[PATCH v5 2/4] dt-bindings: PCI: qcom,pcie-sa8775p: document link_down reset

[Rob Herring (Arm)]

On Fri, 18 Jul 2025 16:17:16 +0800, Ziyue Zhang wrote:
> Each PCIe controller on SA8775P includes a 'link_down' reset line in
> hardware. This patch documents the reset in the device tree binding.
> 
> The 'link_down' reset is used to forcefully bring down the PCIe link
> layer, which is useful in scenarios such as link recovery after errors,
> power management transitions, and hotplug events. Including this reset
> line improves robustness and provides finer control over PCIe controller
> behavior.
> 
> As the 'link_down' reset was omitted in the initial submission, it is now
> being documented. While this reset is not required for most of the block's
> basic functionality, and device trees lacking it will continue to function
> correctly in most cases, it is necessary to ensure maximum robustness when
> shutting down or recovering the PCIe core. Therefore, its inclusion is
> justified despite the minor ABI change.
> 
> Signed-off-by: Ziyue Zhang <ziyue.zhang at oss.qualcomm.com>
> ---
>  .../devicetree/bindings/pci/qcom,pcie-sa8775p.yaml    | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 

Reviewed-by: Rob Herring (Arm) <robh at kernel.org>