Re: [PATCH v2 1/3] dt/bindings: da8xx-usb: Add binding for the CPPI 4.1 DMA controller

On 1/18/2017 1:21 PM, Sekhar Nori wrote:

quoted

quoted

quoted

quoted

DT binding for the TI DA8xx/OMAP-L1x/AM17xx/AM18xx cppi41 dma
controller.

Signed-off-by: Alexandre Bailon <abailon-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
---
 .../devicetree/bindings/usb/da8xx-usb.txt          | 42
++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/da8xx-usb.txt

b/Documentation/devicetree/bindings/usb/da8xx-usb.txt
index ccb844a..aed3169 100644

--- a/Documentation/devicetree/bindings/usb/da8xx-usb.txt
+++ b/Documentation/devicetree/bindings/usb/da8xx-usb.txt

@@ -18,10 +18,26 @@ Required properties:

  - phy-names: Should be "usb-phy"

+ - dmas: specifies the dma channels
+
+ - dma-names: specifies the names of the channels. Use "rxN" for

receive
+   and "txN" for transmit endpoints. N specifies the endpoint number.
+
 Optional properties:
 ~~~~~~~~~~~~~~~~~~~~
  - vbus-supply: Phandle to a regulator providing the USB bus power.

+DMA
+~~~
+- compatible: ti,da8xx-cppi41

   Almost missed this -- wildcards in this property are forbidden.
We should use "ti,da830-cppi41" as a least common denominator.

Documentation/devicetree/bindings/submitting-patches.txt states:

"
  5) The wildcard "<chip>" may be used in compatible strings, as in
     the following example:

         - compatible: Must contain '"nvidia,<chip>-pcie",
           "nvidia,tegra20-pcie"' where <chip> is tegra30, tegra132, ...
"

I take this to mean that using wildcards to denote an SoC family on
which the same IP is present is okay to do.> With that understanding, I
think using ti,da8xx-cppi41 is fine too.

   It doesn't really follow. I repeat, x's are not allowed.

Can you clarify here? If x's are indeed not allowed,

   I have no idea where you got that they are allowed.

then I think the
document is being ambiguous about what constitutes "The wildcard "<chip>""

   There 's no ambiguity because the wildcard is the word "<chip>" itself, not anything other. Even if "<chip>" is used in the bindings, its possible values should be documented anyway.

Thanks,
Sekhar

MBR, Sergei

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