gpio: rcar: Prevent module clock disable when wake-up is enabled

When the GPIO module is needed for wake-up, it's module clock must not
be disabled. Hence implement irq_chip.irq_set_wake(), which
increments/decrements the clock's enable_count when needed, and forwards
the wake-up state to the upstream interrupt controller.

This fixes wake-up from s2ram using gpio-keys when using a PM Domain to
manage the module clock.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-rcar.c

@@ -14,6 +14,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/gpio.h>
 #include <linux/init.h>
@@ -37,6 +38,8 @@ struct gpio_rcar_priv {
 	struct platform_device *pdev;
 	struct gpio_chip gpio_chip;
 	struct irq_chip irq_chip;
+	unsigned int irq_parent;
+	struct clk *clk;
 };
 
 #define IOINTSEL 0x00	/* General IO/Interrupt Switching Register */
@@ -169,6 +172,25 @@ static int gpio_rcar_irq_set_type(struct irq_data *d, unsigned int type)
 	return 0;
 }
 
+static int gpio_rcar_irq_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct gpio_rcar_priv *p = container_of(gc, struct gpio_rcar_priv,
+						gpio_chip);
+
+	irq_set_irq_wake(p->irq_parent, on);
+
+	if (!p->clk)
+		return 0;
+
+	if (on)
+		clk_enable(p->clk);
+	else
+		clk_disable(p->clk);
+
+	return 0;
+}
+
 static irqreturn_t gpio_rcar_irq_handler(int irq, void *dev_id)
 {
 	struct gpio_rcar_priv *p = dev_id;
@@ -367,6 +389,12 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, p);
 
+	p->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(p->clk)) {
+		dev_warn(dev, "unable to get clock\n");
+		p->clk = NULL;
+	}
+
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 
@@ -404,8 +432,8 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 	irq_chip->irq_mask = gpio_rcar_irq_disable;
 	irq_chip->irq_unmask = gpio_rcar_irq_enable;
 	irq_chip->irq_set_type = gpio_rcar_irq_set_type;
-	irq_chip->flags	= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_SET_TYPE_MASKED
-			 | IRQCHIP_MASK_ON_SUSPEND;
+	irq_chip->irq_set_wake = gpio_rcar_irq_set_wake;
+	irq_chip->flags	= IRQCHIP_SET_TYPE_MASKED | IRQCHIP_MASK_ON_SUSPEND;
 
 	ret = gpiochip_add(gpio_chip);
 	if (ret) {
@@ -420,6 +448,7 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 		goto err1;
 	}
 
+	p->irq_parent = irq->start;
 	if (devm_request_irq(dev, irq->start, gpio_rcar_irq_handler,
 			     IRQF_SHARED, name, p)) {
 		dev_err(dev, "failed to request IRQ\n");