<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Feb 22, 2017 at 8:57 PM, Dana Myers <span dir="ltr"><<a href="mailto:k6jq@comcast.net" target="_blank">k6jq@comcast.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<div class="gmail-m_-5593086319371465818m_4148322773140317813moz-cite-prefix">On 2/22/2017 6:18 PM, L. D. Pinney
wrote:<br>
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<div>spi-mt7621.c has bugs ... isn't very helpful.</div>
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I am a bit surprised you're not already aware of the SPI issues.<br>
<br></div></blockquote><div><br></div><div>I am not surprised at all ... ALL of my MT76x8 devices have only a single SPI-NOR Chip connected to the SPI.</div><div>On every device it works as intended ... load the OS.</div><div><br></div><div>Whenever you (or anyone) adds functionality to a device you can expect problems.</div><div>In this case some device foreign to the actual device in question.</div><div>More specifically a device such as a RFID module or STM32.</div><div><br></div><div>If you have a working patch...You can start here :</div><div><br></div><div><a href="https://lede-project.org/docs/guide-developer/the-source-code">https://lede-project.org/docs/guide-developer/the-source-code</a></div><div> </div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div bgcolor="#FFFFFF">
You can start here:<br>
<br>
<a class="gmail-m_-5593086319371465818m_4148322773140317813moz-txt-link-freetext" href="https://community.onion.io/topic/1560/spi-pins-for-the-omega2/20" target="_blank">https://community.onion.io/top<wbr>ic/1560/spi-pins-for-the-omega<wbr>2/20</a><br>
<br>
which links to another forum thread which contains this *very*
informative<br>
posting:<br>
<br>
<a class="gmail-m_-5593086319371465818m_4148322773140317813moz-txt-link-freetext" href="http://52.76.69.244/jforum/posts/list/30/3683.page#12266" target="_blank">http://52.76.69.244/jforum/pos<wbr>ts/list/30/3683.page#12266</a><br>
<br>
and suggested patch:<br>
<br>
<a class="gmail-m_-5593086319371465818m_4148322773140317813moz-txt-link-freetext" href="http://52.76.69.244/jforum/posts/list/30/3683.page#12299" target="_blank">http://52.76.69.244/jforum/pos<wbr>ts/list/30/3683.page#12299</a><br>
<br>
which is the basis of the patch I'm using.<br>
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<div>Please describe the problem?</div>
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berniwa does a much better job than me in the above-linked posting.<br>
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<div>Can I reproduce the same problem on one of my many MT76x8
devices?</div>
<div>If so how?</div>
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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>
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<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>
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<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>
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<div class="gmail_quote">On Wed, Feb 22, 2017 at 7:00 PM, Dana
Myers <span dir="ltr"><<a href="mailto:k6jq@comcast.net" target="_blank">k6jq@comcast.net</a>></span>
wrote:<br>
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<div class="gmail-m_-5593086319371465818m_4148322773140317813m_651582301430210751moz-cite-prefix">On
2/22/2017 4:27 PM, L. D. Pinney wrote:<br>
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<div dir="ltr">Are you using <a href="https://github.com/OnionIoT/source" target="_blank">https://github.com/Onion<wbr>IoT/source</a>
onion-omega2 branch ?</div>
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<br>
I am not; I'm using <a class="gmail-m_-5593086319371465818m_4148322773140317813m_651582301430210751moz-txt-link-freetext" href="https://github.com/lede-project/source" target="_blank">https://github.com/lede-projec<wbr>t/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>
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<div class="gmail_quote">On Wed, Feb 22, 2017 at 2:30
PM, Dana Myers <span dir="ltr"><<a href="mailto:k6jq@comcast.net" target="_blank">k6jq@comcast.net</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);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>
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