Rob Herring wrote at Wednesday, January 04, 2012 12:54 PM: > On 01/04/2012 12:39 PM, Stephen Warren wrote: > > Tegra20's GPIO controller has 7 banks, and Tegra30's controller has 8 > > banks. Allow the number of banks to be configured at run-time by the > > device tree. ... > > diff --git a/Documentation/devicetree/bindings/gpio/gpio_nvidia.txt ... > > Required properties: > > - compatible : "nvidia,tegra20-gpio" > > - reg : Physical base address and length of the controller's registers. > > +- nvidia,num-banks : The number of GPIO banks. This should be 7 for > > + Tegra20 and 8 for Tegra30. This must match the number of interrupt > > + specifiers in the interrupts property. > > You can determine the number of banks based on the compatible property > rather than needing an additional property. That's certainly possible. However, if say nvidia,tegraNNN-gpio has 9 banks, we then have to explicitly edit the driver to know that, whereas by using a property, we wouldn't have to change the driver at all to support a future GPIO controller. So, isn't it better to explicitly represent this in DT? Note that I have no idea how many GPIO banks our future chips will have, so this might not turn out to save any work at all, but perhaps. -- nvpublic -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
