drm/msm/mdp4: add mdp axi clk

Downstream kernel holds this clk via a fake-parent relationship.
Upstream clock framework requires that we hold it explicitly.
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c

@@ -176,6 +176,8 @@ int mdp4_disable(struct mdp4_kms *mdp4_kms)
 	if (mdp4_kms->pclk)
 		clk_disable_unprepare(mdp4_kms->pclk);
 	clk_disable_unprepare(mdp4_kms->lut_clk);
+	if (mdp4_kms->axi_clk)
+		clk_disable_unprepare(mdp4_kms->axi_clk);
 
 	return 0;
 }
@@ -188,6 +190,8 @@ int mdp4_enable(struct mdp4_kms *mdp4_kms)
 	if (mdp4_kms->pclk)
 		clk_prepare_enable(mdp4_kms->pclk);
 	clk_prepare_enable(mdp4_kms->lut_clk);
+	if (mdp4_kms->axi_clk)
+		clk_prepare_enable(mdp4_kms->axi_clk);
 
 	return 0;
 }
@@ -335,6 +339,13 @@ struct msm_kms *mdp4_kms_init(struct drm_device *dev)
 		goto fail;
 	}
 
+	mdp4_kms->axi_clk = devm_clk_get(&pdev->dev, "mdp_axi_clk");
+	if (IS_ERR(mdp4_kms->axi_clk)) {
+		dev_err(dev->dev, "failed to get axi_clk\n");
+		ret = PTR_ERR(mdp4_kms->axi_clk);
+		goto fail;
+	}
+
 	clk_set_rate(mdp4_kms->clk, config->max_clk);
 	clk_set_rate(mdp4_kms->lut_clk, config->max_clk);
 

drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.h

@@ -42,6 +42,7 @@ struct mdp4_kms {
 	struct clk *clk;
 	struct clk *pclk;
 	struct clk *lut_clk;
+	struct clk *axi_clk;
 
 	struct mdp_irq error_handler;