[PATCH] clocksource/drivers/timer-microchip-pit64b: add clocksource suspend/resume

From: Claudiu Beznea
Date: Tue Dec 08 2020 - 12:20:45 EST


Add suspend/resume support for clocksource timer.

Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
---
drivers/clocksource/timer-microchip-pit64b.c | 86 +++++++++++++++++++++++-----
1 file changed, 71 insertions(+), 15 deletions(-)

diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c
index 59e11ca8ee73..ab623b25a47b 100644
--- a/drivers/clocksource/timer-microchip-pit64b.c
+++ b/drivers/clocksource/timer-microchip-pit64b.c
@@ -71,10 +71,24 @@ struct mchp_pit64b_clkevt {
struct clock_event_device clkevt;
};

-#define to_mchp_pit64b_timer(x) \
+#define clkevt_to_mchp_pit64b_timer(x) \
((struct mchp_pit64b_timer *)container_of(x,\
struct mchp_pit64b_clkevt, clkevt))

+/**
+ * mchp_pit64b_clksrc - PIT64B clocksource data structure
+ * @timer: PIT64B timer
+ * @clksrc: clocksource
+ */
+struct mchp_pit64b_clksrc {
+ struct mchp_pit64b_timer timer;
+ struct clocksource clksrc;
+};
+
+#define clksrc_to_mchp_pit64b_timer(x) \
+ ((struct mchp_pit64b_timer *)container_of(x,\
+ struct mchp_pit64b_clksrc, clksrc))
+
/* Base address for clocksource timer. */
static void __iomem *mchp_pit64b_cs_base;
/* Default cycles for clockevent timer. */
@@ -116,6 +130,36 @@ static inline void mchp_pit64b_reset(struct mchp_pit64b_timer *timer,
writel_relaxed(MCHP_PIT64B_CR_START, timer->base + MCHP_PIT64B_CR);
}

+static void mchp_pit64b_suspend(struct mchp_pit64b_timer *timer)
+{
+ writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);
+ if (timer->mode & MCHP_PIT64B_MR_SGCLK)
+ clk_disable_unprepare(timer->gclk);
+ clk_disable_unprepare(timer->pclk);
+}
+
+static void mchp_pit64b_resume(struct mchp_pit64b_timer *timer)
+{
+ clk_prepare_enable(timer->pclk);
+ if (timer->mode & MCHP_PIT64B_MR_SGCLK)
+ clk_prepare_enable(timer->gclk);
+}
+
+static void mchp_pit64b_clksrc_suspend(struct clocksource *cs)
+{
+ struct mchp_pit64b_timer *timer = clksrc_to_mchp_pit64b_timer(cs);
+
+ mchp_pit64b_suspend(timer);
+}
+
+static void mchp_pit64b_clksrc_resume(struct clocksource *cs)
+{
+ struct mchp_pit64b_timer *timer = clksrc_to_mchp_pit64b_timer(cs);
+
+ mchp_pit64b_resume(timer);
+ mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0);
+}
+
static u64 mchp_pit64b_clksrc_read(struct clocksource *cs)
{
return mchp_pit64b_cnt_read(mchp_pit64b_cs_base);
@@ -128,7 +172,7 @@ static u64 mchp_pit64b_sched_read_clk(void)

static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev)
{
- struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+ struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);

writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);

@@ -137,7 +181,7 @@ static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev)

static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev)
{
- struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+ struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);

mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_CONT,
MCHP_PIT64B_IER_PERIOD);
@@ -148,7 +192,7 @@ static int mchp_pit64b_clkevt_set_periodic(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 = to_mchp_pit64b_timer(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);
@@ -158,21 +202,16 @@ static int mchp_pit64b_clkevt_set_next_event(unsigned long evt,

static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev)
{
- struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+ struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);

- writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);
- if (timer->mode & MCHP_PIT64B_MR_SGCLK)
- clk_disable_unprepare(timer->gclk);
- clk_disable_unprepare(timer->pclk);
+ mchp_pit64b_suspend(timer);
}

static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev)
{
- struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+ struct mchp_pit64b_timer *timer = clkevt_to_mchp_pit64b_timer(cedev);

- clk_prepare_enable(timer->pclk);
- if (timer->mode & MCHP_PIT64B_MR_SGCLK)
- clk_prepare_enable(timer->gclk);
+ mchp_pit64b_resume(timer);
}

static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id)
@@ -296,20 +335,37 @@ static int __init mchp_pit64b_init_mode(struct mchp_pit64b_timer *timer,
static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer,
u32 clk_rate)
{
+ struct mchp_pit64b_clksrc *cs;
int ret;

+ cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+ if (!cs)
+ return -ENOMEM;
+
mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0);

mchp_pit64b_cs_base = timer->base;

- ret = clocksource_mmio_init(timer->base, MCHP_PIT64B_NAME, clk_rate,
- 210, 64, mchp_pit64b_clksrc_read);
+ cs->timer.base = timer->base;
+ cs->timer.pclk = timer->pclk;
+ cs->timer.gclk = timer->gclk;
+ cs->timer.mode = timer->mode;
+ cs->clksrc.name = MCHP_PIT64B_NAME;
+ cs->clksrc.mask = CLOCKSOURCE_MASK(64);
+ cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+ cs->clksrc.rating = 210;
+ cs->clksrc.read = mchp_pit64b_clksrc_read;
+ cs->clksrc.suspend = mchp_pit64b_clksrc_suspend;
+ cs->clksrc.resume = mchp_pit64b_clksrc_resume;
+
+ ret = clocksource_register_hz(&cs->clksrc, clk_rate);
if (ret) {
pr_debug("clksrc: Failed to register PIT64B clocksource!\n");

/* Stop timer. */
writel_relaxed(MCHP_PIT64B_CR_SWRST,
timer->base + MCHP_PIT64B_CR);
+ kfree(cs);

return ret;
}
--
2.7.4