Fix pwmio on iMX RT.

It now handles deinit, never_reset and sharing tracking. PWM
now runs in the WAIT state as well during a time.sleep().

_reset_ok() was removed because it was called in one spot right
before deinit().

Some PWMOut were also switched to a bitmap for use instead of
reference count. That way init and deinit are idempotent.

Fixes #6589. Fixes #4841. Fixes #4541.

Author: tannewt

ports/atmel-samd/common-hal/pwmio/PWMOut.c

@@ -67,10 +67,6 @@ void common_hal_pwmio_pwmout_never_reset(pwmio_pwmout_obj_t *self) {
     never_reset_pin_number(self->pin->number);
 }
 
-void common_hal_pwmio_pwmout_reset_ok(pwmio_pwmout_obj_t *self) {
-    timer_reset_ok(self->timer->index, self->timer->is_tc);
-}
-
 void pwmout_reset(void) {
     // Reset all timers
     for (int i = 0; i < TCC_INST_NUM; i++) {
@@ -267,6 +263,7 @@ void common_hal_pwmio_pwmout_deinit(pwmio_pwmout_obj_t *self) {
     if (common_hal_pwmio_pwmout_deinited(self)) {
         return;
     }
+    timer_reset_ok(self->timer->index, self->timer->is_tc);
     const pin_timer_t *t = self->timer;
     if (t->is_tc) {
         Tc *tc = tc_insts[t->index];

ports/cxd56/common-hal/pwmio/PWMOut.c

@@ -90,6 +90,8 @@ void common_hal_pwmio_pwmout_deinit(pwmio_pwmout_obj_t *self) {
         return;
     }
 
+    pwmout_dev[self->number].reset = true;
+
     ioctl(pwmout_dev[self->number].fd, PWMIOC_STOP, 0);
     close(pwmout_dev[self->number].fd);
     pwmout_dev[self->number].fd = -1;
@@ -134,10 +136,6 @@ void common_hal_pwmio_pwmout_never_reset(pwmio_pwmout_obj_t *self) {
     pwmout_dev[self->number].reset = false;
 }
 
-void common_hal_pwmio_pwmout_reset_ok(pwmio_pwmout_obj_t *self) {
-    pwmout_dev[self->number].reset = true;
-}
-
 void pwmout_reset(void) {
     for (int i = 0; i < MP_ARRAY_SIZE(pwmout_dev); i++) {
         if (pwmout_dev[i].fd >= 0 && pwmout_dev[i].reset) {

ports/espressif/common-hal/pwmio/PWMOut.c

@@ -164,24 +164,6 @@ void common_hal_pwmio_pwmout_never_reset(pwmio_pwmout_obj_t *self) {
     never_reset_pin_number(self->pin->number);
 }
 
-void common_hal_pwmio_pwmout_reset_ok(pwmio_pwmout_obj_t *self) {
-    never_reset_tim[self->tim_handle.timer_num] = false;
-    // Search if any other channel is using the timer and is never reset.
-    // Otherwise, we clear never_reset for the timer as well.
-    bool other_never_reset = false;
-    for (size_t i = 0; i < LEDC_CHANNEL_MAX; i++) {
-        if (i != self->chan_handle.channel &&
-            reserved_channels[i] == self->tim_handle.timer_num &&
-            never_reset_chan[i]) {
-            other_never_reset = true;
-            break;
-        }
-    }
-    if (!other_never_reset) {
-        never_reset_chan[self->chan_handle.channel] = false;
-    }
-}
-
 bool common_hal_pwmio_pwmout_deinited(pwmio_pwmout_obj_t *self) {
     return self->deinited == true;
 }
@@ -196,14 +178,21 @@ void common_hal_pwmio_pwmout_deinit(pwmio_pwmout_obj_t *self) {
     }
     reserved_channels[self->chan_handle.channel] = INDEX_EMPTY;
     never_reset_chan[self->chan_handle.channel] = false;
+
     // Search if any other channel is using the timer
     bool taken = false;
+    bool other_never_reset = false;
     for (size_t i = 0; i < LEDC_CHANNEL_MAX; i++) {
         if (reserved_channels[i] == self->tim_handle.timer_num) {
             taken = true;
+            other_never_reset = never_reset_chan[i];
             break;
         }
     }
+    // Clear the timer's never reset if the other channel isn't never reset.
+    if (!other_never_reset) {
+        never_reset_tim[self->tim_handle.timer_num] = false;
+    }
     // Variable frequency means there's only one channel on the timer
     if (!taken || self->variable_frequency) {
         ledc_timer_rst(LEDC_LOW_SPEED_MODE, self->tim_handle.timer_num);