[PATCH 12/12] soc: fsl: qe: Add support of IRQs in QE GPIO

[Paul Louvel <paul.louvel@bootlin.com>]

Some QE GPIO pins have an associated interrupt line in the QE PIC to
signal state changes on the pin.

Because the GPIO controller does not perform any interrupt handling
itself, a nexus node (interrupt-map) is used to map each GPIO line
supporting IRQ to the parent QE PIC interrupt domain.

Add the to_irq() method in the corresponding GPIO controller driver,
that uses the nexus node to perform the translation.

Signed-off-by: Paul Louvel <paul.louvel@bootlin.com>
---
 drivers/soc/fsl/qe/gpio.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/fsl/qe/gpio.c b/drivers/soc/fsl/qe/gpio.c
index 66828f2a3577..f8919642f40d 100644
--- a/drivers/soc/fsl/qe/gpio.c
+++ b/drivers/soc/fsl/qe/gpio.c
@@ -16,6 +16,7 @@
 #include <linux/gpio/driver.h>
 #include <linux/slab.h>
 #include <linux/export.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 
 #include <soc/fsl/qe/qe.h>
@@ -23,6 +24,7 @@
 #define PIN_MASK(gpio) (1UL << (QE_PIO_PINS - 1 - (gpio)))
 
 struct qe_gpio_chip {
+	struct device_node *np;
 	struct gpio_chip gc;
 	void __iomem *regs;
 	spinlock_t lock;
@@ -135,6 +137,29 @@ static int qe_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 	return 0;
 }
 
+static int qe_gpio_to_irq(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct qe_gpio_chip *qe_gc = gpiochip_get_data(gc);
+	struct of_phandle_args oirq;
+	struct irq_domain *domain;
+	int ret;
+
+	oirq.np = qe_gc->np;
+	oirq.args_count = 2;
+	oirq.args[0] = gpio;
+	oirq.args[1] = 0;
+
+	ret = of_irq_parse_raw(NULL, &oirq);
+	if (ret)
+		return ret;
+
+	domain = irq_find_host(oirq.np);
+	if (!domain)
+		return -EPROBE_DEFER;
+
+	return irq_create_of_mapping(&oirq);
+}
+
 struct qe_pin {
 	/*
 	 * The qe_gpio_chip name is unfortunate, we should change that to
@@ -299,7 +324,7 @@ static int qe_gpio_probe(struct platform_device *ofdev)
 	qe_gc = devm_kzalloc(dev, sizeof(*qe_gc), GFP_KERNEL);
 	if (!qe_gc)
 		return -ENOMEM;
-
+	qe_gc->np = np;
 	spin_lock_init(&qe_gc->lock);
 
 	gc = &qe_gc->gc;
@@ -311,6 +336,7 @@ static int qe_gpio_probe(struct platform_device *ofdev)
 	gc->get = qe_gpio_get;
 	gc->set = qe_gpio_set;
 	gc->set_multiple = qe_gpio_set_multiple;
+	gc->to_irq = qe_gpio_to_irq;
 	gc->parent = dev;
 	gc->owner = THIS_MODULE;
 

-- 
2.55.0