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>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index ec8403557ed4..a72cdcafc933 100644
--- a/drivers/memory/tegra/mc.c
+++ b/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)
 {