On Sat, Apr 11, 2015 at 07:18:16PM +0300, Aleksei Mamlin wrote: > On Thu, 2 Apr 2015 11:22:59 +0200 > Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx> 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. I'm confused, who changes that address then? The controller itself? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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