From: Neil Armstrong <neil.armstrong@linaro.org>
To: Amjad Ouled-Ameur <aouledameur@baylibre.com>, broonie@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org,
narmstrong@baylibre.com
Subject: Re: [PATCH 0/2] spi: amlogic: meson-spicc: Use pinctrl to drive CLK line when idle
Date: Tue, 27 Sep 2022 10:30:06 +0200 [thread overview]
Message-ID: <09081275-be9c-9d0c-856b-ed2df8fc0b13@linaro.org> (raw)
In-Reply-To: <20220809172017.215412-1-aouledameur@baylibre.com>
Hi Amjad,
On 09/08/2022 19:20, Amjad Ouled-Ameur wrote:
> Between SPI transactions, all SPI pins are in HiZ state. When using the SS
> signal from the SPICC controller it's not an issue because when the
> transaction resumes all pins come back to the right state at the same time
> as SS.
>
> The problem is when we use CS as a GPIO. In fact, between the GPIO CS
> state change and SPI pins state change from idle, you can have a missing or
> spurious clock transition.
>
> Set a bias on the clock depending on the clock polarity requested before CS
> goes active, by passing a special "idle-low" and "idle-high" pinctrl state
> and setting the right state at a start of a message.
>
> Amjad Ouled-Ameur (2):
> spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI
> signal states
> spi: meson-spicc: Use pinctrl to drive CLK line when idle
>
> .../bindings/spi/amlogic,meson-gx-spicc.yaml | 15 +++++++
> arch/arm64/boot/dts/amlogic/meson-gxl.dtsi | 14 +++++++
> drivers/spi/spi-meson-spicc.c | 39 ++++++++++++++++++-
> 3 files changed, 67 insertions(+), 1 deletion(-)
>
Will you send a v2 with comments adresses ?
_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
next prev parent reply other threads:[~2022-09-27 8:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-09 17:20 [PATCH 0/2] spi: amlogic: meson-spicc: Use pinctrl to drive CLK line when idle Amjad Ouled-Ameur
2022-08-09 17:20 ` [PATCH 1/2] spi: dt-bindings: amlogic, meson-gx-spicc: Add pinctrl names for SPI signal states Amjad Ouled-Ameur
2022-09-27 8:29 ` Neil Armstrong
2022-09-27 9:35 ` Amjad Ouled-Ameur
2022-08-09 17:20 ` [PATCH 2/2] spi: meson-spicc: Use pinctrl to drive CLK line when idle Amjad Ouled-Ameur
2022-08-10 8:52 ` Jerome Brunet
2022-08-10 9:19 ` Neil Armstrong
2022-09-27 8:30 ` Neil Armstrong [this message]
2022-09-27 9:36 ` [PATCH 0/2] spi: amlogic: " Amjad Ouled-Ameur
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=09081275-be9c-9d0c-856b-ed2df8fc0b13@linaro.org \
--to=neil.armstrong@linaro.org \
--cc=aouledameur@baylibre.com \
--cc=broonie@kernel.org \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
--cc=narmstrong@baylibre.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).