pm: device: Remove transitional states

PM_DEVICE_STATE_RESUMING and PM_DEVICE_STATE_SUSPENDING
are transitional states and are only used in device runtime. Remove it
and use device flag to keep track of a transition.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>

doc/reference/power_management/index.rst

@@ -253,16 +253,6 @@ The four device power states:
    Most device context is lost by the hardware. Device drivers must save and
    restore or reinitialize any context lost by the hardware.
 
-:code:`PM_DEVICE_STATE_SUSPENDING`
-
-   Device is currently transitioning from :c:macro:`PM_DEVICE_STATE_ACTIVE` to
-   :c:macro:`PM_DEVICE_STATE_SUSPENDED`.
-
-:code:`PM_DEVICE_STATE_RESUMING`
-
-   Device is currently transitioning from :c:macro:`PM_DEVICE_STATE_SUSPENDED`
-   to :c:macro:`PM_DEVICE_STATE_ACTIVE`.
-
 :code:`PM_DEVICE_STATE_OFF`
 
    Power has been fully removed from the device. The device context is lost

include/pm/device.h

@@ -48,11 +48,7 @@ enum pm_device_state {
 	 * @note
 	 *     Device context is lost.
 	 */
-	PM_DEVICE_STATE_OFF,
+	PM_DEVICE_STATE_OFF
-	/** Device is being resumed. */
-	PM_DEVICE_STATE_RESUMING,
-	/** Device is being suspended. */
-	PM_DEVICE_STATE_SUSPENDING,
 };
 
 /** @brief Device PM flags. */
@@ -66,6 +62,8 @@ enum pm_device_flag {
 	PM_DEVICE_FLAGS_WS_CAPABLE,
 	/** Indicates if the device is being used as wakeup source. */
 	PM_DEVICE_FLAGS_WS_ENABLED,
+	/** Indicates that the device is changing its state */
+	PM_DEVICE_FLAG_TRANSITIONING,
 	/** Number of flags (internal use only). */
 	PM_DEVICE_FLAG_COUNT
 };
@@ -161,8 +159,9 @@ const char *pm_device_state_str(enum pm_device_state state);
  *
  * @retval 0 If successful.
  * @retval -ENOTSUP If requested state is not supported.
- * @retval -EALREADY If device is already at (or transitioning to) the requested
+ * @retval -EALREADY If device is already at the requested state.
- *         state.
+ * @retval -EBUSY If device is changing its state.
+
  * @retval Errno Other negative errno on failure.
  */
 int pm_device_state_set(const struct device *dev,

subsys/pm/device.c

@@ -103,10 +103,13 @@ int pm_device_state_set(const struct device *dev,
 		return -ENOSYS;
 	}
 
+	if (atomic_test_bit(&dev->pm->flags, PM_DEVICE_FLAG_TRANSITIONING)) {
+		return -EBUSY;
+	}
+
 	switch (state) {
 	case PM_DEVICE_STATE_SUSPENDED:
-		if ((dev->pm->state == PM_DEVICE_STATE_SUSPENDED) ||
+		if (dev->pm->state == PM_DEVICE_STATE_SUSPENDED) {
-		    (dev->pm->state == PM_DEVICE_STATE_SUSPENDING)) {
 			return -EALREADY;
 		} else if (dev->pm->state == PM_DEVICE_STATE_OFF) {
 			return -ENOTSUP;
@@ -115,8 +118,7 @@ int pm_device_state_set(const struct device *dev,
 		action = PM_DEVICE_ACTION_SUSPEND;
 		break;
 	case PM_DEVICE_STATE_ACTIVE:
-		if ((dev->pm->state == PM_DEVICE_STATE_ACTIVE) ||
+		if (dev->pm->state == PM_DEVICE_STATE_ACTIVE) {
-		    (dev->pm->state == PM_DEVICE_STATE_RESUMING)) {
 			return -EALREADY;
 		}
 

subsys/pm/device_runtime.c

@@ -24,6 +24,9 @@ static void pm_device_runtime_state_set(struct pm_device *pm)
 	const struct device *dev = pm->dev;
 	int ret = 0;
 
+	/* Clear transitioning flags */
+	atomic_clear_bit(&dev->pm->flags, PM_DEVICE_FLAG_TRANSITIONING);
+
 	switch (dev->pm->state) {
 	case PM_DEVICE_STATE_ACTIVE:
 		if ((dev->pm->usage == 0) && dev->pm->enable) {
@@ -35,11 +38,6 @@ static void pm_device_runtime_state_set(struct pm_device *pm)
 			ret = pm_device_state_set(dev, PM_DEVICE_STATE_ACTIVE);
 		}
 		break;
-	case PM_DEVICE_STATE_SUSPENDING:
-		__fallthrough;
-	case PM_DEVICE_STATE_RESUMING:
-		/* Do nothing: We are waiting for resume/suspend to finish */
-		break;
 	default:
 		LOG_ERR("Invalid state!!\n");
 	}
@@ -127,13 +125,13 @@ static int pm_device_request(const struct device *dev,
 
 	/* Return in case of Async request */
 	if (pm_flags & PM_DEVICE_ASYNC) {
+		atomic_set_bit(&dev->pm->flags, PM_DEVICE_FLAG_TRANSITIONING);
 		(void)k_work_schedule(&dev->pm->work, K_NO_WAIT);
 		goto out_unlock;
 	}
 
 	while ((k_work_delayable_is_pending(&dev->pm->work)) ||
-		(dev->pm->state == PM_DEVICE_STATE_SUSPENDING) ||
+	       atomic_test_bit(&dev->pm->flags, PM_DEVICE_FLAG_TRANSITIONING)) {
-		(dev->pm->state == PM_DEVICE_STATE_RESUMING)) {
 		ret = k_condvar_wait(&dev->pm->condvar, &dev->pm->lock,
 			       K_FOREVER);
 		if (ret != 0) {
@@ -238,8 +236,7 @@ int pm_device_wait(const struct device *dev, k_timeout_t timeout)
 
 	k_mutex_lock(&dev->pm->lock, K_FOREVER);
 	while ((k_work_delayable_is_pending(&dev->pm->work)) ||
-		(dev->pm->state == PM_DEVICE_STATE_SUSPENDING) ||
+	       atomic_test_bit(&dev->pm->flags, PM_DEVICE_FLAG_TRANSITIONING)) {
-		(dev->pm->state == PM_DEVICE_STATE_RESUMING)) {
 		ret = k_condvar_wait(&dev->pm->condvar, &dev->pm->lock,
 			       timeout);
 		if (ret != 0) {