RE: Question: I2C touchscreen controller

On Thursday, August 25, 2011 12:23 AM, Henrik Rydberg wrote:

quoted

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