[PATCH v22 1/4] dt-bindings: soc: Add documentation for the MediaTek GCE unit
From: robh@kernel.org (Rob Herring)
Date: 2018-07-03 02:30:50
Also in:
linux-devicetree, linux-mediatek, lkml
On Wed, Jun 27, 2018 at 07:16:09PM +0800, Houlong Wei wrote:
quoted hunk ↗ jump to hunk
This adds documentation for the MediaTek Global Command Engine (GCE) unit found in MT8173 SoCs. Signed-off-by: Houlong Wei <houlong.wei@mediatek.com> Signed-off-by: HS Liao <redacted> --- Hi Rob, I don't add your ACK in this version since the dt-binding description has been changed. Thanks. --- .../devicetree/bindings/mailbox/mtk-gce.txt | 65 ++++++++++++++++++++ include/dt-bindings/gce/mt8173-gce.h | 48 +++++++++++++++ 2 files changed, 113 insertions(+) create mode 100644 Documentation/devicetree/bindings/mailbox/mtk-gce.txt create mode 100644 include/dt-bindings/gce/mt8173-gce.hdiff --git a/Documentation/devicetree/bindings/mailbox/mtk-gce.txt b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt new file mode 100644 index 0000000..26f65a4 --- /dev/null +++ b/Documentation/devicetree/bindings/mailbox/mtk-gce.txt@@ -0,0 +1,65 @@ +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 +- thread-num: Maximum threads count of GCE.
mediatek,thread-num Is this needed for anything other than error checking the thread id in the mbox cells? if that's it, then drop it.
+- #mbox-cells: Should be 4. + <&phandle channel timeout priority atomic_exec> + phandle: Label name of a gce node. + channel: Channel of mailbox. Be equal to the thread id of GCE. + timeout: Maximum time of software waiting GCE processing done, in unit + of millisecond. + 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. +- gce-subsys: Specify the sub-system id which is corresponding to the register + address.
What is this for?
+ +Optional properties for a client device: +- gce-event: Specify the event if the client has any. Because the event is + parsed by client, so client can replace 'gce-event' with other meaningful + name.
If the client sets the name, then no point having here. It must be documented in the client binding. But then, what is this for in the first place?
+
+Some vaules of properties are defined in 'dt-bindings/gce/mt8173-gce.h'. Such as
+thread number, sub-system ids, thread priority, event ids.
+
+Example:
+
+ gce: gce at 10212000 {mailbox at ...
+ 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";
+ thread-num = CMDQ_THR_MAX_COUNT;
+ #mbox-cells = <4>;
+ };
+
+Example for a client device:
+
+ mmsys: clock-controller at 14000000 {
+ compatible = "mediatek,mt8173-mmsys";
+ mboxes = <&gce 0 2000 CMDQ_THR_PRIO_LOWEST 1>,
+ <&gce 1 2000 CMDQ_THR_PRIO_LOWEST 1>;
+ gce-subsys = <SUBSYS_1400XXXX>;
+ mutex-event-eof = <CMDQ_EVENT_MUTEX0_STREAM_EOF
+ CMDQ_EVENT_MUTEX1_STREAM_EOF>;
+
+ ...
+ };