zephyrCommon: Use available tone timers

To allow more flexible timer allocation,
we search for and use unused timers.

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

Author: soburi

cores/arduino/zephyrCommon.cpp

@@ -221,7 +221,7 @@ PinStatus digitalRead(pin_size_t pinNumber) {
 static struct pin_timer {
   struct k_timer timer;
   uint32_t count;
-  pin_size_t pin;
+  pin_size_t pin{pin_size_t(-1)};
   bool infinity;
 } arduino_pin_timers[MAX_TONE_PINS];
 
@@ -232,6 +232,7 @@ void tone_expiry_cb(struct k_timer *timer) {
   if (pt->count == 0) {
     k_timer_stop(timer);
     gpio_pin_set_dt(spec, 0);
+    pt->pin = pin_size_t(-1);
   } else {
     gpio_pin_toggle_dt(spec);
     if (!pt->infinity) {
@@ -243,17 +244,24 @@ 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];
+  size_t timerIndex = -1;
   struct k_timer *timer;
   k_timeout_t timeout;
 
-  if (pinNumber >= MAX_TONE_PINS) {
+  for (size_t i = 0; i < ARRAY_SIZE(arduino_pin_timers); i++) {
+    if (arduino_pin_timers[i].pin == pin_size_t(-1)) {
+      timerIndex = i;
+    }
+  }
+
+  if (timerIndex == size_t(-1)) {
     return;
   }
 
-  timer = &arduino_pin_timers[pinNumber].timer;
+  timer = &arduino_pin_timers[timerIndex].timer;
 
   pinMode(pinNumber, OUTPUT);
-  k_timer_stop(&arduino_pin_timers[pinNumber].timer);
+  k_timer_stop(&arduino_pin_timers[timerIndex].timer);
 
   if (frequency == 0) {
     gpio_pin_set_dt(spec, 0);
@@ -265,10 +273,10 @@ 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 *
+  arduino_pin_timers[timerIndex].infinity = (duration == 0);
+  arduino_pin_timers[timerIndex].count = (uint64_t)duration * frequency *
 				        (MSEC_PER_SEC / TOGGLES_PER_CYCLE);
-  arduino_pin_timers[pinNumber].pin = pinNumber;
+  arduino_pin_timers[timerIndex].pin = pinNumber;
   k_timer_init(timer, tone_expiry_cb, NULL);
 
   gpio_pin_set_dt(spec, 0);
@@ -277,9 +285,21 @@ void tone(pin_size_t pinNumber, unsigned int frequency,
 
 void noTone(pin_size_t pinNumber) {
   const struct gpio_dt_spec *spec = &arduino_pins[pinNumber];
+  uint32_t timerIndex = -1;
+
+  for (size_t i = 0; i < ARRAY_SIZE(arduino_pin_timers); i++) {
+    if (arduino_pin_timers[i].pin == pinNumber) {
+      timerIndex = i;
+    }
+  }
+
+  if (timerIndex == size_t(-1)) {
+    return;
+  }
 
-  k_timer_stop(&arduino_pin_timers[pinNumber].timer);
+  k_timer_stop(&arduino_pin_timers[timerIndex].timer);
   gpio_pin_set_dt(spec, 0);
+  arduino_pin_timers[timerIndex].pin = pin_size_t(-1);
 }
 
 void delay(unsigned long ms) {