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+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * (C) Copyright 2012
+ * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef _DM_UCLASS_H
+#define _DM_UCLASS_H
+
+#include <dm/uclass-id.h>
+#include <linux/list.h>
+
+/**
+ * struct uclass - a U-Boot drive class, collecting together similar drivers
+ *
+ * A uclass provides an interface to a particular function, which is
+ * implemented by one or more drivers. Every driver belongs to a uclass even
+ * if it is the only driver in that uclass. An example uclass is GPIO, which
+ * provides the ability to change read inputs, set and clear outputs, etc.
+ * There may be drivers for on-chip SoC GPIO banks, I2C GPIO expanders and
+ * PMIC IO lines, all made available in a unified way through the uclass.
+ *
+ * @priv: Private data for this uclass
+ * @uc_drv: The driver for the uclass itself, not to be confused with a
+ * 'struct driver'
+ * dev_head: List of devices in this uclass (devices are attached to their
+ * uclass when their bind method is called)
+ * @sibling_node: Next uclass in the linked list of uclasses
+ */
+struct uclass {
+ void *priv;
+ struct uclass_driver *uc_drv;
+ struct list_head dev_head;
+ struct list_head sibling_node;
+};
+
+struct device;
+
+/**
+ * struct uclass_driver - Driver for the uclass
+ *
+ * A uclass_driver provides a consistent interface to a set of related
+ * drivers.
+ *
+ * @name: Name of uclass driver
+ * @id: ID number of this uclass
+ * @post_bind: Called after a new device is bound to this uclass
+ * @pre_unbind: Called before a device is unbound from this uclass
+ * @post_probe: Called after a new device is probed
+ * @pre_remove: Called before a device is removed
+ * @init: Called to set up the uclass
+ * @destroy: Called to destroy the uclass
+ * @priv_auto_alloc_size: If non-zero this is the size of the private data
+ * to be allocated in the uclass's ->priv pointer. If zero, then the uclass
+ * driver is responsible for allocating any data required.
+ * @per_device_auto_alloc_size: Each device can hold private data owned
+ * by the uclass. If required this will be automatically allocated if this
+ * value is non-zero.
+ * @ops: Uclass operations, providing the consistent interface to devices
+ * within the uclass.
+ */
+struct uclass_driver {
+ const char *name;
+ enum uclass_id id;
+ int (*post_bind)(struct device *dev);
+ int (*pre_unbind)(struct device *dev);
+ int (*post_probe)(struct device *dev);
+ int (*pre_remove)(struct device *dev);
+ int (*init)(struct uclass *class);
+ int (*destroy)(struct uclass *class);
+ int priv_auto_alloc_size;
+ int per_device_auto_alloc_size;
+ const void *ops;
+};
+
+/* Declare a new uclass_driver */
+#define UCLASS_DRIVER(__name) \
+ ll_entry_declare(struct uclass_driver, __name, uclass)
+
+/**
+ * uclass_get() - Get a uclass based on an ID, creating it if needed
+ *
+ * Every uclass is identified by an ID, a number from 0 to n-1 where n is
+ * the number of uclasses. This function allows looking up a uclass by its
+ * ID.
+ *
+ * @key: ID to look up
+ * @ucp: Returns pointer to uclass (there is only one per ID)
+ * @return 0 if OK, -ve on error
+ */
+int uclass_get(enum uclass_id key, struct uclass **ucp);
+
+/**
+ * uclass_get_device() - Get a uclass device based on an ID and index
+ *
+ * id: ID to look up
+ * @index: Device number within that uclass (0=first)
+ * @ucp: Returns pointer to uclass (there is only one per for each ID)
+ * @return 0 if OK, -ve on error
+ */
+int uclass_get_device(enum uclass_id id, int index, struct device **ucp);
+
+/**
+ * uclass_first_device() - Get the first device in a uclass
+ *
+ * @id: Uclass ID to look up
+ * @devp: Returns pointer to the first device in that uclass, or NULL if none
+ * @return 0 if OK (found or not found), -1 on error
+ */
+int uclass_first_device(enum uclass_id id, struct device **devp);
+
+/**
+ * uclass_next_device() - Get the next device in a uclass
+ *
+ * @devp: On entry, pointer to device to lookup. On exit, returns pointer
+ * to the next device in the same uclass, or NULL if none
+ * @return 0 if OK (found or not found), -1 on error
+ */
+int uclass_next_device(struct device **devp);
+
+/**
+ * uclass_foreach_dev() - Helper function to iteration through devices
+ *
+ * This creates a for() loop which works through the available devices in
+ * a uclass in order from start to end.
+ *
+ * @pos: struct device * to hold the current device. Set to NULL when there
+ * are no more devices.
+ * uc: uclass to scan
+ */
+#define uclass_foreach_dev(pos, uc) \
+ for (pos = list_entry((&(uc)->dev_head)->next, typeof(*pos), \
+ uclass_node); \
+ prefetch(pos->uclass_node.next), \
+ &pos->uclass_node != (&(uc)->dev_head); \
+ pos = list_entry(pos->uclass_node.next, typeof(*pos), \
+ uclass_node))
+
+#endif