[PATCH 1/2 V3] iio: mxs: Implement support for touchscreen

[Marek Vasut]

Dear Lauri Hintsala,

> Hi,
> 
> On 01/11/2013 01:43 AM, Marek Vasut wrote:
> > This patch implements support for sampling of a touchscreen into
> > the MXS LRADC driver. The LRADC block allows configuring some of
> > it's channels into special mode where they either output the drive
> > voltage or sample it, allowing it to operate a 4-wire or 5-wire
> > resistive touchscreen.
> > 
> > In case the touchscreen mode is enabled, the LRADC slot #7 is
> > reserved for touchscreen only, therefore it is not possible to
> > sample 8 LRADC channels at time, but only 7 channels.
> > 
> > The touchscreen controller is configured such that the PENDOWN event
> > disables touchscreen interrupts and triggers execution of worker
> > thread, which then polls the touchscreen controller for X, Y and
> > Pressure values. This reduces the overhead of interrupt-driven
> > operation. Upon the PENUP event, the worker thread re-enables the
> > PENDOWN detection interrupt and exits.
> > 
> > Signed-off-by: Marek Vasut <marex at denx.de>
> > Cc: Dmitry Torokhov <dmitry.torokhov at gmail.com>
> > Cc: Fabio Estevam <fabio.estevam at freescale.com>
> > Cc: Jonathan Cameron <jic23 at kernel.org>
> > Cc: Shawn Guo <shawn.guo at linaro.org>
> > ---
> > 
> >   .../bindings/staging/iio/adc/mxs-lradc.txt         |    6 +
> >   drivers/staging/iio/adc/mxs-lradc.c                |  473
> >   +++++++++++++++++++- 2 files changed, 455 insertions(+), 24
> >   deletions(-)
> 
> Works fine with apx4devkit.
> 
> Tested-by: Lauri Hintsala <lauri.hintsala at bluegiga.com>

Thanks Lauri :)

Best regards,
Marek Vasut