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References: <20210618064625.14131-1-pkshih@realtek.com> <20210618064625.14131-5-pkshih@realtek.com>
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From:   Brian Norris <briannorris@chromium.org>
Date:   Mon, 12 Jul 2021 18:57:37 -0700
Message-ID: <CA+ASDXMLLEM0aYKU5u6E-xQJfJz+HkqFZjgYKirq8po6HsYc3Q@mail.gmail.com>
Subject: Re: [PATCH 04/24] rtw89: add debug files
To:     Pkshih <pkshih@realtek.com>
Cc:     Oleksij Rempel <o.rempel@pengutronix.de>,
        "kvalo@codeaurora.org" <kvalo@codeaurora.org>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
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On Mon, Jul 5, 2021 at 1:59 AM Pkshih <pkshih@realtek.com> wrote:
> > -----Original Message-----
> > From: Oleksij Rempel [mailto:o.rempel@pengutronix.de]

> > Based on this and other part of this driver I would recommend to use
> > regmap. It will provide to additional interface for the register
> > access. And typically for the network devices we have an ethtool
> > interface for that.
> >
>
> Could I know the 'regmap' you mentioned?

include/linux/regmap.h
drivers/base/regmap/

It's a driver framework and API for abstracting register accesses,
whether they are accessed directly via MMIO, or behind some kind of
indirect bus (I2C, SPI, etc.). It also happens to have its own debugfs
operators for doing various kinds of register get/set/dump. So if you
can successfully teach your driver to use it, then you don't need to
implement your own debugfs files for it.

I've only ever used regmap with Device Tree systems (which can more
easily specify syscon nodes, etc. -- see
Documentation/devicetree/bindings/regmap/regmap.txt). I'm totally
unfamiliar how to use this with ACPI (which I'm sure you want to
support). I'm sure it's possible somehow.

FWIW, search engines turn up a few basic articles about it, if you
find its documentation or code examples too sparse:
https://www.collabora.com/news-and-blog/blog/2020/05/27/using-regmaps-to-make-linux-drivers-more-generic/

Brian