Hello Thierry,
I still haven't found the time to look at device tree things in detail,
but still some comments inline. Overall I think the tree looks ok and is
a great thing to get started.
Am Dienstag, den 26.06.2012, 12:55 +0200 schrieb Thierry Reding:
> Hi,
>
> while I haven't got much time to work on the actual code right now, I
> think it might still be useful if we could get the device tree binding
> to a point where everybody is happy with it. That'll also save me some
> time once I get to writing the code because I won't have to redo it over
> again. =)
>
> So here's the current proposal:
>
> host1x {
> compatible = "nvidia,tegra20-host1x", "simple-bus";
> reg = <0x50000000 0x00024000>;
> interrupts = <0 64 0x04 /* cop syncpt */
> 0 65 0x04 /* mpcore syncpt */
> 0 66 0x04 /* cop general */
> 0 67 0x04>; /* mpcore general */
>
> #address-cells = <1>;
> #size-cells = <1>;
>
> ranges = <0x54000000 0x54000000 0x04000000>;
>
> status = "disabled";
>
> gart = <&gart>;
>
Do we really need this here? IMHO the GART is one kind of a IOMMU
managing a part of the bus where the host1x driver is hanging of. So I
can't see why we would need a pointer to the gart dev directly.
Though I may be off here, as I don't grok everything related to the
initiation order yet, so please correct me if I'm wrong.
> /* video-encoding/decoding */
> mpe {
> reg = <0x54040000 0x00040000>;
> interrupts = <0 68 0x04>;
> status = "disabled";
> };
>
> /* video input */
> vi {
> reg = <0x54080000 0x00040000>;
> interrupts = <0 69 0x04>;
> status = "disabled";
> };
>
> /* EPP */
> epp {
> reg = <0x540c0000 0x00040000>;
> interrupts = <0 70 0x04>;
> status = "disabled";
> };
>
> /* ISP */
> isp {
> reg = <0x54100000 0x00040000>;
> interrupts = <0 71 0x04>;
> status = "disabled";
> };
>
> /* 2D engine */
> gr2d {
> reg = <0x54140000 0x00040000>;
> interrupts = <0 72 0x04>;
> status = "disabled";
> };
>
> /* 3D engine */
> gr3d {
> reg = <0x54180000 0x00040000>;
> status = "disabled";
> };
>
> /* display controllers */
> dc1: dc@54200000 {
> compatible = "nvidia,tegra20-dc";
> reg = <0x54200000 0x00040000>;
> interrupts = <0 73 0x04>;
> status = "disabled";
> };
>
> dc2: dc@54240000 {
> compatible = "nvidia,tegra20-dc";
> reg = <0x54240000 0x00040000>;
> interrupts = <0 74 0x04>;
> status = "disabled";
> };
>
> /* outputs */
> rgb {
> compatible = "nvidia,tegra20-rgb";
> status = "disabled";
> };
>
> hdmi {
> compatible = "nvidia,tegra20-hdmi";
> reg = <0x54280000 0x00040000>;
> interrupts = <0 75 0x04>;
> status = "disabled";
> };
>
> tvo {
> compatible = "nvidia,tegra20-tvo";
> reg = <0x542c0000 0x00040000>;
> interrupts = <0 76 0x04>;
> status = "disabled";
> };
>
> dsi {
> compatible = "nvidia,tegra20-dsi";
> reg = <0x54300000 0x00040000>;
> status = "disabled";
> };
> };
>
> This really isn't anything new but merely brings the Tegra DRM binding
> in sync with other devices in tegra20.dtsi (disable devices by default,
> leave out unit addresses for unique nodes). The only actual change is
> that host1x clients are now children of the host1x node. The children
> are instantiated by the initial call to of_platform_populate() since the
> host1x node is also marked compatible with "simple-bus".
>
We should not rely on OF code doing the instantiation of the children,
as expressed by Grant Likely. [1]
> An alternative would be to call of_platform_populate() from the host1x
> driver. This has the advantage that it could integrate better with the
> host1x bus implementation that Terje is working on, but it also needs
> additional code to tear down the devices when the host1x driver is
> unloaded because a module reload would try to create duplicate devices
> otherwise.
>
[snip]
[1]
http://www.mail-archive.com/linuxppc-dev@xxxxxxxxxxxxxxxx/msg28044.html
Thanks,
Lucas
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