[PATCH 3/3] clocksource/drivers/timer-mediatek: Request and enable the bus clock

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

MediaTek APXGPT general purpose timers may optionally depend on a bus
clock. If this clock is not enabled the timers don't actually run. Boot
loaders usually turn it on, but later the kernel turns it off since it's
never requested by any driver.

Some platforms (like mt6735) declare it as a critical clock in their
clock definitions to keep it running, but at least on mt8167 it's not
actually required for a successful boot.

If a bus clock is declared in the device tree, make sure it is enabled
by driver probe and associated to the device.

Signed-off-by: Luca Leonardo Scorcia <l.scorcia@gmail.com>
---
 drivers/clocksource/timer-mediatek.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index a9e7ff6908a3..842d6ee4259e 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -9,6 +9,7 @@
 
 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
 
+#include <linux/clk.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
 #include <linux/interrupt.h>
@@ -283,8 +284,9 @@ static struct timer_of to = {
 	},
 };
 
-static int mtk_syst_init(struct device_node *node)
+static int mtk_syst_init(struct platform_device *pdev)
 {
+	struct device_node *node = pdev->dev.of_node;
 	int ret;
 
 	to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT;
@@ -305,10 +307,14 @@ static int mtk_syst_init(struct device_node *node)
 	return 0;
 }
 
-static int __init mtk_gpt_init(struct device_node *node)
+static int mtk_gpt_init(struct platform_device *pdev)
 {
+	struct device_node *node = pdev->dev.of_node;
+	struct clk *clk_bus;
 	int ret;
 
+	clk_bus = devm_clk_get_optional_enabled(&pdev->dev, "bus");
+
 	to.clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 	to.clkevt.set_state_shutdown = mtk_gpt_clkevt_shutdown;
 	to.clkevt.set_state_periodic = mtk_gpt_clkevt_set_periodic;
@@ -344,11 +350,10 @@ static int __init mtk_gpt_init(struct device_node *node)
 
 static int mtk_timer_probe(struct platform_device *pdev)
 {
-	int (*timer_init)(struct device_node *node);
-	struct device_node *np = pdev->dev.of_node;
+	int (*timer_init)(struct platform_device *pdev);
 
 	timer_init = of_device_get_match_data(&pdev->dev);
-	return timer_init(np);
+	return timer_init(pdev);
 }
 
 static const struct of_device_id mtk_timer_match_table[] = {
-- 
2.43.0