dm: core: Add device-based 'read' functions to access DT
It is common to read a device-tree property from the node associated with a device. Add convenience functions to do this so that drivers do not need to deal with accessing the ofnode from the device. These functions all start with 'dev_read_' to provide consistent naming for all functions which read information from a device's device tree node. These are inlined when using the flat DT to save code size. The live tree implementation is added in a later commit. Signed-off-by: Simon Glass <sjg@chromium.org>
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@ -215,4 +215,8 @@ config OF_ISA_BUS
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mistranslation of device addresses, so ensure that this is
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enabled if your board does include an ISA bus.
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config DM_DEV_READ_INLINE
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bool
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default y if !OF_LIVE
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endmenu
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383
include/dm/read.h
Normal file
383
include/dm/read.h
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@ -0,0 +1,383 @@
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/*
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* Function to read values from the device tree node attached to a udevice.
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*
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* Copyright (c) 2017 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef _DM_READ_H
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#define _DM_READ_H
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#include <dm/fdtaddr.h>
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#include <dm/ofnode.h>
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#include <dm/uclass.h>
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#if CONFIG_IS_ENABLED(OF_LIVE)
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static inline const struct device_node *dev_np(struct udevice *dev)
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{
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return ofnode_to_np(dev->node);
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}
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#else
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static inline const struct device_node *dev_np(struct udevice *dev)
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{
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return NULL;
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}
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#endif
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/**
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* dev_ofnode() - get the DT node reference associated with a udevice
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*
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* @dev: device to check
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* @return reference of the the device's DT node
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*/
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static inline ofnode dev_ofnode(struct udevice *dev)
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{
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return dev->node;
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}
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static inline bool dev_of_valid(struct udevice *dev)
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{
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return ofnode_valid(dev_ofnode(dev));
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}
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#ifdef CONFIG_DM_DEV_READ_INLINE
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static inline int dev_read_u32_default(struct udevice *dev,
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const char *propname, int def)
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{
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return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
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}
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/**
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* dev_read_string() - Read a string from a device's DT property
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*
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* @dev: device to read DT property from
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* @propname: name of the property to read
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* @return string from property value, or NULL if there is no such property
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*/
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static inline const char *dev_read_string(struct udevice *dev,
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const char *propname)
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{
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return ofnode_read_string(dev_ofnode(dev), propname);
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}
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/**
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* dev_read_bool() - read a boolean value from a device's DT property
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*
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* @dev: device to read DT property from
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* @propname: name of property to read
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* @return true if property is present (meaning true), false if not present
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*/
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static inline bool dev_read_bool(struct udevice *dev, const char *propname)
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{
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return ofnode_read_bool(dev_ofnode(dev), propname);
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}
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/**
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* dev_read_subnode() - find a named subnode of a device
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*
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* @dev: device whose DT node contains the subnode
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* @subnode_name: name of subnode to find
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* @return reference to subnode (which can be invalid if there is no such
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* subnode)
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*/
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static inline ofnode dev_read_subnode(struct udevice *dev,
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const char *subbnode_name)
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{
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return ofnode_find_subnode(dev_ofnode(dev), subbnode_name);
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}
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/**
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* dev_read_size() - read the size of a property
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*
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* @dev: device to check
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* @propname: property to check
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* @return size of property if present, or -EINVAL if not
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*/
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static inline int dev_read_size(struct udevice *dev, const char *propname)
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{
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return ofnode_read_size(dev_ofnode(dev), propname);
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}
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/**
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* dev_read_addr_index() - Get the indexed reg property of a device
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*
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* @dev: Device to read from
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* @index: the 'reg' property can hold a list of <addr, size> pairs
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* and @index is used to select which one is required
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*
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* @return address or FDT_ADDR_T_NONE if not found
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*/
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static inline fdt_addr_t dev_read_addr_index(struct udevice *dev, int index)
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{
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return devfdt_get_addr_index(dev, index);
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}
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/**
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* dev_read_addr() - Get the reg property of a device
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*
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* @dev: Device to read from
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*
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* @return address or FDT_ADDR_T_NONE if not found
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*/
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static inline fdt_addr_t dev_read_addr(struct udevice *dev)
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{
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return devfdt_get_addr(dev);
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}
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/**
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* dev_read_addr_size() - get address and size from a device property
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*
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* This does no address translation. It simply reads an property that contains
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* an address and a size value, one after the other.
