[PATCH v2] ARM: tegra: add Acer Chromebook 13 device tree

Olof Johansson olof at lixom.net
Wed Aug 20 06:29:14 PDT 2014

On Mon, Aug 18, 2014 at 4:43 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 08/18/2014 05:24 PM, Andrew Bresticker wrote:
>> On Mon, Aug 18, 2014 at 9:10 AM, Stephen Warren <swarren at wwwdotorg.org>
>> wrote:
>>> On 08/16/2014 09:20 AM, Andreas Färber wrote:
>>>> Hi,
>>>> Am 13.08.2014 21:14, schrieb Dylan Reid:
>>>>> The Acer Chromebook 13, codenamed Big, contains an NVIDIA tegra124
>>>>> processor and is similar to the Venice2 reference platform.
>>>>> The keyboard, USB 2, audio, HDMI, sdcard, and emmc have been tested
>>>>> and work on the 1266x768 models.  The HD models haven't yet been
>>>>> tested.
>>>>> WiFi does not work yet, it needs at least some PMIC changes to enable
>>>>> the 32k clock.
>>>>> The elan trackpad is not yet functional but hopefully will be soon as
>>>>> there are patches under review.
>>>>> There is also an issue on reboot because the TPM isn't reset.  It will
>>>>> cause the stock firmware to enter recovery mode.  This can be worked
>>>>> around by an EC-reset, press the refresh and power keys at the same
>>>>> time.
>>>>> diff --git a/arch/arm/boot/dts/tegra124-nyan-big.dts
>>>>> b/arch/arm/boot/dts/tegra124-nyan-big.dts
>>>>> new file mode 100644
>>>>> index 0000000..79f1852
>>>>> --- /dev/null
>>>>> +++ b/arch/arm/boot/dts/tegra124-nyan-big.dts
>>>>> @@ -0,0 +1,1136 @@
>>>>> +/dts-v1/;
>>>>> +
>>>>> +#include <dt-bindings/input/input.h>
>>>>> +#include "tegra124.dtsi"
>>>>> +
>>>>> +/ {
>>>>> +       model = "Acer Chromebook 13";
>>>>> +       compatible = "google,nyan-big", "nvidia,tegra124";
>>>> In light of v1 and the above commit message referring to this as Google
>>>> Big, shouldn't this be "google,big", "nvidia,tegra124" and optionally
>>>> "google,nyan" as secondary string, independent of the new file name?
>>> Despite this board having been derived from Nyan, it isn't Nyan, so I
>>> don't
>>> think Nyan should be part of any compatible value, nor a separate
>>> compatible
>>> value.
>> "google,nyan-big" is the compatible string that the bootloader on
>> these devices looks for.  It's also the convention we are now using
>> for our ARM devices, as Olof has already mentioned.
> I don't understand "that the bootloader looks for"; why is the bootloader
> doing anything w.r.t the compatible value in the DT that's passed to the
> kernel.
> Olof also mentioned that if I had any better ideas on file naming, I should
> point them out. As I mentioned in response, there's zero need for all the
> files or compatible values to have "nyan" in them in order to include any
> common .dtsi file, which was the justification for having "nyan" in the
> filename, IIRC.

Yes, I asked for input, not full veto on things that you happened to
not like. I also didn't say that we could change everything depending
on said input -- some of them might be longer-term changes that we'll
have to consider for a future project, etc. Some of them we might even
disagree on! (see below).

> Again, this board *isn't* Nyan, so it should pretend that it is.

It is a derivative design of the nyan reference platform, and it is
compatible with it. It is perfectly fine to claim to be compatible
with it. I'm sorry, but you're just wrong here.


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