linux-kernel - [RFC v8 18/28] clockevents: purge ->min_delta

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Date:   Sat, 19 Nov 2016 17:10:26 +0100
From:   Nicolai Stange <nicstange@...il.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     John Stultz <john.stultz@...aro.org>, linux-kernel@...r.kernel.org,
        Nicolai Stange <nicstange@...il.com>
Subject: [RFC v8 18/28] clockevents: purge ->min_delta_ns

The struct clock_event_device's ->min_delta_ns member isn't used anymore.

Purge it.

In __clockevents_update_bounds(), shortcut the
  ->min_delta_ticks => ->min_delta_ns => ->min_delta_ticks_adjusted
calculation detour -- it had been made solely for the purpose of ensuring
that ->min_delta_ticks_adjusted corresponds to something >= 1us.

Signed-off-by: Nicolai Stange <nicstange@...il.com>
---
 include/linux/clockchips.h |  2 --
 kernel/time/clockevents.c  | 13 +++++++------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 6342b76..5c4670a 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -88,7 +88,6 @@ enum clock_event_state {
  * @broadcast:		function to broadcast events
  * @min_delta_ticks:	minimum delta value in ticks stored for reconfiguration
  * @max_delta_ticks:	maximum delta value in ticks stored for reconfiguration
- * @min_delta_ns:	minimum delta value in ns
  * @name:		ptr to clock event name
  * @rating:		variable to rate clock event devices
  * @irq:		IRQ number (only for non CPU local devices)
@@ -121,7 +120,6 @@ struct clock_event_device {
 	void			(*resume)(struct clock_event_device *);
 	unsigned long		min_delta_ticks;
 	unsigned long		max_delta_ticks;
-	u64			min_delta_ns;
 
 	const char		*name;
 	int			rating;
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 36dd024..57b00b0 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -443,14 +443,15 @@ static void __clockevents_update_bounds(struct clock_event_device *dev)
 	    (dev->features & CLOCK_EVT_FEAT_DUMMY))
 		return;
 
+	dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
+
 	/*
-	 * cev_delta2ns() never returns values less than 1us and thus,
-	 * we'll never program any ced with anything less.
+	 * Enforce ->min_delta_ticks_adjusted to correspond to a value
+	 * >= 1us.
 	 */
-	dev->min_delta_ns = cev_delta2ns(dev->min_delta_ticks, dev, false);
-	dev->max_delta_ns = cev_delta2ns(dev->max_delta_ticks, dev, true);
-	dev->min_delta_ticks_adjusted = (unsigned long)((dev->min_delta_ns *
-						dev->mult) >> dev->shift);
+	dev->min_delta_ticks_adjusted =
+		max(dev->min_delta_ticks,
+			(unsigned long)((1000ULL * dev->mult) >> dev->shift));
 }
 
 /**
-- 
2.10.2