* Question: I2C touchscreen controller
@ 2011-08-24 18:23 H Hartley Sweeten
2011-08-24 19:54 ` Dmitry Torokhov
0 siblings, 1 reply; 6+ messages in thread
From: H Hartley Sweeten @ 2011-08-24 18:23 UTC (permalink / raw)
To: linux-input
Hello all,
I have a question...
Are there any I2C touchscreen controllers that do not need irq support?
I have a system with an I2C bus available to connect to the touchscreen
controller but I don't have an IRQ pin available. Right now I'm just
trying to discover if there is a possible solution or if I will need to
modify my board somehow to get an IRQ.
Any information will be appreciated.
Regards,
Hartley
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Question: I2C touchscreen controller
2011-08-24 18:23 Question: I2C touchscreen controller H Hartley Sweeten
@ 2011-08-24 19:54 ` Dmitry Torokhov
2011-08-24 20:19 ` H Hartley Sweeten
0 siblings, 1 reply; 6+ messages in thread
From: Dmitry Torokhov @ 2011-08-24 19:54 UTC (permalink / raw)
To: H Hartley Sweeten; +Cc: linux-input
Hi Hartley,
On Wed, Aug 24, 2011 at 01:23:59PM -0500, H Hartley Sweeten wrote:
> Hello all,
>
> I have a question...
>
> Are there any I2C touchscreen controllers that do not need irq support?
>
> I have a system with an I2C bus available to connect to the touchscreen
> controller but I don't have an IRQ pin available. Right now I'm just
> trying to discover if there is a possible solution or if I will need to
> modify my board somehow to get an IRQ.
Without IRQ you are limited to polling mode which, for touchscreens,
needs to be done at fairly high rate to provide adequate responsiveness.
This, in turn, will put considerable load on the system thus driving up
power requirements... IOW not very suitable for production use, that is
why I've been asking people to submit IRQ-driven drivers, if at all
possible.
If polling is your only option then input-polldev is your friend.
--
Dmitry
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: Question: I2C touchscreen controller
2011-08-24 19:54 ` Dmitry Torokhov
@ 2011-08-24 20:19 ` H Hartley Sweeten
2011-08-24 20:46 ` Dmitry Torokhov
2011-08-25 7:23 ` Henrik Rydberg
0 siblings, 2 replies; 6+ messages in thread
From: H Hartley Sweeten @ 2011-08-24 20:19 UTC (permalink / raw)
To: Dmitry Torokhov; +Cc: linux-input
On Wednesday, August 24, 2011 12:55 PM, Dmitry Torokhov wrote:
> Hi Hartley,
Hello!
> On Wed, Aug 24, 2011 at 01:23:59PM -0500, H Hartley Sweeten wrote:
>> Hello all,
>>
>> I have a question...
>>
>> Are there any I2C touchscreen controllers that do not need irq support?
>>
>> I have a system with an I2C bus available to connect to the touchscreen
>> controller but I don't have an IRQ pin available. Right now I'm just
>> trying to discover if there is a possible solution or if I will need to
>> modify my board somehow to get an IRQ.
>
> Without IRQ you are limited to polling mode which, for touchscreens,
> needs to be done at fairly high rate to provide adequate responsiveness.
> This, in turn, will put considerable load on the system thus driving up
> power requirements... IOW not very suitable for production use, that is
> why I've been asking people to submit IRQ-driven drivers, if at all
> possible.
>
> If polling is your only option then input-polldev is your friend.
Hmmm... Kind of what I figured.
