gpiolib: add support to register sparse pin range

Add support to register for GPIO<->pin mapping using a list of non
consecutive pins. The core already supports sparse pin range (pins member
of struct pinctrl_gpio_range), but it was not possible to register one. If
pins is not NULL the core uses it, otherwise it assumes that a consecutive
pin range was registered and it uses pin_base.

The function gpiochip_add_pin_range() which allocates and fills the struct
pinctrl_gpio_range was renamed to gpiochip_add_pin_range_with_pins() and
the pins parameter was added.

Two new functions were added, gpiochip_add_pin_range() and
gpiochip_add_sparse_pin_range() to register a consecutive or sparse pins
range. Both use gpiochip_add_pin_range_with_pins().

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
Link: https://lore.kernel.org/r/20250811-aaeon-up-board-pinctrl-support-v9-1-29f0cbbdfb30@bootlin.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

1 files changed, 20 insertions, 9 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 0d2b470a252e..98d2fa602490 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2349,11 +2349,13 @@ int gpiochip_add_pingroup_range(struct gpio_chip *gc,
 EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
 
 /**
- * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
+ * gpiochip_add_pin_range_with_pins() - add a range for GPIO <-> pin mapping
  * @gc: the gpiochip to add the range for
  * @pinctl_name: the dev_name() of the pin controller to map to
  * @gpio_offset: the start offset in the current gpio_chip number space
  * @pin_offset: the start offset in the pin controller number space
+ * @pins: the list of non consecutive pins to accumulate in this range (if not
+ *	NULL, pin_offset is ignored by pinctrl core)
  * @npins: the number of pins from the offset of each pin space (GPIO and
  *	pin controller) to accumulate in this range
  *
@@ -2365,9 +2367,12 @@ EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);
  * Returns:
  * 0 on success, or a negative errno on failure.
  */
-int gpiochip_add_pin_range(struct gpio_chip *gc, const char *pinctl_name,
-			   unsigned int gpio_offset, unsigned int pin_offset,
-			   unsigned int npins)
+int gpiochip_add_pin_range_with_pins(struct gpio_chip *gc,
+				     const char *pinctl_name,
+				     unsigned int gpio_offset,
+				     unsigned int pin_offset,
+				     unsigned int const *pins,
+				     unsigned int npins)
 {
 	struct gpio_pin_range *pin_range;
 	struct gpio_device *gdev = gc->gpiodev;
@@ -2385,6 +2390,7 @@ int gpiochip_add_pin_range(struct gpio_chip *gc, const char *pinctl_name,
 	pin_range->range.name = gc->label;
 	pin_range->range.base = gdev->base + gpio_offset;
 	pin_range->range.pin_base = pin_offset;
+	pin_range->range.pins = pins;
 	pin_range->range.npins = npins;
 	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
 			&pin_range->range);
@@ -2394,16 +2400,21 @@ int gpiochip_add_pin_range(struct gpio_chip *gc, const char *pinctl_name,
 		kfree(pin_range);
 		return ret;
 	}
-	chip_dbg(gc, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
-		 gpio_offset, gpio_offset + npins - 1,
-		 pinctl_name,
-		 pin_offset, pin_offset + npins - 1);
+	if (pin_range->range.pins)
+		chip_dbg(gc, "created GPIO range %d->%d ==> %s %d sparse PIN range { %d, ... }",
+			 gpio_offset, gpio_offset + npins - 1,
+			 pinctl_name, npins, pins[0]);
+	else
+		chip_dbg(gc, "created GPIO range %d->%d ==> %s PIN %d->%d\n",
+			 gpio_offset, gpio_offset + npins - 1,
+			 pinctl_name,
+			 pin_offset, pin_offset + npins - 1);
 
 	list_add_tail(&pin_range->node, &gdev->pin_ranges);
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
+EXPORT_SYMBOL_GPL(gpiochip_add_pin_range_with_pins);
 
 /**
  * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings