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

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Date:   Tue, 7 May 2019 14:38:44 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Esben Haabendal <esben@...bendal.dk>
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

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"?

> 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.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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