From: Peter Geis <pgwipeout@gmail.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
Jaehoon Chung <jh80.chung@samsung.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>
Cc: linux-mmc@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"open list:ARM/Rockchip SoC..."
<linux-rockchip@lists.infradead.org>,
devicetree@vger.kernel.org
Subject: [BUG] mmc_regulator_set_ocr can't cope with regulator-fixed
Date: Wed, 4 Aug 2021 10:32:52 -0400 [thread overview]
Message-ID: <CAMdYzYrx8pgeyK7u=kcopZ+Wae+fQdr_uM4AuVjqWKfZYikgcA@mail.gmail.com> (raw)
Good Morning,
I've encountered a fun issue with the dw-mmc driver while working on
enabling support for the Quartz-64 Model A.
The regulator-fixed driver supports enabling via a gpio, but does not
have the ops to set voltage as it is fixed.
The dw-mmc calls mmc_regulator_set_ocr for vmmc, which attempts to set
the voltage first but fails due to the lack of the voltage ops. It
then bails returning -EINVAL.
This leads to the following message :
dwmmc_rockchip fe2b0000.mmc: could not set regulator OCR (-22)
This can be fixed by switching to regulator-gpio for the vmmc supply
to the sdmmc controller, however the sdio controller vmmc is provided
by a fixed regulator that is always on. Obviously the regulator-gpio
isn't an option, as it has no gpio to enable.
Removing the vmmc phandle from the sdio node is an option, but then it
doesn't fully describe the hardware (it's also a non-standard 4.4v).
I had considered changing the check in dw-mmc.c [1] to continue in the
case of -EINVAL, but there are other places in the regulator framework
that can also return that and it doesn't address the underlying issue.
As such I'm reaching out to the experts to see what the best course of
action is here.
Please weigh in with what you think.
Very Respectfully,
Peter Geis
next reply other threads:[~2021-08-04 14:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210804143357epcas1p1c67eca591d8bb557c11b8175baaa8550@epcas1p1.samsung.com>
2021-08-04 14:32 ` Peter Geis [this message]
2021-08-04 16:15 ` [BUG] mmc_regulator_set_ocr can't cope with regulator-fixed Mark Brown
2021-08-05 10:00 ` Jaehoon Chung
2021-08-05 11:38 ` Peter Geis
2021-08-05 12:46 ` Mark Brown
2021-08-05 12:58 ` Peter Geis
2021-08-05 13:08 ` Mark Brown
2021-08-06 8:14 ` Ravikumar Kattekola
2021-08-06 10:59 ` Mark Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAMdYzYrx8pgeyK7u=kcopZ+Wae+fQdr_uM4AuVjqWKfZYikgcA@mail.gmail.com' \
--to=pgwipeout@gmail.com \
--cc=broonie@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=jh80.chung@samsung.com \
--cc=lgirdwood@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mmc@vger.kernel.org \
--cc=linux-rockchip@lists.infradead.org \
--cc=robh+dt@kernel.org \
--cc=ulf.hansson@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).