memory: tegra: Add and use devm_tegra_memory_controller_get()

Multiple Tegra drivers need to retrieve Memory Controller and there is
duplication of the retrieval code among the drivers.

Add new devm_tegra_memory_controller_get() helper to remove the code's
duplication and to fix put_device() which was missed in the duplicated
code. Make EMC drivers to use the new helper.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20201104164923.21238-29-digetx@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

drivers/memory/tegra/mc.c

@@ -42,6 +42,54 @@ static const struct of_device_id tegra_mc_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_mc_of_match);
 
+static void tegra_mc_devm_action_put_device(void *data)
+{
+	struct tegra_mc *mc = data;
+
+	put_device(mc->dev);
+}
+
+/**
+ * devm_tegra_memory_controller_get() - get Tegra Memory Controller handle
+ * @dev: device pointer for the consumer device
+ *
+ * This function will search for the Memory Controller node in a device-tree
+ * and retrieve the Memory Controller handle.
+ *
+ * Return: ERR_PTR() on error or a valid pointer to a struct tegra_mc.
+ */
+struct tegra_mc *devm_tegra_memory_controller_get(struct device *dev)
+{
+	struct platform_device *pdev;
+	struct device_node *np;
+	struct tegra_mc *mc;
+	int err;
+
+	np = of_parse_phandle(dev->of_node, "nvidia,memory-controller", 0);
+	if (!np)
+		return ERR_PTR(-ENOENT);
+
+	pdev = of_find_device_by_node(np);
+	of_node_put(np);
+	if (!pdev)
+		return ERR_PTR(-ENODEV);
+
+	mc = platform_get_drvdata(pdev);
+	if (!mc) {
+		put_device(&pdev->dev);
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	err = devm_add_action(dev, tegra_mc_devm_action_put_device, mc);
+	if (err) {
+		put_device(mc->dev);
+		return ERR_PTR(err);
+	}
+
+	return mc;
+}
+EXPORT_SYMBOL_GPL(devm_tegra_memory_controller_get);
+
 static int tegra_mc_block_dma_common(struct tegra_mc *mc,
 				     const struct tegra_mc_reset *rst)
 {

drivers/memory/tegra/tegra124-emc.c

@@ -1177,7 +1177,6 @@ static void emc_debugfs_init(struct device *dev, struct tegra_emc *emc)
 
 static int tegra_emc_probe(struct platform_device *pdev)
 {
-	struct platform_device *mc;
 	struct device_node *np;
 	struct tegra_emc *emc;
 	struct resource *res;
@@ -1195,20 +1194,9 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	if (IS_ERR(emc->regs))
 		return PTR_ERR(emc->regs);
 
-	np = of_parse_phandle(pdev->dev.of_node, "nvidia,memory-controller", 0);
-	if (!np) {
-		dev_err(&pdev->dev, "could not get memory controller\n");
-		return -ENOENT;
-	}
-
-	mc = of_find_device_by_node(np);
-	of_node_put(np);
-	if (!mc)
-		return -ENOENT;
-
-	emc->mc = platform_get_drvdata(mc);
-	if (!emc->mc)
-		return -EPROBE_DEFER;
+	emc->mc = devm_tegra_memory_controller_get(&pdev->dev);
+	if (IS_ERR(emc->mc))
+		return PTR_ERR(emc->mc);
 
 	ram_code = tegra_read_ram_code();
 

drivers/memory/tegra/tegra210-emc-core.c

@@ -1828,7 +1828,6 @@ static int tegra210_emc_probe(struct platform_device *pdev)
 {
 	struct thermal_cooling_device *cd;
 	unsigned long current_rate;
-	struct platform_device *mc;
 	struct tegra210_emc *emc;
 	struct device_node *np;
 	unsigned int i;
@@ -1846,35 +1845,19 @@ static int tegra210_emc_probe(struct platform_device *pdev)
 	spin_lock_init(&emc->lock);
 	emc->dev = &pdev->dev;
 
