From: Neil Armstrong <neil.armstrong@linaro.org>
To: Igor Velkov <iav@iav.lv>
Cc: Neil Armstrong <neil.armstrong@linaro.org>,
Conor Dooley <conor+dt@kernel.org>, Rob Herring <robh@kernel.org>,
Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
Kevin Hilman <khilman@baylibre.com>,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-amlogic@lists.infradead.org,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Jerome Brunet <jbrunet@baylibre.com>
Subject: Re: [PATCH] arm64: dts: amlogic: meson-sm1-odroid-hc4: add the fan tachometer
Date: Tue, 06 Oct 2026 15:03:29 +0200 [thread overview]
Message-ID: <179129180999.592940.1230542534490853306.b4-reply@b4> (raw)
In-Reply-To: <179126094299.1095177.4869656735733059341@iav.lv>
On 2026-10-06 07:29:02+03:00, Igor Velkov wrote:
> On Tue, 06 Oct 2026 04:17:33 +0000, sashiko-bot@kernel.org wrote:
>
> > Without an explicit pinctrl-0 property in the fan0 node, will the fan
> > tachometer silently fail to read the fan speed (always reporting 0) on systems
> > where the bootloader leaves GPIOX_7 configured as an alternate function (such
> > as uart_b_rx or pwm_f_x) instead of a GPIO input?
>
> Checked on the board: with GPIOX_7 muxed to uart_b_rx, the interrupt
> counts edges as it does with the pin as GPIO (452 vs 445 in 5 s).
> U-Boot leaves the pin as GPIO. The PHY interrupt on this board is
> described the same way, without pinctrl.
Actually on Amlogic platforms the GPIO Interrup HW block
directly gets the pin input directly from the pin, so
the pin doesn't need to be set as input.
Nevertheless, so be sure there's no remaining pull-up
or pull-down remaining on the pin, it's safer to add
a pinctrl mux node for the pin.
Thamks,
Neil
>
> Igor
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prev parent reply other threads:[~2026-10-06 13:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-06 4:07 Igor Velkov via B4 Relay
2026-10-06 4:17 ` sashiko-bot
2026-10-06 4:29 ` Igor Velkov
2026-10-06 13:03 ` Neil Armstrong [this message]
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