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References: <20210805174219.3000667-1-piyush.mehta@xilinx.com> <20210805174219.3000667-2-piyush.mehta@xilinx.com>
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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Wed, 11 Aug 2021 15:08:35 +0200
Message-ID: <CACRpkdYo5e7uTJJRqnK1R4QLtUzRGNbsvNvm-47UFZOr4_R9Cw@mail.gmail.com>
Subject: Re: [PATCH V2 1/3] firmware: zynqmp: Add MMIO read and write support
 for PS_MODE pin
To:     Piyush Mehta <piyush.mehta@xilinx.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, Zou Wei <zou_wei@huawei.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Michal Simek <michal.simek@xilinx.com>, wendy.liang@xilinx.com,
        Nobuhiro Iwamatsu <iwamatsu@nigauri.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>, rajan.vaja@xilinx.com,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, git <git@xilinx.com>,
        Srinivas Goud <sgoud@xilinx.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Thu, Aug 5, 2021 at 7:42 PM Piyush Mehta <piyush.mehta@xilinx.com> wrote:

> Add Xilinx ZynqMP firmware MMIO APIs support to set and get PS_MODE
> pins value and status. These APIs create an interface path between
> mode pin controller driver and low-level API to access GPIO pins.
>
> Signed-off-by: Piyush Mehta <piyush.mehta@xilinx.com>
> ---
> Changes in v2:
> - Added Xilinx ZynqMP firmware MMIO API support to set and get pin
>   value and status.

I doubt this is "GPIO".
General Purpose? I think not. It seems to be about boot mode.

If you need a userspace ABI, then add sysfs files to this firmware
driver instead of bridging it to the GPIO subsystem.

However I can be argued down from usecases etc that it is used as
GPIO but I need to push back on this.

Yours,
Linus Walleij