All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tony Lindgren <tony@atomide.com>
To: "H. Nikolaus Schaller" <hns@goldelico.com>
Cc: "Benoît Cousson" <bcousson@baylibre.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	broonie@kernel.org, linus.walleij@linaro.org,
	stable@vger.kernel.org, linux-spi@vger.kernel.org,
	linux-omap@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, letux-kernel@openphoenux.org,
	kernel@pyra-handheld.com
Subject: Re: [PATCH v2] DTS: ARM: gta04: introduce legacy spi-cs-high to make display work again
Date: Mon, 23 Sep 2019 10:34:41 -0700	[thread overview]
Message-ID: <20190923173441.GV5610@atomide.com> (raw)
In-Reply-To: <c031340840daba810bb2a612c35eea7fab307e56.1568995874.git.hns@goldelico.com>

* H. Nikolaus Schaller <hns@goldelico.com> [190920 09:12]:
> commit 6953c57ab172 "gpio: of: Handle SPI chipselect legacy bindings"
> 
> did introduce logic to centrally handle the legacy spi-cs-high property
> in combination with cs-gpios. This assumes that the polarity
> of the CS has to be inverted if spi-cs-high is missing, even
> and especially if non-legacy GPIO_ACTIVE_HIGH is specified.
> 
> The DTS for the GTA04 was orginally introduced under the assumption
> that there is no need for spi-cs-high if the gpio is defined with
> proper polarity GPIO_ACTIVE_HIGH.
> 
> This was not a problem until gpiolib changed the interpretation of
> GPIO_ACTIVE_HIGH and missing spi-cs-high.
> 
> The effect is that the missing spi-cs-high is now interpreted as CS being
> low (despite GPIO_ACTIVE_HIGH) which turns off the SPI interface when the
> panel is to be programmed by the panel driver.
> 
> Therefore, we have to add the redundant and legacy spi-cs-high property
> to properly activate CS.

Thanks applying into fixes.

Tony

      reply	other threads:[~2019-09-23 17:34 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-20 16:11 [PATCH v2] DTS: ARM: gta04: introduce legacy spi-cs-high to make display work again H. Nikolaus Schaller
2019-09-23 17:34 ` Tony Lindgren [this message]

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=20190923173441.GV5610@atomide.com \
    --to=tony@atomide.com \
    --cc=bcousson@baylibre.com \
    --cc=broonie@kernel.org \
    --cc=devicetree@vger.kernel.org \
    --cc=hns@goldelico.com \
    --cc=kernel@pyra-handheld.com \
    --cc=letux-kernel@openphoenux.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-omap@vger.kernel.org \
    --cc=linux-spi@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=robh+dt@kernel.org \
    --cc=stable@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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.