linux-kernel - Re: [PATCH v1 1/1] pinctrl: core: Show pin numbers for the controllers with base = 0

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Date:   Tue, 20 Apr 2021 00:32:18 -0700
From:   Drew Fustini <drew@...gleboard.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] pinctrl: core: Show pin numbers for the
 controllers with base = 0

On Thu, Apr 15, 2021 at 04:03:56PM +0300, Andy Shevchenko wrote:
> The commit f1b206cf7c57 ("pinctrl: core: print gpio in pins debugfs file")
> enabled GPIO pin number and label in debugfs for pin controller. However,
> it limited that feature to the chips where base is positive number. This,
> in particular, excluded chips where base is 0 for the historical or backward
> compatibility reasons. Refactor the code to include the latter as well.
> 
> Fixes: f1b206cf7c57 ("pinctrl: core: print gpio in pins debugfs file")
> Cc: Drew Fustini <drew@...gleboard.org>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/pinctrl/core.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
> index df7f5f049139..8ef24af88b75 100644
> --- a/drivers/pinctrl/core.c
> +++ b/drivers/pinctrl/core.c
> @@ -1604,8 +1604,8 @@ static int pinctrl_pins_show(struct seq_file *s, void *what)
>  	unsigned i, pin;
>  #ifdef CONFIG_GPIOLIB
>  	struct pinctrl_gpio_range *range;
> -	unsigned int gpio_num;
>  	struct gpio_chip *chip;
> +	int gpio_num;
>  #endif
>  
>  	seq_printf(s, "registered pins: %d\n", pctldev->desc->npins);
> @@ -1625,7 +1625,7 @@ static int pinctrl_pins_show(struct seq_file *s, void *what)
>  		seq_printf(s, "pin %d (%s) ", pin, desc->name);
>  
>  #ifdef CONFIG_GPIOLIB
> -		gpio_num = 0;
> +		gpio_num = -1;
>  		list_for_each_entry(range, &pctldev->gpio_ranges, node) {
>  			if ((pin >= range->pin_base) &&
>  			    (pin < (range->pin_base + range->npins))) {
> @@ -1633,10 +1633,12 @@ static int pinctrl_pins_show(struct seq_file *s, void *what)
>  				break;
>  			}
>  		}
> -		chip = gpio_to_chip(gpio_num);
> -		if (chip && chip->gpiodev && chip->gpiodev->base)
> -			seq_printf(s, "%u:%s ", gpio_num -
> -				chip->gpiodev->base, chip->label);
> +		if (gpio_num >= 0)
> +			chip = gpio_to_chip(gpio_num);
> +		else
> +			chip = NULL;
> +		if (chip)
> +			seq_printf(s, "%u:%s ", gpio_num - chip->gpiodev->base, chip->label);
>  		else
>  			seq_puts(s, "0:? ");
>  #endif
> -- 
> 2.30.2

Thank you, this makes sense to me. I had failed to consider what would
happen when chip->gpiodev->base == 0. I have tested on the BeagleBone
(AM3358) and the output works as expected. 

/sys/kernel/debug/pinctrl/44e10800.pinmux-pinctrl-single# more pins
registered pins: 142
pin 0 (PIN0) 0:gpio-0-31 44e10800 00000027 pinctrl-single
pin 1 (PIN1) 1:gpio-0-31 44e10804 00000027 pinctrl-single
pin 2 (PIN2) 2:gpio-0-31 44e10808 00000027 pinctrl-single
pin 3 (PIN3) 3:gpio-0-31 44e1080c 00000027 pinctrl-single
pin 4 (PIN4) 4:gpio-0-31 44e10810 00000027 pinctrl-single
pin 5 (PIN5) 5:gpio-0-31 44e10814 00000027 pinctrl-single
pin 6 (PIN6) 6:gpio-0-31 44e10818 00000027 pinctrl-single
pin 7 (PIN7) 7:gpio-0-31 44e1081c 00000027 pinctrl-single
pin 8 (PIN8) 22:gpio-96-127 44e10820 00000027 pinctrl-single
pin 9 (PIN9) 23:gpio-96-127 44e10824 00000037 pinctrl-single
pin 10 (PIN10) 26:gpio-96-127 44e10828 00000037 pinctrl-single
pin 11 (PIN11) 27:gpio-96-127 44e1082c 00000037 pinctrl-single
pin 12 (PIN12) 12:gpio-0-31 44e10830 00000037 pinctrl-single
pin 13 (PIN13) 13:gpio-0-31 44e10834 00000037 pinctrl-single
pin 14 (PIN14) 14:gpio-0-31 44e10838 00000037 pinctrl-single
pin 15 (PIN15) 15:gpio-0-31 44e1083c 00000037 pinctrl-single
pin 16 (PIN16) 16:gpio-0-31 44e10840 00000027 pinctrl-single
<snip>

Tested-by: Drew Fustini <drew@...gleboard.org>
Reviewed-by: Drew Fustini <drew@...gleboard.org>