Re: [PATCH v2 4/4] ARM: dts: keystone: Add "ti,da830-uart" compatible string

[Santosh Shilimkar]

On 1/5/2017 1:04 AM, Sekhar Nori wrote:
> Hi Santosh,
>
> On Thursday 05 January 2017 03:30 AM, Santosh Shilimkar wrote:
> > On 1/4/2017 12:30 PM, David Lechner wrote:
> > > The TI Keystone SoCs have extra UART registers beyond the standard 8250
> > > registers, so we need a new compatible string to indicate this. Also, at
> > > least one of these registers uses the full 32 bits, so we need to specify
> > > reg-io-width in addition to reg-shift.
> > >
> > > "ns16550a" is left in the compatible specification since it does work as
> > > long as the bootloader configures the SoC UART power management
> > > registers.
> > NAK!!
> > We can't break the booting boards with existing boot loaders.
>
> Sorry, but it not clear to me how this breaks booting with older
> bootloaders? If older DTB is ROM'ed, it will continue to work because of
> match with ns16550a.
>
> I just verified boot on K2E with these patches applied and using 2016.05
> based U-Boot from a TI release.
>
> http://pastebin.ubuntu.com/23744719/
Thanks for test. As long as it doesn't break the boot, am fine
with it.

> > I suggest you to first get the driver updated to take care of
> > the UART PM register and then enable the support for it.
>
> Isn't that what patch 2/4 is doing?
I see that now. Thanks for clarifying.

Serial patch needs to go via Greg's tree. I will pick up the
DTS bits.

Regards,
Santosh