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

Rob Herring
2016-10-10T21:48:21Z

On Sun, Oct 09, 2016 at 03:49:10PM +0800, Shawn Guo wrote:
> On Mon, Oct 03, 2016 at 12:44:29PM -0500, Rob Herring wrote:
> > > +Example:
> > > +
> > > +vou: vou@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).

It is fine, but it's just better policy to limit the scope of things.

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

Looks fine. With that,

Acked-by: Rob Herring <robh@kernel.org>

>
> 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@1440000 {
> + dpc: dpc@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@1440000 {
> "main_wclk", "aux_wclk";
> };
>
> - hdmi: hdmi@144c000 {
> + hdmi: hdmi@c000 {
> compatible = "zte,zx296718-hdmi";
> - reg = <0x144c000 0x4000>;
> + reg = <0xc000 0x4000>;
> interrupts = <GIC_SPI 82 IRQ_TYPE_EDGE_RISING>;