[PATCH v2 6/7] clocksource/drivers/exynos_mct: Add module support

[Will McVicker <willmcvicker@google.com>]

From: Donghoon Yu <hoony.yu@samsung.com>

On Arm64 platforms the Exynos MCT driver can be built as a module. On
boot (and even after boot) the arch_timer is used as the clocksource and
tick timer. Once the MCT driver is loaded, it can be used as the wakeup
source for the arch_timer.

Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
[original commit from https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]
Signed-off-by: Will McVicker <willmcvicker@google.com>
---
 drivers/clocksource/Kconfig      |  3 +-
 drivers/clocksource/exynos_mct.c | 49 +++++++++++++++++++++++++++-----
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 487c85259967..e89373827c3a 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -443,7 +443,8 @@ config ATMEL_TCB_CLKSRC
 	  Support for Timer Counter Blocks on Atmel SoCs.
 
 config CLKSRC_EXYNOS_MCT
-	bool "Exynos multi core timer driver" if COMPILE_TEST
+	tristate "Exynos multi core timer driver" if ARM64
+	default y if ARCH_EXYNOS || COMPILE_TEST
 	depends on ARM || ARM64
 	depends on ARCH_ARTPEC || ARCH_EXYNOS || COMPILE_TEST
 	help
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 62febeb4e1de..8943274378be 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -15,9 +15,11 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/percpu.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 #include <linux/clocksource.h>
 #include <linux/sched_clock.h>
 
@@ -241,7 +243,7 @@ static cycles_t exynos4_read_current_timer(void)
 }
 #endif
 
-static int __init exynos4_clocksource_init(bool frc_shared)
+static int exynos4_clocksource_init(bool frc_shared)
 {
 	/*
 	 * When the frc is shared, the main processor should have already
@@ -511,7 +513,7 @@ static int exynos4_mct_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
-static int __init exynos4_timer_resources(struct device_node *np)
+static int exynos4_timer_resources(struct device_node *np)
 {
 	struct clk *mct_clk, *tick_clk;
 
@@ -539,7 +541,7 @@ static int __init exynos4_timer_resources(struct device_node *np)
  * @local_idx: array mapping CPU numbers to local timer indices
  * @nr_local: size of @local_idx array
  */
-static int __init exynos4_timer_interrupts(struct device_node *np,
+static int exynos4_timer_interrupts(struct device_node *np,
 					   unsigned int int_type,
 					   const u32 *local_idx,
 					   size_t nr_local)
@@ -652,7 +654,7 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
 	return err;
 }
 
-static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
+static int mct_init_dt(struct device_node *np, unsigned int int_type)
 {
 	bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
 	u32 local_idx[MCT_NR_LOCAL] = {0};
@@ -700,15 +702,48 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
 	return exynos4_clockevent_init();
 }
 
-
-static int __init mct_init_spi(struct device_node *np)
+static int mct_init_spi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_SPI);
 }
 
-static int __init mct_init_ppi(struct device_node *np)
+static int mct_init_ppi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_PPI);
 }
+
+#ifdef MODULE
+static int exynos4_mct_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int (*mct_init)(struct device_node *np);
+
+	mct_init = of_device_get_match_data(dev);
+	if (!mct_init)
+		return -EINVAL;
+
+	return mct_init(dev->of_node);
+}
+
+static const struct of_device_id exynos4_mct_match_table[] = {
+	{ .compatible = "samsung,exynos4210-mct", .data = &mct_init_spi, },
+	{ .compatible = "samsung,exynos4412-mct", .data = &mct_init_ppi, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, exynos4_mct_match_table);
+
+static struct platform_driver exynos4_mct_driver = {
+	.probe		= exynos4_mct_probe,
+	.driver		= {
+		.name	= "exynos-mct",
+		.of_match_table = exynos4_mct_match_table,
+	},
+};
+module_platform_driver(exynos4_mct_driver);
+#else
 TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
 TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
+#endif
+
+MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
+MODULE_LICENSE("GPL");
-- 
2.49.0.472.ge94155a9ec-goog