1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/component.h>
3 #include <linux/export.h>
4 #include <linux/list.h>
5 #include <linux/of_graph.h>
6
7 #include <drm/drm_bridge.h>
8 #include <drm/drm_crtc.h>
9 #include <drm/drm_device.h>
10 #include <drm/drm_encoder.h>
11 #include <drm/drm_of.h>
12 #include <drm/drm_panel.h>
13
14 /**
15 * DOC: overview
16 *
17 * A set of helper functions to aid DRM drivers in parsing standard DT
18 * properties.
19 */
20
21 static void drm_release_of(struct device *dev, void *data)
22 {
23 of_node_put(data);
24 }
25
26 /**
27 * drm_of_crtc_port_mask - find the mask of a registered CRTC by port OF node
28 * @dev: DRM device
29 * @port: port OF node
30 *
31 * Given a port OF node, return the possible mask of the corresponding
32 * CRTC within a device's list of CRTCs. Returns zero if not found.
33 */
34 uint32_t drm_of_crtc_port_mask(struct drm_device *dev,
35 struct device_node *port)
36 {
37 unsigned int index = 0;
38 struct drm_crtc *tmp;
39
40 drm_for_each_crtc(tmp, dev) {
41 if (tmp->port == port)
42 return 1 << index;
43
44 index++;
45 }
46
47 return 0;
48 }
49 EXPORT_SYMBOL(drm_of_crtc_port_mask);
50
51 /**
52 * drm_of_find_possible_crtcs - find the possible CRTCs for an encoder port
53 * @dev: DRM device
54 * @port: encoder port to scan for endpoints
55 *
56 * Scan all endpoints attached to a port, locate their attached CRTCs,
57 * and generate the DRM mask of CRTCs which may be attached to this
58 * encoder.
59 *
60 * See Documentation/devicetree/bindings/graph.txt for the bindings.
61 */
62 uint32_t drm_of_find_possible_crtcs(struct drm_device *dev,
63 struct device_node *port)
64 {
65 struct device_node *remote_port, *ep;
66 uint32_t possible_crtcs = 0;
67
68 for_each_endpoint_of_node(port, ep) {
69 remote_port = of_graph_get_remote_port(ep);
70 if (!remote_port) {
71 of_node_put(ep);
72 return 0;
73 }
74
75 possible_crtcs |= drm_of_crtc_port_mask(dev, remote_port);
76
77 of_node_put(remote_port);
78 }
79
80 return possible_crtcs;
81 }
82 EXPORT_SYMBOL(drm_of_find_possible_crtcs);
83
84 /**
85 * drm_of_component_match_add - Add a component helper OF node match rule
86 * @master: master device
87 * @matchptr: component match pointer
88 * @compare: compare function used for matching component
89 * @node: of_node
90 */
91 void drm_of_component_match_add(struct device *master,
92 struct component_match **matchptr,
93 int (*compare)(struct device *, void *),
94 struct device_node *node)
95 {
96 of_node_get(node);
97 component_match_add_release(master, matchptr, drm_release_of,
98 compare, node);
99 }
100 EXPORT_SYMBOL_GPL(drm_of_component_match_add);
101
102 /**
103 * drm_of_component_probe - Generic probe function for a component based master
104 * @dev: master device containing the OF node
105 * @compare_of: compare function used for matching components
106 * @m_ops: component master ops to be used
107 *
108 * Parse the platform device OF node and bind all the components associated
109 * with the master. Interface ports are added before the encoders in order to
110 * satisfy their .bind requirements
111 * See Documentation/devicetree/bindings/graph.txt for the bindings.
112 *
113 * Returns zero if successful, or one of the standard error codes if it fails.
