hwrng: exynos - Use devm_clk_get_enabled() to get the clock

Use devm_clk_get_enabled() helper instead of calling devm_clk_get() and
then clk_prepare_enable(). It simplifies the error handling and makes
the code more compact. Also use dev_err_probe() to handle possible
-EPROBE_DEFER errors if the clock is not available yet.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: Sam Protsenko

drivers/char/hw_random/exynos-trng.c

@@ -134,32 +134,23 @@ static int exynos_trng_probe(struct platform_device *pdev)
 		goto err_pm_get;
 	}
 
-	trng->clk = devm_clk_get(&pdev->dev, "secss");
+	trng->clk = devm_clk_get_enabled(&pdev->dev, "secss");
 	if (IS_ERR(trng->clk)) {
-		ret = PTR_ERR(trng->clk);
-		dev_err(&pdev->dev, "Could not get clock.\n");
-		goto err_clock;
-	}
-
-	ret = clk_prepare_enable(trng->clk);
-	if (ret) {
-		dev_err(&pdev->dev, "Could not enable the clk.\n");
+		ret = dev_err_probe(&pdev->dev, PTR_ERR(trng->clk),
+				    "Could not get clock\n");
 		goto err_clock;
 	}
 
 	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not register hwrng device.\n");
-		goto err_register;
+		goto err_clock;
 	}
 
 	dev_info(&pdev->dev, "Exynos True Random Number Generator.\n");
 
 	return 0;
 
-err_register:
-	clk_disable_unprepare(trng->clk);
-
 err_clock:
 	pm_runtime_put_noidle(&pdev->dev);
 
@@ -171,10 +162,6 @@ static int exynos_trng_probe(struct platform_device *pdev)
 
 static void exynos_trng_remove(struct platform_device *pdev)
 {
-	struct exynos_trng_dev *trng = platform_get_drvdata(pdev);
-
-	clk_disable_unprepare(trng->clk);
-
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }