Subject: [PATCH v2 1/2] dt-bindings: add bindings doc for ZTE VOU display controller

From: [email-masked] (Shawn Guo)
Date: Sun, 9 Oct 2016 15:49:10 +0800

On Mon, Oct 03, 2016 at 12:44:29PM -0500, Rob Herring wrote:
> > +Example:
> > +
> > +vou: vou at 1440000 {
> > +	compatible = "zte,zx296718-vou";
> > +	#address-cells = <1>;
> > +	#size-cells = <1>;
> > +	reg = <0x1440000 0x10000>;
> > +	ranges;
> 
> You still have overlapping addresses. Explicitly list the sub ranges in 
> reg here used by the VOU driver if the driver usage doesn't overlap. If 
> there is overlap (2 drivers accessing the same range), then you need 
> some APIs between the components (or possibly regmap).

The driver matching "zte,zx296718-vou" doesn't map or access the any
'reg' address.  The 'reg' property here is more like a hint telling
that the VOU block covers the address space of all child devices.

I will simply drop the 'reg' property here.

> Also, don't do an empty ranges here. Fill it in so the child nodes are 
> just offsets of 0x1440000

Okay.  I thought that empty 'ranges' is fine as long as parent and child
address spaces are identical (1:1 mapping).

So with your suggestion, I made the changes below.  Let me know if this
is still not what you are asking for.

Shawn

-----8<-----------------

diff --git a/Documentation/devicetree/bindings/display/zte,vou.txt b/Documentation/devicetree/bindings/display/zte,vou.txt
index d03ba4c4810c..6bb4ab2517ef 100644
--- a/Documentation/devicetree/bindings/display/zte,vou.txt
+++ b/Documentation/devicetree/bindings/display/zte,vou.txt
@@ -56,14 +56,13 @@ vou: vou@1440000 {
        compatible = "zte,zx296718-vou";
        #address-cells = <1>;
        #size-cells = <1>;
-       reg = <0x1440000 0x10000>;
-       ranges;
+       ranges = <0 0x1440000 0x10000>;
 
-       dpc: dpc at 1440000 {
+       dpc: dpc at 0 {
                compatible = "zte,zx296718-dpc";
-               reg = <0x1440000 0x1000>, <0x1441000 0x1000>,
-                     <0x1445000 0x1000>, <0x1446000 0x1000>,
-                     <0x144a000 0x1000>;
+               reg = <0x0000 0x1000>, <0x1000 0x1000>,
+                     <0x5000 0x1000>, <0x6000 0x1000>,
+                     <0xa000 0x1000>;
                reg-names = "osd", "timing_ctrl",
                            "dtrc", "vou_ctrl",
                            "otfppu";
@@ -74,9 +73,9 @@ vou: vou at 1440000 {
                              "main_wclk", "aux_wclk";
        };
 
-       hdmi: hdmi at 144c000 {
+       hdmi: hdmi at c000 {
                compatible = "zte,zx296718-hdmi";
-               reg = <0x144c000 0x4000>;
+               reg = <0xc000 0x4000>;
                interrupts = <GIC_SPI 82 IRQ_TYPE_EDGE_RISING>;