device: re-implement device_init

Re-implement device_init using device_get(). For now, recommend
direct usage of device_get(). This allows to keep client code the
same regardless of when a device is initialized.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

Author: gmarull

include/zephyr/device.h

@@ -835,22 +835,6 @@ size_t z_device_get_all_static(const struct device **devices);
  */
 __syscall bool device_is_ready(const struct device *dev);
 
-/**
- * @brief Initialize a device.
- *
- * A device whose initialization was deferred (by marking it as
- * ``zephyr,deferred-init`` on devicetree) needs to be initialized manually via
- * this call. Note that only devices whose initialization was deferred can be
- * initialized via this call - one can not try to initialize a non
- * initialization deferred device that failed initialization with this call.
- *
- * @param dev device to be initialized.
- *
- * @retval -ENOENT If device was not found - or isn't a deferred one.
- * @retval -errno For other errors.
- */
-__syscall int device_init(const struct device *dev);
-
 /**
  * Get a device.
  *
@@ -866,6 +850,27 @@ __syscall int device_init(const struct device *dev);
  */
 __syscall int device_get(const struct device *dev);
 
+/**
+ * @brief Initialize a device.
+ *
+ * A device whose initialization was deferred (by marking it as
+ * ``zephyr,deferred-init`` on devicetree) needs to be initialized manually via
+ * this call. Note that only devices whose initialization was deferred can be
+ * initialized via this call - one can not try to initialize a non
+ * initialization deferred device that failed initialization with this call.
+ *
+ * @param dev device to be initialized.
+ *
+ * @note Usage of device_get() is preferred, this function will be deprecated.
+ *
+ * @retval -ENOENT If device was not found - or isn't a deferred one.
+ * @retval -errno For other errors.
+ */
+static inline int device_init(const struct device *dev)
+{
+	return device_get(dev);
+}
+
 /**
  * @}
  */

kernel/init.c

@@ -373,33 +373,6 @@ static void z_sys_init_run_level(enum init_level level)
 	}
 }
 
-
-int z_impl_device_init(const struct device *dev)
-{
-	const struct device *devs;
-	size_t devc;
-
-	devc = z_device_get_all_static(&devs);
-
-	for (const struct device *dev_ = devs; dev_ < (devs + devc); dev_++) {
-		if ((dev_ == dev) && ((dev->flags & DEVICE_FLAG_INIT_DEFERRED) != 0U)) {
-			return do_device_init(dev);
-		}
-	}
-
-	return -ENOENT;
-}
-
-#ifdef CONFIG_USERSPACE
-static inline int z_vrfy_device_init(const struct device *dev)
-{
-	K_OOPS(K_SYSCALL_OBJ_INIT(dev, K_OBJ_ANY));
-
-	return z_impl_device_init(dev);
-}
-#include <zephyr/syscalls/device_init_mrsh.c>
-#endif
-
 extern void boot_banner(void);
 
 #ifdef CONFIG_BOOTARGS