[PATCH v4] gpiolib: support parsing gpio three-cell interrupts scheme

[Yixun Lan]

gpio irq which using three-cell scheme should always call
instance_match() function to find the correct irqdomain.

The select() function will be called with !DOMAIN_BUS_ANY,
so for specific gpio irq driver, it need to set bus token
explicitly, something like:
  irq_domain_update_bus_token(girq->domain, DOMAIN_BUS_WIRED);

Signed-off-by: Yixun Lan <dlan at gentoo.org>
---
In this patch [1], the GPIO controller add support for describing
hardware with a three-cell scheme:

    gpios = <&gpio instance offset flags>;

It also result describing interrupts in three-cell as this in DT:

    node {
            interrupt-parent = <&gpio>;
            interrupts = <instance hwirq irqflag>;
    }

This series try to extend describing interrupts with three-cell scheme.

The first patch will add capability for parsing irq number and flag
from last two cells which eventually will support the three-cells
interrupt, the second patch support finding irqdomain according to
interrupt instance index.

Link: https://lore.kernel.org/all/20250225-gpio-ranges-fourcell-v3-0-860382ba4713@linaro.org [1]
---
Changes in v4:
- rebase patch [2/2] to gpio's for-next branch, no changes
- drop [1/2] of patch v3 which merged into irq tree
- Link to v3: https://lore.kernel.org/r/20250326-04-gpio-irq-threecell-v3-0-aab006ab0e00@gentoo.org

Changes in v3:
- explicitly introduce *_twothreecell() to support 3 cell interrupt
- Link to v2: https://lore.kernel.org/r/20250302-04-gpio-irq-threecell-v2-0-34f13ad37ea4@gentoo.org

Changes in v2:
- introduce generic irq_domain_translate_cells(), other inline cells function 
- hide the OF-specific things into gpiolib-of.c|h
- Link to v1: https://lore.kernel.org/r/20250227-04-gpio-irq-threecell-v1-0-4ae4d91baadc@gentoo.org
---
 drivers/gpio/gpiolib-of.c |  8 ++++++++
 drivers/gpio/gpiolib-of.h |  6 ++++++
 drivers/gpio/gpiolib.c    | 22 ++++++++++++++++++----
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index f29143c71e9db61a6ad6d45d64e88a3f3f2d4fa7..3651c4178b81a1346809ec43b91a532e9f48af2b 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -1285,3 +1285,11 @@ void of_gpiochip_remove(struct gpio_chip *chip)
 {
 	of_node_put(dev_of_node(&chip->gpiodev->dev));
 }
+
+bool of_gpiochip_instance_match(struct gpio_chip *gc, unsigned int index)
+{
+	if (gc->of_node_instance_match)
+		return gc->of_node_instance_match(gc, index);
+
+	return false;
+}
diff --git a/drivers/gpio/gpiolib-of.h b/drivers/gpio/gpiolib-of.h
index 16d6ac8cb156c02232ea868b755bbdc46c78e3c7..3eebfac290c571e3b90e4437295db8eaacb021a3 100644
--- a/drivers/gpio/gpiolib-of.h
+++ b/drivers/gpio/gpiolib-of.h
@@ -22,6 +22,7 @@ struct gpio_desc *of_find_gpio(struct device_node *np,
 			       unsigned long *lookupflags);
 int of_gpiochip_add(struct gpio_chip *gc);
 void of_gpiochip_remove(struct gpio_chip *gc);
+bool of_gpiochip_instance_match(struct gpio_chip *gc, unsigned int index);
 int of_gpio_count(const struct fwnode_handle *fwnode, const char *con_id);
 #else
 static inline struct gpio_desc *of_find_gpio(struct device_node *np,
@@ -33,6 +34,11 @@ static inline struct gpio_desc *of_find_gpio(struct device_node *np,
 }
 static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; }
 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
+static inline bool of_gpiochip_instance_match(struct gpio_chip *gc,
+					      unsigned int index)
+{
+	return false;
+}
 static inline int of_gpio_count(const struct fwnode_handle *fwnode,
 				const char *con_id)
 {
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 8252a671d7208105a315bdc914acb092d5f95e79..ed8397a88dea1d92c3d4cb3cc9a6b30be29d31f6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1507,9 +1507,8 @@ static int gpiochip_hierarchy_irq_domain_translate(struct irq_domain *d,
 						   unsigned int *type)
 {
 	/* We support standard DT translation */
-	if (is_of_node(fwspec->fwnode) && fwspec->param_count == 2) {
-		return irq_domain_translate_twocell(d, fwspec, hwirq, type);
-	}
+	if (is_of_node(fwspec->fwnode))
+		return irq_domain_translate_twothreecell(d, fwspec, hwirq, type);
 
 	/* This is for board files and others not using DT */
 	if (is_fwnode_irqchip(fwspec->fwnode)) {
@@ -1811,11 +1810,26 @@ static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
 	irq_set_chip_data(irq, NULL);
 }
 
+static int gpiochip_irq_select(struct irq_domain *d, struct irq_fwspec *fwspec,
+			       enum irq_domain_bus_token bus_token)
+{
+	struct fwnode_handle *fwnode = fwspec->fwnode;
+	struct gpio_chip *gc = d->host_data;
+	unsigned int index = fwspec->param[0];
+
+	if (fwspec->param_count == 3 && is_of_node(fwnode))
+		return of_gpiochip_instance_match(gc, index);
+
+	/* Fallback for twocells */
+	return (fwnode && (d->fwnode == fwnode) && (d->bus_token == bus_token));
+}
+
 static const struct irq_domain_ops gpiochip_domain_ops = {
 	.map	= gpiochip_irq_map,
 	.unmap	= gpiochip_irq_unmap,
+	.select	= gpiochip_irq_select,
 	/* Virtually all GPIO irqchips are twocell:ed */
-	.xlate	= irq_domain_xlate_twocell,
+	.xlate	= irq_domain_xlate_twothreecell,
 };
 
 static struct irq_domain *gpiochip_simple_create_domain(struct gpio_chip *gc)

---
base-commit: 9ed74dfa0822ba58eacaec61fb16bd4feb34a5a6
change-id: 20250227-04-gpio-irq-threecell-66e1e073c806

Best regards,
-- 
Yixun Lan