Re: [PATCH 0/6] mmc: core: hs400(es) fix probe/init

From: Ulf Hansson
Date: Fri Jan 22 2021 - 07:42:07 EST

+ Adrian

On Tue, 8 Dec 2020 at 07:19, Chris Ruehl <chris.ruehl@xxxxxxxxxxxx> wrote:
> Fix the probe if hs400-1_8v / hs400-1_2v is used in the
> dts and mmc-hs400-enhanced-strobe isn't set.
> That was the first attemped, but it turns out that some
> more cleanups and simplifications can be done.

My apologies for the delay with reviewing. I have looped in Adrian as
well, as he might have some input to our discussion.

Before I go into doing a detailed review, I want to make sure I
understand the problem correctly.

Are you saying that switching to eMMC HS400 mode doesn't work, unless
the enhanced strobe is supported, no? Or is this a DT only related

In any case, the main point with mmc_hs400_to_hs200() is to prepare
for tuning to run in HS200 mode (it's getting called from
mmc_retune()). In other words, there *should* be no need to support
enhanced strobe to support hs400, but I might be missing something.

In particular, the following commit could be of interest for you:

Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Date: Thu May 7 13:10:20 2015 +0300
mmc: core: Add support for HS400 re-tuning

> * move mmc_select_hs400() in between hs200 & hs400es (preparation)
> * make mmc_select_hs400() independent and move it out
> of the hs200. Run hs400 tuning inside mmc_select_hs400();
> * merge hs400 with hs400es function
> * remove mmc_select_hs400es function
> * remove mmc_hs200_tuning()
> * cleanup host->caps2 for hs400-1_8(2)v
> Signed-off-by: Chris Ruehl <chris.ruehl@xxxxxxxxxxxx>
> ---
> Replace patch set [PATCH 0/3] mmc: core: hs400 fix probe

Kind regards