[U-Boot] [PATCH v2] rockchip: rk3288-evb: dts: remove 'vmmc' from emmc node

[Kever Yang]

On 12/11/2018 02:20 AM, Tom Rini wrote:
> On Sat, Dec 08, 2018 at 12:27:42PM +0800, Kever Yang wrote:
>> Hi Tom,
>>
>>
>> On 12/07/2018 10:13 PM, Tom Rini wrote:
>>> On Fri, Dec 07, 2018 at 02:24:22PM +0100, Philipp Tomsich wrote:
>>>> Kever,
>>>>
>>>>> On 07.12.2018, at 02:39, Kever Yang <kever.yang at rock-chips.com> wrote:
>>>>>
>>>>> Hi Philipp,
>>>>>
>>>>> On 12/06/2018 09:50 PM, Philipp Tomsich wrote:
>>>>>> +Tom
>>>>>>
>>>>>>> On 05.12.2018, at 03:25, Kever Yang <kever.yang at rock-chips.com> wrote:
>>>>>>>
>>>>>>> The U-Boot eMMC does not need to care about the power for Rockchip
>>>>>>> SoC, because if the board is using eMMC, the power will default on
>>>>>>> (for bootrom), and we do not do power management for it like kernel,
>>>>>>> so the 'vmmc', 'vqmmc' is only useful for SD in U-Boot.
>>>>>>>
>>>>>>> This make U-Boot can boot into kernel even if the pmic driver is
>>>>>>> broken.
>>>>>> If the PMIC driver is broken, we should fix the PMIC driver.
>>>>>> I would feel more comfortable w/o this statement.
>>>>>>
>>>>>>> The rk3288-evb dts may be used in many boards using rockchip reference
>>>>>>> schematic but with little change, so we hope it can be more robust to
>>>>>>> boot into next stage.
>>>>>> Again, this is not how the DTS should be used.  I believe that Heiko, Fabio and
>>>>>> I had already highlighted this in comments to the earlier thread.
>>>>>     Not sure if you have read my previous mail for answer all your comments,
>>>>>
>>>>> I do agree DTS should represent the hardware, but please note that the DTS
>>>>> is no kind of standard, and people always choose what they need and add
>>>>> those part in there dts, but not always add all the property and
>>>>> everyone use the same model. I would say there are many boards does not have this
>>>>> 'vmmc-supply’ in there emmc node.
>>>> That is exactly the reason why I bumped the decision up the stairs (to Tom and/or
>>>> Simon): what you are saying makes sense to me (viewed through your eyes and 
>>>> from your specific usecase), but it directly contradicts how the DTS usage is intended.
>>>>
>>>> In other words: Tom (as the top-level decision maker) or Simon (who owns the 
>>>> device-model and therefore will also have an opinion on DTS usage) should make
>>>> the final call.
>>> My answer is that I would strongly suspect that over in linux "we have N
>>> different close-enough boards using this one DTS" isn't acceptable.  You
>>> make a dtsi and include it from the board and things that aren't common
>>> don't go into the dtsi.  And yes, when starting off everyone (myself
>>> included) copies the reference platform dts and then changes it as
>>> needed, and sometimes misses a thing or two.  But no, I don't think we
>>> want a wrong dts and I'm pretty sure the kernel really wouldn't want
>>> wrong dts files and the general goal is that excluding the -u-boot.dtsi
>>> files, ours are copies of the kernel.
>> I don't think this is a "wrong dts" after my patch, these two nodes are
>> not mark
>> as required property in kernel, so many dts emmc node does not have it.
>> I check the latest kernel dtsi in arch/arm/boot/dts/rk3288-evb.dtsi [1],
>> the emmc node do not have 'vmmc' and 'vqmmc' while the SD node have, which
>> just like description in my commit message.
> OK.  So this would fall into the category of "sync with upstream dts"
> then, right?  That is what we want.

OK, Got it, 'sync with upstream dts' is a good and acceptable commit
message
rather than the real reason why we need the patch.

Philipp,
    Do you need me to send out a patch with update the commit message?

Thanks,
- Kever
>> Well, I don't know why U-Boot project is so difficult to accept a
>> reasonable patch now, I don't
>> want to make you unhappy, but make 'every board must have its own dts'
>> in U-Boot to make
>> every developer to join U-Boot does not make sense to me. The kernel
>> need different
>> dts for different board because they need to use/control those different
>> feature, but U-Boot
>> is not the case, U-Boot should work if the storage driver works.
> Well, here's the thing.  If you want U-Boot to then load and pass the
> correct DTB to the kernel, we need per-board tweaks to the code anyhow
> to find and load that DTB (see the various "findfdt" environment scripts
> for example).  If you want to rework things so that you have a "generic"
> type board under U-Boot that's more clearly not tied to any specific
> board but instead runs on many, that might help clear things up too.
> Hope this helps!
>