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References: <20210625235532.19575-1-dipenp@nvidia.com> <20210625235532.19575-9-dipenp@nvidia.com>
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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Sun, 27 Jun 2021 13:38:10 +0200
Message-ID: <CACRpkdY=b44SLJNobNqfteYyuEcpB+aGZ3xRBwUSG7Yx116YuA@mail.gmail.com>
Subject: Re: [RFC 08/11] gpiolib: cdev: Add hardware timestamp clock type
To:     Dipen Patel <dipenp@nvidia.com>
Cc:     "thierry.reding@gmail.com" <thierry.reding@gmail.com>,
        Jon Hunter <jonathanh@nvidia.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-tegra <linux-tegra@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Kent Gibson <warthog618@gmail.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>
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On Sat, Jun 26, 2021 at 1:48 AM Dipen Patel <dipenp@nvidia.com> wrote:

> This patch adds new clock type for the GPIO controller which can
> timestamp gpio lines using hardware means. To expose such
> functionalities to the userspace, code has been added in this patch
> where during line create call, it checks for new clock type and if
> requested, calls hardware timestamp related API from gpiolib.c.
> During line change event, it retrieves timestamp in nano seconds by
> calling gpiod_get_hw_timestamp API from gpiolib.c. At the line release,
> it disables this functionality by calling gpiod_hw_timestamp_control.
>
> Signed-off-by: Dipen Patel <dipenp@nvidia.com>

This looks good to me, pretty much exactly as I imagine it should be
done, and it is also nice that we only implement it
for the v2 UAPI.

Yours,
Linus Walleij