-	np = of_parse_phandle(pdev->dev.of_node, "nvidia,memory-controller", 0);
-	if (!np) {
-		dev_err(&pdev->dev, "could not get memory controller\n");
-		return -ENOENT;
-	}
-
-	mc = of_find_device_by_node(np);
-	of_node_put(np);
-	if (!mc)
-		return -ENOENT;
-
-	emc->mc = platform_get_drvdata(mc);
-	if (!emc->mc) {
-		put_device(&mc->dev);
-		return -EPROBE_DEFER;
-	}
+	emc->mc = devm_tegra_memory_controller_get(&pdev->dev);
+	if (IS_ERR(emc->mc))
+		return PTR_ERR(emc->mc);
 
 	emc->regs = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(emc->regs)) {
-		err = PTR_ERR(emc->regs);
-		goto put_mc;
-	}
+	if (IS_ERR(emc->regs))
+		return PTR_ERR(emc->regs);
 
 	for (i = 0; i < 2; i++) {
 		emc->channel[i] = devm_platform_ioremap_resource(pdev, 1 + i);
-		if (IS_ERR(emc->channel[i])) {
-			err = PTR_ERR(emc->channel[i]);
-			goto put_mc;
-		}
+		if (IS_ERR(emc->channel[i]))
+			return PTR_ERR(emc->channel[i]);
+
 	}
 
 	tegra210_emc_detect(emc);
@@ -1884,7 +1867,7 @@ static int tegra210_emc_probe(struct platform_device *pdev)
 	err = of_reserved_mem_device_init_by_name(emc->dev, np, "nominal");
 	if (err < 0) {
 		dev_err(emc->dev, "failed to get nominal EMC table: %d\n", err);
-		goto put_mc;
+		return err;
 	}
 
 	err = of_reserved_mem_device_init_by_name(emc->dev, np, "derated");
@@ -2015,8 +1998,7 @@ detach:
 	tegra210_clk_emc_detach(emc->clk);
 release:
 	of_reserved_mem_device_release(emc->dev);
-put_mc:
-	put_device(emc->mc->dev);
+
 	return err;
 }
 
@@ -2027,7 +2009,6 @@ static int tegra210_emc_remove(struct platform_device *pdev)
 	debugfs_remove_recursive(emc->debugfs.root);
 	tegra210_clk_emc_detach(emc->clk);
 	of_reserved_mem_device_release(emc->dev);
-	put_device(emc->mc->dev);
 
 	return 0;
 }

drivers/memory/tegra/tegra30-emc.c

@@ -1258,7 +1258,6 @@ static void tegra_emc_debugfs_init(struct tegra_emc *emc)
 
 static int tegra_emc_probe(struct platform_device *pdev)
 {
-	struct platform_device *mc;
 	struct device_node *np;
 	struct tegra_emc *emc;
 	int err;
@@ -1269,17 +1268,6 @@ static int tegra_emc_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	np = of_parse_phandle(pdev->dev.of_node, "nvidia,memory-controller", 0);
-	if (!np) {
-		dev_err(&pdev->dev, "could not get memory controller node\n");
-		return -ENOENT;
-	}
-
-	mc = of_find_device_by_node(np);
-	of_node_put(np);
-	if (!mc)
-		return -ENOENT;
-
 	np = emc_find_node_by_ram_code(&pdev->dev);
 	if (!np)
 		return -EINVAL;
@@ -1290,9 +1278,9 @@ static int tegra_emc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	emc->mc = platform_get_drvdata(mc);
-	if (!emc->mc)
-		return -EPROBE_DEFER;
+	emc->mc = devm_tegra_memory_controller_get(&pdev->dev);
+	if (IS_ERR(emc->mc))
+		return PTR_ERR(emc->mc);
 
 	emc->clk_nb.notifier_call = emc_clk_change_notify;
 	emc->dev = &pdev->dev;

include/soc/tegra/mc.h

@@ -184,4 +184,14 @@ struct tegra_mc {
 int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
 unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
 
+#ifdef CONFIG_TEGRA_MC
+struct tegra_mc *devm_tegra_memory_controller_get(struct device *dev);
+#else
+static inline struct tegra_mc *
+devm_tegra_memory_controller_get(struct device *dev)
+{
+	ERR_PTR(-ENODEV);
+}
+#endif
+
 #endif /* __SOC_TEGRA_MC_H__ */