Re: Raspberry Pi support for Rev-2 & BL

Hi Markus

On Tuesday 22 January 2013, Markus Dolze wrote:
> There is one point left I would like to know your opinion about:
>
> The default pin for driving the backlight is GPIO28 which is routed
> to P5. As P5 is not available on Rev 1 boards and not populated on
> Rev 2 boards, I would like to assign the default pin to a GPIO line
> available on P1 - currently I prefer GPIO17 which is P1-11.

There are two spare GPIO pins in the ALT-0 group that are currently 
unused and common to both board revisions - GPIO17 and GPIO22.
Using any of the other GPIO pins risks conflicts if the Serial/I2C/SPI 
kernel drivers are loaded.... Which raises a (minor) problem for EN 
currently driven by GPIO8 - This is used by the SPI driver if it is 
loaded.

> Any objections?

No objections to GPIO17 being used, could you switch EN to the remaining 
unused GPIO22 - Perhaps a note in the docs about possible GPIO 
conflicts when kernel drivers are loaded might be in order.


Regards, Paul.