linux-kernel - Re: [RESEND PATCH v3 2/2] serial: uartps: Change uart ID port allocation

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Date:   Mon, 24 Sep 2018 09:37:08 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Michal Simek <michal.simek@...inx.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Michal Simek <monstr@...str.eu>,
        Greg KH <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        "open list:SERIAL DRIVERS" <linux-serial@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RESEND PATCH v3 2/2] serial: uartps: Change uart ID port allocation

Hi Michal,

On Thu, Sep 20, 2018 at 1:42 PM Michal Simek <michal.simek@...inx.com> wrote:
> For IPs which have alias algorightm all the time using that alias and
> minor number. It means serial20 alias ends up as ttyPS20.
>
> If alias is not setup for probed IP instance the first unused position is
> used but that needs to be checked if it is really empty because another
> instance doesn't need to be probed at that time. of_alias_get_alias_list()
> fills alias bitmap which exactly shows which ID is free.
> If alias pointing to different not compatible IP, it is free to use.
>
> cdns_get_id() call is placed below structure allocation to simplify
> error path.
>
> Signed-off-by: Michal Simek <michal.simek@...inx.com>

JFTR, for sh-sci, I used a different approach, as all ports in the static DTB
can have an alias (if aliases are needed at all), and only DT overlays cannot
have them. Cfr. commit 7678f4c20fa7670f ("serial: sh-sci: Add support for
dynamic instances").

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds