[U-Boot] [PATCHv4 3/3] ARM64: poplar: hi3798cv200: u-boot support for Poplar 96Boards

[Simon Glass]

Hi Tom,

On 25 May 2017 at 15:12, Tom Rini <trini at konsulko.com> wrote:
> On Thu, May 25, 2017 at 10:58:20PM +0200, Jorge Ramirez wrote:
>> On 05/25/2017 10:55 PM, Jorge Ramirez wrote:
>> >On 05/25/2017 10:31 PM, Tom Rini wrote:
>> >>On Thu, May 25, 2017 at 08:38:47PM +0200, Jorge Ramirez wrote:
>> >>>On 05/18/2017 12:06 AM, Tom Rini wrote:
>> >>>>>>>having platform data.
>> >>>>>>No, I think we're going for overkill here by not doing
>> >>>>>>serial_pl01x.c as
>> >>>>>>platform data.  ns16550 does platform data for this already.  This
>> >>>>>>sounds like the lowest overhead way to get the clock
>> >>>>>>populated and not
>> >>>>>>have some DT data that's not going to be accepted upstream.
>> >>>>>>
>> >>>>>ummmm I am a bit lost at this point, could we recap please?
>> >>>>Lets update the recap:
>> >>>>- Please re-submit the dts file, now with whatever form is
>> >>>>in v4.12-rc1,
>> >>>>   saying as such in the commit (if it's just the commit message that
>> >>>>   changes, that's fine and great).
>> >>>The DTS file in v4.12-rc2 still does NOT contain the usb node.
>> >>>
>> >>>==> Should I then not use the DM on USB so I can avoid DTS changes?
>> >>Well, you can either put it in the -u-boot.dtsi file for the board, and
>> >>remove that later once it's upstream.
>>
>>
>> yes I'll do that. thanks.
>>
>> >
>> >>
>> >>>>- Please update serial_pl01x.c to be able to get the clock
>> >>>>via platform
>> >>>>   data, update and test your board to confirm it works.
>> >>>um, It gets tricky;
>> >>>I can not use platform_data since I can not use SERIAL_DM because
>> >>>the device tree does have a UART node which gets picked up.
>> >>How about disabling the node in -u-boot.dtsi for the board and then you
>> >>can use platform data,
>> >
>>
>> I dont think that would because CONFIG_OF is enabled for USB; so the
>> kernel dtsi that contains the uart node (without the clock!) will be
>> picked by u-boot and the uart will not be initialized properly.
>> I still think that the simplest solution is to let me merge with the
>> kernel's device tree plus this u-boot.dtsi [1];
>> then just get rid of the file when possible (and NEIHER the source
>> code NOR the configs) would need to change
>>
>> [1] https://github.com/ldts/poplar-u-boot/blob/upstream/arch/arm/dts/hi3798cv200-u-boot.dtsi
>
> Yes, sorry.  [1] needs to be updated to disable uart0 so that you can
> use platform data, at least for now.  I do want to talk more with Rob
> about the general problem this exposes.

Using platform data because we cannot put a clock frequency in the DT
node seems unfortunate to me. With a little flexibility, DT can be
made to work. But IMO the sort of pedantry makes great the enemy of
good.

Regards,
Simon