[PATCH] ARM: dts: sun7i: Add Goodix GT911 nodes for Wexler TAB7200

Aleksei Mamlin mamlinav at gmail.com
Sat Apr 11 09:18:16 PDT 2015


On Thu, 2 Apr 2015 11:22:59 +0200
Maxime Ripard <maxime.ripard at free-electrons.com> wrote:

> On Tue, Mar 31, 2015 at 10:14:20PM +0300, Aleksei Mamlin wrote:
> > On Tue, 31 Mar 2015 07:43:38 -0700
> > Maxime Ripard <maxime.ripard at free-electrons.com> wrote:
> > 
> > > Hi,
> > > 
> > > On Tue, Mar 31, 2015 at 11:18:17AM +0300, Aleksei Mamlin wrote:
> > > > This patch adds nodes for the Goodix GT911 touchscreen controller found
> > > > on the Wexler TAB7200 tablet. Controller uses one of following I2C
> > > > addresses: 0x5d or 0x14, so just add two nodes.
> > > 
> > > In which case are these different addresses encountered? Different
> > > revisions of the same board?
> >
> > According to the datasheet it is a feature of the controller. 
> > The address(0x5d or 0x14) can be configured using a reset sequence,
> > which has not yet been implemented in the driver.
> 
> Which address is set up by the bootloader then?
> 
I assume that bootloader(u-boot) didn't sets up any address, but touchscreen
controller usually uses 0x5d. Sometimes, after hard reset, it uses 0x14.
For this we need nodes on both adresses.
>
> Maxime
> 
> -- 
> Maxime Ripard, Free Electrons
> Embedded Linux, Kernel and Android engineering
> http://free-electrons.com


-- 
Thanks and regards,
Aleksei Mamlin



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