From: Bjorn Andersson <bjorn@kryo.se>
To: Tim Kryger <tim.kryger@gmail.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
Alexandre Courbot <acourbot@nvidia.com>,
Sachin Kamat <spk.linux@gmail.com>,
linux-mmc <linux-mmc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Alexandre Courbot <gnurou@gmail.com>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>
Subject: Re: Possible regression with commit 52221610d
Date: Tue, 16 Dec 2014 10:18:59 -0800 [thread overview]
Message-ID: <CAJAp7OhWKoAoZfq+zWspLnqUkoJb3izMD41Vyfn0AW4Jni8HAQ@mail.gmail.com> (raw)
In-Reply-To: <CAJAp7Oh+ziadeEDWsus_k_2w33vPJxGGcGZyMNQkpLemf7SAhg@mail.gmail.com>
On Mon, Dec 15, 2014 at 10:27 PM, Bjorn Andersson <bjorn@kryo.se> wrote:
> On Sun, Dec 14, 2014 at 8:48 PM, Tim Kryger <tim.kryger@gmail.com> wrote:
>> On Sat, Dec 13, 2014 at 11:22 PM, Bjorn Andersson <bjorn@kryo.se> wrote:
> [..]
>>> Or simply; what is vmmc (in the code) supposed to represent?
>>
>> Hi Bjorn,
>>
>> VMMC is the supply that delivers power out to the SD card itself (aka VDD).
>>
>> It is not the internal power rail/power domain of the host controller
>> within the SoC.
>>
>
> Thanks for you answer Tim, I'll write up a patch for the Qualcomm
> driver that add the possibility of specifying an internal supply for
> the devices where that uses that.
>
> My only concern is that for any standard compliant sdhci driver we're
> supposed to have a info printout that vmmc was not found (but vqmmc is
> there). But I guess that's a matter of proper documentation and hoping
> people don't pay too much attention to it?
>
Sorry, this is wrong.
We are routing the regulators straight to vdd of the memory and should
hence use vmmc to specify this. However unless I actually program 0x29
in the Qualcomm sdhci block I get no responses from the card.
Which I believe is correct behavior as the SDHC specification [1] says
the following about BIT(0) of 0x29:
"If this bit is cleared, the Host Controller shall immediately stop
driving CMD and DAT[3:0] (tri-state) and drive SDCLK to low level".
So I think 52221610d is indeed incorrect.
[1] https://www.sdcard.org/downloads/pls/simplified_specs/archive/partA2_300.pdf
Regards,
Bjorn
next prev parent reply other threads:[~2014-12-16 18:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-04 3:05 Possible regression with commit 52221610d Alexandre Courbot
2014-11-04 5:28 ` Tim Kryger
2014-11-04 9:00 ` Alexandre Courbot
2014-11-04 15:31 ` Tim Kryger
2014-11-05 8:10 ` Alexandre Courbot
2014-11-05 15:27 ` Tim Kryger
2014-11-06 2:15 ` Alexandre Courbot
2014-12-14 7:22 ` Bjorn Andersson
2014-12-15 4:48 ` Tim Kryger
2014-12-16 6:27 ` Bjorn Andersson
2014-12-16 18:18 ` Bjorn Andersson [this message]
2014-12-17 6:20 ` Tim Kryger
2014-12-17 19:57 ` Bjorn Andersson
2014-12-22 3:01 ` Tim Kryger
2015-01-05 19:52 ` Bjorn Andersson
2015-01-12 10:31 ` Ulf Hansson
2015-01-13 16:00 ` Tim Kryger
2015-01-13 15:59 ` Tim Kryger
2015-01-14 5:00 ` Tim Kryger
2014-12-16 18:46 ` Stephen Warren
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=CAJAp7OhWKoAoZfq+zWspLnqUkoJb3izMD41Vyfn0AW4Jni8HAQ@mail.gmail.com \
--to=bjorn@kryo.se \
--cc=acourbot@nvidia.com \
--cc=gnurou@gmail.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mmc@vger.kernel.org \
--cc=spk.linux@gmail.com \
--cc=tim.kryger@gmail.com \
--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).