linux-kernel - [PATCH v3 1/3] memory: tegra: Add devm_tegra_get_memory

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Date:   Wed, 30 Sep 2020 01:42:56 -0700
From:   Nicolin Chen <nicoleotsuka@...il.com>
To:     thierry.reding@...il.com, joro@...tes.org, krzk@...nel.org,
        digetx@...il.com
Cc:     vdumpa@...dia.com, jonathanh@...dia.com,
        linux-tegra@...r.kernel.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 1/3] memory: tegra: Add devm_tegra_get_memory_controller()

From: Dmitry Osipenko <digetx@...il.com>

Multiple Tegra drivers need to retrieve Memory Controller and hence there
is quite some duplication of the retrieval code among the drivers. Let's
add a new common helper for the retrieval of the MC.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
Signed-off-by: Nicolin Chen <nicoleotsuka@...il.com>
---

Changelog
v2->v3:
 * Replaced with Dimtry's devm_tegra_get_memory_controller()
v1->v2:
 * N/A

 drivers/memory/tegra/mc.c | 39 +++++++++++++++++++++++++++++++++++++++
 include/soc/tegra/mc.h    | 17 +++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index ec8403557ed4..dd691dc3738e 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -42,6 +42,45 @@ 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);
+}
+
+struct tegra_mc *devm_tegra_get_memory_controller(struct device *dev)
+{
+	struct platform_device *pdev;
+	struct device_node *np;
+	struct tegra_mc *mc;
+	int err;
+
+	np = of_find_matching_node_and_match(NULL, tegra_mc_of_match, NULL);
+	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(mc->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_get_memory_controller);
+
 static int tegra_mc_block_dma_common(struct tegra_mc *mc,
 				     const struct tegra_mc_reset *rst)
 {
diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
index 1238e35653d1..c05142e3e244 100644
--- a/include/soc/tegra/mc.h
+++ b/include/soc/tegra/mc.h
@@ -184,4 +184,21 @@ 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
+/**
+ * devm_tegra_get_memory_controller() - Get the tegra_mc pointer.
+ * @dev: Device that will be interacted with
+ *
+ * Return: ERR_PTR() on error or a valid pointer to a struct tegra_mc.
+ *
+ * The mc->dev counter will be automatically put by the device management code.
+ */
+struct tegra_mc *devm_tegra_get_memory_controller(struct device *dev);
+#else
+static inline struct tegra_mc *devm_tegra_get_memory_controller(struct device *dev)
+{
+	return ERR_PTR(-ENODEV);
+}
+#endif
+
 #endif /* __SOC_TEGRA_MC_H__ */
-- 
2.17.1