From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: DENG Qingfang <dqfext@gmail.com>
Cc: "Andrew Lunn" <andrew@lunn.ch>,
"Vivien Didelot" <vivien.didelot@gmail.com>,
"Florian Fainelli" <f.fainelli@gmail.com>,
"Vladimir Oltean" <olteanv@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Rob Herring" <robh+dt@kernel.org>,
"Matthias Brugger" <matthias.bgg@gmail.com>,
"Sean Wang" <sean.wang@mediatek.com>,
"Landen Chao" <Landen.Chao@mediatek.com>,
"Philipp Zabel" <p.zabel@pengutronix.de>,
netdev <netdev@vger.kernel.org>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>,
linux-kernel@vger.kernel.org,
"René van Dorst" <opensource@vdorst.com>,
"Frank Wunderlich" <frank-w@public-files.de>
Subject: Re: [PATCH net-next 2/2] drivers: net: dsa: mt7530: MT7530 optional GPIO support
Date: Mon, 11 Jan 2021 13:55:09 +0000 [thread overview]
Message-ID: <20210111135509.GT1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <CALW65jaqciOiRxJxzPiEADgpmKa7-q2QfQnBdaVMcOa5YDHjRA@mail.gmail.com>
On Mon, Jan 11, 2021 at 09:40:00PM +0800, DENG Qingfang wrote:
> On Mon, Jan 11, 2021 at 7:04 PM Russell King - ARM Linux admin
> <linux@armlinux.org.uk> wrote:
> >
> > FYI, Documentation/driver-api/gpio/consumer.rst says:
> >
> > For output GPIOs, the value provided becomes the initial output value.
> > This helps avoid signal glitching during system startup.
> >
> > Setting the pin to be an output, and then setting its initial value
> > does not avoid the glitch. You may wish to investigate whether you
> > can set the value before setting the pin as an output to avoid this
> > issue.
> >
>
> So, setting the Output Enable bit _after_ setting the direction and
> initial value should avoid this issue. Right?
It depends on the hardware. I don't know how your hardware works, so
I can't say whether doing anything will result in correct behaviour,
or even work.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2021-01-11 13:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 5:44 [PATCH net-next 0/2] dsa: add MT7530 GPIO support DENG Qingfang
2021-01-11 5:44 ` [PATCH net-next 1/2] dt-bindings: net: dsa: add MT7530 GPIO controller binding DENG Qingfang
2021-01-14 19:11 ` Rob Herring
2021-01-18 14:43 ` Linus Walleij
2021-01-11 5:44 ` [PATCH net-next 2/2] drivers: net: dsa: mt7530: MT7530 optional GPIO support DENG Qingfang
2021-01-11 11:04 ` Russell King - ARM Linux admin
2021-01-11 13:40 ` DENG Qingfang
2021-01-11 13:55 ` Russell King - ARM Linux admin [this message]
2021-01-18 14:55 ` Linus Walleij
2021-01-19 3:20 ` DENG Qingfang
2021-01-22 10:06 ` Linus Walleij
2021-01-11 13:43 ` [PATCH net-next 0/2] dsa: add MT7530 " Vladimir Oltean
2021-01-14 9:36 ` Bartosz Golaszewski
2021-01-11 15:46 ` Marek Behún
2021-01-12 2:50 ` DENG Qingfang
2021-01-14 17:08 ` Florian Fainelli
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