linux-kernel - Re: [PATCH v6] gpio: pca953x: Add Maxim MAX7313 PWM support

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Message-ID: <20200630235609.52611e41@xps13>
Date:   Tue, 30 Jun 2020 23:56:09 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        linux-pwm@...r.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6] gpio: pca953x: Add Maxim MAX7313 PWM support

Hello,

Andy Shevchenko <andy.shevchenko@...il.com> wrote on Wed, 1 Jul 2020
00:27:31 +0300:

> On Tue, Jun 30, 2020 at 3:45 PM Uwe Kleine-König
> <u.kleine-koenig@...gutronix.de> wrote:
> > On Tue, Jun 30, 2020 at 11:13:31AM +0200, Bartosz Golaszewski wrote:
> > > I can't find anything in any of the previous threads. What was the
> > > reason to not go the MFD way here?
> >
> > MFD doesn't work because the different "modes" are not orthogonal. So
> > this is not a single device that provides several functions at the same
> > time that can be used in parallel.
> 
> Did I get this correctly that it's either *all* pins are GPIO or *all* are PWM?
> 
> Otherwise, it fits from my point of view.
> 

Sorry for not being clear in the first place : the choice between
pure GPIO and PWM is on a per output basis. As Uwe said, the two
"modes" are not orthogonal hence the MFD does not fit here IMHO.

Thanks,
Miquèl