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From: Vladimir Oltean <olteanv@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Chen Minqiang <ptpt52@gmail.com>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	"Chester A. Unal" <chester.a.unal@arinc9.com>,
	Daniel Golle <daniel@makrotopia.org>,
	DENG Qingfang <dqfext@gmail.com>,
	Sean Wang <sean.wang@mediatek.com>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, netdev@vger.kernel.org
Subject: Re: [PATCH v3 2/2] net: dsa: mt7530: Use GPIO polarity to generate correct reset sequence
Date: Sun, 30 Nov 2025 10:07:31 +0200	[thread overview]
Message-ID: <20251130080731.ty2dlxaypxvodxiw@skbuf> (raw)
In-Reply-To: <0675b35f-217d-4261-9e3f-2eb24753d43c@lunn.ch>

On Sun, Nov 30, 2025 at 02:11:05AM +0100, Andrew Lunn wrote:
> > -		gpiod_set_value_cansleep(priv->reset, 0);
> > +		int is_active_low = !!gpiod_is_active_low(priv->reset);
> > +		gpiod_set_value_cansleep(priv->reset, is_active_low);
> 
> I think you did not correctly understand what Russell said. You pass
> the logical value to gpiod_set_value(). If the GPIO has been marked as
> active LOW, the GPIO core will invert the logical values to the raw
> value. You should not be using gpiod_is_active_low().
> 
> But as i said to the previous patch, i would just leave everything as
> it is, except document the issue.
> 
> 	Andrew
> 

It was my suggestion to do it like this (but I don't understand why I'm
again not in CC).

We _know_ that the reset pin of the switch should be active low. So by
using gpiod_is_active_low(), we can determine whether the device tree is
wrong or not, and we can work with a wrong device tree too (just invert
the logical values).


  reply	other threads:[~2025-11-30  8:07 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-29 23:46 [PATCH v3 1/2] ARM64: dts: mediatek: fix MT7531 reset GPIO polarity on multiple boards Chen Minqiang
2025-11-29 23:46 ` [PATCH v3 2/2] net: dsa: mt7530: Use GPIO polarity to generate correct reset sequence Chen Minqiang
2025-11-30  1:11   ` Andrew Lunn
2025-11-30  8:07     ` Vladimir Oltean [this message]
2025-11-30 20:17       ` Andrew Lunn
2025-12-01  7:48         ` Krzysztof Kozlowski
2025-12-02 11:52           ` Frank Wunderlich
2025-12-02 12:20             ` Daniel Golle
2025-12-04 13:16               ` Vladimir Oltean
2025-12-04 13:50                 ` Daniel Golle
2025-12-04 15:45                   ` Vladimir Oltean
2025-12-04 14:49                 ` Krzysztof Kozlowski
2025-12-04 16:02                   ` Vladimir Oltean
2025-12-04 16:48                     ` Krzysztof Kozlowski
2025-12-04 17:11                       ` Vladimir Oltean
2025-12-04 17:23                         ` Krzysztof Kozlowski
2025-12-04 17:32                           ` Krzysztof Kozlowski
2025-12-04 20:47                             ` Russell King (Oracle)
2025-12-04 17:45                           ` Russell King (Oracle)
2025-12-04 18:21                             ` Vladimir Oltean
2025-12-04 15:22                 ` Andrew Lunn
2025-12-04 15:37                   ` Vladimir Oltean
2025-12-04 15:50                     ` Andrew Lunn
2025-12-04 15:52                     ` Krzysztof Kozlowski
2025-12-04 16:33                       ` Vladimir Oltean
2025-11-30  8:22   ` Vladimir Oltean
2025-12-01  7:50   ` Krzysztof Kozlowski
2025-11-30  1:00 ` [PATCH v3 1/2] ARM64: dts: mediatek: fix MT7531 reset GPIO polarity on multiple boards Andrew Lunn

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