[PATCH 0/3] clocksource/drivers/timer-microchip-pit64b: improve clock management

[PATCH 0/3] clocksource/drivers/timer-microchip-pit64b: improve clock management

[Claudiu Beznea]

Hi,

This series improves clock management on PIT64B driver such that PIT64B
clocks to be disabled in case driver has been probed to be used as
clockevent but there is already a better clockevent timer available.

Along with it added a patch to fix compilation warnings.

Patches were initially part of series at [1].

Thank you,
Claudiu Beznea

[1] https://lore.kernel.org/linux-arm-kernel/80f949af-ddab-b54d-b6ee-0fbcb1f74b51@linaro.org/T/#mc9969713b69f7874dd3bc6de07e8e8bc9568ead5

Claudiu Beznea (3):
  clocksource/drivers/timer-microchip-pit64b: remove suspend/resume ops
    for ce
  clocksource/drivers/timer-microchip-pit64b: use mchp_pit64b_{suspend,
    resume}
  clocksource/drivers/timer-microchip-pit64b: fix compilation warnings

 drivers/clocksource/timer-microchip-pit64b.c | 64 +++++++++-----------
 1 file changed, 27 insertions(+), 37 deletions(-)

-- 
2.34.1

[PATCH 1/3] clocksource/drivers/timer-microchip-pit64b: remove suspend/resume ops for ce

[Claudiu Beznea]

Remove suspend and resume ops for clockevent and add set_state_oneshot()
instead. Along with this mchp_pit64b_{suspend, resume}() were called on
proper function to disable/enable clocks. This will allow disabling clocks
for clockevent in case it is not selected as active clockevent.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/clocksource/timer-microchip-pit64b.c | 30 +++++++++++---------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c
index abce83d2f00b..b51259395ac3 100644
--- a/drivers/clocksource/timer-microchip-pit64b.c
+++ b/drivers/clocksource/timer-microchip-pit64b.c
@@ -173,7 +173,8 @@ static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev)
 {
 	struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);
 
-	writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);
+	if (!clockevent_state_detached(cedev))
+		mchp_pit64b_suspend(timer);
 
 	return 0;
 }
@@ -182,35 +183,37 @@ static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev)
 {
 	struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);
 
+	if (clockevent_state_shutdown(cedev))
+		mchp_pit64b_resume(timer);
+
 	mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_CONT,
 			  MCHP_PIT64B_IER_PERIOD);
 
 	return 0;
 }
 
-static int mchp_pit64b_clkevt_set_next_event(unsigned long evt,
-					     struct clock_event_device *cedev)
+static int mchp_pit64b_clkevt_set_oneshot(struct clock_event_device *cedev)
 {
 	struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);
 
-	mchp_pit64b_reset(timer, evt, MCHP_PIT64B_MR_ONE_SHOT,
+	if (clockevent_state_shutdown(cedev))
+		mchp_pit64b_resume(timer);
+
+	mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_ONE_SHOT,
 			  MCHP_PIT64B_IER_PERIOD);
 
 	return 0;
 }
 
-static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev)
+static int mchp_pit64b_clkevt_set_next_event(unsigned long evt,
+					     struct clock_event_device *cedev)
 {
 	struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);
 
-	mchp_pit64b_suspend(timer);
-}
-
-static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev)
-{
-	struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);
+	mchp_pit64b_reset(timer, evt, MCHP_PIT64B_MR_ONE_SHOT,
+			  MCHP_PIT64B_IER_PERIOD);
 
-	mchp_pit64b_resume(timer);
+	return 0;
 }
 
 static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id)
@@ -395,9 +398,8 @@ static int __init mchp_pit64b_init_clkevt(struct mchp_pit64b_timer *timer,
 	ce->clkevt.rating = 150;
 	ce->clkevt.set_state_shutdown = mchp_pit64b_clkevt_shutdown;
 	ce->clkevt.set_state_periodic = mchp_pit64b_clkevt_set_periodic;
+	ce->clkevt.set_state_oneshot = mchp_pit64b_clkevt_set_oneshot;
 	ce->clkevt.set_next_event = mchp_pit64b_clkevt_set_next_event;
-	ce->clkevt.suspend = mchp_pit64b_clkevt_suspend;
-	ce->clkevt.resume = mchp_pit64b_clkevt_resume;
 	ce->clkevt.cpumask = cpumask_of(0);
 	ce->clkevt.irq = irq;
 
-- 
2.34.1

[PATCH 2/3] clocksource/drivers/timer-microchip-pit64b: use mchp_pit64b_{suspend, resume}

[Claudiu Beznea]

