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Date:   Wed, 19 May 2021 21:42:11 +0200
From:   Michael Walle <michael@walle.cc>
To:     Robert Marko <robert.marko@sartura.hr>
Cc:     Lee Jones <lee.jones@linaro.org>, robh+dt@kernel.org,
        Linus Walleij <linus.walleij@linaro.org>,
        bgolaszewski@baylibre.com, jdelvare@suse.com,
        Guenter Roeck <linux@roeck-us.net>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
        linux-hwmon@vger.kernel.org, Luka Perkov <luka.perkov@sartura.hr>,
        jmp@epiphyte.org, Paul Menzel <pmenzel@molgen.mpg.de>,
        Donald Buczek <buczek@molgen.mpg.de>
Subject: Re: [PATCH 1/6] mfd: Add Delta TN48M CPLD driver
In-Reply-To: <CA+HBbNHCnpg9qCzZbT9KVNqX-daC68iaJKNdyEf7do3w98miWw@mail.gmail.com>
References: <20210430123511.116057-1-robert.marko@sartura.hr>
 <af4923ef1ed0693fcd67d7986348b164@walle.cc>
 <CA+HBbNHCnpg9qCzZbT9KVNqX-daC68iaJKNdyEf7do3w98miWw@mail.gmail.com>
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Hi,

Am 2021-05-19 13:53, schrieb Robert Marko:
> On Thu, May 6, 2021 at 6:34 PM Michael Walle <michael@walle.cc> wrote:
>> Am 2021-04-30 14:35, schrieb Robert Marko:
>> > Delta TN48M switches have a Lattice CPLD that serves
>> > multiple purposes including being a GPIO expander.
>> > So lets add the MFD core driver for it.
>> 
>> Did you have a look at mfd/simple-mfd-i2c.c?
> 
> Yes, that was my first idea but we have a requirement to expose CPLD
> information via debugfs as there are userspace applications using it.
> And simple-mfd-i2c does not allow us to do so.

Mh, last time Lee wasn't very fond of having a driver that just 
populates
sub-drivers while doing almost nothing itself. See
https://lore.kernel.org/lkml/20200605065709.GD3714@dell/

That being said, I'd also like to expose our CPLD version, but until now
haven't found a good solution.

-michael