After looking a bit deeper it appears I do have and IRQ pin available. It's
just a bit of a pain to get to... ;-)
It looks like these are the current I2C touchscreen drivers in mainline:
CONFIG_TOUCHSCREEN_88PM860X pmic mfd device? probably not standalone
CONFIG_TOUCHSCREEN_AD7879_I2C datasheet looks simple enough
CONFIG_TOUCHSCREEN_ATMEL_MXT needs firmware? probably complicated
CONFIG_TOUCHSCREEN_BU21013 can't find a datasheet
CONFIG_TOUCHSCREEN_CY8CTMG110 looks like the chip may be obsolete
CONFIG_TOUCHSCREEN_MAX11801 Maxim usually has long lead times
CONFIG_TOUCHSCREEN_MCS5000 can't find a datasheet
CONFIG_TOUCHSCREEN_STMPE datasheet looks simple enough
CONFIG_TOUCHSCREEN_TSC2007 datasheet looks simple enough
Based on that I'm considering the Analog Devices, STMicro, and TI parts.
Do you know if any of these work better than the others?
Thanks for the reply,
Hartley
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Question: I2C touchscreen controller
2011-08-24 20:19 ` H Hartley Sweeten
@ 2011-08-24 20:46 ` Dmitry Torokhov
2011-08-25 7:23 ` Henrik Rydberg
1 sibling, 0 replies; 6+ messages in thread
From: Dmitry Torokhov @ 2011-08-24 20:46 UTC (permalink / raw)
To: H Hartley Sweeten; +Cc: linux-input
On Wed, Aug 24, 2011 at 03:19:26PM -0500, H Hartley Sweeten wrote:
> On Wednesday, August 24, 2011 12:55 PM, Dmitry Torokhov wrote:
> > Hi Hartley,
>
> Hello!
>
> > On Wed, Aug 24, 2011 at 01:23:59PM -0500, H Hartley Sweeten wrote:
> >> Hello all,
> >>
> >> I have a question...
> >>
> >> Are there any I2C touchscreen controllers that do not need irq support?
> >>
> >> I have a system with an I2C bus available to connect to the touchscreen
> >> controller but I don't have an IRQ pin available. Right now I'm just
> >> trying to discover if there is a possible solution or if I will need to
> >> modify my board somehow to get an IRQ.
> >
> > Without IRQ you are limited to polling mode which, for touchscreens,
> > needs to be done at fairly high rate to provide adequate responsiveness.
> > This, in turn, will put considerable load on the system thus driving up
> > power requirements... IOW not very suitable for production use, that is
> > why I've been asking people to submit IRQ-driven drivers, if at all
> > possible.
> >
> > If polling is your only option then input-polldev is your friend.
>
> Hmmm... Kind of what I figured.
>
> After looking a bit deeper it appears I do have and IRQ pin available. It's
> just a bit of a pain to get to... ;-)
>
> It looks like these are the current I2C touchscreen drivers in mainline:
>
> CONFIG_TOUCHSCREEN_88PM860X pmic mfd device? probably not standalone
> CONFIG_TOUCHSCREEN_AD7879_I2C datasheet looks simple enough
> CONFIG_TOUCHSCREEN_ATMEL_MXT needs firmware? probably complicated
I do not believe you'll need custom firmware for this one. I think it is
being used in Samsung's Galaxy S series...
> CONFIG_TOUCHSCREEN_BU21013 can't find a datasheet
> CONFIG_TOUCHSCREEN_CY8CTMG110 looks like the chip may be obsolete
> CONFIG_TOUCHSCREEN_MAX11801 Maxim usually has long lead times
> CONFIG_TOUCHSCREEN_MCS5000 can't find a datasheet
> CONFIG_TOUCHSCREEN_STMPE datasheet looks simple enough
> CONFIG_TOUCHSCREEN_TSC2007 datasheet looks simple enough
>
> Based on that I'm considering the Analog Devices, STMicro, and TI parts.
>
> Do you know if any of these work better than the others?
No, I do not, sorry.
