dt-bindings: mediatek: add descriptions for mediatek mt2701 iommu and smi

This patch defines the local arbitor port IDs for mediatek SoC MT2701 and
add descriptions of binding for mediatek generation one iommu and smi.

Signed-off-by: Honghui Zhang <honghui.zhang@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 18 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.txt b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.txt
index 06a83ceebba7..aa614b2d7cab 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.txt
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.txt
@@ -2,16 +2,31 @@ SMI (Smart Multimedia Interface) Common
 
 The hardware block diagram please check bindings/iommu/mediatek,iommu.txt
 
+Mediatek SMI have two generations of HW architecture, mt8173 uses the second
+generation of SMI HW while mt2701 uses the first generation HW of SMI.
+
+There's slight differences between the two SMI, for generation 2, the
+register which control the iommu port is at each larb's register base. But
+for generation 1, the register is at smi ao base(smi always on register
+base). Besides that, the smi async clock should be prepared and enabled for
+SMI generation 1 to transform the smi clock into emi clock domain, but that is
+not needed for SMI generation 2.
+
 Required properties:
-- compatible : must be "mediatek,mt8173-smi-common"
+- compatible : must be one of :
+	"mediatek,mt2701-smi-common"
+	"mediatek,mt8173-smi-common"
 - reg : the register and size of the SMI block.
 - power-domains : a phandle to the power domain of this local arbiter.
 - clocks : Must contain an entry for each entry in clock-names.
-- clock-names : must contain 2 entries, as follows:
+- clock-names : must contain 3 entries for generation 1 smi HW and 2 entries
+  for generation 2 smi HW as follows:
   - "apb" : Advanced Peripheral Bus clock, It's the clock for setting
 	    the register.
   - "smi" : It's the clock for transfer data and command.
-  They may be the same if both source clocks are the same.
+	    They may be the same if both source clocks are the same.
+  - "async" : asynchronous clock, it help transform the smi clock into the emi
+	      clock domain, this clock is only needed by generation 1 smi HW.
 
 Example:
 	smi_common: smi@14022000 {