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

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Message-ID: <Y3DlsTAQMi6kKObJ@smile.fi.intel.com>
Date:   Sun, 13 Nov 2022 14:40:17 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     William Breathitt Gray <william.gray@...aro.org>
Cc:     linus.walleij@...aro.org, brgl@...ev.pl,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        michael@...le.cc, broonie@...nel.org
Subject: Re: [PATCH v2 1/4] gpio: regmap: Always set gpio_chip get_direction

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>

> 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