dt-bindings: serial: snps-dw-apb-uart: Allow use of a power-domain

The UART controllers in most Rockchip SoCs are part of power domains
that are always powered on. These always powered on power domains have
typically not been described in the device tree.

Because these power domains have been left out of the device tree there
has not been any real need to properly describe the UART controllers
power domain of Rockchip SoCs.

On Rockchip RK3528 the UART controllers are spread out among the
described PD_RKVENC, PD_VO and PD_VPU power domains. However, one UART
controller belong to an undescribed always powered on power domain.

Add support to describe an optional power-domains for the UART
controllers.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250723085654.2273324-5-jonas@kwiboo.se
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index 8f1b7f704c5bc7cb9552b7d4825d96199cbc6c4f..cb9da6c97afcfd27a315414959b2b17beb4454cf 100644 (file)
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -108,6 +108,9 @@ properties:
       parameter. Define this if your UART does not implement the busy functionality.
     type: boolean
 
+  power-domains:
+    maxItems: 1
+
   resets:
     minItems: 1
     maxItems: 2