Add bridged amplifiers to cs42l43

Merge series from Charles Keepax <ckeepax@opensource.cirrus.com>:

In some cs42l43 systems a couple of cs35l56 amplifiers are attached
to the cs42l43's SPI and I2S. On Windows the cs42l43 is controlled
by a SDCA class driver and these two amplifiers are controlled by
firmware running on the cs42l43. However, under Linux the decision
was made to interact with the cs42l43 directly, affording the user
greater control over the audio system. However, this has resulted
in an issue where these two bridged cs35l56 amplifiers are not
populated in ACPI and must be added manually. There is at least an
SDCA extension unit DT entry we can key off.

The process of adding this is handled using a software node, firstly the
ability to add native chip selects to software nodes must be added.
Secondly, an additional flag for naming the SPI devices is added this
allows the machine driver to key to the correct amplifier. Then finally,
the cs42l43 SPI driver adds the two amplifiers directly onto its SPI
bus.

An additional series will follow soon to add the audio machine driver
parts (in the sof-sdw driver), however that is fairly orthogonal to
this part of the process, getting the actual amplifiers registered.

5 files changed, 67 insertions, 23 deletions

diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 9de66bbbb3d1..4782edcbe7b9 100644
--- a/kernel/time/posix-clock.c
+++ b/kernel/time/posix-clock.c
@@ -129,15 +129,17 @@ static int posix_clock_open(struct inode *inode, struct file *fp)
 		goto out;
 	}
 	pccontext->clk = clk;
-	fp->private_data = pccontext;
-	if (clk->ops.open)
+	if (clk->ops.open) {
 		err = clk->ops.open(pccontext, fp->f_mode);
-	else
-		err = 0;
-
-	if (!err) {
-		get_device(clk->dev);
+		if (err) {
+			kfree(pccontext);
+			goto out;
+		}
 	}
+
+	fp->private_data = pccontext;
+	get_device(clk->dev);
+	err = 0;
 out:
 	up_read(&clk->rwsem);
 	return err;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 269e21590df5..1331216a9cae 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -697,6 +697,7 @@ bool tick_nohz_tick_stopped_cpu(int cpu)
 
 /**
  * tick_nohz_update_jiffies - update jiffies when idle was interrupted
+ * @now: current ktime_t
  *
  * Called from interrupt entry when the CPU was idle
  *
@@ -794,7 +795,7 @@ static u64 get_cpu_sleep_time_us(struct tick_sched *ts, ktime_t *sleeptime,
  * This time is measured via accounting rather than sampling,
  * and is as accurate as ktime_get() is.
  *
- * This function returns -1 if NOHZ is not enabled.
+ * Return: -1 if NOHZ is not enabled, else total idle time of the @cpu
  */
 u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
 {
@@ -820,7 +821,7 @@ EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
  * This time is measured via accounting rather than sampling,
  * and is as accurate as ktime_get() is.
  *
- * This function returns -1 if NOHZ is not enabled.
+ * Return: -1 if NOHZ is not enabled, else total iowait time of @cpu
  */
 u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)
 {
@@ -1287,6 +1288,8 @@ void tick_nohz_irq_exit(void)
 
 /**
  * tick_nohz_idle_got_tick - Check whether or not the tick handler has run
+ *
+ * Return: %true if the tick handler has run, otherwise %false
  */
 bool tick_nohz_idle_got_tick(void)
 {
@@ -1305,6 +1308,8 @@ bool tick_nohz_idle_got_tick(void)
  * stopped, it returns the next hrtimer.
  *
  * Called from power state control code with interrupts disabled
+ *
+ * Return: the next expiration time
  */
 ktime_t tick_nohz_get_next_hrtimer(void)
 {
@@ -1320,6 +1325,8 @@ ktime_t tick_nohz_get_next_hrtimer(void)
  * The return value of this function and/or the value returned by it through the
  * @delta_next pointer can be negative which must be taken into account by its
  * callers.
+ *
+ * Return: the expected length of the current sleep
  */
 ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
 {
@@ -1357,8 +1364,11 @@ ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
 /**
  * tick_nohz_get_idle_calls_cpu - return the current idle calls counter value
  * for a particular CPU.
+ * @cpu: target CPU number
  *
  * Called from the schedutil frequency scaling governor in scheduler context.
+ *
+ * Return: the current idle calls counter value for @cpu
  */
 unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
 {
@@ -1371,6 +1381,8 @@ unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
  * tick_nohz_get_idle_calls - return the current idle calls counter value
  *
  * Called from the schedutil frequency scaling governor in scheduler context.
+ *
+ * Return: the current idle calls counter value for the current CPU
  */
 unsigned long tick_nohz_get_idle_calls(void)
 {
@@ -1559,7 +1571,7 @@ early_param("skew_tick", skew_tick);
 
 /**
  * tick_setup_sched_timer - setup the tick emulation timer
- * @mode: tick_nohz_mode to setup for
+ * @hrtimer: whether to use the hrtimer or not
  */
 void tick_setup_sched_timer(bool hrtimer)
 {
diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
index e11c4dc65bcb..b4a7822f495d 100644
--- a/kernel/time/tick-sched.h
+++ b/kernel/time/tick-sched.h
@@ -46,8 +46,8 @@ struct tick_device {
  * @next_tick:		Next tick to be fired when in dynticks mode.
  * @idle_jiffies:	jiffies at the entry to idle for idle time accounting
  * @idle_waketime:	Time when the idle was interrupted
+ * @idle_sleeptime_seq:	sequence counter for data consistency
  * @idle_entrytime:	Time when the idle call was entered
- * @nohz_mode:		Mode - one state of tick_nohz_mode
  * @last_jiffies:	Base jiffies snapshot when next event was last computed
  * @timer_expires_base:	Base time clock monotonic for @timer_expires
  * @timer_expires:	Anticipated timer expiration time (in case sched tick is stopped)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index dee29f1f5b75..3baf2fbe6848 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -64,15 +64,15 @@ EXPORT_SYMBOL(jiffies_64);
 
 /*
  * The timer wheel has LVL_DEPTH array levels. Each level provides an array of
- * LVL_SIZE buckets. Each level is driven by its own clock and therefor each
+ * LVL_SIZE buckets. Each level is driven by its own clock and therefore each
  * level has a different granularity.
  *
- * The level granularity is:		LVL_CLK_DIV ^ lvl
+ * The level granularity is:		LVL_CLK_DIV ^ level
  * The level clock frequency is:	HZ / (LVL_CLK_DIV ^ level)
  *
  * The array level of a newly armed timer depends on the relative expiry
  * time. The farther the expiry time is away the higher the array level and
- * therefor the granularity becomes.
+ * therefore the granularity becomes.
  *
  * Contrary to the original timer wheel implementation, which aims for 'exact'
  * expiry of the timers, this implementation removes the need for recascading
@@ -207,7 +207,7 @@ EXPORT_SYMBOL(jiffies_64);
  * struct timer_base - Per CPU timer base (number of base depends on config)
  * @lock:		Lock protecting the timer_base
  * @running_timer:	When expiring timers, the lock is dropped. To make
- *			sure not to race agains deleting/modifying a
+ *			sure not to race against deleting/modifying a
  *			currently running timer, the pointer is set to the
  *			timer, which expires at the moment. If no timer is
  *			running, the pointer is NULL.
@@ -737,7 +737,7 @@ static bool timer_is_static_object(void *addr)
 }
 
 /*
- * fixup_init is called when:
+ * timer_fixup_init is called when:
  * - an active object is initialized
  */
 static bool timer_fixup_init(void *addr, enum debug_obj_state state)
@@ -761,7 +761,7 @@ static void stub_timer(struct timer_list *unused)
 }
 
 /*
- * fixup_activate is called when:
+ * timer_fixup_activate is called when:
  * - an active object is activated
  * - an unknown non-static object is activated
  */
@@ -783,7 +783,7 @@ static bool timer_fixup_activate(void *addr, enum debug_obj_state state)
 }
 
