From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Martin Schiller <ms@dev.tdt.de>
Cc: hauke@hauke-m.de, dmitry.torokhov@gmail.com,
rdunlap@infradead.org, robh@kernel.org, bhelgaas@google.com,
linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] MIPS: pci: lantiq: restore reset gpio polarity
Date: Tue, 11 Jun 2024 16:12:18 +0200 [thread overview]
Message-ID: <ZmhbQgXxyhZ7shBh@alpha.franken.de> (raw)
In-Reply-To: <20240607090400.1816612-1-ms@dev.tdt.de>
On Fri, Jun 07, 2024 at 11:04:00AM +0200, Martin Schiller wrote:
> Commit 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API") not
> only switched to the gpiod API, but also inverted / changed the polarity
> of the GPIO.
>
> According to the PCI specification, the RST# pin is an active-low
> signal. However, most of the device trees that have been widely used for
> a long time (mainly in the openWrt project) define this GPIO as
> active-high and the old driver code inverted the signal internally.
>
> Apparently there are actually boards where the reset gpio must be
> operated inverted. For this reason, we cannot use the GPIOD_OUT_LOW/HIGH
> flag for initialization. Instead, we must explicitly set the gpio to
> value 1 in order to take into account any "GPIO_ACTIVE_LOW" flag that
> may have been set.
>
> In order to remain compatible with all these existing device trees, we
> should therefore keep the logic as it was before the commit.
>
> Fixes: 90c2d2eb7ab5 ("MIPS: pci: lantiq: switch to using gpiod API")
> Cc: stable@vger.kernel.org
> Signed-off-by: Martin Schiller <ms@dev.tdt.de>
> ---
> arch/mips/pci/pci-lantiq.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
applied to mips-fixes
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
next prev parent reply other threads:[~2024-06-11 14:15 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-07 9:04 [PATCH] MIPS: pci: lantiq: restore reset gpio polarity Martin Schiller
2024-06-11 14:12 ` Thomas Bogendoerfer [this message]
2024-06-12 15:38 ` Dmitry Torokhov
2024-06-12 17:47 ` Dmitry Torokhov
2024-06-12 18:39 ` Martin Schiller
2024-06-12 19:47 ` Martin Schiller
2024-06-12 21:45 ` Dmitry Torokhov
2024-06-12 23:32 ` Dmitry Torokhov
2024-06-13 6:01 ` Martin Schiller
2024-06-13 6:29 ` Dmitry Torokhov
2024-06-13 20:06 ` Hauke Mehrtens
2024-06-14 8:43 ` Martin Schiller
2024-06-20 0:54 ` Dmitry Torokhov
2024-06-24 8:16 ` Martin Schiller
2024-06-13 8:10 ` Thomas Bogendoerfer
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