drm/exynos: add runtime pm feature for fimd

This adds runtime PM feature for fimd. The runtime PM functions control
clocks for fimd and prevent to access the register of fimd for vblank
when clock is turned off by suspend of runtime PM.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
+#include <linux/pm_runtime.h>
 
 #include <drm/exynos_drm.h>
 #include <plat/regs-fb-v4.h>
@@ -85,6 +86,7 @@ struct fimd_context {
 	unsigned long			irq_flags;
 	u32				vidcon0;
 	u32				vidcon1;
+	bool				suspended;
 
 	struct fb_videomode		*timing;
 };
@@ -137,7 +139,19 @@ static void fimd_dpms(struct device *subdrv_dev, int mode)
 {
 	DRM_DEBUG_KMS("%s, %d\n", __FILE__, mode);
 
-	/* TODO */
+	switch (mode) {
+	case DRM_MODE_DPMS_ON:
+		pm_runtime_get_sync(subdrv_dev);
+		break;
+	case DRM_MODE_DPMS_STANDBY:
+	case DRM_MODE_DPMS_SUSPEND:
+	case DRM_MODE_DPMS_OFF:
+		pm_runtime_put_sync(subdrv_dev);
+		break;
+	default:
+		DRM_DEBUG_KMS("unspecified mode %d\n", mode);
+		break;
+	}
 }
 
 static void fimd_apply(struct device *subdrv_dev)
@@ -210,6 +224,9 @@ static int fimd_enable_vblank(struct device *dev)
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
+	if (ctx->suspended)
+		return -EPERM;
+
 	if (!test_and_set_bit(0, &ctx->irq_flags)) {
 		val = readl(ctx->regs + VIDINTCON0);
 
@@ -234,6 +251,9 @@ static void fimd_disable_vblank(struct device *dev)
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
+	if (ctx->suspended)
+		return;
+
 	if (test_and_clear_bit(0, &ctx->irq_flags)) {
 		val = readl(ctx->regs + VIDINTCON0);
 
@@ -760,6 +780,10 @@ static int __devinit fimd_probe(struct platform_device *pdev)
 		goto err_req_irq;
 	}
 
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+
 	for (win = 0; win < WINDOWS_NR; win++)
 		fimd_clear_win(ctx, win);
 
@@ -812,14 +836,25 @@ err_clk_get:
 
 static int __devexit fimd_remove(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct fimd_context *ctx = platform_get_drvdata(pdev);
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
 	exynos_drm_subdrv_unregister(&ctx->subdrv);
 
+	if (ctx->suspended)
+		goto out;
+
 	clk_disable(ctx->lcd_clk);
 	clk_disable(ctx->bus_clk);
+
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_sync(dev);
+
+out:
+	pm_runtime_disable(dev);
+
 	clk_put(ctx->lcd_clk);
 	clk_put(ctx->bus_clk);
 
@@ -833,12 +868,53 @@ static int __devexit fimd_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_RUNTIME
+static int fimd_runtime_suspend(struct device *dev)
+{
+	struct fimd_context *ctx = get_fimd_context(dev);
+
+	DRM_DEBUG_KMS("%s\n", __FILE__);
+
+	clk_disable(ctx->lcd_clk);
+	clk_disable(ctx->bus_clk);
+
+	ctx->suspended = true;
+	return 0;
+}
+
+static int fimd_runtime_resume(struct device *dev)
+{
+	struct fimd_context *ctx = get_fimd_context(dev);
+	int ret;
+
+	DRM_DEBUG_KMS("%s\n", __FILE__);
+
+	ret = clk_enable(ctx->bus_clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(ctx->lcd_clk);
+	if  (ret < 0) {
+		clk_disable(ctx->bus_clk);
+		return ret;
+	}
+
+	ctx->suspended = false;
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops fimd_pm_ops = {
+	SET_RUNTIME_PM_OPS(fimd_runtime_suspend, fimd_runtime_resume, NULL)
+};
+
 static struct platform_driver fimd_driver = {
 	.probe		= fimd_probe,
 	.remove		= __devexit_p(fimd_remove),
 	.driver		= {
 		.name	= "exynos4-fb",
 		.owner	= THIS_MODULE,
+		.pm	= &fimd_pm_ops,
 	},
 };