[PATCH v1 0/1] tegra_mmc: get tap and trim from dts

[Svyatoslav Ryhel]

24 серпня 2023 р. 16:27:19 GMT+03:00, Thierry Reding <thierry.reding at gmail.com> написав(-ла):
>On Wed, Aug 23, 2023 at 02:30:48PM +0300, Svyatoslav Ryhel wrote:
>> 
>> 
>> 23 серпня 2023 р. 13:53:26 GMT+03:00, Thierry Reding <thierry.reding at gmail.com> написав(-ла):
>> >On Sat, Aug 19, 2023 at 06:35:00PM +0300, Svyatoslav Ryhel wrote:
>> >> Default-tap and default-trim values are used for eMMC setup
>> >> mostly on T114+ devices. As for now, those values are hardcoded
>> >> for T210 and ignored for all other Tegra generations. Fix this
>> >> by passing tap and trim values from dts.
>> >> 
>> >> This commit will cause regression on T210 (emmc may not work),
>> >> fix is applied in tegra210.dtsi and will be sent next week.
>> >
>> >Heh... I don't think so. If you already know that this will cause a
>> >regression on Tegra210 you need to rework this. Adding regressions
>> >accidentally is already bad enough, but doing so knowingly is a big
>> >no-no.
>> 
>> DTS change for t210 was sent in "General tegra and board improvements"
>> patchset. This is why this pathset contains only 1 (one) patch and a
>> warning. It has a dependency.
>
>For U-Boot this may not matter as much because the control DTB is always
>linked into the binary, but for Linux for example we need to make sure
>that the kernel always remains backwards compatible with older device
>trees. I think that's good to follow in general, so making sure there
>are sensible defaults to fall back to if the DTB is missing some
>properties is good practice.
>
>Anyway, the way you posted these there was a future dependency, so if
>someone had applied the driver change without the DTB change having been
>applied first this would've caused a regression, which is always bad if
>it happens at random points because it makes things like bisections very
>painful.
>
>So unless the patch is fixed to fall back to defaults for Tegra210 we
>need to carefully coordinate in which order these patches go in. The DT
>change needs to go in first, followed by the driver change that relies
>on the DTB update.
>

You are right, it was my miss that I did not include tegra210 fix here. I will add it in v2. Thanks.

>Thierry