mmc: sdio: use the generic runtime PM handlers

Assign the generic runtime PM handlers for SDIO.

These handlers invoke the relevant SDIO function drivers'
handlers, if exist, otherwise they just return success
(so SDIO drivers don't have to define any runtime PM handlers
unless they need to).

Runtime PM is still disabled by default, so this patch alone
has no immediate effect.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/sdio_bus.c

@@ -14,6 +14,7 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 
 #include <linux/mmc/card.h>
 #include <linux/mmc/sdio_func.h>
@@ -154,13 +155,32 @@ static int sdio_bus_remove(struct device *dev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_RUNTIME
+
+static const struct dev_pm_ops sdio_bus_pm_ops = {
+	SET_RUNTIME_PM_OPS(
+		pm_generic_runtime_suspend,
+		pm_generic_runtime_resume,
+		pm_generic_runtime_idle
+	)
+};
+
+#define SDIO_PM_OPS_PTR	(&sdio_bus_pm_ops)
+
+#else /* !CONFIG_PM_RUNTIME */
+
+#define SDIO_PM_OPS_PTR	NULL
+
+#endif /* !CONFIG_PM_RUNTIME */
+
 static struct bus_type sdio_bus_type = {
 	.name		= "sdio",
 	.dev_attrs	= sdio_dev_attrs,
 	.match		= sdio_bus_match,
 	.uevent		= sdio_bus_uevent,
 	.probe		= sdio_bus_probe,
 	.remove		= sdio_bus_remove,
+	.pm		= SDIO_PM_OPS_PTR,
 };
 
 int sdio_register_bus(void)