linux-kernel - Re: [PATCH v4 2/9] pinctrl: Renesas RZ/A1 pin and gpio controller

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Message-ID: <20170426142757.GJ11761@w540>
Date:   Wed, 26 Apr 2017 16:28:07 +0200
From:   jmondi <jacopo@...ndi.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Chris Brandt <chris.brandt@...esas.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 2/9] pinctrl: Renesas RZ/A1 pin and gpio controller

Hi Geert,

On Wed, Apr 26, 2017 at 02:21:34PM +0200, Geert Uytterhoeven wrote:
> Hi Jacopo,
>
> On Wed, Apr 5, 2017 at 4:07 PM, Jacopo Mondi <jacopo+renesas@...ndi.org> wrote:
> > Add combined gpio and pin controller driver for Renesas RZ/A1
> > r7s72100 SoC.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
>
> > --- /dev/null
> > +++ b/drivers/pinctrl/pinctrl-rza1.c
>
> > +/*
> > + * Keep this up-to-date with pinconf-generic.h: it performs packing of
> > + * pin conf flags and argument during pinconf_generic_parse_dt_config();
> > + * we simply discard pinconf argument here
> > + */
> > +#define PIN_CONF_UNPACK(pinconf)       ((pinconf) & 0xffUL)
>
> Perhaps this should be moved to pinconf-generic.h, to make sure it stays
> up-to-date?
>

Not sure, I'm discarding the argument of the configuration flag with
this macro...

I would keep this internal to this driver, or make two of them, one to
retrieve the flag, and one to retrieve argument..


> > +static inline int rza1_get_bit(struct rza1_port *port, unsigned int reg,
>
> I'd use "unsigned int" as the return type.
> It doesn't matter much as register values are 16-bit, but people might copy
> from this driver when writing their own.
>
> > +                              unsigned int bit)
> > +{
> > +       void __iomem *mem = RZA1_ADDR(port->base, reg, port->id);
> > +
> > +       return ioread16(mem) & BIT(bit);
> > +}
>
> > +static inline int rza1_pin_get_direction(struct rza1_port *port,
> > +                                        unsigned int pin)
> > +{
> > +       unsigned long irqflags;
> > +       int input;
> > +
> > +       spin_lock_irqsave(&port->lock, irqflags);
> > +       input = rza1_get_bit(port, RZA1_PM_REG, pin);
> > +       spin_unlock_irqrestore(&port->lock, irqflags);
> > +
> > +       return input;
>
> return !!input;
>
> gpio_chip.get_direction() should return 0, 1, or a negative error value.
>
> > +}
>
> 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