Re: [PATCH v3 2/3] Input: cyttsp - add device tree bindings

From: Oreste Salerno
Date: Mon Jan 11 2016 - 12:54:33 EST


On Sun, Jan 10, 2016 at 09:01:56PM -0600, Rob Herring wrote:
> On Sun, Jan 10, 2016 at 06:36:08PM +0100, Oreste Salerno wrote:
> > Signed-off-by: Oreste Salerno <oreste.salerno@xxxxxxxxxx>
> > ---
> > .../bindings/input/touchscreen/cyttsp.txt | 82 +++++++++++++
> > drivers/input/touchscreen/cyttsp_core.c | 134 +++++++++++++++++++--
> > include/linux/input/cyttsp.h | 3 +
> > 3 files changed, 212 insertions(+), 7 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt
> >
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt b/Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt
> > new file mode 100644
> > index 0000000..2dc5c65
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt
> > @@ -0,0 +1,82 @@
> > +* Cypress cyttsp touchscreen controller
> > +
> > +Required properties:
> > +- compatible : must be "cypress,cyttsp-i2c" or "cypress,cyttsp-spi"
> > +- reg : Device I2C address or SPI chip select number
> > +- spi-max-frequency : Maximum SPI clocking speed of the device (for cyttsp-spi)
> > +- interrupt-parent : the phandle for the gpio controller
> > + (see interrupt binding[0]).
> > +- interrupts : (gpio) interrupt to which the chip is connected
> > + (see interrupt binding[0]).
> > +- reset-gpios : the reset gpio the chip is connected to
> > + (see GPIO binding[1] for more details).
> > +- touchscreen-size-x : horizontal resolution of touchscreen (in pixels)
> > +- touchscreen-size-y : vertical resolution of touchscreen (in pixels)
> > +- bootloader-key : the 8-byte bootloader key that is required to switch
> > + the chip from bootloader mode (default mode) to
> > + application mode.
> > + This property has to be specified as an array of 8
> > + '/bits/ 8' values.
> > +
> > +Optional properties:
> > +- active-distance : the distance in pixels beyond which a touch must move
> > + before movement is detected and reported by the device.
> > + Valid values: 0-15.
>
> Wouldn't this be the same as touchscreen-fuzz-(x|y) which is the
> replacement for the deprecated moving-threshold?
>

It is somewhat related. But I understand that the touchscreen-fuzz-(x|y) properties
are meant to be used as parameters passed to input_set_abs_params(), which are used
for a SW-based jitter filtering.
The active-distance value instead is used to set a HW register in the chip which
effectively performs the filtering in the HW.
The driver is currently passing 0 as fuzz parameter to input_set_abs_params().

> > +- active-interval-ms : the minimum period in ms between consecutive
> > + scanning/processing cycles when the chip is in active mode.
> > + Valid values: 0-255.
> > +- lowpower-interval-ms : the minimum period in ms between consecutive
> > + scanning/processing cycles when the chip is in low-power mode.
> > + Valid values: 0-2550
> > +- touch-timeout-ms : minimum time in ms spent in the active power state while no
> > + touches are detected before entering low-power mode.
> > + Valid values: 0-2550
> > +
>
> Otherwise, looks fine.

I am still waiting for a review from the driver maintainer (Ferruh Yigit), but I see
that he hasn't been actively reviewing patches for the cyttsp* drivers for a while.
I wonder what would be the process in this case?