linux-kernel - Re: [PATCH] pcmcia: at91_cf: switch to using gpiod API

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Message-ID: <Yy/fE9lUmWTpsyTL@google.com>
Date:   Sat, 24 Sep 2022 21:54:43 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Dominik Brodowski <linux@...inikbrodowski.net>
Cc:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Claudiu Beznea <claudiu.beznea@...rochip.com>
Subject: Re: [PATCH] pcmcia: at91_cf: switch to using gpiod API

On Sat, Sep 24, 2022 at 04:17:20PM +0200, Dominik Brodowski wrote:
> Am Sat, Sep 24, 2022 at 01:42:37PM +0200 schrieb Alexandre Belloni:
> > On 24/09/2022 10:33:29+0200, Arnd Bergmann wrote:
> > > On Sat, Sep 24, 2022, at 8:04 AM, Dmitry Torokhov wrote:
> > > > This patch switches the driver to use newer gpiod API instead of legacy
> > > > gpio API. This moves us closer to the goal of stopping exporting
> > > > OF-specific APIs of gpiolib.
> > > >
> > > > While at it, stop using module-global for regmap.
> > > >
> > > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> > > 
> > > This looks good to me overall. Three comments:
> > > 
> > > > @@ -63,7 +62,7 @@ struct at91_cf_socket {
> > > > 
> > > >  static inline int at91_cf_present(struct at91_cf_socket *cf)
> > > >  {
> > > > -	return !gpio_get_value(cf->board->det_pin);
> > > > +	return gpiod_get_value(cf->board->det_pin);
> > > >  }
> > > 
> > > a) The change in polarity looks wrong here, I can't really tell
> > > from the patch. If this is intentional, maybe explain it in
> > > the changelog. With that addressed (either way)

Oh, yes, you are right. I at first thought that card detect pin might be
active low, was not able to confirm it, but forgot to restore polarity.

Anyway, I think this does not matter given Dominik's patch below.

> > > 
> > > Reviewed-by: Arnd Bergmann <arnd@...db.de>
> > > 
> > > 
> > > b) In case you are doing more patches like this one at the moment,
> > > note that I'm in the process of removing all unused board files
> > > for arch/arm/, which will in turn make a lot of drivers unused.
> > > I should be able to provide a branch soon, which can be used to
> > > identify drivers that don't have DT support any more and don't
> > > have any board files. Rather than converting them to gpio
> > > descriptors, we can probably just remove those drivers.
> > > 
> > > c) I'm not sure about the state of the at91_cf driver. Apparently
> > > we used to have three drivers for the same hardware (pcmcia,
> > > pata and ide), and only the pcmcia driver remained in the tree
> > > after drivers/ide/ was removed and pata_at91 did not get converted
> > > to DT. I think in the long run we will remove the pcmcia layer,
> > > so if you are actually trying to use this hardware, we may want to
> > > revive the pata variant and drop this one instead.

Nope, I am interested in dropping legacy gpio API, that is all.

> > > There is no dts file in tree that actually declares either of them,
> > > so chances are that nobody is actually using the CF slot on at91
> > > any more.
> > > 
> > 
> > I'm pretty sure it is broken since eaa9a21dd14b ("pcmcia: at91_cf: Use
> > syscon to configure the MC/smc") as this change has never been tested.
> 
> Well, that's a pretty strong reason to remove this driver. May I get ACKs on
> this patch, please?

Not sure if this is worth anything, but

Acked-by: Dmitry Torokhov <dmitry.torokhov@...il.com>

Thanks.

-- 
Dmitry