[Arm-netbook] How best to get touch working on EOMA?

[luke.leighton]

-da

On Mon, Dec 9, 2013 at 2:23 PM, joem <joem at martindale-electric.co.uk> wrote:
> How best to get touch working on EOMA?

 you mean EOMA68?

 almost most all capacitive panels are I2C.  goodix ICs or futuretech
(e.g. FT5306).  these are already fully supported under linux: drivers
are easy to find and many of them are already in the sunxi 3.4 kernel
tree.  i had to do a bit of searching for the one that goes with the
flying squirrel's [current] chosen touchpanel, eventually found it in
a rockchip kernel source tarball somewhere.

 so, I2C is on EOMA68: therefore capacitive touchpanels are
automatically not a problem.  just remember that the pull-down for I2C
is *already* done on the CPU Card.

 resistive panels: that's a different matter.  they're analogue, so
you'd need either a dedicated IC or to do it yourself with a voltage
source (or two?) and any IC that has a couple of ADCs (or three?).  to
be honest, i'd recommend just using a dedicated IC.  the one i used to
be familiar with is a TI TSC230somethingsomething.... TSC2200.  oh.
arse.  it's SPI.

 hmmm, let's see...
http://www.ti.com/lsds/ti/data-converters/touch-screen-controller-products.page
I2C tum te tum.... exclude automotive parts... lowest-priced item
iiiis:

 http://www.ti.com/product/tsc2014

 ta-daaa :)  ok, if you prefer a QFN package you'd have to use the
tsc2004 which is $1.75 not $1.30 in 1k volumes.

 that's with 5 mins of searching.  if you spent a bit more time
looking i'm sure there would be lower-cost options easily found.

is there a linux kernel driver for the TSC2014 and the TSC2004?
answer: yes. http://www.ti.com/tool/tsc2004-linux-drv

 so that's sorted.

l.