[v5 1/2] dt-bindings: gpio: aspeed: Add SGPIO support
hongweiz at ami.com
Wed Jul 31 05:25:37 AEST 2019
Hello Linus and Andrew,
Thanks for your detailed comments, I just submitted v6 of our update:
please ignore my previous patches sent on 07/28, they does not have proper serial
title and one of the patch is missing.
> From: Linus Walleij <linus.walleij at linaro.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 at vger.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 at 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.
> Linus Walleij
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