From: Stephen Boyd <email@example.com> To: Alexandru M Stan <firstname.lastname@example.org> Cc: Mark Brown <email@example.com>, linux-kernel <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org, Akash Asthana <email@example.com>, Bjorn Andersson <firstname.lastname@example.org>, Douglas Anderson <email@example.com> Subject: Re: [PATCH] spi: spi-geni-qcom: Use the new method of gpio CS control Date: Wed, 02 Dec 2020 16:47:27 -0800 Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <email@example.com> Quoting Stephen Boyd (2020-12-02 15:28:45) > Quoting Alexandru M Stan (2020-12-02 14:18:20) > > Unfortunately this patch makes my cros-ec (the main EC that used to > > work even before my debugging) also fail to probe: > > [ 0.839533] cros-ec-spi spi6.0: EC failed to respond in time > > [ 1.040453] cros-ec-spi spi6.0: EC failed to respond in time > > [ 1.040852] cros-ec-spi spi6.0: Cannot identify the EC: error -110 > > [ 1.040855] cros-ec-spi spi6.0: cannot register EC, fallback to spidev > > [ 1.040942] cros-ec-spi: probe of spi6.0 failed with error -110 > > > > I wasn't closely looking at this part closely when I was using my > > other spi port with spidev, so this is why I haven't noticed it > > before. > > Doug suggests this might be a polarity issue. More scoping to be had. > > > > Ah I see. It looks like the cs-gpios polarity is wrong for the DTS on > sc7180. That's a patch that Doug has sent in for the qcom tree, commit > 37dd4b777942 ("arm64: dts: qcom: sc7180: Provide pinconf for SPI to use > GPIO for CS") and it is pending for the next release (v5.11). Doug says > he will send in a fix for the DTS side, but this patch is still "good" > as far as I can tell. It moves us to use gpio descriptors and also finds > bugs like this in the DTS file that we would have missed otherwise > because the legacy mode doesn't look at the polarity flags in DT. And that is wrong. With even more investigation and Doug's eagle eyes it seems that the cros-ec driver is overriding the spi::mode to clear out the SPI_CS_HIGH bit that the spi core sets in there when using the gpio descriptors. I'll send a patch for cros-ec-spi shortly.
next prev parent reply index Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-02 21:49 Stephen Boyd 2020-12-02 22:18 ` Alexandru M Stan 2020-12-02 23:28 ` Stephen Boyd 2020-12-03 0:47 ` Stephen Boyd [this message] 2020-12-03 20:06 ` Doug Anderson 2020-12-04 0:10 ` Stephen Boyd 2020-12-04 9:13 ` Enric Balletbo i Serra 2020-12-04 17:00 ` Mark Brown 2020-12-29 20:15 ` patchwork-bot+linux-arm-msm
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