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<div class="moz-cite-prefix">On 2/22/2017 6:18 PM, L. D. Pinney
wrote:<br>
</div>
<blockquote
cite="mid:CAJOqq5R-Mm=BnunaZbWiXVeqDL2BQghcSo=gwQ=wtQyHQbMetg@mail.gmail.com"
type="cite">
<div dir="ltr"><br>
<div>spi-mt7621.c has bugs ... isn't very helpful.</div>
</div>
</blockquote>
<br>
I am a bit surprised you're not already aware of the SPI issues.<br>
<br>
You can start here:<br>
<br>
<a class="moz-txt-link-freetext" href="https://community.onion.io/topic/1560/spi-pins-for-the-omega2/20">https://community.onion.io/topic/1560/spi-pins-for-the-omega2/20</a><br>
<br>
which links to another forum thread which contains this *very*
informative<br>
posting:<br>
<br>
<a class="moz-txt-link-freetext" href="http://52.76.69.244/jforum/posts/list/30/3683.page#12266">http://52.76.69.244/jforum/posts/list/30/3683.page#12266</a><br>
<br>
and suggested patch:<br>
<br>
<a class="moz-txt-link-freetext" href="http://52.76.69.244/jforum/posts/list/30/3683.page#12299">http://52.76.69.244/jforum/posts/list/30/3683.page#12299</a><br>
<br>
which is the basis of the patch I'm using.<br>
<br>
<blockquote
cite="mid:CAJOqq5R-Mm=BnunaZbWiXVeqDL2BQghcSo=gwQ=wtQyHQbMetg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Please describe the problem?</div>
<div><br>
</div>
</div>
</blockquote>
berniwa does a much better job than me in the above-linked posting.<br>
<br>
<br>
<blockquote
cite="mid:CAJOqq5R-Mm=BnunaZbWiXVeqDL2BQghcSo=gwQ=wtQyHQbMetg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Can I reproduce the same problem on one of my many MT76x8
devices?</div>
<div>If so how?</div>
</div>
</blockquote>
<br>
I've only seen reports of the issue on MT7688-based devices (LinkIt
7688, Omega2)<br>
and I personally have observed it on the Omega2.<br>
<br>
The easiest way to reproduce it is to attempt to send an SPI
sequence<br>
starting with the '10' bit sequence (first nibble of 0x8 .. 0xb).
You'll find<br>
the leading '1' bit is sent as a '0'.<br>
<br>
I'd be somewhat surprised if the same issue wasn't present on all
devices which<br>
incorporate the MT7621 SPI peripheral given the likelihood that
MediaTek<br>
reproduces the same logic on every chip that includes the
peripheral.<br>
<br>
The SPI driver also exposes the transfer limit of 16 bytes, which
berniwa's<br>
patch addresses by breaking up a transfer as needed (keeping chip
select<br>
asserted).<br>
<blockquote
cite="mid:CAJOqq5R-Mm=BnunaZbWiXVeqDL2BQghcSo=gwQ=wtQyHQbMetg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div><br>
</div>
<div>The MediaTek Linkit github is based on OpenWrt 15.05 using
a 3.18 kernel.</div>
<div>The patches needed for 3.18 vs. 4.4 or 4.9 will be quite
different.</div>
</div>
</blockquote>
<br>
Understood; I didn't say that MediaTek was using the *same* patch,
but that<br>
this issue is present on all MT7688 devices and that MediaTek has
incorporated<br>
a patch for it. The patch I'm using is for 4.4, of course.<br>
<br>
If you could confirm the presence of the issue on other
MT7621-based SPI<br>
peripherals, that would address my initial inquiry indirectly if we
could just<br>
patch all instances of the MT7621 SPI build :-)<br>
<br>
Cheers,<br>
Dana K6JQ<br>
<br>
<blockquote
cite="mid:CAJOqq5R-Mm=BnunaZbWiXVeqDL2BQghcSo=gwQ=wtQyHQbMetg@mail.gmail.com"
type="cite">
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<div><br>
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<div> </div>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Feb 22, 2017 at 7:00 PM, Dana
Myers <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:k6jq@comcast.net" target="_blank">k6jq@comcast.net</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div class="m_651582301430210751moz-cite-prefix">On
2/22/2017 4:27 PM, L. D. Pinney wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Are you using <a moz-do-not-send="true"
href="https://github.com/OnionIoT/source"
target="_blank">https://github.com/<wbr>OnionIoT/source</a>
onion-omega2 branch ?</div>
<div class="gmail_extra"><br>
</div>
</blockquote>
<br>
I am not; I'm using <a moz-do-not-send="true"
class="m_651582301430210751moz-txt-link-freetext"
href="https://github.com/lede-project/source"
target="_blank">https://github.com/lede-<wbr>project/source</a>
(master branch)<br>
<br>
However, I don't believe it makes any difference -
spi-mt7621.c appears<br>
to be identical in both and the same patch applies; and
this isn't an<br>
Omega2-specific issue. All MT7688-based systems have this
issue; MediaTek<br>
Labs patched their LinkIt repo for this. A fix really
belongs upstream.<br>
<br>
Thanks -<br>
Dana<br>
<br>
<br>
<blockquote type="cite">
<div class="gmail_extra">
<div class="gmail_quote">On Wed, Feb 22, 2017 at 2:30
PM, Dana Myers <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:k6jq@comcast.net" target="_blank">k6jq@comcast.net</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
I'm working with the Onion Omega2, which is based
on an MT7688 SoC.<br>
The MT7688 SoC is a variant of the MT76xx family;
in particular, it<br>
shares the same SPI peripheral. Support for SPI is
in ..../drivers/spi/mt7621.c<br>
<br>
However, there's bugs with the SPI in the MT7688
which require a patch<br>
to spi-mt7621.c - and I don't know if the same
bugs are present in the<br>
other MT76xx family members. It is possible the
other MT76xx SoCs have<br>
the same hardware issue (I'd be surprised if not)
but I can only test<br>
the MT7688 I have.<br>
<br>
I think I want to patch the source file only when
building only the MT7688<br>
target, but I'm not sure how to do that or if it's
supported.<br>
<br>
So I'm looking for advice on how I might
incorporate this patch so<br>
that it is only applied when building
ramips/mt7688.<br>
<br>
Thanks,<br>
Dana K6JQ<br>
______________________________<wbr>_________________<br>
openwrt-devel mailing list<br>
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href="mailto:openwrt-devel@lists.openwrt.org"
target="_blank">openwrt-devel@lists.openwrt.or<wbr>g</a><br>
<a moz-do-not-send="true"
href="https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel"
rel="noreferrer" target="_blank">https://lists.openwrt.org/cgi-<wbr>bin/mailman/listinfo/openwrt-d<wbr>evel</a><br>
</blockquote>
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