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 
22 static struct list_head dss_conv_list __initdata;
23 
24 static const char prefix[] __initconst = "omapdss,";
25 
26 struct dss_conv_node {
27 	struct list_head list;
28 	struct device_node *node;
29 	bool root;
30 };
31 
omapdss_count_strings(const struct property * prop)32 static 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 
omapdss_update_prop(struct device_node * node,char * compat,int len)44 static 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 
omapdss_prefix_strcpy(char * dst,int dst_len,const char * src,int src_len)60 static 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," */
omapdss_omapify_node(struct device_node * node)80 static 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 
omapdss_add_to_list(struct device_node * node,bool root)111 static 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 
omapdss_list_contains(const struct device_node * node)122 static 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 
omapdss_walk_device(struct device_node * node,bool root)134 static 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 
170 static 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 
omapdss_boot_init(void)179 static 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 
218 subsys_initcall(omapdss_boot_init);
219