pinctrl: core: Show pin numbers for the controllers with base = 0

The commit f1b206c ("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: f1b206c ("pinctrl: core: print gpio in pins debugfs file")
Cc: Drew Fustini <drew@beagleboard.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Drew Fustini <drew@beagleboard.org>
Reviewed-by: Drew Fustini <drew@beagleboard.org>
Link: https://lore.kernel.org/r/20210415130356.15885-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: andy-shev

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);
@@ -1625,18 +1625,20 @@ 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))) {
 				gpio_num = range->base + (pin - range->pin_base);
 				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