[U-Boot] [PATCH v2 3/6] tegra: dts: Sync tegra20 device tree files with Linux

[Simon Glass]

Hi Stephen,

On 9 May 2016 at 11:09, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 05/08/2016 04:55 PM, Simon Glass wrote:
>>
>> Sync everything except the display panel, which will come in a future
>> patch.
>> One USB port is left disabled since we don't want to support it in U-Boot.
>
>
> I'd rather be a bit more careful here, and only import the DT nodes directly
> related to display output.
>
> This change brings in a slew of other nodes that aren't used by U-Boot
> (something we've historically explicitly avoided) such as pinctrl, audio,
> Tegra KBC, I2C mux, & regulators.

I believe that audio, KBC and regulators are used.

>
> It also doesn't sync the /aliases node with the kernel (e.g. Seaboard I2C,
> and I think USB for all boards), and at least Harmony's USB nodes don't seem
> to match what's in the kernel so I'm not sure where the DT content came
> from, e.g. consider usb at c5004000's nvidia,phy-reset-gpio used an integer
> rather than GPIO_ACTIVE_LOW, which is present in at least the most recent
> kernel release (v4.5).

This was against v4.4, but I may have messed up the merge in some
cases. since I had to change the addresses from 64 bit.

>
> Splitting this up a bit or limiting it to just display-related nodes would
> make it easier to debug any issues that crop up with the sync. Also, have we
> made an explicit decision to change the policy of only including DT nodes
> that U-Boot actually uses, rather than simply copying the entire kernel DT
> into U-Boot? I'm pretty sure that some board(s) have deliberate differences
> in areas other than display, e.g. since U-Boot doesn't (or at least didn't)
> support pinctrl-based I2C muxed which are used on some Tegra20 boards in the
> kernel at least, and hence U-Boot likely either disabled those I2C ports or
> picked an explicit pinmux configuration to hard-code to.

I think I know what you mean, and I don't believe that actually
affects any I2C ports that are used in U-Boot. Do you have any
example?

I'd rather have the DT completely in sync, so far as can be done. We
have this merge window to find problems. I don't see a big benefit to
leaving stuff out...at least with other boards we've defaulted to just
bringing everything in.

Are we mostly talking about the pinmux stuff?

Regards,
Simon