[PATCH v2 3/7] gpiolib: Introduce ->add_pin_ranges() callback

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

When IRQ chip is being added by GPIO library, the ACPI based platform expects
GPIO <-> pin mapping ranges to be initialized in order to correctly initialize
ACPI event mechanism on affected platforms. Unfortunately this step is missed.

Introduce ->add_pin_ranges() callback to fill the above mentioned gap.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/gpio/gpiolib.c      | 12 ++++++++++++
 include/linux/gpio/driver.h |  5 +++++
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index aaf9c0a74c38..f888e46f0e93 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -390,6 +390,14 @@ static void gpiochip_free_valid_mask(struct gpio_chip *gpiochip)
 	gpiochip->valid_mask = NULL;
 }
 
+static int gpiochip_add_pin_ranges(struct gpio_chip *gc)
+{
+	if (gc->add_pin_ranges)
+		return gc->add_pin_ranges(gc);
+
+	return 0;
+}
+
 bool gpiochip_line_is_valid(const struct gpio_chip *gpiochip,
 				unsigned int offset)
 {
@@ -1407,6 +1415,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 		}
 	}
 
+	ret = gpiochip_add_pin_ranges(chip);
+	if (ret)
+		goto err_remove_of_chip;
+
 	acpi_gpiochip_add(chip);
 
 	machine_gpiochip_add(chip);
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index fd860c553ff4..424d03770b26 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -287,6 +287,9 @@ struct gpio_irq_chip {
  *	state (such as pullup/pulldown configuration).
  * @init_valid_mask: optional routine to initialize @valid_mask, to be used if
  *	not all GPIOs are valid.
+ * @add_pin_ranges: optional routine to initialize pin ranges, to be used when
+ *	requires special mapping of the pins that provides GPIO functionality.
+ *	It is called after adding GPIO chip and before adding IRQ chip.
  * @base: identifies the first GPIO number handled by this chip;
  *	or, if negative during registration, requests dynamic ID allocation.
  *	DEPRECATION: providing anything non-negative and nailing the base
@@ -377,6 +380,8 @@ struct gpio_chip {
 						   unsigned long *valid_mask,
 						   unsigned int ngpios);
 
+	int			(*add_pin_ranges)(struct gpio_chip *chip);
+
 	int			base;
 	u16			ngpio;
 	const char		*const *names;
-- 
2.24.0.rc1