 /*
- * fixup_free is called when:
+ * timer_fixup_free is called when:
  * - an active object is freed
  */
 static bool timer_fixup_free(void *addr, enum debug_obj_state state)
@@ -801,7 +801,7 @@ static bool timer_fixup_free(void *addr, enum debug_obj_state state)
 }
 
 /*
- * fixup_assert_init is called when:
+ * timer_fixup_assert_init is called when:
  * - an untracked/uninit-ed object is found
  */
 static bool timer_fixup_assert_init(void *addr, enum debug_obj_state state)
@@ -914,7 +914,7 @@ static void do_init_timer(struct timer_list *timer,
  * @key: lockdep class key of the fake lock used for tracking timer
  *       sync lock dependencies
  *
- * init_timer_key() must be done to a timer prior calling *any* of the
+ * init_timer_key() must be done to a timer prior to calling *any* of the
  * other timer functions.
  */
 void init_timer_key(struct timer_list *timer,
@@ -1417,7 +1417,7 @@ static int __timer_delete(struct timer_list *timer, bool shutdown)
 	 * If @shutdown is set then the lock has to be taken whether the
 	 * timer is pending or not to protect against a concurrent rearm
 	 * which might hit between the lockless pending check and the lock
-	 * aquisition. By taking the lock it is ensured that such a newly
+	 * acquisition. By taking the lock it is ensured that such a newly
 	 * enqueued timer is dequeued and cannot end up with
 	 * timer->function == NULL in the expiry code.
 	 *
@@ -2306,7 +2306,7 @@ static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem,
 
 		/*
 		 * When timer base is not set idle, undo the effect of
-		 * tmigr_cpu_deactivate() to prevent inconsitent states - active
+		 * tmigr_cpu_deactivate() to prevent inconsistent states - active
 		 * timer base but inactive timer migration hierarchy.
 		 *
 		 * When timer base was already marked idle, nothing will be
diff --git a/kernel/time/timer_migration.c b/kernel/time/timer_migration.c
index c63a0afdcebe..ccba875d2234 100644
--- a/kernel/time/timer_migration.c
+++ b/kernel/time/timer_migration.c
@@ -751,6 +751,33 @@ bool tmigr_update_events(struct tmigr_group *group, struct tmigr_group *child,
 
 		first_childevt = evt = data->evt;
 
+		/*
+		 * Walking the hierarchy is required in any case when a
+		 * remote expiry was done before. This ensures to not lose
+		 * already queued events in non active groups (see section
+		 * "Required event and timerqueue update after a remote
+		 * expiry" in the documentation at the top).
+		 *
+		 * The two call sites which are executed without a remote expiry
+		 * before, are not prevented from propagating changes through
+		 * the hierarchy by the return:
+		 *  - When entering this path by tmigr_new_timer(), @evt->ignore
+		 *    is never set.
+		 *  - tmigr_inactive_up() takes care of the propagation by
+		 *    itself and ignores the return value. But an immediate
+		 *    return is possible if there is a parent, sparing group
+		 *    locking at this level, because the upper walking call to
+		 *    the parent will take care about removing this event from
+		 *    within the group and update next_expiry accordingly.
+		 *
+		 * However if there is no parent, ie: the hierarchy has only a
+		 * single level so @group is the top level group, make sure the
+		 * first event information of the group is updated properly and
+		 * also handled properly, so skip this fast return path.
+		 */
+		if (evt->ignore && !remote && group->parent)
+			return true;
+
 		raw_spin_lock(&group->lock);
 
 		childstate.state = 0;
@@ -762,8 +789,11 @@ bool tmigr_update_events(struct tmigr_group *group, struct tmigr_group *child,
 	 * queue when the expiry time changed only or when it could be ignored.
 	 */
 	if (timerqueue_node_queued(&evt->nextevt)) {
-		if ((evt->nextevt.expires == nextexp) && !evt->ignore)
+		if ((evt->nextevt.expires == nextexp) && !evt->ignore) {
+			/* Make sure not to miss a new CPU event with the same expiry */
+			evt->cpu = first_childevt->cpu;
 			goto check_toplvl;
+		}
 
 		if (!timerqueue_del(&group->events, &evt->nextevt))
 			WRITE_ONCE(group->next_expiry, KTIME_MAX);