Merge tag 'timers-core-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "The time and timers updates contain:

  Core changes:

   - Allow runtime power management when the clocksource is changed.

   - A correctness fix for clock_adjtime32() so that the return value on
     success is not overwritten by the result of the copy to user.

   - Allow late installment of broadcast clockevent devices which was
     broken because nothing switched them over to oneshot mode. This
     went unnoticed so far because clockevent devices used to be built
     in, but now people started to make them modular.

   - Debugfs related simplifications

   - Small cleanups and improvements here and there

  Driver changes:

   - The usual set of device tree binding updates for a wide range of
     drivers/devices.

   - The usual updates and improvements for drivers all over the place
     but nothing outstanding.

   - No new clocksource/event drivers. They'll come back next time"

* tag 'timers-core-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  posix-timers: Preserve return value in clock_adjtime32()
  tick/broadcast: Allow late registered device to enter oneshot mode
  tick: Use tick_check_replacement() instead of open coding it
  time/timecounter: Mark 1st argument of timecounter_cyc2time() as const
  dt-bindings: timer: nuvoton,npcm7xx: Add wpcm450-timer
  clocksource/drivers/arm_arch_timer: Add __ro_after_init and __init
  clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940
  clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue
  clocksource/drivers/dw_apb_timer_of: Add handling for potential memory leak
  clocksource/drivers/npcm: Add support for WPCM450
  clocksource/drivers/sh_cmt: Don't use CMTOUT_IE with R-Car Gen2/3
  clocksource/drivers/pistachio: Fix trivial typo
  clocksource/drivers/ingenic_ost: Fix return value check in ingenic_ost_probe()
  clocksource/drivers/timer-ti-dm: Add missing set_state_oneshot_stopped
  clocksource/drivers/timer-ti-dm: Fix posted mode status check order
  dt-bindings: timer: renesas,cmt: Document R8A77961
  dt-bindings: timer: renesas,cmt: Add r8a779a0 CMT support
  clocksource/drivers/ingenic-ost: Add support for the JZ4760B
  clocksource/drivers/ingenic: Add support for the JZ4760
  dt-bindings: timer: ingenic: Add compatible strings for JZ4760(B)
  ...

1 files changed, 28 insertions, 18 deletions

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 6aee5768c86f..81fe2a33b80c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -596,14 +596,14 @@ EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
  * careful cache layout of the timekeeper because the sequence count and
  * struct tk_read_base would then need two cache lines instead of one.
  *
- * Access to the time keeper clock source is disabled accross the innermost
+ * Access to the time keeper clock source is disabled across the innermost
  * steps of suspend/resume. The accessors still work, but the timestamps
  * are frozen until time keeping is resumed which happens very early.
  *
  * For regular suspend/resume there is no observable difference vs. sched
  * clock, but it might affect some of the nasty low level debug printks.
  *
- * OTOH, access to sched clock is not guaranteed accross suspend/resume on
+ * OTOH, access to sched clock is not guaranteed across suspend/resume on
  * all systems either so it depends on the hardware in use.
  *
  * If that turns out to be a real problem then this could be mitigated by
@@ -899,7 +899,7 @@ ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
 EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);
 
 /**
- * ktime_mono_to_any() - convert mononotic time to any other time
+ * ktime_mono_to_any() - convert monotonic time to any other time
  * @tmono:	time to convert.
  * @offs:	which offset to use
  */
@@ -1427,35 +1427,45 @@ static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
 static int change_clocksource(void *data)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
-	struct clocksource *new, *old;
+	struct clocksource *new, *old = NULL;
 	unsigned long flags;
+	bool change = false;
 
 	new = (struct clocksource *) data;
 
-	raw_spin_lock_irqsave(&timekeeper_lock, flags);
-	write_seqcount_begin(&tk_core.seq);
-
-	timekeeping_forward_now(tk);
 	/*
 	 * If the cs is in module, get a module reference. Succeeds
 	 * for built-in code (owner == NULL) as well.
 	 */
 	if (try_module_get(new->owner)) {
-		if (!new->enable || new->enable(new) == 0) {
-			old = tk->tkr_mono.clock;
-			tk_setup_internals(tk, new);
-			if (old->disable)
-				old->disable(old);
-			module_put(old->owner);
-		} else {
+		if (!new->enable || new->enable(new) == 0)
+			change = true;
+		else
 			module_put(new->owner);
-		}
 	}
+
+	raw_spin_lock_irqsave(&timekeeper_lock, flags);
+	write_seqcount_begin(&tk_core.seq);
+
+	timekeeping_forward_now(tk);
+
+	if (change) {
+		old = tk->tkr_mono.clock;
+		tk_setup_internals(tk, new);
+	}
+
 	timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
 	write_seqcount_end(&tk_core.seq);
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 
+	if (old) {
+		if (old->disable)
+			old->disable(old);
+
+		module_put(old->owner);
+	}
+
 	return 0;
 }
 
@@ -1948,7 +1958,7 @@ static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
 	 *	xtime_nsec_1 = offset + xtime_nsec_2
 	 * Which gives us:
 	 *	xtime_nsec_2 = xtime_nsec_1 - offset
-	 * Which simplfies to:
+	 * Which simplifies to:
 	 *	xtime_nsec -= offset
 	 */
 	if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
@@ -2336,7 +2346,7 @@ static int timekeeping_validate_timex(const struct __kernel_timex *txc)
 
 		/*
 		 * Validate if a timespec/timeval used to inject a time
-		 * offset is valid.  Offsets can be postive or negative, so
+		 * offset is valid.  Offsets can be positive or negative, so
 		 * we don't check tv_sec. The value of the timeval/timespec
 		 * is the sum of its fields,but *NOTE*:
 		 * The field tv_usec/tv_nsec must always be non-negative and