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.

1 files changed, 15 insertions, 3 deletions

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)
 {