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

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Date:   Sun, 13 Nov 2022 08:21:21 -0500
From:   William Breathitt Gray <william.gray@...aro.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        michael@...le.cc, robert.marko@...tura.hr
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 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.

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
> 
> 

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