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;
MIME-Version: 1.0
References: <20210302053059.1049035-1-drew@beagleboard.org>
 <20210302053059.1049035-3-drew@beagleboard.org> <349b09f8-fe99-d0d4-dd11-c288bf66cb4d@metux.net>
In-Reply-To: <349b09f8-fe99-d0d4-dd11-c288bf66cb4d@metux.net>
From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Mon, 15 Mar 2021 17:24:21 +0100
Message-ID: <CACRpkda=_qSY04mjyYUt1ox_yGgmTR3YPRrOYeJeMLjvba0ADA@mail.gmail.com>
Subject: Re: [PATCH v9 2/4] pinctrl: pinmux: Add pinmux-select debugfs file
To:     "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Cc:     Drew Fustini <drew@beagleboard.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Tony Lindgren <tony@atomide.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
        Jason Kridner <jkridner@beagleboard.org>,
        Robert Nelson <robertcnelson@beagleboard.org>,
        Joe Perches <joe@perches.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Mar 12, 2021 at 2:57 PM Enrico Weigelt, metux IT consult
<lkml@metux.net> wrote:
> On 02.03.21 06:30, Drew Fustini wrote:
>
> Hi folks,
>
> > Add "pinmux-select" to debugfs which will activate a pin function for a
> > given pin group:
> >
> >    echo "<group-name function-name>" > pinmux-select
> >
> > The write operation pinmux_select() handles this by checking that the
> > names map to valid selectors and then calling ops->set_mux().
>
> I've already been playing with similar idea, but for external muxes.
> For example, some boards have multiple SIM slots that can be switched
> via some gpio pin.
>
> Not sure whether traditional pinmux would be a good match for that.

What is wrong with the subsystem
drivers/mux?

It's exactly for this usecase I think. Peter Rosin already wrote
a GPIO-controlled mux driver too.

Yours,
Linus Walleij