Re: [RFC PATCH 0/1] input/touchscreen: Synaptics Touchscreen Driver

[Christopher Heiny]

On 03/22/2010 08:04 PM, Arve Hjønnevåg wrote:
> On Mon, Mar 22, 2010 at 7:07 PM, Christopher Heiny<cheiny@xxxxxxxxxxxxx>  wrote:
> ...
> > There are two existing drivers for similar Synaptics devices in the
> > current kernel tree (excluding the PS/2 touchpad driver).  These are:
> >
> > ./linux-2.6/drivers/input/mouse/synaptics_i2c.c
> >       A driver for the Exeda 15mm touchpad, written by Mike Rapoport
> >       <mike@xxxxxxxxxxxxxx>  and Igor Grinberg<grinberg@xxxxxxxxxxxxxx>
> >
> > ./linux-2.6/drivers/staging/dream/synaptics_i2c_rmi.c
> >       A driver for the HTC Dream ClearPad, written by Arve Hjønnevåg
> >       <arve@xxxxxxxxxxx>
> >
> > We have not extended these drivers for a couple of reasons.  First, the
> > two drivers are specific to particular Synaptics products, and it is our
> > desire to produce a general solution that takes advantage of the 'self
> > describing' features of products that use the RMI protocol.
>
> Do you plan to add platform data to align the reported touchscreen
> data with the screen behind it, or do the new hardware allow the the
> firmware handle this? In the past we even needed separate parameters
> for different firmware versions (seen in
> drivers/staging/dream/synaptics_i2c_rmi.h).

Hi Arve,

RMI4 touchscreens allow adjustment of the reported coordinate range (see 
the F11_2D_Ctrl6..9 registers, page 48 of the current version of the 
spec at http://www.synaptics.com/developers/manuals).  Using this 
feature, the device can be configured to report the same number of 
positions on each axis as there are pixels on the display.

We plan to make these settings accessible via sysfs, so that it can be 
dynamically tweaked if the user changes the display resolution (not 
likely on a phone, probable on a tablet/slate/ereader type device). 
Assuming there are no significant issues with our current patch, we plan 
to include that in the next one.  We're holding off that implementation 
because we're still finding our feet on the submission process, and 
wanted to keep the initial submits small so changes would be more 
manageable.

Coordinate rotation/reflection settings will be handled at the driver 
level, again via sysfs.

These features should be independent of the touchscreen firmware level. 
 Initial settings for these features should probably be done at the 
platform level.

					Chris
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