--
Dmitry
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Question: I2C touchscreen controller
2011-08-24 20:19 ` H Hartley Sweeten
2011-08-24 20:46 ` Dmitry Torokhov
@ 2011-08-25 7:23 ` Henrik Rydberg
2011-08-26 17:06 ` H Hartley Sweeten
1 sibling, 1 reply; 6+ messages in thread
From: Henrik Rydberg @ 2011-08-25 7:23 UTC (permalink / raw)
To: H Hartley Sweeten; +Cc: Dmitry Torokhov, linux-input
> It looks like these are the current I2C touchscreen drivers in mainline:
>
> CONFIG_TOUCHSCREEN_88PM860X pmic mfd device? probably not standalone
> CONFIG_TOUCHSCREEN_AD7879_I2C datasheet looks simple enough
> CONFIG_TOUCHSCREEN_ATMEL_MXT needs firmware? probably complicated
> CONFIG_TOUCHSCREEN_BU21013 can't find a datasheet
> CONFIG_TOUCHSCREEN_CY8CTMG110 looks like the chip may be obsolete
> CONFIG_TOUCHSCREEN_MAX11801 Maxim usually has long lead times
> CONFIG_TOUCHSCREEN_MCS5000 can't find a datasheet
> CONFIG_TOUCHSCREEN_STMPE datasheet looks simple enough
> CONFIG_TOUCHSCREEN_TSC2007 datasheet looks simple enough
>
> Based on that I'm considering the Analog Devices, STMicro, and TI parts.
>
> Do you know if any of these work better than the others?
Out of those, bu21013 (and st1232 not on your list) are dual touch,
and atmel_mxt is true multitouch. The rest are single touch.
Cheers,
Henrik
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: Question: I2C touchscreen controller
2011-08-25 7:23 ` Henrik Rydberg
@ 2011-08-26 17:06 ` H Hartley Sweeten
0 siblings, 0 replies; 6+ messages in thread
From: H Hartley Sweeten @ 2011-08-26 17:06 UTC (permalink / raw)
To: Henrik Rydberg; +Cc: Dmitry Torokhov, linux-input
On Thursday, August 25, 2011 12:23 AM, Henrik Rydberg wrote:
>> It looks like these are the current I2C touchscreen drivers in mainline:
>>
>> CONFIG_TOUCHSCREEN_88PM860X pmic mfd device? probably not standalone
>> CONFIG_TOUCHSCREEN_AD7879_I2C datasheet looks simple enough
>> CONFIG_TOUCHSCREEN_ATMEL_MXT needs firmware? probably complicated
>> CONFIG_TOUCHSCREEN_BU21013 can't find a datasheet
>> CONFIG_TOUCHSCREEN_CY8CTMG110 looks like the chip may be obsolete
>> CONFIG_TOUCHSCREEN_MAX11801 Maxim usually has long lead times
>> CONFIG_TOUCHSCREEN_MCS5000 can't find a datasheet
>> CONFIG_TOUCHSCREEN_STMPE datasheet looks simple enough
>> CONFIG_TOUCHSCREEN_TSC2007 datasheet looks simple enough
>>
>> Based on that I'm considering the Analog Devices, STMicro, and TI parts.
>>
>> Do you know if any of these work better than the others?
>
> Out of those, bu21013 (and st1232 not on your list) are dual touch,
> and atmel_mxt is true multitouch. The rest are single touch.
Henrik,
Thanks for the info and pointing out the st1232 driver. Do you know
of a link to a datasheet for it?
So, is the dual/muti-touch feature just a function of the controller?
Or do you need a touchscreen that actually supports it?
My product is currently using a 5.7" color TFT-LCD from OSD Displays.
They have a version with a built in 4 wire resistance type touchscreen
(p/n OSD057VA01CT). I haven't used a touchscreen before so I don't
know any of the details on how they work, but with the 4 wire interface
(YU, XR, YD, XL) I don't see how you could read more than one touch.
Thanks for any information.
Regards,
Hartley
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-08-26 17:06 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-08-24 18:23 Question: I2C touchscreen controller H Hartley Sweeten
2011-08-24 19:54 ` Dmitry Torokhov
2011-08-24 20:19 ` H Hartley Sweeten
2011-08-24 20:46 ` Dmitry Torokhov
2011-08-25 7:23 ` Henrik Rydberg
2011-08-26 17:06 ` H Hartley Sweeten
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