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*
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* @dev: Device to read from
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* @propname: property to read
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* @sizep: place to put size value (on success)
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* @return address value, or FDT_ADDR_T_NONE on error
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*/
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static inline fdt_addr_t dev_read_addr_size(struct udevice *dev,
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const char *propname,
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fdt_size_t *sizep)
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{
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return ofnode_get_addr_size(dev_ofnode(dev), propname, sizep);
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}
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/**
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* dev_read_name() - get the name of a device's node
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*
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* @node: valid node to look up
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* @return name of node
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*/
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static inline const char *dev_read_name(struct udevice *dev)
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{
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return ofnode_get_name(dev_ofnode(dev));
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}
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/**
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* dev_read_stringlist_search() - find string in a string list and return index
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*
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* Note that it is possible for this function to succeed on property values
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* that are not NUL-terminated. That's because the function will stop after
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* finding the first occurrence of @string. This can for example happen with
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* small-valued cell properties, such as #address-cells, when searching for
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* the empty string.
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*
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* @dev: device to check
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* @propname: name of the property containing the string list
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* @string: string to look up in the string list
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*
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* @return:
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* the index of the string in the list of strings
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* -ENODATA if the property is not found
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* -EINVAL on some other error
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*/
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static inline int dev_read_stringlist_search(struct udevice *dev,
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const char *propname,
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const char *string)
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{
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return ofnode_stringlist_search(dev_ofnode(dev), propname, string);
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}
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/**
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* dev_read_phandle_with_args() - Find a node pointed by phandle in a list
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*
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* This function is useful to parse lists of phandles and their arguments.
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* Returns 0 on success and fills out_args, on error returns appropriate
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* errno value.
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*
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* Caller is responsible to call of_node_put() on the returned out_args->np
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* pointer.
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*
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* Example:
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*
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* phandle1: node1 {
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* #list-cells = <2>;
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* }
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*
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* phandle2: node2 {
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* #list-cells = <1>;
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* }
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*
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* node3 {
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* list = <&phandle1 1 2 &phandle2 3>;
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* }
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*
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* To get a device_node of the `node2' node you may call this:
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* dev_read_phandle_with_args(dev, "list", "#list-cells", 0, 1, &args);
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*
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* @dev: device whose node containing a list
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* @list_name: property name that contains a list
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* @cells_name: property name that specifies phandles' arguments count
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* @cells_count: Cell count to use if @cells_name is NULL
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* @index: index of a phandle to parse out
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* @out_args: optional pointer to output arguments structure (will be filled)
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* @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
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* @list_name does not exist, -EINVAL if a phandle was not found,
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* @cells_name could not be found, the arguments were truncated or there
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* were too many arguments.
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*/
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static inline int dev_read_phandle_with_args(struct udevice *dev,
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const char *list_name, const char *cells_name, int cell_count,
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int index, struct ofnode_phandle_args *out_args)
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{
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return ofnode_parse_phandle_with_args(dev_ofnode(dev), list_name,
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cells_name, cell_count, index,
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out_args);
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}
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/**
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* dev_read_addr_cells() - Get the number of address cells for a device's node
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*
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* This walks back up the tree to find the closest #address-cells property
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* which controls the given node.
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*
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* @dev: devioe to check
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* @return number of address cells this node uses
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*/
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static inline int dev_read_addr_cells(struct udevice *dev)
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{
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return fdt_address_cells(gd->fdt_blob, dev_of_offset(dev));
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}
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/**
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* dev_read_size_cells() - Get the number of size cells for a device's node
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*
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* This walks back up the tree to find the closest #size-cells property
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* which controls the given node.
