dt-bindings: soc: Add documentation for the MediaTek SCPSYS unit

This adds documentation for the MediaTek SCPSYS unit found in MT8173 SoCs.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

diff --git a/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt b/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt
new file mode 100644 (file)
index 0000000..c051114
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+++ b/Documentation/devicetree/bindings/soc/mediatek/scpsys.txt
@@ -0,0 +1,41 @@
+MediaTek SCPSYS
+===============
+
+The System Control Processor System (SCPSYS) has several power management
+related tasks in the system. The tasks include thermal measurement, dynamic
+voltage frequency scaling (DVFS), interrupt filter and lowlevel sleep control.
+The System Power Manager (SPM) inside the SCPSYS is for the MTCMOS power
+domain control.
+
+The driver implements the Generic PM domain bindings described in
+power/power_domain.txt. It provides the power domains defined in
+include/dt-bindings/power/mt8173-power.h.
+
+Required properties:
+- compatible: Must be "mediatek,mt8173-scpsys"
+- #power-domain-cells: Must be 1
+- reg: Address range of the SCPSYS unit
+- infracfg: must contain a phandle to the infracfg controller
+- clock, clock-names: clocks according to the common clock binding.
+                      The clocks needed "mm" and "mfg". These are the
+                     clocks which hardware needs to be enabled before
+                     enabling certain power domains.
+
+Example:
+
+       scpsys: scpsys@10006000 {
+               #power-domain-cells = <1>;
+               compatible = "mediatek,mt8173-scpsys";
+               reg = <0 0x10006000 0 0x1000>;
+               infracfg = <&infracfg>;
+               clocks = <&clk26m>,
+                        <&topckgen CLK_TOP_MM_SEL>;
+               clock-names = "mfg", "mm";
+       };
+
+Example consumer:
+
+       afe: mt8173-afe-pcm@11220000 {
+               compatible = "mediatek,mt8173-afe-pcm";
+               power-domains = <&scpsys MT8173_POWER_DOMAIN_AUDIO>;
+       };