linux-kernel - [PATCH v6 37/52] memory: tegra30-emc: Make driver modular

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Message-Id: <20201025221735.3062-38-digetx@gmail.com>
Date:   Mon, 26 Oct 2020 01:17:20 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Georgi Djakov <georgi.djakov@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Mikko Perttunen <cyndis@...si.fi>,
        Viresh Kumar <vireshk@...nel.org>,
        Peter Geis <pgwipeout@...il.com>,
        Nicolas Chauvet <kwizart@...il.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
Cc:     linux-tegra@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        devicetree@...r.kernel.org
Subject: [PATCH v6 37/52] memory: tegra30-emc: Make driver modular

This patch adds modularization support to the Tegra30 EMC driver. Driver
now can be compiled as a loadable kernel module.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/memory/tegra/Kconfig       |  2 +-
 drivers/memory/tegra/mc.c          |  3 +++
 drivers/memory/tegra/tegra30-emc.c | 17 ++++++++++++-----
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/memory/tegra/Kconfig b/drivers/memory/tegra/Kconfig
index ac3dfe155505..61cdb5c04b18 100644
--- a/drivers/memory/tegra/Kconfig
+++ b/drivers/memory/tegra/Kconfig
@@ -20,7 +20,7 @@ config TEGRA20_EMC
 	  external memory.
 
 config TEGRA30_EMC
-	bool "NVIDIA Tegra30 External Memory Controller driver"
+	tristate "NVIDIA Tegra30 External Memory Controller driver"
 	default y
 	depends on TEGRA_MC && ARCH_TEGRA_3x_SOC
 	help
diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index 53d61b05ebf8..15589bf8f5b6 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -6,6 +6,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
+#include <linux/export.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -346,6 +347,7 @@ int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(tegra_mc_write_emem_configuration);
 
 unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc)
 {
@@ -357,6 +359,7 @@ unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc)
 
 	return dram_count;
 }
+EXPORT_SYMBOL_GPL(tegra_mc_get_emem_device_count);
 
 static int load_one_timing(struct tegra_mc *mc,
 			   struct tegra_mc_timing *timing,
diff --git a/drivers/memory/tegra/tegra30-emc.c b/drivers/memory/tegra/tegra30-emc.c
index 602dc4e08c61..b31e11f95462 100644
--- a/drivers/memory/tegra/tegra30-emc.c
+++ b/drivers/memory/tegra/tegra30-emc.c
@@ -1331,6 +1331,13 @@ static int tegra_emc_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, emc);
 	tegra_emc_debugfs_init(emc);
 
+	/*
+	 * Don't allow the kernel module to be unloaded. Unloading adds some
+	 * extra complexity which doesn't really worth the effort in a case of
+	 * this driver.
+	 */
+	try_module_get(THIS_MODULE);
+
 	return 0;
 
 unset_cb:
@@ -1381,6 +1388,7 @@ static const struct of_device_id tegra_emc_of_match[] = {
 	{ .compatible = "nvidia,tegra30-emc", },
 	{},
 };
+MODULE_DEVICE_TABLE(of, tegra_emc_of_match);
 
 static struct platform_driver tegra_emc_driver = {
 	.probe = tegra_emc_probe,
@@ -1391,9 +1399,8 @@ static struct platform_driver tegra_emc_driver = {
 		.suppress_bind_attrs = true,
 	},
 };
+module_platform_driver(tegra_emc_driver);
 
-static int __init tegra_emc_init(void)
-{
-	return platform_driver_register(&tegra_emc_driver);
-}
-subsys_initcall(tegra_emc_init);
+MODULE_AUTHOR("Dmitry Osipenko <digetx@...il.com>");
+MODULE_DESCRIPTION("NVIDIA Tegra30 EMC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.27.0