Re: [PATCH 1/2] DM_USB: allow building without OF_CONTROL

[Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>]

Hi,

On 19.06.21 г. 21:17 ч., Marek Vasut wrote:
> On 6/19/21 8:14 AM, Ivaylo Dimitrov wrote:
>> Hi Marek,
> 
> Hi,
> 
> [...]
> 
>>>>> Currently DM_USB requires OF_CONTROL to be enabled, otherwise link 
>>>>> errors
>>>>> occur. On the other hand OF_CONTROL requires board code to be 
>>>>> migrated to
>>>>> DT, which is not always possible or required.
>>>>>
>>>>> Fix that by conditionally compiling OF_CONTROL specific sections in 
>>>>> USB
>>>>> related drivers code in the same way like it is done in the other 
>>>>> drivers.
>>>>> Also, auto select OF_LIBFDT if DM_USB is selected but OF_CONTROL is 
>>>>> not.
>>>>> Introduce a new Kconfig option OF_NODE used to compile of_node.c in 
>>>>> case
>>>>> OF_CONTROL is not enabled. Fix deprecation warning condition as well.
>>>
>>> So, what is the use case of this? Why not just enable DM_USB and 
>>> OF_CONTROL ?
>>
>> OF_CONTROL requires migration to device-tree.
> 
> That's where the supported platforms are heading anyway. Or is there 
> some issue with switching the platform you use over to DT ?

OK, let me elaborate: It is about enabling DM_USB on N900 (Nokia rx-51 
board). For various reasons I am not going to discuss (1), migration to 
DM was delayed to the point where we saw "[PATCH] arm: Remove nokia_rx51 
board" with a commit message "This board has not been converted to 
CONFIG_DM_USB by the deadline. Remove it." posted. The missing pieces 
were WDT (a patch is already merged in -next) and DM_USB. The board 
itself does not support host mode, but USB TTY is very useful for 
debugging purposes. The particular task I am after is USB DM migration 
and the $subject patch allows this to be achieved with relatively little 
effort (a couple of defconfig changes), incomparable with the effort 
needed for migration to DT. As we are already past the DM migration 
deadline I think it makes sense to fulfil its requirements before 
undertaking such a big task like migration to DT.

Regards,
Ivo

(1) https://www.mail-archive.com/u-boot@lists.denx.de/msg409064.html