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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Mon, 17 Dec 2018 23:21:47 +0100
Message-ID: <CACRpkdYq5Eg2DrwdED-yTZ4kMoCxew+0rdU-b4zuinOf7BEr6Q@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver
To:     Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc:     Jan Kotas <jank@cadence.com>, Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-gpio <linux-gpio@vger.kernel.org>,
        linux-devicetree <devicetree@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:

> The driver looks good but is there any particular reason not to use
> regmap for register IO?

I thought we only use regmap for MMIO when the register range is
shared (as in a system controller) so that some registers are for this,
some register or even bits in a register for some other driver, so they
need the spinlock in the regmap to protect the register range.

It is also nice for shadowing/caching of register contents I guess,
wat does this driver get from regmap MMIO?

Yours,
Linus Walleij