From: Stephen Boyd <swboyd@chromium.org>
To: Alexandru M Stan <amstan@chromium.org>
Cc: Mark Brown <broonie@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-arm-msm@vger.kernel.org, linux-spi@vger.kernel.org,
Akash Asthana <akashast@codeaurora.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Douglas Anderson <dianders@chromium.org>
Subject: Re: [PATCH] spi: spi-geni-qcom: Use the new method of gpio CS control
Date: Wed, 02 Dec 2020 16:47:27 -0800 [thread overview]
Message-ID: <160695644776.2717324.633265815704005177@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <160695172591.2717324.17788035024164242534@swboyd.mtv.corp.google.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 other threads:[~2020-12-03 0:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 21:49 [PATCH] spi: spi-geni-qcom: Use the new method of gpio CS control 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
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