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Subject[PATCH v2 3/3] clocksource: tegra: Use us counter as delay timer
Date
All Tegra SoCs have a freerunning microsecond counter which can be used as a
delay timer.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
---
drivers/clocksource/tegra20_timer.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c
index d1869f0..d2616ef 100644
--- a/drivers/clocksource/tegra20_timer.c
+++ b/drivers/clocksource/tegra20_timer.c
@@ -27,6 +27,7 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
+#include <linux/delay.h>

#include <asm/mach/time.h>
#include <asm/smp_twd.h>
@@ -53,6 +54,8 @@ static void __iomem *rtc_base;
static struct timespec persistent_ts;
static u64 persistent_ms, last_persistent_ms;

+static struct delay_timer tegra_delay_timer;
+
#define timer_writel(value, reg) \
__raw_writel(value, timer_reg_base + (reg))
#define timer_readl(reg) \
@@ -139,6 +142,11 @@ static void tegra_read_persistent_clock(struct timespec *ts)
*ts = *tsp;
}

+static unsigned long tegra_delay_timer_read_counter_long(void)
+{
+ return readl(timer_reg_base + TIMERUS_CNTR_1US);
+}
+
static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = (struct clock_event_device *)dev_id;
@@ -206,6 +214,11 @@ static void __init tegra20_init_timer(struct device_node *np)
BUG();
}

+ tegra_delay_timer.read_current_timer =
+ tegra_delay_timer_read_counter_long;
+ tegra_delay_timer.freq = 1000000;
+ register_current_timer_delay(&tegra_delay_timer);
+
ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
if (ret) {
pr_err("Failed to register timer IRQ: %d\n", ret);
--
1.7.7.rc0.72.g4b5ea.dirty


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