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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Fri, 12 Feb 2021 10:26:39 +0100
Message-ID: <CACRpkdZ5ZQDcy5RP=CVPJ14Lyktw_4yOuELJRweeDpPKRL3RVA@mail.gmail.com>
Subject: Re: [PATCH v5 2/2] counter: add IRQ or GPIO based event counter
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Rob Herring <robh+dt@kernel.org>,
        William Breathitt Gray <vilhelm.gray@gmail.com>,
        Ahmad Fatoum <a.fatoum@pengutronix.de>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        David Jander <david@protonic.nl>,
        Robin van der Gracht <robin@protonic.nl>,
        linux-iio <linux-iio@vger.kernel.org>,
        Jonathan Cameron <jic23@kernel.org>
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On Mon, Feb 8, 2021 at 2:53 PM Oleksij Rempel <o.rempel@pengutronix.de> wrote:

> Add simple IRQ or GPIO base event counter. This device is used to measure
> rotation speed of some agricultural devices, so no high frequency on the
> counter pin is expected.
>
> The maximal measurement frequency depends on the CPU and system load. On
> the idle iMX6S I was able to measure up to 20kHz without count drops.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

From GPIO and interrupt point of view this driver looks good to me.
I don't know about the userspace interface etc.

Yours,
Linus Walleij