iommu/exynos: add dummy driver for enabling runtime pm for mem port devices

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 01d1c62..76f423d 100644 (file)
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1319,3 +1319,37 @@ static int __init exynos_iommu_init(void)
        return ret;
 }
 arch_initcall(exynos_iommu_init);
+
+/*
+ * Dummy driver to enable runtime power management for memport
+ * devices, which required for correct Exynos SYSMMU operation.
+ * Must be registered before drivers, which will use memport nodes.
+ */
+static int __init exynos_memport_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       pm_runtime_enable(dev);
+       return 0;
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id memport_of_match[] __initconst = {
+       { .compatible   = "samsung,memport", },
+       { },
+};
+#endif
+
+static struct platform_driver exynos_memport_driver __refdata = {
+       .probe  = exynos_memport_probe,
+       .driver = {
+               .owner          = THIS_MODULE,
+               .name           = "exynos-memport",
+               .of_match_table = of_match_ptr(memport_of_match),
+       }
+};
+
+static int __init exynos_memport_init(void)
+{
+       return platform_driver_register(&exynos_memport_driver);
+}
+subsys_initcall(exynos_memport_init);