114 */
115 int drm_of_component_probe(struct device *dev,
116 int (*compare_of)(struct device *, void *),
117 const struct component_master_ops *m_ops)
118 {
119 struct device_node *ep, *port, *remote;
120 struct component_match *match = NULL;
121 int i;
122
123 if (!dev->of_node)
124 return -EINVAL;
125
126 /*
127 * Bind the crtc's ports first, so that drm_of_find_possible_crtcs()
128 * called from encoder's .bind callbacks works as expected
129 */
130 for (i = 0; ; i++) {
131 port = of_parse_phandle(dev->of_node, "ports", i);
132 if (!port)
133 break;
134
135 if (of_device_is_available(port->parent))
136 drm_of_component_match_add(dev, &match, compare_of,
137 port);
138
139 of_node_put(port);
140 }
141
142 if (i == 0) {
143 dev_err(dev, "missing 'ports' property\n");
144 return -ENODEV;
145 }
146
147 if (!match) {
148 dev_err(dev, "no available port\n");
149 return -ENODEV;
150 }
151
152 /*
153 * For bound crtcs, bind the encoders attached to their remote endpoint
154 */
155 for (i = 0; ; i++) {
156 port = of_parse_phandle(dev->of_node, "ports", i);
157 if (!port)
158 break;
159
160 if (!of_device_is_available(port->parent)) {
161 of_node_put(port);
162 continue;
163 }
164
165 for_each_child_of_node(port, ep) {
166 remote = of_graph_get_remote_port_parent(ep);
167 if (!remote || !of_device_is_available(remote)) {
168 of_node_put(remote);
169 continue;
170 } else if (!of_device_is_available(remote->parent)) {
171 dev_warn(dev, "parent device of %pOF is not available\n",
172 remote);
173 of_node_put(remote);
174 continue;
175 }
176
177 drm_of_component_match_add(dev, &match, compare_of,
178 remote);
179 of_node_put(remote);
180 }
181 of_node_put(port);
182 }
183
184 return component_master_add_with_match(dev, m_ops, match);
185 }
186 EXPORT_SYMBOL(drm_of_component_probe);
187
188 /*
189 * drm_of_encoder_active_endpoint - return the active encoder endpoint
190 * @node: device tree node containing encoder input ports
191 * @encoder: drm_encoder
192 *
193 * Given an encoder device node and a drm_encoder with a connected crtc,
194 * parse the encoder endpoint connecting to the crtc port.
195 */
196 int drm_of_encoder_active_endpoint(struct device_node *node,
197 struct drm_encoder *encoder,
198 struct of_endpoint *endpoint)
199 {
200 struct device_node *ep;
201 struct drm_crtc *crtc = encoder->crtc;
202 struct device_node *port;
203 int ret;
204
205 if (!node || !crtc)
206 return -EINVAL;
207
208 for_each_endpoint_of_node(node, ep) {
209 port = of_graph_get_remote_port(ep);
210 of_node_put(port);
211 if (port == crtc->port) {
212 ret = of_graph_parse_endpoint(ep, endpoint);
213 of_node_put(ep);
214 return ret;
215 }
216 }
217
218 return -EINVAL;
219 }
220 EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);
221
222 /**
223 * drm_of_find_panel_or_bridge - return connected panel or bridge device
224 * @np: device tree node containing encoder output ports
225 * @port: port in the device tree node
226 * @endpoint: endpoint in the device tree node
227 * @panel: pointer to hold returned drm_panel
228 * @bridge: pointer to hold returned drm_bridge
229 *
230 * Given a DT node's port and endpoint number, find the connected node and
231 * return either the associated struct drm_panel or drm_bridge device. Either
232 * @panel or @bridge must not be NULL.
233 *
234 * Returns zero if successful, or one of the standard error codes if it fails.
235 */
236 int drm_of_find_panel_or_bridge(const struct device_node *np,
237 int port, int endpoint,
238 struct drm_panel **panel,
239 struct drm_bridge **bridge)
240 {
241 int ret = -EPROBE_DEFER;
242 struct device_node *remote;
243
244 if (!panel && !bridge)
245 return -EINVAL;
246 if (panel)
247 *panel = NULL;
248
249 remote = of_graph_get_remote_node(np, port, endpoint);
250 if (!remote)
251 return -ENODEV;
252
253 if (!of_device_is_available(remote)) {
254 of_node_put(remote);
255 return -ENODEV;
256 }
257
258 if (panel) {
259 *panel = of_drm_find_panel(remote);
260 if (!IS_ERR(*panel))
261 ret = 0;
262 else
263 *panel = NULL;
264 }
265
266 /* No panel found yet, check for a bridge next. */
267 if (bridge) {
268 if (ret) {
269 *bridge = of_drm_find_bridge(remote);
270 if (*bridge)
271 ret = 0;
272 } else {
273 *bridge = NULL;
274 }
275
276 }
277
278 of_node_put(remote);
279 return ret;
280 }
281 EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);