[PATCH 6/6] gpio: tegra: Parameterize the number of banks
swarren at nvidia.com
Wed Jan 4 15:00:26 EST 2012
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.
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