zephyrCommon: Make configurable the max number of tones

Allows you to change the maximum number of notes that can be
played with `tone()`.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

Author: soburi

Kconfig

@@ -34,4 +34,11 @@ config ARDUINO_ENTRY
 	bool "Provide arduino setup and loop entry points"
 	default y
 
+config ARDUINO_MAX_TONES
+	int "Maximum number of tones that can be played simultaneously with tone()"
+	default -1
+	help
+	  Specify the maximum number of tones that can be played simultaneously with tone().
+	  If set to a negative value, the maximum number will be determined from the
+	  system's digital pin configuration.
 endif

cores/arduino/zephyrCommon.cpp

@@ -7,6 +7,8 @@
 #include <Arduino.h>
 #include "zephyrInternal.h"
 
+#include <zephyr/spinlock.h>
+
 static const struct gpio_dt_spec arduino_pins[] = {DT_FOREACH_PROP_ELEM_SEP(
 	DT_PATH(zephyr_user), digital_pin_gpios, GPIO_DT_SPEC_GET_BY_IDX, (, ))};
 
@@ -212,25 +214,59 @@ PinStatus digitalRead(pin_size_t pinNumber) {
   return (gpio_pin_get_dt(&arduino_pins[pinNumber]) == 1) ? HIGH : LOW;
 }
 
-#ifndef MAX_TONE_PINS
+#if CONFIG_ARDUINO_MAX_TONES < 0
 #define MAX_TONE_PINS DT_PROP_LEN(DT_PATH(zephyr_user), digital_pin_gpios)
+#else
+#define MAX_TONE_PINS CONFIG_ARDUINO_MAX_TONES
 #endif
 
 #define TOGGLES_PER_CYCLE 2ULL
 
 static struct pin_timer {
   struct k_timer timer;
-  uint32_t count;
-  pin_size_t pin;
-  bool infinity;
+  uint32_t count{0};
+  pin_size_t pin{pin_size_t(-1)};
+  bool infinity{false};
+  struct k_spinlock lock;
 } arduino_pin_timers[MAX_TONE_PINS];
 
+static struct pin_timer* find_pin_timer(pin_size_t pinNumber, bool active_only) {
+  size_t unusedIndex = size_t(-1);
+
+  for (size_t i = 0; i < ARRAY_SIZE(arduino_pin_timers); i++) {
+    k_spinlock_key_t key = k_spin_lock(&arduino_pin_timers[i].lock);
+    size_t pin = arduino_pin_timers[i].pin;
+
+    k_spin_unlock(&arduino_pin_timers[i].lock, key);
+
+
+    if (pin == pin_size_t(-1)) {
+      unusedIndex = i;
+    }
+
+    if (pin == pinNumber) {
+      return &arduino_pin_timers[i];
+    }
+  }
+
+  if (unusedIndex != size_t(-1) && !active_only) {
+    return &arduino_pin_timers[unusedIndex];
+  }
+
+  return nullptr;
+}
+
 void tone_expiry_cb(struct k_timer *timer) {
   struct pin_timer *pt = CONTAINER_OF(timer, struct pin_timer, timer);
   const struct gpio_dt_spec *spec = &arduino_pins[pt->pin];
+  k_spinlock_key_t key;
 
   if (pt->count == 0 && !pt->infinity) {
+    key = k_spin_lock(&pt->lock);
     k_timer_stop(timer);
+    pt->pin = pin_size_t(-1);
+    k_spin_unlock(&pt->lock, key);
+
     gpio_pin_set_dt(spec, 0);
   } else {
     gpio_pin_toggle_dt(spec);
@@ -241,17 +277,18 @@ void tone_expiry_cb(struct k_timer *timer) {
 void tone(pin_size_t pinNumber, unsigned int frequency,
           unsigned long duration) {
   const struct gpio_dt_spec *spec = &arduino_pins[pinNumber];
-  struct k_timer *timer;
+  k_spinlock_key_t key;
+  struct pin_timer *pt;
   k_timeout_t timeout;
 
-  if (pinNumber >= MAX_TONE_PINS) {
+  pt = find_pin_timer(pinNumber, false);
+
+  if (pt == nullptr) {
     return;
   }
 
-  timer = &arduino_pin_timers[pinNumber].timer;
-
   pinMode(pinNumber, OUTPUT);
-  k_timer_stop(&arduino_pin_timers[pinNumber].timer);
+  k_timer_stop(&pt->timer);
 
   if (frequency == 0) {
     gpio_pin_set_dt(spec, 0);
@@ -263,20 +300,34 @@ void tone(pin_size_t pinNumber, unsigned int frequency,
     timeout.ticks = 1;
   }
 
-  arduino_pin_timers[pinNumber].infinity = (duration == 0);
-  arduino_pin_timers[pinNumber].count = (uint64_t)duration * frequency *
-				        (MSEC_PER_SEC / TOGGLES_PER_CYCLE);
-  arduino_pin_timers[pinNumber].pin = pinNumber;
-  k_timer_init(timer, tone_expiry_cb, NULL);
+  key = k_spin_lock(&pt->lock);
+  pt->infinity = (duration == 0);
+  pt->count = (uint64_t)duration * frequency * (MSEC_PER_SEC / TOGGLES_PER_CYCLE);
+  pt->pin = pinNumber;
+  k_spin_unlock(&pt->lock, key);
+
+  k_timer_init(&pt->timer, tone_expiry_cb, NULL);
 
   gpio_pin_set_dt(spec, 0);
-  k_timer_start(timer, timeout, timeout);
+  k_timer_start(&pt->timer, timeout, timeout);
 }
 
 void noTone(pin_size_t pinNumber) {
   const struct gpio_dt_spec *spec = &arduino_pins[pinNumber];
+  struct pin_timer *pt;
+  k_spinlock_key_t key;
+
+  pt = find_pin_timer(pinNumber, true);
+
+  if (pt == nullptr) {
+    return;
+  }
+
+  key = k_spin_lock(&pt->lock);
+  k_timer_stop(&pt->timer);
+  pt->pin = pin_size_t(-1);
+  k_spin_unlock(&pt->lock, key);
 
-  k_timer_stop(&arduino_pin_timers[pinNumber].timer);
   gpio_pin_set_dt(spec, 0);
 }