gpio: rcar: Add minimal runtime PM support

This is just enough to automatically enable the functional clock, if
present. Clock management during suspend/resume is still to be added.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: linux-gpio@vger.kernel.org
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-rcar.c

@@ -26,6 +26,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_data/gpio-rcar.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 
@@ -377,6 +378,9 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, p);
 
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+
 	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 
@@ -460,6 +464,8 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 err1:
 	irq_domain_remove(p->irq_domain);
 err0:
+	pm_runtime_put(dev);
+	pm_runtime_disable(dev);
 	return ret;
 }
 
@@ -473,6 +479,8 @@ static int gpio_rcar_remove(struct platform_device *pdev)
 		return ret;
 
 	irq_domain_remove(p->irq_domain);
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
 	return 0;
 }