Linux-ARM-MSM Archive on lore.kernel.org
 help / color / Atom feed
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
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.

  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

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=160695644776.2717324.633265815704005177@swboyd.mtv.corp.google.com \
    --to=swboyd@chromium.org \
    --cc=akashast@codeaurora.org \
    --cc=amstan@chromium.org \
    --cc=bjorn.andersson@linaro.org \
    --cc=broonie@kernel.org \
    --cc=dianders@chromium.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-spi@vger.kernel.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

Linux-ARM-MSM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-msm/0 linux-arm-msm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-msm linux-arm-msm/ https://lore.kernel.org/linux-arm-msm \
		linux-arm-msm@vger.kernel.org
	public-inbox-index linux-arm-msm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-arm-msm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git