linux-kernel - Re: [PATCH v2 2/2] gpio: mmio: Use new flag BGPIOF_NO

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Message-ID: <Y+jds9U1PgYpXBHT@smile.fi.intel.com>
Date:   Sun, 12 Feb 2023 14:38:11 +0200
From:   Andy Shevchenko <andriy.shevchenko@...el.com>
To:     Niall Leonard <nl250060@....com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] gpio: mmio: Use new flag BGPIOF_NO_INPUT.

On Tue, Jan 31, 2023 at 01:49:38PM +0000, Niall Leonard wrote:
> Add new flag BGPIOF_NO_INPUT to header file.
> Use the existing shadow data register 'bgpio_data' to allow
> the last written value to be returned by the read operation
> when BGPIOF_NO_INPUT flag is set.
> Ensure this change only applies to the specific binding "wd,mbl-gpio".

I'm wondering why do we need that.

I mean the reading back the (possible cached) output value is the right thing
to do by default for GPIO (in output mode) or GPO. So, instead you can simply
check the current direction of the pin and return (cached) value.

Or did I miss something?

-- 
With Best Regards,
Andy Shevchenko