1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2013 Texas Instruments
4  * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
5  */
6 
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/of_graph.h>
12 #include <linux/seq_file.h>
13 
14 #include <video/omapfb_dss.h>
15 
16 #include "dss.h"
17 
18 struct device_node *
19 omapdss_of_get_next_port(const struct device_node *parent,
20 			 struct device_node *prev)
21 {
22 	struct device_node *port = NULL;
23 
24 	if (!parent)
25 		return NULL;
26 
27 	if (!prev) {
28 		struct device_node *ports;
29 		/*
30 		 * It's the first call, we have to find a port subnode
31 		 * within this node or within an optional 'ports' node.
32 		 */
33 		ports = of_get_child_by_name(parent, "ports");
34 		if (ports)
35 			parent = ports;
36 
37 		port = of_get_child_by_name(parent, "port");
38 
39 		/* release the 'ports' node */
40 		of_node_put(ports);
41 	} else {
42 		struct device_node *ports;
43 
44 		ports = of_get_parent(prev);
45 		if (!ports)
46 			return NULL;
47 
48 		do {
49 			port = of_get_next_child(ports, prev);
50 			if (!port) {
51 				of_node_put(ports);
52 				return NULL;
53 			}
54 			prev = port;
55 		} while (!of_node_name_eq(port, "port"));
56 
57 		of_node_put(ports);
58 	}
59 
60 	return port;
61 }
62 EXPORT_SYMBOL_GPL(omapdss_of_get_next_port);
63 
64 struct device_node *
65 omapdss_of_get_next_endpoint(const struct device_node *parent,
66 			     struct device_node *prev)
67 {
68 	struct device_node *ep = NULL;
69 
70 	if (!parent)
71 		return NULL;
72 
73 	do {
74 		ep = of_get_next_child(parent, prev);
75 		if (!ep)
76 			return NULL;
77 		prev = ep;
78 	} while (!of_node_name_eq(ep, "endpoint"));
79 
80 	return ep;
81 }
82 EXPORT_SYMBOL_GPL(omapdss_of_get_next_endpoint);
83 
84 struct device_node *dss_of_port_get_parent_device(struct device_node *port)
85 {
86 	struct device_node *np;
87 	int i;
88 
89 	if (!port)
90 		return NULL;
91 
92 	np = of_get_parent(port);
93 
94 	for (i = 0; i < 2 && np; ++i) {
95 		struct property *prop;
96 
97 		prop = of_find_property(np, "compatible", NULL);
98 
99 		if (prop)
100 			return np;
101 
102 		np = of_get_next_parent(np);
103 	}
104 
105 	return NULL;
106 }
107 
108 u32 dss_of_port_get_port_number(struct device_node *port)
109 {
110 	int r;
111 	u32 reg;
112 
113 	r = of_property_read_u32(port, "reg", &reg);
114 	if (r)
115 		reg = 0;
116 
117 	return reg;
118 }
119 
120 static struct device_node *omapdss_of_get_remote_port(const struct device_node *node)
121 {
122 	struct device_node *np;
123 
124 	np = of_graph_get_remote_endpoint(node);
125 	if (!np)
126 		return NULL;
127 
128 	np = of_get_next_parent(np);
129 
130 	return np;
131 }
132 
133 struct device_node *
134 omapdss_of_get_first_endpoint(const struct device_node *parent)
135 {
136 	struct device_node *port, *ep;
137 
138 	port = omapdss_of_get_next_port(parent, NULL);
139 
140 	if (!port)
141 		return NULL;
142 
143 	ep = omapdss_of_get_next_endpoint(port, NULL);
144 
145 	of_node_put(port);
146 
147 	return ep;
148 }
149 EXPORT_SYMBOL_GPL(omapdss_of_get_first_endpoint);
150 
151 struct omap_dss_device *
152 omapdss_of_find_source_for_first_ep(struct device_node *node)
153 {
154 	struct device_node *ep;
155 	struct device_node *src_port;
156 	struct omap_dss_device *src;
157 
158 	ep = omapdss_of_get_first_endpoint(node);
159 	if (!ep)
160 		return ERR_PTR(-EINVAL);
161 
162 	src_port = omapdss_of_get_remote_port(ep);
163 	if (!src_port) {
164 		of_node_put(ep);
165 		return ERR_PTR(-EINVAL);
166 	}
167 
168 	of_node_put(ep);
169 
170 	src = omap_dss_find_output_by_port_node(src_port);
171 
172 	of_node_put(src_port);
173 
174 	return src ? src : ERR_PTR(-EPROBE_DEFER);
175 }
176 EXPORT_SYMBOL_GPL(omapdss_of_find_source_for_first_ep);
177