drm/etnaviv: Don't ignore errors on getting clocks

There might be good reasons why the getting a clock failed. To treat the
clocks as optional we're specifically only interested in ignoring -ENOENT,
and devm_clk_get_optional() does just that.

Note that this preserves the original behavior of all clocks being
optional. The binding document mandates the "bus" clock while the dove
machine only specifies "core".
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

@@ -1786,26 +1786,26 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 	}
 
 	/* Get Clocks: */
-	gpu->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	gpu->clk_reg = devm_clk_get_optional(&pdev->dev, "reg");
 	DBG("clk_reg: %p", gpu->clk_reg);
 	if (IS_ERR(gpu->clk_reg))
-		gpu->clk_reg = NULL;
+		return PTR_ERR(gpu->clk_reg);
 
-	gpu->clk_bus = devm_clk_get(&pdev->dev, "bus");
+	gpu->clk_bus = devm_clk_get_optional(&pdev->dev, "bus");
 	DBG("clk_bus: %p", gpu->clk_bus);
 	if (IS_ERR(gpu->clk_bus))
-		gpu->clk_bus = NULL;
+		return PTR_ERR(gpu->clk_bus);
 
-	gpu->clk_core = devm_clk_get(&pdev->dev, "core");
+	gpu->clk_core = devm_clk_get_optional(&pdev->dev, "core");
 	DBG("clk_core: %p", gpu->clk_core);
 	if (IS_ERR(gpu->clk_core))
-		gpu->clk_core = NULL;
+		return PTR_ERR(gpu->clk_core);
 	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
 
-	gpu->clk_shader = devm_clk_get(&pdev->dev, "shader");
+	gpu->clk_shader = devm_clk_get_optional(&pdev->dev, "shader");
 	DBG("clk_shader: %p", gpu->clk_shader);
 	if (IS_ERR(gpu->clk_shader))
-		gpu->clk_shader = NULL;
+		return PTR_ERR(gpu->clk_shader);
 	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
 
 	/* TODO: figure out max mapped size */