linux-next/include/linux/of_graph.h
Kuninori Morimoto 58fe47d6ac of: property: add of_graph_get_next_port_endpoint()
We already have of_graph_get_next_endpoint(), but it is not
intuitive to use in some case.

(X)	node {
(Y)		ports {
(P0)			port@0 { endpoint { remote-endpoint = ...; };};
(P10)			port@1 { endpoint { remote-endpoint = ...; };
(P11)				 endpoint { remote-endpoint = ...; };};
(P2)			port@2 { endpoint { remote-endpoint = ...; };};
		};
	};

For example, if I want to handle port@1's 2 endpoints (= P10, P11),
I want to use like below

	P10 = of_graph_get_next_endpoint(port1, NULL);
	P11 = of_graph_get_next_endpoint(port1, P10);

But 1st one will be error, because of_graph_get_next_endpoint()
requested 1st parameter is "node" (X) or "ports" (Y), not but "port".
Below works well, but it will get P0

	P0 = of_graph_get_next_endpoint(node,  NULL);
	P0 = of_graph_get_next_endpoint(ports, NULL);

In other words, we can't handle P10/P11 directly via
of_graph_get_next_endpoint().

There is another non intuitive behavior on of_graph_get_next_endpoint().
In case of if I could get P10 pointer for some way, and if I want to
handle port@1 things by loop, I would like use it like below

	/*
	 * "ep" is now P10, and handle port1 things here,
	 * but we don't know how many endpoints port1 have.
	 *
	 * Because "ep" is non NULL now, we can use port1
	 * as of_graph_get_next_endpoint(port1, xxx)
	 */
	do {
		/* do something for port1 specific things here */
	} while (ep = of_graph_get_next_endpoint(port1, ep))

But it also not worked as I expected.
I expect it will be P10 -> P11 -> NULL,
but      it will be P10 -> P11 -> P2,    because
of_graph_get_next_endpoint() will fetch "endpoint" beyond the "port".
It is not useful for generic driver.

To handle endpoint more intuitive, create of_graph_get_next_port_endpoint()

	of_graph_get_next_port_endpoint(port1, NULL); // P10
	of_graph_get_next_port_endpoint(port1, P10);  // P11
	of_graph_get_next_port_endpoint(port1, P11);  // NULL

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87jzdyb5t5.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
2024-10-24 16:35:48 -05:00

177 lines
5.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* OF graph binding parsing helpers
*
* Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
* Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
*
* Copyright (C) 2012 Renesas Electronics Corp.
* Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
*/
#ifndef __LINUX_OF_GRAPH_H
#define __LINUX_OF_GRAPH_H
#include <linux/cleanup.h>
#include <linux/types.h>
#include <linux/errno.h>
/**
* struct of_endpoint - the OF graph endpoint data structure
* @port: identifier (value of reg property) of a port this endpoint belongs to
* @id: identifier (value of reg property) of this endpoint
* @local_node: pointer to device_node of this endpoint
*/
struct of_endpoint {
unsigned int port;
unsigned int id;
const struct device_node *local_node;
};
/**
* for_each_endpoint_of_node - iterate over every endpoint in a device node
* @parent: parent device node containing ports and endpoints
* @child: loop variable pointing to the current endpoint node
*
* When breaking out of the loop, of_node_put(child) has to be called manually.
*/
#define for_each_endpoint_of_node(parent, child) \
for (child = of_graph_get_next_endpoint(parent, NULL); child != NULL; \
child = of_graph_get_next_endpoint(parent, child))
/**
* for_each_of_graph_port - iterate over every port in a device or ports node
* @parent: parent device or ports node containing port
* @child: loop variable pointing to the current port node
*
* When breaking out of the loop, and continue to use the @child, you need to
* use return_ptr(@child) or no_free_ptr(@child) not to call __free() for it.
*/
#define for_each_of_graph_port(parent, child) \
for (struct device_node *child __free(device_node) = of_graph_get_next_port(parent, NULL);\
child != NULL; child = of_graph_get_next_port(parent, child))
/**
* for_each_of_graph_port_endpoint - iterate over every endpoint in a port node
* @parent: parent port node
* @child: loop variable pointing to the current endpoint node
*
* When breaking out of the loop, and continue to use the @child, you need to
* use return_ptr(@child) or no_free_ptr(@child) not to call __free() for it.
*/
#define for_each_of_graph_port_endpoint(parent, child) \
for (struct device_node *child __free(device_node) = of_graph_get_next_port_endpoint(parent, NULL);\
child != NULL; child = of_graph_get_next_port_endpoint(parent, child))
#ifdef CONFIG_OF
bool of_graph_is_present(const struct device_node *node);
int of_graph_parse_endpoint(const struct device_node *node,
struct of_endpoint *endpoint);
unsigned int of_graph_get_endpoint_count(const struct device_node *np);
unsigned int of_graph_get_port_count(struct device_node *np);
struct device_node *of_graph_get_port_by_id(struct device_node *node, u32 id);
struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
struct device_node *previous);
struct device_node *of_graph_get_next_port(const struct device_node *parent,
struct device_node *port);
struct device_node *of_graph_get_next_port_endpoint(const struct device_node *port,
struct device_node *prev);
struct device_node *of_graph_get_endpoint_by_regs(
const struct device_node *parent, int port_reg, int reg);
struct device_node *of_graph_get_remote_endpoint(
const struct device_node *node);
struct device_node *of_graph_get_port_parent(struct device_node *node);
struct device_node *of_graph_get_remote_port_parent(
const struct device_node *node);
struct device_node *of_graph_get_remote_port(const struct device_node *node);
struct device_node *of_graph_get_remote_node(const struct device_node *node,
u32 port, u32 endpoint);
#else
static inline bool of_graph_is_present(const struct device_node *node)
{
return false;
}
static inline int of_graph_parse_endpoint(const struct device_node *node,
struct of_endpoint *endpoint)
{
return -ENOSYS;
}
static inline unsigned int of_graph_get_endpoint_count(const struct device_node *np)
{
return 0;
}
static inline unsigned int of_graph_get_port_count(struct device_node *np)
{
return 0;
}
static inline struct device_node *of_graph_get_port_by_id(
struct device_node *node, u32 id)
{
return NULL;
}
static inline struct device_node *of_graph_get_next_endpoint(
const struct device_node *parent,
struct device_node *previous)
{
return NULL;
}
static inline struct device_node *of_graph_get_next_port(
const struct device_node *parent,
struct device_node *previous)
{
return NULL;
}
static inline struct device_node *of_graph_get_next_port_endpoint(
const struct device_node *parent,
struct device_node *previous)
{
return NULL;
}
static inline struct device_node *of_graph_get_endpoint_by_regs(
const struct device_node *parent, int port_reg, int reg)
{
return NULL;
}
static inline struct device_node *of_graph_get_remote_endpoint(
const struct device_node *node)
{
return NULL;
}
static inline struct device_node *of_graph_get_port_parent(
struct device_node *node)
{
return NULL;
}
static inline struct device_node *of_graph_get_remote_port_parent(
const struct device_node *node)
{
return NULL;
}
static inline struct device_node *of_graph_get_remote_port(
const struct device_node *node)
{
return NULL;
}
static inline struct device_node *of_graph_get_remote_node(
const struct device_node *node,
u32 port, u32 endpoint)
{
return NULL;
}
#endif /* CONFIG_OF */
#endif /* __LINUX_OF_GRAPH_H */