mfd: exynos-lpass: Add runtime PM support

Convert exisitng lpass-suspend/resume callbacks into runtime PM callbacks.
This way Exynos LPASS driver will be ready for use with power domains
enabled. LPASS will be runtime resumed/suspended as a result of its child
devices runtime PM transitions.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/exynos-lpass.c

@@ -22,6 +22,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/soc/samsung/exynos-regs-pmu.h>
 #include <linux/types.h>
@@ -133,6 +134,8 @@ static int exynos_lpass_probe(struct platform_device *pdev)
 	}
 
 	platform_set_drvdata(pdev, lpass);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
 	exynos_lpass_enable(lpass);
 
 	return of_platform_populate(dev->of_node, NULL, NULL, dev);
@@ -143,6 +146,9 @@ static int exynos_lpass_remove(struct platform_device *pdev)
 	struct exynos_lpass *lpass = platform_get_drvdata(pdev);
 
 	exynos_lpass_disable(lpass);
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		exynos_lpass_disable(lpass);
 	regmap_exit(lpass->top);
 
 	return 0;
@@ -166,8 +172,11 @@ static int __maybe_unused exynos_lpass_resume(struct device *dev)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(lpass_pm_ops, exynos_lpass_suspend,
-					exynos_lpass_resume);
+static const struct dev_pm_ops lpass_pm_ops = {
+	SET_RUNTIME_PM_OPS(exynos_lpass_suspend, exynos_lpass_resume, NULL)
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				     pm_runtime_force_resume)
+};
 
 static const struct of_device_id exynos_lpass_of_match[] = {
 	{ .compatible = "samsung,exynos5433-lpass" },