memory: tegra20-emc: Factor out clk initialization

Factor out clk initialization and make it resource-managed. This makes
easier to follow code and will help to make further changes cleaner.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201111011456.7875-4-digetx@gmail.comSigned-off-by: Krzysztof Kozlowski <krzk@kernel.org>

drivers/memory/tegra/tegra20-emc.c

@@ -960,6 +960,49 @@ static int tegra_emc_opp_table_init(struct tegra_emc *emc)
 	return err;
 }
 
+static void devm_tegra_emc_unset_callback(void *data)
+{
+	tegra20_clk_set_emc_round_callback(NULL, NULL);
+}
+
+static void devm_tegra_emc_unreg_clk_notifier(void *data)
+{
+	struct tegra_emc *emc = data;
+
+	clk_notifier_unregister(emc->clk, &emc->clk_nb);
+}
+
+static int tegra_emc_init_clk(struct tegra_emc *emc)
+{
+	int err;
+
+	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
+
+	err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback,
+				       NULL);
+	if (err)
+		return err;
+
+	emc->clk = devm_clk_get(emc->dev, NULL);
+	if (IS_ERR(emc->clk)) {
+		dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk);
+		return PTR_ERR(emc->clk);
+	}
+
+	err = clk_notifier_register(emc->clk, &emc->clk_nb);
+	if (err) {
+		dev_err(emc->dev, "failed to register clk notifier: %d\n", err);
+		return err;
+	}
+
+	err = devm_add_action_or_reset(emc->dev,
+				       devm_tegra_emc_unreg_clk_notifier, emc);
+	if (err)
+		return err;
+
+	return 0;
+}
+
 static int tegra_emc_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
@@ -1003,25 +1046,13 @@ static int tegra_emc_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
-
-	emc->clk = devm_clk_get(&pdev->dev, "emc");
-	if (IS_ERR(emc->clk)) {
-		err = PTR_ERR(emc->clk);
-		dev_err(&pdev->dev, "failed to get emc clock: %d\n", err);
-		goto unset_cb;
-	}
-
-	err = clk_notifier_register(emc->clk, &emc->clk_nb);
-	if (err) {
-		dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
-			err);
-		goto unset_cb;
-	}
+	err = tegra_emc_init_clk(emc);
+	if (err)
+		return err;
 
 	err = tegra_emc_opp_table_init(emc);
 	if (err)
-		goto unreg_notifier;
+		return err;
 
 	platform_set_drvdata(pdev, emc);
 	tegra_emc_rate_requests_init(emc);
@@ -1036,13 +1067,6 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	try_module_get(THIS_MODULE);
 
 	return 0;
-
-unreg_notifier:
-	clk_notifier_unregister(emc->clk, &emc->clk_nb);
-unset_cb:
-	tegra20_clk_set_emc_round_callback(NULL, NULL);
-
-	return err;
 }
 
 static const struct of_device_id tegra_emc_of_match[] = {