linux-kernel - Re: [PATCH V3 2/6] tty: serial: meson: Request the register region in meson_uart

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Message-ID: <CAFBinCBtye7KiEqFbUeNDeRGSQkhnQ-XH-Gr-KMUWYupvioP1g@mail.gmail.com>
Date:   Thu, 30 Dec 2021 23:28:55 +0100
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Yu Tu <yu.tu@...ogic.com>, linux-serial@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Jiri Slaby <jirislaby@...nel.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Vyacheslav <adeep@...ina.in>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>
Subject: Re: [PATCH V3 2/6] tty: serial: meson: Request the register region in meson_uart_probe()

Hi Greg,

On Thu, Dec 30, 2021 at 1:29 PM Greg Kroah-Hartman
<gregkh@...uxfoundation.org> wrote:
[...]
> >  static void meson_uart_release_port(struct uart_port *port)
> >  {
> > -     devm_iounmap(port->dev, port->membase);
> > -     port->membase = NULL;
> > -     devm_release_mem_region(port->dev, port->mapbase, port->mapsize);
> > +     /* nothing to do */
> >  }
>
> Are you sure a release call like this can be "empty"?  That goes against
> the normal way the driver model works.  If it is empty, why have it at
> all?
In patch #4 from this series some logic is added here again.
I can think of three options here (in no particular order):
- keep this patch as-is
- remove the empty function from this patch and it back in patch #4
from this series
- try to split some of the logic from patch #4 so the relevant
clk_prepare_enable/clk_disable_unpepare calls are added here (meaning
that this function has logic inside it at all times throughout this
series)
- (if you have another suggestion then please let us know)


Best regards,
Martin