[U-Boot] [PATCH 11/60] ARM: tegra: add DT alias for GPIO controller

Simon Glass
2016-04-20T19:26:11Z

On 19 April 2016 at 14:58, Stephen Warren <swarren@wwwdotorg.org> wrote:
> From: Stephen Warren <swarren@nvidia.com>
>
> Future Tegra chips contain multiple entirely separate GPIO controllers. It
> is plausible that boards using those chips will end up with non-DT-driven
> code that manipulates GPIOs, just like a few Tegra boards do today. In
> that case, we'll want to make sure that the mapping from the global
> integer GPIO numbering to GPIO controller occurs in a defined order, so
> that the right GPIO is chosen in each case. To guarantee that order, GPIO
> controllers must have specific DM "seq" values. This can be ensured via DT
> aliases.
>
> This is a no-op for current chips since there's only one GPIO controller.
> However, it provides a good example for cargo-cult programming:-)
>
> The aliases are added to the SoC DTSI files since there is no need for
> them to vary between boards, and doing so avoids having to duplicate the
> entry in each board's DT file. Any additional board-specific GPIO
> controllers can be referenced by additional aliases (starting at 1) in
> board DT files if needed.
>
> Signed-off-by: Stephen Warren <swarren@nvidia.com>
> ---
> arch/arm/dts/tegra114.dtsi | 4 ++++
> arch/arm/dts/tegra20.dtsi | 4 ++++
> arch/arm/dts/tegra210.dtsi | 4 ++++
> arch/arm/dts/tegra30.dtsi | 4 ++++
> 4 files changed, 16 insertions(+)

Reviewed-by: Simon Glass <sjg@chromium.org>