I need to write a Custom GPIO driver for an add on board that uses GPIO 18 as a PWM output. I am familiar with writing device drivers, I have looked at the source for the existing GPIO driver library and believe I know what I need to do. However I believe I am blocked by the device descriptor for the Raspberry Pi itself where it has the elements below. As far as I can see this prevents me from adding a custom device descriptor. Is there a work around to allow a custom device descriptor that I can distribute? For development I can add my driver ID to those allowed.

  <AllowOnly>
    <!--GPIOs; must be set because AllowOnly is global and not limited to this connector-->
    <DeviceIdentification deviceType="504" deviceId="0000 0000" />
  </AllowOnly>
  <AllowOnly>
    <!--GPIOs; must be set because AllowOnly is global and not limited to this connector-->
    <DeviceIdentification deviceType="504" deviceId="0000 0001" />
  </AllowOnly>

Hi David,

I have added an JIRA issue for this,
sure this should be possible to use your customized GPIO's.
At the moment you need to change the original Pi devdesc's for testing purpose.

BR
Edwin