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| -rw-r--r-- | Documentation/devicetree/bindings/mailbox/mtk-gce.txt | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mailbox/mtk-gce.txt b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt new file mode 100644 index 000000000..7771ecaac --- /dev/null +++ b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt @@ -0,0 +1,64 @@ +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: can be "mediatek,mt8173-gce", "mediatek,mt8183-gce" or + "mediatek,mt6779-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 2. + <&phandle channel priority> + phandle: Label name of a gce node. + channel: Channel of mailbox. Be equal to the thread id of GCE. + priority: Priority of GCE thread. + +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. +Optional properties for a client device: +- mediatek,gce-client-reg: Specify the sub-system id which is corresponding + to the register address, it should have this property and list of phandle, + sub-system specifiers. + <&phandle subsys_number start_offset size> + phandle: Label name of a gce node. + subsys_number: specify the sub-system id which is corresponding + to the register address. + start_offset: the start offset of register address that GCE can access. + size: the total size of register address that GCE can access. + +Some vaules of properties are defined in 'dt-bindings/gce/mt8173-gce.h', +'dt-binding/gce/mt8183-gce.h' or 'dt-bindings/gce/mt6779-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 = <GIC_SPI 135 IRQ_TYPE_LEVEL_LOW>; + clocks = <&infracfg CLK_INFRA_GCE>; + clock-names = "gce"; + #mbox-cells = <2>; + }; + +Example for a client device: + + mmsys: clock-controller@14000000 { + compatible = "mediatek,mt8173-mmsys"; + mboxes = <&gce 0 CMDQ_THR_PRIO_LOWEST>, + <&gce 1 CMDQ_THR_PRIO_LOWEST>; + mutex-event-eof = <CMDQ_EVENT_MUTEX0_STREAM_EOF + CMDQ_EVENT_MUTEX1_STREAM_EOF>; + mediatek,gce-client-reg = <&gce SUBSYS_1400XXXX 0x3000 0x1000>, + <&gce SUBSYS_1401XXXX 0x2000 0x100>; + ... + }; |