[PATCH] ARM: dts: da850: Add basic DTS for the L138/C6748 Dev Kit

[Rob Herring]

+Peter H

On Thu, Aug 4, 2016 at 4:03 PM, Karl Beldan <kbeldan at baylibre.com> wrote:
> On Thu, Aug 04, 2016 at 01:29:02PM -0500, Rob Herring wrote:
>> On Thu, Aug 04, 2016 at 02:43:32PM +0000, Karl Beldan wrote:
>> > The LCDK is the successor to the late Hawkboard and has the same machine
>> > number.
>> > Among the differences are the flash (16bits vs 8bits) and some pins
>> > (MMC, LEDs, buttons, some external connectors), however the main
>> > components remain the same (eth. PHY, Audio Codec, Video decoder and
>> > DAC) except for the main PMIC, different and hard-wired on the LCDK (the
>> > LDOs and DCDCs are always ON).
>> > A DT-only boot with this addition gives functional uart, reboot via
>> > watchdog, rtc, ethernet and MMC (I added the CD gpio for the MMC
>> > although davinci_mmc doesn't call yet the mmc core OF facilities).

[...]

>> > +   aliases {
>> > +           serial2 = &serial2;
>> > +   };
>> > +
>> > +   chosen {
>> > +           bootargs = "console=ttyS2,115200n8 earlycon";
>>
>> You don't need console with stdout-path set. And really, earlycon should
>> not be the default.
>>
> Ok for earlycon.
>
> For the console, I thought likewise .. until I _struggled_ to understand
> why the console was disappearing under my feet.
> It seemed even stranger when I started looking at the codepath because
> drivers/of/base.c would properly add_preferred_console as expected after
> the corresponding UART was added. But the reality was there, without it
> the console was not like stdout-path.
> Among the commits that could instill doubt as to whether stdout-path
> rules is f64255b5072d:
> "The assumption that at least 1 preferred console will be registered
> when the stdout-path property is set is invalid, which can result in
> _no_ consoles.", though it didn't answer my question.
> I started looking whether tty0 was not getting in the way and in the end
> I came up with setting console.
> But you seem affirmative.

There have been some issues in this area, but I thought they were in
conjunction with earlycon and solved now. This is a fairly common
review request for dts files, so I'm surprised if it doesn't work
right. Maybe having tty0 or not has some influence. Or people just
accept review comments without testing or caring...

Rob