pm: policy: Fix possible undefined reference

When PM_POLICY_DEVICE_CONSTRAINTS is enabled, we create a list of
devices with the property “zephyr,disabling-power-states” and their
respective states to lock. However, if a device is declared but not
built (e.g., due to a Kconfig option), we have an undefined reference.

This PR changes the code to use the device name instead of the
reference. This increases lookup time (which could be cached at
runtime), and we still have an entry for a non-existent device.

Signed-off-by: Flavio Ceolin <[email protected]>

Author: ceolin

subsys/pm/policy/policy_device_lock.c

@@ -11,7 +11,7 @@
 #include <zephyr/pm/device.h>
 
 struct pm_state_device_constraint {
-	const struct device *const dev;
+	const char *const dev;
 	size_t pm_constraints_size;
 	struct pm_state_constraint *constraints;
 };
@@ -71,7 +71,7 @@ DT_FOREACH_STATUS_OKAY_NODE(DEVICE_CONSTRAINTS_DEFINE)
  */
 #define PM_STATE_DEVICE_CONSTRAINT_INIT(node_id)                                              \
 	{                                                                                     \
-		.dev = DEVICE_DT_GET(node_id),                                                \
+		.dev = DEVICE_DT_NAME(node_id),                                                \
 		.pm_constraints_size = DT_PROP_LEN(node_id, zephyr_disabling_power_states),   \
 		.constraints = PM_CONSTRAINTS_NAME(node_id),                                  \
 	},
@@ -91,7 +91,9 @@ void pm_policy_device_power_lock_get(const struct device *dev)
 {
 #if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
 	for (size_t i = 0; i < ARRAY_SIZE(_devices_constraints); i++) {
-		if (_devices_constraints[i].dev == dev) {
+		const struct device *device = device_get_binding(_devices_constraints[i].dev);
+
+		if ((device != NULL) && (device == dev)) {
 			for (size_t j = 0; j < _devices_constraints[i].pm_constraints_size; j++) {
 				pm_policy_state_lock_get(
 						_devices_constraints[i].constraints[j].state,
@@ -107,7 +109,9 @@ void pm_policy_device_power_lock_put(const struct device *dev)
 {
 #if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
 	for (size_t i = 0; i < ARRAY_SIZE(_devices_constraints); i++) {
-		if (_devices_constraints[i].dev == dev) {
+		const struct device *device = device_get_binding(_devices_constraints[i].dev);
+
+		if ((device != NULL) && (device == dev)) {
 			for (size_t j = 0; j < _devices_constraints[i].pm_constraints_size; j++) {
 				pm_policy_state_lock_put(
 						_devices_constraints[i].constraints[j].state,