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Message-ID: <1564514737-4638-1-git-send-email-hongweiz@ami.com>
Date: Tue, 30 Jul 2019 15:25:37 -0400
From: Hongwei Zhang <hongweiz@....com>
To: Andrew Jeffery <andrew@...id.au>,
Linus Walleij <linus.walleij@...aro.org>,
<linux-gpio@...r.kernel.org>
CC: Hongwei Zhang <hongweiz@....com>, Joel Stanley <joel@....id.au>,
<devicetree@...r.kernel.org>, <linux-aspeed@...ts.ozlabs.org>,
Bartosz Golaszewski <bgolaszewski@...libre.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
<linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: [v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support
Hello Linus and Andrew,
Thanks for your detailed comments, I just submitted v6 of our update:
_http://patchwork.ozlabs.org/cover/1139035/
_http://patchwork.ozlabs.org/patch/1139038/
_http://patchwork.ozlabs.org/patch/1139040/
please ignore my previous patches sent on 07/28, they does not have proper serial
title and one of the patch is missing.
--Hongwei
> From: Linus Walleij <linus.walleij@...aro.org>
> Sent: Monday, July 29, 2019 5:57 PM
> To: Andrew Jeffery
> Cc: Hongwei Zhang; open list:GPIO SUBSYSTEM; Joel Stanley; open list:OPEN FIRMWARE AND
> FLATTENED DEVICE TREE BINDINGS; linux-aspeed; Bartosz Golaszewski; Rob Herring; Mark Rutland;
> linux-kernel@...r.kernel.org; Linux ARM
> Subject: Re: [v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support
>
> On Mon, Jul 29, 2019 at 2:19 AM Andrew Jeffery <andrew@...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
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