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*
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* @dev: devioe to check
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* @return number of size cells this node uses
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*/
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static inline int dev_read_size_cells(struct udevice *dev)
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{
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return fdt_size_cells(gd->fdt_blob, dev_of_offset(dev));
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}
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/**
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* dev_read_phandle() - Get the phandle from a device
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*
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* @dev: device to check
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* @return phandle (1 or greater), or 0 if no phandle or other error
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*/
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static inline int dev_read_phandle(struct udevice *dev)
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{
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return fdt_get_phandle(gd->fdt_blob, dev_of_offset(dev));
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}
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/**
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* dev_read_prop()- - read a property from a device's node
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*
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* @dev: device to check
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* @propname: property to read
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* @lenp: place to put length on success
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* @return pointer to property, or NULL if not found
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*/
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static inline const u32 *dev_read_prop(struct udevice *dev,
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const char *propname, int *lenp)
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{
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return ofnode_read_prop(dev_ofnode(dev), propname, lenp);
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}
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/**
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* dev_read_alias_seq() - Get the alias sequence number of a node
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*
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* This works out whether a node is pointed to by an alias, and if so, the
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* sequence number of that alias. Aliases are of the form <base><num> where
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* <num> is the sequence number. For example spi2 would be sequence number 2.
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*
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* @dev: device to look up
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* @devnump: set to the sequence number if one is found
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* @return 0 if a sequence was found, -ve if not
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*/
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static inline int dev_read_alias_seq(struct udevice *dev, int *devnump)
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{
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return fdtdec_get_alias_seq(gd->fdt_blob, dev->uclass->uc_drv->name,
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dev_of_offset(dev), devnump);
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}
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/**
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* dev_read_u32_array() - Find and read an array of 32 bit integers
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*
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* Search for a property in a device node and read 32-bit value(s) from
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* it.
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*
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* The out_values is modified only if a valid u32 value can be decoded.
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*
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* @dev: device to look up
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* @propname: name of the property to read
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* @out_values: pointer to return value, modified only if return value is 0
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* @sz: number of array elements to read
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* @return 0 on success, -EINVAL if the property does not exist, -ENODATA if
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* property does not have a value, and -EOVERFLOW if the property data isn't
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* large enough.
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*/
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static inline int dev_read_u32_array(struct udevice *dev, const char *propname,
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u32 *out_values, size_t sz)
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{
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return ofnode_read_u32_array(dev_ofnode(dev), propname, out_values, sz);
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}
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/**
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* dev_read_first_subnode() - find the first subnode of a device's node
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*
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* @dev: device to look up
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* @return reference to the first subnode (which can be invalid if the device's
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* node has no subnodes)
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*/
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static inline ofnode dev_read_first_subnode(struct udevice *dev)
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{
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return ofnode_first_subnode(dev_ofnode(dev));
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}
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/**
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* ofnode_next_subnode() - find the next sibling of a subnode
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*
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* @node: valid reference to previous node (sibling)
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* @return reference to the next subnode (which can be invalid if the node
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* has no more siblings)
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*/
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static inline ofnode dev_read_next_subnode(ofnode node)
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{
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return ofnode_next_subnode(node);
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}
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/**
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* dev_read_u8_array_ptr() - find an 8-bit array
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*
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* Look up a device's node property and return a pointer to its contents as a
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* byte array of given length. The property must have at least enough data
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* for the array (count bytes). It may have more, but this will be ignored.
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* The data is not copied.
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*
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* @dev: device to look up
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* @propname: name of property to find
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* @sz: number of array elements
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* @return pointer to byte array if found, or NULL if the property is not
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* found or there is not enough data
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*/
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static inline const uint8_t *dev_read_u8_array_ptr(struct udevice *dev,
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const char *propname, size_t sz)
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{
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return ofnode_read_u8_array_ptr(dev_ofnode(dev), propname, sz);
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}
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#endif /* CONFIG_DM_DEV_READ_INLINE */
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/**
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* dev_for_each_subnode() - Helper function to iterate through subnodes
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*
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* This creates a for() loop which works through the subnodes in a device's
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* device-tree node.
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*
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* @subnode: ofnode holding the current subnode
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* @dev: device to use for interation (struct udevice *)
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*/
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#define dev_for_each_subnode(subnode, dev) \
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for (subnode = dev_read_first_subnode(dev); \
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ofnode_valid(subnode); \
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subnode = ofnode_next_subnode(subnode))
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#endif
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