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+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bus/socionext,uniphier-system-bus.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: UniPhier System Bus
+
+description: |
+ The UniPhier System Bus is an external bus that connects on-board devices to
+ the UniPhier SoC. It is a simple (semi-)parallel bus with address, data, and
+ some control signals. It supports up to 8 banks (chip selects).
+
+ Before any access to the bus, the bus controller must be configured; the bus
+ controller registers provide the control for the translation from the offset
+ within each bank to the CPU-viewed address. The needed setup includes the
+ base address, the size of each bank. Optionally, some timing parameters can
+ be optimized for faster bus access.
+
+maintainers:
+ - Masahiro Yamada <yamada.masahiro@socionext.com>
+
+properties:
+ compatible:
+ const: socionext,uniphier-system-bus
+
+ reg:
+ maxItems: 1
+
+ "#address-cells":
+ description: |
+ The first cell is the bank number (chip select).
+ The second cell is the address offset within the bank.
+ const: 2
+
+ "#size-cells":
+ const: 1
+
+ ranges:
+ description: |
+ Provide address translation from the System Bus to the parent bus.
+
+ Note:
+ The address region(s) that can be assigned for the System Bus is
+ implementation defined. Some SoCs can use 0x00000000-0x0fffffff and
+ 0x40000000-0x4fffffff, while other SoCs only 0x40000000-0x4fffffff.
+ There might be additional limitations depending on SoCs and the boot mode.
+ The address translation is arbitrary as long as the banks are assigned in
+ the supported address space with the required alignment and they do not
+ overlap one another.
+
+ For example, it is possible to map:
+ bank 0 to 0x42000000-0x43ffffff, bank 5 to 0x46000000-0x46ffffff
+ It is also possible to map:
+ bank 0 to 0x48000000-0x49ffffff, bank 5 to 0x44000000-0x44ffffff
+ There is no reason to stick to a particular translation mapping, but the
+ "ranges" property should provide a "reasonable" default that is known to
+ work. The software should initialize the bus controller according to it.
+
+patternProperties:
+ "^.*@[1-5],[1-9a-f][0-9a-f]+$":
+ description: Devices attached to chip selects
+ type: object
+
+required:
+ - compatible
+ - reg
+ - "#address-cells"
+ - "#size-cells"
+ - ranges
+
+additionalProperties: false
+
+examples:
+ - |
+ // In this example,
+ // - the Ethernet device is connected at the offset 0x01f00000 of CS1 and
+ // mapped to 0x43f00000 of the parent bus.
+ // - the UART device is connected at the offset 0x00200000 of CS5 and
+ // mapped to 0x46200000 of the parent bus.
+
+ system-bus@58c00000 {
+ compatible = "socionext,uniphier-system-bus";
+ reg = <0x58c00000 0x400>;
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges = <1 0x00000000 0x42000000 0x02000000>,
+ <5 0x00000000 0x46000000 0x01000000>;
+
+ ethernet@1,1f00000 {
+ compatible = "smsc,lan9115";
+ reg = <1 0x01f00000 0x1000>;
+ interrupts = <0 48 4>;
+ phy-mode = "mii";
+ };
+
+ serial@5,200000 {
+ compatible = "ns16550a";
+ reg = <5 0x00200000 0x20>;
+ interrupts = <0 49 4>;
+ clock-frequency = <12288000>;
+ };
+ };