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Subject[PATCH] clocksource/drivers/tegra: rework for compensation of suspend time
Date
Since the clocksource framework has the support for suspend time
compensation. Re-work the driver to use that, so we can reduce the
duplicate code.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
---
drivers/clocksource/timer-tegra20.c | 63 +++++++++--------------------
1 file changed, 20 insertions(+), 43 deletions(-)

diff --git a/drivers/clocksource/timer-tegra20.c b/drivers/clocksource/timer-tegra20.c
index fdb3d795a409..919b3568c495 100644
--- a/drivers/clocksource/timer-tegra20.c
+++ b/drivers/clocksource/timer-tegra20.c
@@ -60,9 +60,6 @@
static u32 usec_config;
static void __iomem *timer_reg_base;
#ifdef CONFIG_ARM
-static void __iomem *rtc_base;
-static struct timespec64 persistent_ts;
-static u64 persistent_ms, last_persistent_ms;
static struct delay_timer tegra_delay_timer;
#endif

@@ -199,40 +196,30 @@ static unsigned long tegra_delay_timer_read_counter_long(void)
return readl(timer_reg_base + TIMERUS_CNTR_1US);
}

+static struct timer_of suspend_rtc_to = {
+ .flags = TIMER_OF_BASE | TIMER_OF_CLOCK,
+};
+
/*
* tegra_rtc_read - Reads the Tegra RTC registers
* Care must be taken that this funciton is not called while the
* tegra_rtc driver could be executing to avoid race conditions
* on the RTC shadow register
*/
-static u64 tegra_rtc_read_ms(void)
+static u64 tegra_rtc_read_ms(struct clocksource *cs)
{
- u32 ms = readl(rtc_base + RTC_MILLISECONDS);
- u32 s = readl(rtc_base + RTC_SHADOW_SECONDS);
+ u32 ms = readl(timer_of_base(&suspend_rtc_to) + RTC_MILLISECONDS);
+ u32 s = readl(timer_of_base(&suspend_rtc_to) + RTC_SHADOW_SECONDS);
return (u64)s * MSEC_PER_SEC + ms;
}

-/*
- * tegra_read_persistent_clock64 - Return time from a persistent clock.
- *
- * Reads the time from a source which isn't disabled during PM, the
- * 32k sync timer. Convert the cycles elapsed since last read into
- * nsecs and adds to a monotonically increasing timespec64.
- * Care must be taken that this funciton is not called while the
- * tegra_rtc driver could be executing to avoid race conditions
- * on the RTC shadow register
- */
-static void tegra_read_persistent_clock64(struct timespec64 *ts)
-{
- u64 delta;
-
- last_persistent_ms = persistent_ms;
- persistent_ms = tegra_rtc_read_ms();
- delta = persistent_ms - last_persistent_ms;
-
- timespec64_add_ns(&persistent_ts, delta * NSEC_PER_MSEC);
- *ts = persistent_ts;
-}
+static struct clocksource suspend_rtc_clocksource = {
+ .name = "tegra_suspend_timer",
+ .rating = 200,
+ .read = tegra_rtc_read_ms,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
+};
#endif

static int tegra_timer_common_init(struct device_node *np, struct timer_of *to)
@@ -385,25 +372,15 @@ static int __init tegra_init_timer(struct device_node *np)

static int __init tegra20_init_rtc(struct device_node *np)
{
- struct clk *clk;
+ int ret;

- rtc_base = of_iomap(np, 0);
- if (!rtc_base) {
- pr_err("Can't map RTC registers\n");
- return -ENXIO;
- }
+ ret = timer_of_init(np, &suspend_rtc_to);
+ if (ret)
+ return ret;

- /*
- * rtc registers are used by read_persistent_clock, keep the rtc clock
- * enabled
- */
- clk = of_clk_get(np, 0);
- if (IS_ERR(clk))
- pr_warn("Unable to get rtc-tegra clock\n");
- else
- clk_prepare_enable(clk);
+ clocksource_register_hz(&suspend_rtc_clocksource, 1000);

- return register_persistent_clock(tegra_read_persistent_clock64);
+ return 0;
}
TIMER_OF_DECLARE(tegra20_rtc, "nvidia,tegra20-rtc", tegra20_init_rtc);
#endif
--
2.21.0
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