drm/rockchip: lvds: move pclk preparation in with clk_get

The LVDS block needs a separate pclk only on some socs, so currently
requests and prepares it in the soc-specific probe function, but common
code is required to unprepare it in the error path or on driver remove.

While this works because clk_unprepare just does nothing if clk is NULL,
this mismatch of who is responsible still is not very nice.
The clock-framework already has a helper for clk-get-and-prepare even
with devres support in devm_clk_get_prepared().

This will get and prepare the clock and also unprepare it on driver
removal, saving the driver from having to handle it "manually".

Reviewed-by: Quentin Schulz <[email protected]>
Reviewed-by: Andy Yan <[email protected]>
Signed-off-by: Heiko Stuebner <[email protected]>
Signed-off-by: Heiko Stuebner <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Heiko Stuebner

drivers/gpu/drm/rockchip/rockchip_lvds.c

@@ -448,15 +448,13 @@ struct drm_encoder_helper_funcs px30_lvds_encoder_helper_funcs = {
 static int rk3288_lvds_probe(struct platform_device *pdev,
 			     struct rockchip_lvds *lvds)
 {
-	int ret;
-
 	lvds->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(lvds->regs))
 		return PTR_ERR(lvds->regs);
 
-	lvds->pclk = devm_clk_get(lvds->dev, "pclk_lvds");
+	lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk_lvds");
 	if (IS_ERR(lvds->pclk)) {
-		DRM_DEV_ERROR(lvds->dev, "could not get pclk_lvds\n");
+		DRM_DEV_ERROR(lvds->dev, "could not get or prepare pclk_lvds\n");
 		return PTR_ERR(lvds->pclk);
 	}
 
@@ -480,12 +478,6 @@ static int rk3288_lvds_probe(struct platform_device *pdev,
 		}
 	}
 
-	ret = clk_prepare(lvds->pclk);
-	if (ret < 0) {
-		DRM_DEV_ERROR(lvds->dev, "failed to prepare pclk_lvds\n");
-		return ret;
-	}
-
 	return 0;
 }
 
@@ -728,20 +720,15 @@ static int rockchip_lvds_probe(struct platform_device *pdev)
 	dev_set_drvdata(dev, lvds);
 
 	ret = component_add(&pdev->dev, &rockchip_lvds_component_ops);
-	if (ret < 0) {
+	if (ret < 0)
 		DRM_DEV_ERROR(dev, "failed to add component\n");
-		clk_unprepare(lvds->pclk);
-	}
 
 	return ret;
 }
 
 static void rockchip_lvds_remove(struct platform_device *pdev)
 {
-	struct rockchip_lvds *lvds = platform_get_drvdata(pdev);
-
 	component_del(&pdev->dev, &rockchip_lvds_component_ops);
-	clk_unprepare(lvds->pclk);
 }
 
 struct platform_driver rockchip_lvds_driver = {