[PATCH v3] pinctrl: core: print gpio in pins debugfs file

[Drew Fustini <drew@xxxxxxxxxxxxxxx>]

If there is a gpio range mapping for the pin, then print out the gpio
chip and line index for the pin in the debugfs 'pins' file with the
format: "[gpiochip-label]:line-[index] "

For example, here is a section of 'pins' the PocketBeagle (AM3358):
/sys/kernel/debug/pinctrl/44e10800.pinmux-pinctrl-single/pins

pin 25 (PIN25) gpio-32-63:line-25 44e10864 00000037 pinctrl-single 
pin 26 (PIN26) gpio-32-63:line-26 44e10868 00000037 pinctrl-single 
pin 27 (PIN27) gpio-32-63:line-27 44e1086c 00000037 pinctrl-single 
pin 28 (PIN28) NA 44e10870 00000036 pinctrl-single 
pin 29 (PIN29) NA 44e10874 00000006 pinctrl-single 
pin 30 (PIN30) gpio-32-63:line-28 44e10878 00000027 pinctrl-single 
pin 31 (PIN31) gpio-32-63:line-29 44e1087c 00000037 pinctrl-single 
pin 32 (PIN32) gpio-32-63:line-30 44e10880 00000037 pinctrl-single 
pin 33 (PIN33) gpio-32-63:line-31 44e10884 00000037 pinctrl-single 
pin 34 (PIN34) gpio-64-95:line-0 44e10888 00000037 pinctrl-single 
pin 35 (PIN35) gpio-64-95:line-1 44e1088c 00000037 pinctrl-single 

Suggested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Suggested-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Drew Fustini <drew@xxxxxxxxxxxxxxx>

v3 changes:
- gpio column is now gpiochip label and line index

v2 changes:
- print 'NA' if pin does not have a GPIO number
- change gpio_num from unsigned to unsigned int per checkpatch
---
 drivers/pinctrl/core.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 821242bb4b16..a23dc264cae7 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -27,6 +27,7 @@
 #include <linux/pinctrl/machine.h>
 
 #ifdef CONFIG_GPIOLIB
+#include "../gpio/gpiolib.h"
 #include <asm-generic/gpio.h>
 #endif
 
@@ -1601,6 +1602,9 @@ static int pinctrl_pins_show(struct seq_file *s, void *what)
 	struct pinctrl_dev *pctldev = s->private;
 	const struct pinctrl_ops *ops = pctldev->desc->pctlops;
 	unsigned i, pin;
+	struct pinctrl_gpio_range *range;
+	unsigned int gpio_num;
+	struct gpio_chip *chip;
 
 	seq_printf(s, "registered pins: %d\n", pctldev->desc->npins);
 
@@ -1618,6 +1622,23 @@ 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;
+		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, "%s:line-%u ", chip->label,
+				gpio_num - chip->gpiodev->base);
+		else
+			seq_puts(s, "NA ");
+#endif
+
 		/* Driver-specific info per pin */
 		if (ops->pin_dbg_show)
 			ops->pin_dbg_show(pctldev, s, pin);
-- 
2.25.1