Use mchp_pit64b_suspend() and mchp_pit64b_resume() to disable or
enable timers clocks on init and remove specific
clk_prepare_{disable, enable} calls. This is ok also for clockevent timer
as proper clock enable, disable is done on .set_state_oneshot,
.set_state_periodic, .set_state_shutdown calls.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/clocksource/timer-microchip-pit64b.c | 24 ++++----------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c
index b51259395ac3..f50705698283 100644
--- a/drivers/clocksource/timer-microchip-pit64b.c
+++ b/drivers/clocksource/timer-microchip-pit64b.c
@@ -344,6 +344,7 @@ static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer,
 	if (!cs)
 		return -ENOMEM;
 
+	mchp_pit64b_resume(timer);
 	mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0);
 
 	mchp_pit64b_cs_base = timer->base;
@@ -365,8 +366,7 @@ static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer,
 		pr_debug("clksrc: Failed to register PIT64B clocksource!\n");
 
 		/* Stop timer. */
-		writel_relaxed(MCHP_PIT64B_CR_SWRST,
-			       timer->base + MCHP_PIT64B_CR);
+		mchp_pit64b_suspend(timer);
 		kfree(cs);
 
 		return ret;
@@ -450,19 +450,10 @@ static int __init mchp_pit64b_dt_init_timer(struct device_node *node,
 	if (ret)
 		goto irq_unmap;
 
-	ret = clk_prepare_enable(timer.pclk);
-	if (ret)
-		goto irq_unmap;
-
-	if (timer.mode & MCHP_PIT64B_MR_SGCLK) {
-		ret = clk_prepare_enable(timer.gclk);
-		if (ret)
-			goto pclk_unprepare;
-
+	if (timer.mode & MCHP_PIT64B_MR_SGCLK)
 		clk_rate = clk_get_rate(timer.gclk);
-	} else {
+	else
 		clk_rate = clk_get_rate(timer.pclk);
-	}
 	clk_rate = clk_rate / (MCHP_PIT64B_MODE_TO_PRES(timer.mode) + 1);
 
 	if (clkevt)
@@ -471,15 +462,10 @@ static int __init mchp_pit64b_dt_init_timer(struct device_node *node,
 		ret = mchp_pit64b_init_clksrc(&timer, clk_rate);
 
 	if (ret)
-		goto gclk_unprepare;
+		goto irq_unmap;
 
 	return 0;
 
-gclk_unprepare:
-	if (timer.mode & MCHP_PIT64B_MR_SGCLK)
-		clk_disable_unprepare(timer.gclk);
-pclk_unprepare:
-	clk_disable_unprepare(timer.pclk);
 irq_unmap:
 	irq_dispose_mapping(irq);
 io_unmap:
-- 
2.34.1

[PATCH 3/3] clocksource/drivers/timer-microchip-pit64b: fix compilation warnings

[Claudiu Beznea]

Fix the following compilation warnings:
timer-microchip-pit64b.c:68: warning: cannot understand function prototype: 'struct mchp_pit64b_clkevt '
timer-microchip-pit64b.c:82: warning: cannot understand function prototype: 'struct mchp_pit64b_clksrc '
timer-microchip-pit64b.c:283: warning: Function parameter or member 'timer' not described in 'mchp_pit64b_init_mode'
timer-microchip-pit64b.c:283: warning: Function parameter or member 'max_rate' not described in 'mchp_pit64b_init_mode'

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/clocksource/timer-microchip-pit64b.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c
index f50705698283..d5f1436f33d9 100644
--- a/drivers/clocksource/timer-microchip-pit64b.c
+++ b/drivers/clocksource/timer-microchip-pit64b.c
@@ -61,7 +61,7 @@ struct mchp_pit64b_timer {
 };
 
 /**
- * mchp_pit64b_clkevt - PIT64B clockevent data structure
+ * struct mchp_pit64b_clkevt - PIT64B clockevent data structure
  * @timer: PIT64B timer
  * @clkevt: clockevent
  */
@@ -75,7 +75,7 @@ struct mchp_pit64b_clkevt {
 		struct mchp_pit64b_clkevt, clkevt))
 
 /**
- * mchp_pit64b_clksrc - PIT64B clocksource data structure
+ * struct mchp_pit64b_clksrc - PIT64B clocksource data structure
  * @timer: PIT64B timer
  * @clksrc: clocksource
  */
@@ -245,8 +245,10 @@ static void __init mchp_pit64b_pres_compute(u32 *pres, u32 clk_rate,
 }
 
 /**
- * mchp_pit64b_init_mode - prepare PIT64B mode register value to be used at
- *			   runtime; this includes prescaler and SGCLK bit
+ * mchp_pit64b_init_mode() - prepare PIT64B mode register value to be used at
+ *			     runtime; this includes prescaler and SGCLK bit
+ * @timer: pointer to pit64b timer to init
+ * @max_rate: maximum rate that timer's clock could use
  *
  * PIT64B timer may be fed by gclk or pclk. When gclk is used its rate has to
  * be at least 3 times lower that pclk's rate. pclk rate is fixed, gclk rate
-- 
2.34.1