On 06/25/2014 05:02 PM, Andrew Bresticker wrote:

On Wed, Jun 25, 2014 at 2:54 PM, Stephen Warren [off-list ref] wrote:

quoted

On 06/18/2014 12:16 AM, Andrew Bresticker wrote:

quoted

Add device-tree binding documentation for the XHCI controller present
on Tegra124 and later SoCs.

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diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra124-xhci.txt b/Documentation/devicetree/bindings/usb/nvidia,tegra124-xhci.txt

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+ - clock-names: Must include the following entries:
+    - xusb_host
+    - xusb_falcon_src
+    - xusb_ss
+    - xusb_ss_src
+    - xusb_hs_src
+    - xusb_fs_src

Looking at include/dt-bindings/clock/tegra124-car.h I see a few entries
potentially missing here:

#define TEGRA124_CLK_XUSB_HOST_SRC 252
#define TEGRA124_CLK_XUSB_DEV_SRC 256
#define TEGRA124_CLK_XUSB_DEV 257
#define TEGRA124_CLK_XUSB_SS_DIV2 312

The driver doesn't use them, so I didn't put them in the binding.

I think we should add them in case we need them later. Best to fully
describe the HW rather than the parts of the HW that SW currently uses.

quoted

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+    - pll_u_480m

Not just pll_u?

We specifically want pll_u_480M as that's what we use as the parent of
xusb_ss_src when scaling it to 120Mhz.

OK. I recall text in the TRM implying that SW should just leave PLL_U
alone and not fiddle with the separate output clocks. Still, if we have
a clock ID for each output, and it's the correct parent for the clock,
then it does make sense to use that ID.