RK3528 ships a PCIe Gen2x1 controller that operates in RC mode only.
Since the SoC has no separate MSI controller, the one integrated in the
DWC PCIe IP must be used, and thus its interrupt scheme is similar to
variants found in RK3562 and RK3576.

Older BSP code claimed its integrated MSI controller supports only 8
MSIs[1], but this has been changed in newer BSP[2] and testing proves
the controller works correctly with more than 8 MSIs allocated,
suggesting the controller should be compatible with the RK3568 variant.
Let's document its compatible string.

Link: https://github.com/rockchip-linux/kernel/blob/792a7d4273a5/drivers/pci/controller/dwc/pcie-dw-rockchip.c#L1610-L1613 # [1]
Link: https://github.com/rockchip-linux/kernel/blob/1ba51b059f25/drivers/pci/controller/dwc/pcie-dw-rockchip.c#L904-L906 # [2]
Signed-off-by: Yao Zi <ziyao@disroot.org>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
---
 Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml b/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml
index 6c6d828ce964..67f1a5502048 100644
--- a/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/rockchip-dw-pcie.yaml
@@ -22,6 +22,7 @@ properties:
       - const: rockchip,rk3568-pcie
       - items:
           - enum:
+              - rockchip,rk3528-pcie
               - rockchip,rk3562-pcie
               - rockchip,rk3576-pcie
               - rockchip,rk3588-pcie
@@ -78,6 +79,7 @@ allOf:
           compatible:
             contains:
               enum:
+                - rockchip,rk3528-pcie
                 - rockchip,rk3562-pcie
                 - rockchip,rk3576-pcie
     then:
@@ -89,6 +91,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - rockchip,rk3528-pcie
               - rockchip,rk3562-pcie
               - rockchip,rk3576-pcie
     then:
-- 
2.50.1

Am Donnerstag, 18. September 2025, 17:30:55 Mitteleuropäische Sommerzeit schrieb Yao Zi:
> RK3528 ships a PCIe Gen2x1 controller that operates in RC mode only.
> Since the SoC has no separate MSI controller, the one integrated in the
> DWC PCIe IP must be used, and thus its interrupt scheme is similar to
> variants found in RK3562 and RK3576.
> 
> Older BSP code claimed its integrated MSI controller supports only 8
> MSIs[1], but this has been changed in newer BSP[2] and testing proves
> the controller works correctly with more than 8 MSIs allocated,
> suggesting the controller should be compatible with the RK3568 variant.
> Let's document its compatible string.
> 
> Link: https://github.com/rockchip-linux/kernel/blob/792a7d4273a5/drivers/pci/controller/dwc/pcie-dw-rockchip.c#L1610-L1613 # [1]
> Link: https://github.com/rockchip-linux/kernel/blob/1ba51b059f25/drivers/pci/controller/dwc/pcie-dw-rockchip.c#L904-L906 # [2]
> Signed-off-by: Yao Zi <ziyao@disroot.org>
> Acked-by: Rob Herring (Arm) <robh@kernel.org>

Acked-by: Heiko Stuebner <heiko@sntech.de>

This likely should to go through the PCI tree.
(or needs an Ack from PCI maintainers, for me to pick it up)

Heiko