linux-kernel - Re: [PATCH 2/2] serial: 8250: Add support for 8250/16550 as MFD function

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Message-ID: <87bm05mpmx.fsf@haabendal.dk>
Date:   Tue, 14 May 2019 10:00:54 +0200
From:   Esben Haabendal <esben@...bendal.dk>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     linux-serial@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>, Nishanth Menon <nm@...com>,
        Vignesh R <vigneshr@...com>, Tony Lindgren <tony@...mide.com>,
        Lokesh Vutla <lokeshvutla@...com>,
        Florian Fainelli <f.fainelli@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] serial: 8250: Add support for 8250/16550 as MFD function

Lee Jones <lee.jones@...aro.org> writes:

> On Tue, 07 May 2019, Esben Haabendal wrote:
>
>> Lee Jones <lee.jones@...aro.org> writes:
>> 
>> > On Fri, 26 Apr 2019, Esben Haabendal wrote:
>> >
>> >> The serial8250-mfd driver is for adding 8250/16550 UART ports as functions
>> >> to an MFD driver.
>> >> 
>> >> When calling mfd_add_device(), platform_data should be a pointer to a
>> >> struct plat_serial8250_port, with proper settings like .flags, .type,
>> >> .iotype, .regshift and .uartclk.  Memory (or ioport) and IRQ should be
>> >> passed as cell resources.
>> >
>> > What?  No, please!
>> >
>> > If you *must* create a whole driver just to be able to use
>> > platform_*() helpers (which I don't think you should), then please
>> > call it something else.  This doesn't have anything to do with MFD.
>> 
>> True.
>> 
>> I really don't think it is a good idea to create a whole driver just to
>> be able to use platform_get_*() helpers.  And if I am forced to do this,
>> because I am unable to convince Andy to improve the standard serial8250
>> driver to support that, it should be called MFD.  The driver would be
>
> I assume you mean "shouldn't"?

Of-course.

>> generally usable for all usecases where platform_get_*() works.
>> 
>> I don't have any idea what to call such a driver.  It really would just
>> be a fork of the current serial8250 driver, just allowing use of
>> platform_get_*(), supporting exactly the same hardware.
>> 
>> I am still hoping that we can find a way to improve serial8250 to be
>> usable in these cases.
>
> Me too.

Unfortunately, I don't seem to be able to convince Andy to accept
something like that.

I might have to do this out-of-tree :(

/Esben