From: Linus Walleij <linus.walleij@linaro.org>
To: Andrew Jeffery <andrew@aj.id.au>
Cc: Hongwei Zhang <hongweiz@ami.com>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Joel Stanley <joel@jms.id.au>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
linux-aspeed <linux-aspeed@lists.ozlabs.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support
Date: Mon, 29 Jul 2019 23:57:16 +0200 [thread overview]
Message-ID: <CACRpkdZcLNe+oM1jWPpva0LECc-P48ab3H-kG7eabMmSvmvioA@mail.gmail.com> (raw)
In-Reply-To: <f2875111-9ba9-43b7-b2a4-d00c8725f5a0@www.fastmail.com>
On Mon, Jul 29, 2019 at 2:19 AM Andrew Jeffery <andrew@aj.id.au> wrote:
> The behaviour is to periodically emit the state of all enabled GPIOs
> (i.e. the ngpios value), one per bus clock cycle. There's no explicit
> addressing scheme, the protocol encodes the value for a given GPIO
> by its position in the data stream relative to a pulse on the "load data"
> (LD) line, whose envelope covers the clock cycle for the last GPIO in
> the sequence. Similar to SPI the bus has both out and in lines, which
> cater to output/input GPIOs.
>
> A rough timing diagram for a 16-GPIO configuration looks like what
> I've pasted here:
>
> https://gist.github.com/amboar/c9543af1957854474b8c05ab357f0675
OK that is complex. I agree we need to keep this driver together.
Yours,
Linus Walleij
next prev parent reply other threads:[~2019-07-29 21:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-19 19:24 [v5 0/2] gpio: aspeed: Add SGPIO driver Hongwei Zhang
2019-07-19 19:24 ` [v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support Hongwei Zhang
2019-07-20 8:12 ` Linus Walleij
2019-07-22 1:42 ` Andrew Jeffery
2019-07-28 23:34 ` Linus Walleij
2019-07-29 0:19 ` Andrew Jeffery
2019-07-29 21:57 ` Linus Walleij [this message]
2019-07-30 19:25 ` Hongwei Zhang
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=CACRpkdZcLNe+oM1jWPpva0LECc-P48ab3H-kG7eabMmSvmvioA@mail.gmail.com \
--to=linus.walleij@linaro.org \
--cc=andrew@aj.id.au \
--cc=bgolaszewski@baylibre.com \
--cc=devicetree@vger.kernel.org \
--cc=hongweiz@ami.com \
--cc=joel@jms.id.au \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-aspeed@lists.ozlabs.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=robh+dt@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 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).