drm/fsl-dcu: enable pixel clock when enabling CRTC

The pixel clock should not be on if the CRTC is not in use, hence
move clock enable/disable calls into CRTC callbacks.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Tested-By: Meng Yi <meng.yi@nxp.com>

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c

@@ -51,6 +51,7 @@ static void fsl_dcu_drm_disable_crtc(struct drm_crtc *crtc)
 			   DCU_MODE_DCU_MODE(DCU_MODE_OFF));
 	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
 		     DCU_UPDATE_MODE_READREG);
+	clk_disable_unprepare(fsl_dev->pix_clk);
 }
 
 static void fsl_dcu_drm_crtc_enable(struct drm_crtc *crtc)
@@ -58,6 +59,7 @@ static void fsl_dcu_drm_crtc_enable(struct drm_crtc *crtc)
 	struct drm_device *dev = crtc->dev;
 	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
 
+	clk_prepare_enable(fsl_dev->pix_clk);
 	regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
 			   DCU_MODE_DCU_MODE_MASK,
 			   DCU_MODE_DCU_MODE(DCU_MODE_NORMAL));

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c

@@ -267,12 +267,6 @@ static int fsl_dcu_drm_pm_resume(struct device *dev)
 		return ret;
 	}
 
-	ret = clk_prepare_enable(fsl_dev->pix_clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to enable pix clk\n");
-		goto disable_dcu_clk;
-	}
-
 	if (fsl_dev->tcon)
 		fsl_tcon_bypass_enable(fsl_dev->tcon);
 	fsl_dcu_drm_init_planes(fsl_dev->drm);
@@ -286,10 +280,6 @@ static int fsl_dcu_drm_pm_resume(struct device *dev)
 	enable_irq(fsl_dev->irq);
 
 	return 0;
-
-disable_dcu_clk:
-	clk_disable_unprepare(fsl_dev->clk);
-	return ret;
 }
 #endif
 
@@ -403,18 +393,12 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 		goto disable_clk;
 	}
 
-	ret = clk_prepare_enable(fsl_dev->pix_clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to enable pix clk\n");
-		goto unregister_pix_clk;
-	}
-
 	fsl_dev->tcon = fsl_tcon_init(dev);
 
 	drm = drm_dev_alloc(driver, dev);
 	if (IS_ERR(drm)) {
 		ret = PTR_ERR(drm);
-		goto disable_pix_clk;
+		goto unregister_pix_clk;
 	}
 
 	fsl_dev->dev = dev;
@@ -435,8 +419,6 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 
 unref:
 	drm_dev_unref(drm);
-disable_pix_clk:
-	clk_disable_unprepare(fsl_dev->pix_clk);
 unregister_pix_clk:
 	clk_unregister(fsl_dev->pix_clk);
 disable_clk:
@@ -449,7 +431,6 @@ static int fsl_dcu_drm_remove(struct platform_device *pdev)
 	struct fsl_dcu_drm_device *fsl_dev = platform_get_drvdata(pdev);
 
 	clk_disable_unprepare(fsl_dev->clk);
-	clk_disable_unprepare(fsl_dev->pix_clk);
 	clk_unregister(fsl_dev->pix_clk);
 	drm_put_dev(fsl_dev->drm);