1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2014 Texas Instruments
4 * Author: Tomi Valkeinen <tomi.valkeinen@ti.com>
5 */
6
7/*
8 * As omapdss panel drivers are omapdss specific, but we want to define the
9 * DT-data in generic manner, we convert the compatible strings of the panel and
10 * encoder nodes from "panel-foo" to "omapdss,panel-foo". This way we can have
11 * both correct DT data and omapdss specific drivers.
12 *
13 * When we get generic panel drivers to the kernel, this file will be removed.
14 */
15
16#include <linux/kernel.h>
17#include <linux/of.h>
18#include <linux/of_graph.h>
19#include <linux/slab.h>
20#include <linux/list.h>
21
22static struct list_head dss_conv_list __initdata;
23
24static const char prefix[] __initconst = "omapdss,";
25
26struct dss_conv_node {
27	struct list_head list;
28	struct device_node *node;
29	bool root;
30};
31
32static int __init omapdss_count_strings(const struct property *prop)
33{
34	const char *p = prop->value;
35	int l = 0, total = 0;
36	int i;
37
38	for (i = 0; total < prop->length; total += l, p += l, i++)
39		l = strlen(p) + 1;
40
41	return i;
42}
43
44static void __init omapdss_update_prop(struct device_node *node, char *compat,
45	int len)
46{
47	struct property *prop;
48
49	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
50	if (!prop)
51		return;
52
53	prop->name = "compatible";
54	prop->value = compat;
55	prop->length = len;
56
57	of_update_property(node, prop);
58}
59
60static void __init omapdss_prefix_strcpy(char *dst, int dst_len,
61	const char *src, int src_len)
62{
63	size_t total = 0;
64
65	while (total < src_len) {
66		size_t l = strlen(src) + 1;
67
68		strcpy(dst, prefix);
69		dst += strlen(prefix);
70
71		strcpy(dst, src);
72		dst += l;
73
74		src += l;
75		total += l;
76	}
77}
78
79/* prepend compatible property strings with "omapdss," */
80static void __init omapdss_omapify_node(struct device_node *node)
81{
82	struct property *prop;
83	char *new_compat;
84	int num_strs;
85	int new_len;
86
87	prop = of_find_property(node, "compatible", NULL);
88
89	if (!prop || !prop->value)
90		return;
91
92	if (strnlen(prop->value, prop->length) >= prop->length)
93		return;
94
95	/* is it already prefixed? */
96	if (strncmp(prefix, prop->value, strlen(prefix)) == 0)
97		return;
98
99	num_strs = omapdss_count_strings(prop);
100
101	new_len = prop->length + strlen(prefix) * num_strs;
102	new_compat = kmalloc(new_len, GFP_KERNEL);
103	if (!new_compat)
104		return;
105
106	omapdss_prefix_strcpy(new_compat, new_len, prop->value, prop->length);
107
108	omapdss_update_prop(node, new_compat, new_len);
109}
110
111static void __init omapdss_add_to_list(struct device_node *node, bool root)
112{
113	struct dss_conv_node *n = kmalloc(sizeof(struct dss_conv_node),
114		GFP_KERNEL);
115	if (n) {
116		n->node = node;
117		n->root = root;
118		list_add(&n->list, &dss_conv_list);
119	}
120}
121
122static bool __init omapdss_list_contains(const struct device_node *node)
123{
124	struct dss_conv_node *n;
125
126	list_for_each_entry(n, &dss_conv_list, list) {
127		if (n->node == node)
128			return true;
129	}
130
131	return false;
132}
133
134static void __init omapdss_walk_device(struct device_node *node, bool root)
135{
136	struct device_node *n;
137
138	omapdss_add_to_list(node, root);
139
140	/*
141	 * of_graph_get_remote_port_parent() prints an error if there is no
142	 * port/ports node. To avoid that, check first that there's the node.
143	 */
144	n = of_get_child_by_name(node, "ports");
145	if (!n)
146		n = of_get_child_by_name(node, "port");
147	if (!n)
148		return;
149
150	of_node_put(n);
151
152	n = NULL;
153	while ((n = of_graph_get_next_endpoint(node, n)) != NULL) {
154		struct device_node *pn;
155
156		pn = of_graph_get_remote_port_parent(n);
157
158		if (!pn)
159			continue;
160
161		if (!of_device_is_available(pn) || omapdss_list_contains(pn)) {
162			of_node_put(pn);
163			continue;
164		}
165
166		omapdss_walk_device(pn, false);
167	}
168}
169
170static const struct of_device_id omapdss_of_match[] __initconst = {
171	{ .compatible = "ti,omap2-dss", },
172	{ .compatible = "ti,omap3-dss", },
173	{ .compatible = "ti,omap4-dss", },
174	{ .compatible = "ti,omap5-dss", },
175	{ .compatible = "ti,dra7-dss", },
176	{},
177};
178
179static int __init omapdss_boot_init(void)
180{
181	struct device_node *dss, *child;
182
183	INIT_LIST_HEAD(&dss_conv_list);
184
185	dss = of_find_matching_node(NULL, omapdss_of_match);
186
187	if (dss == NULL || !of_device_is_available(dss)) {
188		of_node_put(dss);
189		return 0;
190	}
191
192	omapdss_walk_device(dss, true);
193
194	for_each_available_child_of_node(dss, child) {
195		if (!of_property_present(child, "compatible"))
196			continue;
197
198		omapdss_walk_device(child, true);
199	}
200
201	while (!list_empty(&dss_conv_list)) {
202		struct dss_conv_node *n;
203
204		n = list_first_entry(&dss_conv_list, struct dss_conv_node,
205			list);
206
207		if (!n->root)
208			omapdss_omapify_node(n->node);
209
210		list_del(&n->list);
211		of_node_put(n->node);
212		kfree(n);
213	}
214
215	return 0;
216}
217
218subsys_initcall(omapdss_boot_init);
219