Re: [PATCH 6/9] input: goodix: write configuration data to device

[Bastien Nocera <hadess@hadess.net>]

On Thu, 2015-05-28 at 13:51 +0000, Tirdea, Irina wrote:
> 
> > -----Original Message-----
> > From: Mark Rutland [mailto:mark.rutland@arm.com]
> > Sent: 28 May, 2015 16:22
> > To: Tirdea, Irina
> > Cc: Dmitry Torokhov; Bastien Nocera; linux-input@vger.kernel.org; 
> > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org;
> > Purdila, Octavian
> > Subject: Re: [PATCH 6/9] input: goodix: write configuration data to 
> > device
> > 
> > On Thu, May 28, 2015 at 01:47:42PM +0100, Irina Tirdea wrote:
> > > Goodix devices can be configured by writing this information
> > > to the device at init. The configuration data can
> > > be provided through the ACPI/device tree property
> > > "device-config". If "device-config" is not set, the default
> > > device configuration will be used.
> > > 
> > > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> > > Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> > > ---
> > >  .../bindings/input/touchscreen/goodix.txt          |   5 +
> > >  drivers/input/touchscreen/goodix.c                 | 143 
> > > +++++++++++++++++++++
> > >  2 files changed, 148 insertions(+)
> > > 
> > > diff --git 
> > > a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > index 7137881..9e4ff69 100644
> > > --- 
> > > a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > +++ 
> > > b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > @@ -15,6 +15,11 @@ Required properties:
> > >   - irq-gpio              : GPIO pin used for IRQ
> > >   - reset-gpio            : GPIO pin used for reset
> > > 
> > > +Optional properties:
> > > +
> > > + - device-config : device configuration information 
> > > (specified as byte
> > > +                   array). Maximum size is 240 bytes.
> > 
> > Generally we frown on passing opaque data.
> > 
> > What exactly is encoded in device-config? The description is very 
> > vague.
> > 
> > Does this correspond to anything in a data sheet or manual?
> 
> Yes, it is configuration data described in chapter 6.2. b of the 
> datasheet: 
> https://drive.google.com/folderview?id=0BxCVOQS3ZymGfmJyY2RKbE5XbVlKN
> lktVTlwV0lxNEdxd2dzeWZER094cmJPVnMxN1F0Yzg&usp=sharing.
> This includes things like x/y resolution, maximum touch numbers 
> supported, 
> interrupt flags, various sensitivity factors. 
> 
> I should have included a link to the datasheet in the commit message 
> - will do that in v2 for all patches.
> 
> I did consider writing this as firmware, but it seems that some 
> Goodix touchscreens have a
> real firmware they need to write in addition to this configuration 
> data.
> If there is a better way to do this, please let me know and I will 
> change it.

I would at least expect an excerpt from an ACPI DSDT that would make
use of that feature.