From: Peter Maydell <peter.maydell@linaro.org>
To: Joe Komlodi <komlodi@google.com>
Cc: qemu-devel@nongnu.org, wuhaotsh@google.com, kfting@nuvoton.com,
qemu-arm@nongnu.org, "Cédric Le Goater" <clg@kaod.org>
Subject: Re: [PATCH 0/2] hw/arm/npcm7xx_gpio: Add some pin state QOM
Date: Thu, 13 Apr 2023 13:51:39 +0100 [thread overview]
Message-ID: <CAFEAcA-2_gwOUgapmgSSFGVNiOk9Grse_E3TVo=pQTf-OgW2vg@mail.gmail.com> (raw)
In-Reply-To: <20230406002447.4046378-1-komlodi@google.com>
On Thu, 6 Apr 2023 at 01:25, Joe Komlodi <komlodi@google.com> wrote:
>
> Hi all,
>
> This series adds a couple QOM properties for retrieving and setting pin
> state via qom-get and qom-get.
>
> We ran into a situation in multi-SoC simulation where the BMC would need
> to update its input pin state based on behavior from the other SoC. It
> made the most sense to expose this over QMP, so this adds properties to
> allow people to do so.
This does leave the simulation in an odd situation if
the input GPIO was connected to some other device -- the
other device thinks it's put the GPIO line low, but then something
external has reached in and set it to 1, so the two ends of
what is conceptually a single signal line now disagree about
what voltage it's at...
It looks like the hw/gpio/aspeed_gpio device has been here before
you, only that device chose to use one bool property per GPIO
line. It would be nice to be consistent -- if we want to allow
QOM to set/get the GPIO line values, it should be the same
interface regardless of GPIO controller.
-- PMM
prev parent reply other threads:[~2023-04-13 12:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-06 0:24 [PATCH 0/2] hw/arm/npcm7xx_gpio: Add some pin state QOM Joe Komlodi
2023-04-06 0:24 ` [PATCH 1/2] hw/gpio/npcm7xx: Add GPIO DIN object property Joe Komlodi
2023-04-06 0:24 ` [PATCH 2/2] hw/gpio/npcm7xx: Support qom-get on GPIO pin level Joe Komlodi
2023-04-13 12:51 ` Peter Maydell [this message]
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