Amlogic Meson8, Meson8b and Meson8m2 SoCs have a DDR clock controller in
the MMCBUS registers. There is no public documentation on this, but the
GPL u-boot sources from the Amlogic BSP show that:
- it uses the same XTAL input as the main clock controller
- it contains a PLL which seems to be implemented just like the other
PLLs in this SoC
- there is a power-of-two PLL post-divider
Add the documentation and header file for this DDR clock controller.
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
--- /dev/null
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/amlogic,meson8-ddr-clkc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Amlogic DDR Clock Controller Device Tree Bindings
+
+maintainers:
+ - Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+
+properties:
+ compatible:
+ enum:
+ - amlogic,meson8-ddr-clkc
+ - amlogic,meson8b-ddr-clkc
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ maxItems: 1
+
+ clock-names:
+ items:
+ - const: xtal
+
+ "#clock-cells":
+ const: 1
+
+required:
+ - compatible
+ - reg
+ - clocks
+ - clock-names
+ - "#clock-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ ddr_clkc: clock-controller@400 {
+ compatible = "amlogic,meson8-ddr-clkc";
+ reg = <0x400 0x20>;
+ clocks = <&xtal>;
+ clock-names = "xtal";
+ #clock-cells = <1>;
+ };
+
+...
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define DDR_CLKID_DDR_PLL_DCO 0
+#define DDR_CLKID_DDR_PLL 1