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>
This commit is contained in:
Simon Glass 2017-05-18 20:09:03 -06:00
parent b7e0d73bad
commit f11c7ab94d
2 changed files with 387 additions and 0 deletions

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@ -215,4 +215,8 @@ config OF_ISA_BUS
mistranslation of device addresses, so ensure that this is
enabled if your board does include an ISA bus.
config DM_DEV_READ_INLINE
bool
default y if !OF_LIVE
endmenu

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