[PATCH 2/3] clocksource/drivers/timer-mediatek: Convert to OF probing

[Luca Leonardo Scorcia <l.scorcia@gmail.com>]

MediaTek APXGPT general purpose timer driver is registered via
TIMER_OF_DECLARE to be loaded early in the boot process. It depends on
a reference 13 MHz clock that is assigned via the clocks property of
its DT node.
On platforms like mt8516/mt8167 this clock is provided by a driver that
is loaded using OF probing and becomes available only later during boot.
This leads to a silent EDEFER error during timer init, which is not
recovered by TIMER_OF_DECLARE and GPT clocks are not registered at all.

Since those clocks are not critical for boot, convert the timer-mediatek
to OF probing and drop the TIMER_OF_DECLARE instructions.

Signed-off-by: Luca Leonardo Scorcia <l.scorcia@gmail.com>
---
 drivers/clocksource/timer-mediatek.c | 36 ++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index e20075b09fab..a9e7ff6908a3 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -13,6 +13,9 @@
 #include <linux/clocksource.h>
 #include <linux/interrupt.h>
 #include <linux/irqreturn.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
 #include <linux/sched_clock.h>
 #include <linux/slab.h>
 #include "timer-of.h"
@@ -215,8 +218,7 @@ static irqreturn_t mtk_gpt_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void
-__init mtk_gpt_setup(struct timer_of *to, u8 timer, u8 option)
+static void mtk_gpt_setup(struct timer_of *to, u8 timer, u8 option)
 {
 	writel(GPT_CTRL_CLEAR | GPT_CTRL_DISABLE,
 	       timer_of_base(to) + GPT_CTRL_REG(timer));
@@ -281,7 +283,7 @@ static struct timer_of to = {
 	},
 };
 
-static int __init mtk_syst_init(struct device_node *node)
+static int mtk_syst_init(struct device_node *node)
 {
 	int ret;
 
@@ -339,5 +341,29 @@ static int __init mtk_gpt_init(struct device_node *node)
 
 	return 0;
 }
-TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
-TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
+
+static int mtk_timer_probe(struct platform_device *pdev)
+{
+	int (*timer_init)(struct device_node *node);
+	struct device_node *np = pdev->dev.of_node;
+
+	timer_init = of_device_get_match_data(&pdev->dev);
+	return timer_init(np);
+}
+
+static const struct of_device_id mtk_timer_match_table[] = {
+	{ .compatible = "mediatek,mt6577-timer", .data = mtk_gpt_init },
+	{ .compatible = "mediatek,mt6765-timer", .data = mtk_syst_init },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver mtk_timer_driver = {
+	.probe = mtk_timer_probe,
+	.driver = {
+		.name = "mediatek-timer",
+		.of_match_table = mtk_timer_match_table,
+	},
+};
+module_platform_driver(mtk_timer_driver);
+
+MODULE_DESCRIPTION("MediaTek Timer driver");
-- 
2.43.0