Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 19 May 2021 03:02:35 -0700
From:   Drew Fustini <drew@beagleboard.org>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Dario Binacchi <dariobin@libero.it>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Vladimir Zapolskiy <vz@mleia.com>
Subject: Re: [PATCH 1/2] pinctrl: core: configure pinmux from pins debug file
Message-ID: <20210519100235.GA3063522@x1>
References: <20210516135531.2203-1-dariobin@libero.it>
 <20210516135531.2203-2-dariobin@libero.it>
 <CAHp75Vd8875hRNk1JK6gkmfxjqxBSu4cRNE1zJt9TyEW7TvsMg@mail.gmail.com>
 <1735504854.166374.1621346262270@mail1.libero.it>
 <CAHp75VeADiRKdfnsXQ=y3z1WAJBbtZ+P=8tdyYtVQpJrSrQ63Q@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAHp75VeADiRKdfnsXQ=y3z1WAJBbtZ+P=8tdyYtVQpJrSrQ63Q@mail.gmail.com>
Precedence: bulk

On Tue, May 18, 2021 at 05:01:30PM +0300, Andy Shevchenko wrote:
> On Tue, May 18, 2021 at 4:57 PM Dario Binacchi <dariobin@libero.it> wrote:
> > > Il 17/05/2021 22:02 Andy Shevchenko <andy.shevchenko@gmail.com> ha scritto:
> > > On Sun, May 16, 2021 at 7:43 PM Dario Binacchi <dariobin@libero.it> wrote:
> 
> ...
> 
> > > Can't you use strncpy_from_user() ?
> >
> > Ok, I'll use strncpy_from_user() in the next version of the patch
> 
> Don't be in a hurry.
> 
> We need to settle down the interface first. We still haven't heard
> from the maintainer (Linus?) about it. Neither we have a clear view if
> we need to revert that patch that dropped pinconf-config (Drew, what
> do you think?).

Vladimir Zapolskiy wrote in e73339037f6b ("pinctrl: remove unused
'pinconf-config' debugfs interface"):
    
    Of course it might be possible to increase MAX_NAME_LEN, and then add
    .pin_config_dbg_parse_modify callbacks to the drivers, but the whole
    idea of such a limited debug option looks inviable. A more flexible
    way to functionally substitute the original approach is to implicitly
    or explicitly use pinctrl_select_state() function whenever needed.

This makes me think it is not a good idea to bring back pinconf-config.
The pinmux-select debugfs file that I add added in commit 6199f6becc86
("pinctrl: pinmux: Add pinmux-select debugfs file") provides a method to
activate a pin function and pin group which I think provides the same
capability as long as the possible pin functions are described in dts.

thanks,
drew