[U-Boot] [PATCH 0/8] arm: ls1021atwr: Convert to driver model and enable serial support

[Bin Meng]

Hi Alison,

On Thu, Jan 7, 2016 at 2:19 PM, Huan Wang <alison.wang at nxp.com> wrote:
> Hi, Bin,
>
>> On Thu, Jan 7, 2016 at 2:01 PM, Huan Wang <alison.wang at nxp.com> wrote:
>> > Hi, Bin,
>> >
>> >> On Wed, Jan 6, 2016 at 1:31 PM, Huan Wang <alison.wang at nxp.com> wrote:
>> >> > Hi,
>> >> >
>> >> >         I tested this set on my LS1021ATWR board. NOR boot using
>> >> > DUART
>> >> as serial output is ok. But NOR boot using LPUART as serial output
>> >> failed. How about your test result?
>> >> >
>> >>
>> >> Yes, I tested NOR boot using DUART or LPUART. Both boot. I suspect
>> >> you forgot to update the RCW for LPUART, or change the jumper setting
>> >> (J19,
>> >> J20) to route the LPUART signal.
>> >>
>> > [Alison Wang] I updated the RCW for LPUART and changed the jumper
>> > setting (J19, J20). Without this set, NOR boot using LPUART is ok. But
>> > after adding this set, NOR boot using LPUART failed.
>> >
>>
>> That's strange. Can you please send your build instructions? Did you
>> program the u-boot-dtb.bin (not u-boot.bin anymore) to the NOR?
>>
> [Alison Wang] My build instructions are,
>
> make ARCH=arm ls1021atwr_nor_lpuart_defconfig
> make
>
> Yes. I programmed u-boot-dtb.bin to NOR flash.
>

Oh, it turns out the last thing to suspect is the /chose node :)

See comments in patch#8 in this series
(http://patchwork.ozlabs.org/patch/561859/)

  chosen {
+ /*
+ * With ls1021atwr_nor_lpuart_defconfig configuration,
+ * this needs to be changed to &lpuart0.
+ */
  stdout-path = &uart0;
  };

I was wondering whether I should introduce another separate dts file
for this LPUART configuration, something like ls1021a-twr_lpuart.dts,
but I felt it's quite some duplication thus I chose to just add some
comments under the /chosen node in the original dts file.

I've done the PCI UART support on the Crown Bay before using the same
way. Simon, do you have some better way to handle this?

Regards,
Bin