PM / devfreq: exynos: Use Use devm_clk_get_enabled() helpers

The devm_clk_get_enabled() helpers:
    - call devm_clk_get()
    - call clk_prepare_enable() and register what is needed in order to
     call clk_disable_unprepare() when needed, as a managed resource.

This simplifies the code and avoids the calls to clk_disable_unprepare().

While at it, use dev_err_probe consistently, and use its return value
to return the error code.

Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Anand Moon <[email protected]>
Signed-off-by: Chanwoo Choi <[email protected]>

Author: moonlinux

drivers/devfreq/exynos-bus.c

@@ -160,7 +160,6 @@ static void exynos_bus_exit(struct device *dev)
 	platform_device_unregister(bus->icc_pdev);
 
 	dev_pm_opp_of_remove_table(dev);
-	clk_disable_unprepare(bus->clk);
 	dev_pm_opp_put_regulators(bus->opp_token);
 }
 
@@ -171,7 +170,6 @@ static void exynos_bus_passive_exit(struct device *dev)
 	platform_device_unregister(bus->icc_pdev);
 
 	dev_pm_opp_of_remove_table(dev);
-	clk_disable_unprepare(bus->clk);
 }
 
 static int exynos_bus_parent_parse_of(struct device_node *np,
@@ -247,23 +245,16 @@ static int exynos_bus_parse_of(struct device_node *np,
 	int ret;
 
 	/* Get the clock to provide each bus with source clock */
-	bus->clk = devm_clk_get(dev, "bus");
-	if (IS_ERR(bus->clk)) {
-		dev_err(dev, "failed to get bus clock\n");
-		return PTR_ERR(bus->clk);
-	}
-
-	ret = clk_prepare_enable(bus->clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to get enable clock\n");
-		return ret;
-	}
+	bus->clk = devm_clk_get_enabled(dev, "bus");
+	if (IS_ERR(bus->clk))
+		return dev_err_probe(dev, PTR_ERR(bus->clk),
+				"failed to get bus clock\n");
 
 	/* Get the freq and voltage from OPP table to scale the bus freq */
 	ret = dev_pm_opp_of_add_table(dev);
 	if (ret < 0) {
 		dev_err(dev, "failed to get OPP table\n");
-		goto err_clk;
+		return ret;
 	}
 
 	rate = clk_get_rate(bus->clk);
@@ -281,8 +272,6 @@ static int exynos_bus_parse_of(struct device_node *np,
 
 err_opp:
 	dev_pm_opp_of_remove_table(dev);
-err_clk:
-	clk_disable_unprepare(bus->clk);
 
 	return ret;
 }
@@ -453,7 +442,6 @@ static int exynos_bus_probe(struct platform_device *pdev)
 
 err:
 	dev_pm_opp_of_remove_table(dev);
-	clk_disable_unprepare(bus->clk);
 err_reg:
 	dev_pm_opp_put_regulators(bus->opp_token);