that period of time.
> >
> >
> > Regards,
> > Girish
> 
> This feature allows the TWL4030 keypad internal sequencer to go to idle state if no keypresses are made for the period of time programmed in the timeout register.The reason why you are seeing this only after a release is because this timeout feature is activated only after a release event.Thus when a key is release you see a keyreleased event interrupt and after the programmed timeout interval is over a timeout event interrupt.This timeout interrupt does nothing but tell you that the keypad internal sequencer is going to idle state.
> This is not a must to have feature but there is nothing wrong with having it also.

Ok, got it. :-)
thanks for the clarification :-)

-- 
	- Balbi