linux-kernel - Re: [PATCH v2 1/4] gpio: regmap: Always set gpio_chip get

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Date:   Wed, 16 Nov 2022 12:34:35 +0100
From:   Robert Marko <robert.marko@...tura.hr>
To:     William Breathitt Gray <william.gray@...aro.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        michael@...le.cc, linus.walleij@...aro.org, brgl@...ev.pl,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        broonie@...nel.org
Subject: Re: [PATCH v2 1/4] gpio: regmap: Always set gpio_chip get_direction

On Sun, Nov 13, 2022 at 2:21 PM William Breathitt Gray
<william.gray@...aro.org> wrote:
>
> On Sun, Nov 13, 2022 at 02:40:17PM +0200, Andy Shevchenko wrote:
> > On Thu, Nov 10, 2022 at 08:55:50PM -0500, William Breathitt Gray wrote:
> > > If you only have reg_dat_base set, then it is input-only; if you only
> > > have reg_set_base set, then it is output-only. Thus, we can always set
> > > gpio_chip get_direction to gpio_regmap_get_direction and return
> > > GPIO_LINE_DIRECTION_IN/GPIO_LINE_DIRECTION_OUT given the respective
> > > register base addresses configuration.
> >
> > Seems legit to me. Have you checked if we have any gpio-regmap drivers that
> > have something like this in their configuration already? In such cases we need
> > to be sure they behave as expected.
> >
> > From the code perspective:
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
>
> I see gpio-sl28cpld has two device types SL28CPLD_GPO (output-only) and
> SL28CPLD_GPI (input-only); gpio-tn48m similarly has two device types
> TN48M_GPO (output-only) and TN48M_GPI (input-only). It doesn't look like
> the change in this patch will cause problems for them, but I'll let
> Michael Walle and Robert Marko comment if they see issues here.

Hi, sorry for the late reply.
This should work fine for TN48M.

Regards,
Robert
>
> William Breathitt Gray
>
> > > Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
> > > ---
> > >  drivers/gpio/gpio-regmap.c | 7 ++++++-
> > >  1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
> > > index 6383136cbe59..f907c9c19fce 100644
> > > --- a/drivers/gpio/gpio-regmap.c
> > > +++ b/drivers/gpio/gpio-regmap.c
> > > @@ -111,6 +111,11 @@ static int gpio_regmap_get_direction(struct gpio_chip *chip,
> > >     unsigned int base, val, reg, mask;
> > >     int invert, ret;
> > >
> > > +   if (gpio->reg_dat_base && !gpio->reg_set_base)
> > > +           return GPIO_LINE_DIRECTION_IN;
> > > +   if (gpio->reg_set_base && !gpio->reg_dat_base)
> > > +           return GPIO_LINE_DIRECTION_OUT;
> > > +
> > >     if (gpio->reg_dir_out_base) {
> > >             base = gpio_regmap_addr(gpio->reg_dir_out_base);
> > >             invert = 0;
> > > @@ -265,8 +270,8 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
> > >     else if (gpio->reg_set_base)
> > >             chip->set = gpio_regmap_set;
> > >
> > > +   chip->get_direction = gpio_regmap_get_direction;
> > >     if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
> > > -           chip->get_direction = gpio_regmap_get_direction;
> > >             chip->direction_input = gpio_regmap_direction_input;
> > >             chip->direction_output = gpio_regmap_direction_output;
> > >     }
> > > --
> > > 2.38.1
> > >
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
> >
> >



-- 
Robert Marko
Staff Embedded Linux Engineer
Sartura Ltd.
Lendavska ulica 16a
10000 Zagreb, Croatia
Email: robert.marko@...tura.hr
Web: www.sartura.hr