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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Fri, 18 Jun 2021 11:13:57 +0200
Message-ID: <CACRpkda9g5JJyroTWi4C=2+YCABhKTyxvwvo3C4zGa=+xGWWfg@mail.gmail.com>
Subject: Re: [PATCH V3 1/3] gpio: Add virtio-gpio driver
To:     "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        "Enrico Weigelt, metux IT consult" <info@metux.net>,
        Viresh Kumar <vireshk@kernel.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Bill Mills <bill.mills@linaro.org>,
        "Alex Benn?e" <alex.bennee@linaro.org>,
        stratos-dev@op-lists.linaro.org,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        "Stefano Garzarella --cc virtualization @ lists . linux-foundation . org" 
        <sgarzare@redhat.com>, virtualization@lists.linux-foundation.org,
        Alistair Strachan <astrachan@google.com>
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On Wed, Jun 16, 2021 at 5:52 PM Enrico Weigelt, metux IT consult
<lkml@metux.net> wrote:
> On 16.06.21 05:30, Bjorn Andersson wrote:
>
> > Combined with the virtio-i2c effort this could provide an alternative by
> > simply tunneling the busses and GPIOs into Linux and use standard iio
> > drivers, for cases where this suits your product requirements better.
>
> So, you wanna use virtio as logical interface between the two CPUs ?
> Interesting idea. Usually folks use rpmsg for those things.

rpmsg is using shared memory as transport mechanism and virtio
is providing this. rpmsg is conceptually a child of virtio: when the
subsystem was proposed by TI Arnd noted that virtio has large
similarities in shared memory transport and as the potential reuse
for buffer handling etc was excellent virtio was used as
a base for rpmsg/remoteproc work.

Yours,
Linus Walleij