From 1c82407aa302774b24bf619e56973aa97cbf25bd Mon Sep 17 00:00:00 2001 From: Houlong Wei Date: Wed, 25 Jul 2018 09:26:39 +0800 Subject: dt-bindings: soc: Add documentation for the MediaTek GCE unit This adds documentation for the MediaTek Global Command Engine (GCE) unit found in MT8173 SoCs. Signed-off-by: Houlong Wei Signed-off-by: HS Liao Reviewed-by: Rob Herring Signed-off-by: Jassi Brar --- .../devicetree/bindings/mailbox/mtk-gce.txt | 57 ++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt (limited to 'Documentation/devicetree/bindings/mailbox') diff --git a/Documentation/devicetree/bindings/mailbox/mtk-gce.txt b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt new file mode 100644 index 000000000000..7d72b21c9e94 --- /dev/null +++ b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt @@ -0,0 +1,57 @@ +MediaTek GCE +=============== + +The Global Command Engine (GCE) is used to help read/write registers with +critical time limitation, such as updating display configuration during the +vblank. The GCE can be used to implement the Command Queue (CMDQ) driver. + +CMDQ driver uses mailbox framework for communication. Please refer to +mailbox.txt for generic information about mailbox device-tree bindings. + +Required properties: +- compatible: Must be "mediatek,mt8173-gce" +- reg: Address range of the GCE unit +- interrupts: The interrupt signal from the GCE block +- clock: Clocks according to the common clock binding +- clock-names: Must be "gce" to stand for GCE clock +- #mbox-cells: Should be 3. + <&phandle channel priority atomic_exec> + phandle: Label name of a gce node. + channel: Channel of mailbox. Be equal to the thread id of GCE. + priority: Priority of GCE thread. + atomic_exec: GCE processing continuous packets of commands in atomic + way. + +Required properties for a client device: +- mboxes: Client use mailbox to communicate with GCE, it should have this + property and list of phandle, mailbox specifiers. +- mediatek,gce-subsys: u32, specify the sub-system id which is corresponding + to the register address. + +Some vaules of properties are defined in 'dt-bindings/gce/mt8173-gce.h'. Such as +sub-system ids, thread priority, event ids. + +Example: + + gce: gce@10212000 { + compatible = "mediatek,mt8173-gce"; + reg = <0 0x10212000 0 0x1000>; + interrupts = ; + clocks = <&infracfg CLK_INFRA_GCE>; + clock-names = "gce"; + thread-num = CMDQ_THR_MAX_COUNT; + #mbox-cells = <3>; + }; + +Example for a client device: + + mmsys: clock-controller@14000000 { + compatible = "mediatek,mt8173-mmsys"; + mboxes = <&gce 0 CMDQ_THR_PRIO_LOWEST 1>, + <&gce 1 CMDQ_THR_PRIO_LOWEST 1>; + mediatek,gce-subsys = ; + mutex-event-eof = ; + + ... + }; -- cgit v1.2.3