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
 21static 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 */
 34uint32_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}
 49EXPORT_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 */
 62uint32_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}
 82EXPORT_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 */
 91void 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}
100EXPORT_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 */
115int 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}
186EXPORT_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 */
196int 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}
220EXPORT_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 */
236int 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	/*
250	 * of_graph_get_remote_node() produces a noisy error message if port
251	 * node isn't found and the absence of the port is a legit case here,
252	 * so at first we silently check whether graph presents in the
253	 * device-tree node.
254	 */
255	if (!of_graph_is_present(np))
256		return -ENODEV;
257
258	remote = of_graph_get_remote_node(np, port, endpoint);
259	if (!remote)
260		return -ENODEV;
261
262	if (panel) {
263		*panel = of_drm_find_panel(remote);
264		if (!IS_ERR(*panel))
265			ret = 0;
266		else
267			*panel = NULL;
268	}
269
270	/* No panel found yet, check for a bridge next. */
271	if (bridge) {
272		if (ret) {
273			*bridge = of_drm_find_bridge(remote);
274			if (*bridge)
275				ret = 0;
276		} else {
277			*bridge = NULL;
278		}
279
280	}
281
282	of_node_put(remote);
283	return ret;
284}
285EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
286
287enum drm_of_lvds_pixels {
288	DRM_OF_LVDS_EVEN = BIT(0),
289	DRM_OF_LVDS_ODD = BIT(1),
290};
291
292static int drm_of_lvds_get_port_pixels_type(struct device_node *port_node)
293{
294	bool even_pixels =
295		of_property_read_bool(port_node, "dual-lvds-even-pixels");
296	bool odd_pixels =
297		of_property_read_bool(port_node, "dual-lvds-odd-pixels");
298
299	return (even_pixels ? DRM_OF_LVDS_EVEN : 0) |
300	       (odd_pixels ? DRM_OF_LVDS_ODD : 0);
301}
302
303static int drm_of_lvds_get_remote_pixels_type(
304			const struct device_node *port_node)
305{
306	struct device_node *endpoint = NULL;
307	int pixels_type = -EPIPE;
308
309	for_each_child_of_node(port_node, endpoint) {
310		struct device_node *remote_port;
311		int current_pt;
312
313		if (!of_node_name_eq(endpoint, "endpoint"))
314			continue;
315
316		remote_port = of_graph_get_remote_port(endpoint);
317		if (!remote_port) {
318			of_node_put(remote_port);
319			return -EPIPE;
320		}
321
322		current_pt = drm_of_lvds_get_port_pixels_type(remote_port);
323		of_node_put(remote_port);
324		if (pixels_type < 0)
325			pixels_type = current_pt;
326
327		/*
328		 * Sanity check, ensure that all remote endpoints have the same
329		 * pixel type. We may lift this restriction later if we need to
330		 * support multiple sinks with different dual-link
331		 * configurations by passing the endpoints explicitly to
332		 * drm_of_lvds_get_dual_link_pixel_order().
333		 */
334		if (!current_pt || pixels_type != current_pt)
335			return -EINVAL;
336	}
337
338	return pixels_type;
339}
340
341/**
342 * drm_of_lvds_get_dual_link_pixel_order - Get LVDS dual-link pixel order
343 * @port1: First DT port node of the Dual-link LVDS source
344 * @port2: Second DT port node of the Dual-link LVDS source
345 *
346 * An LVDS dual-link connection is made of two links, with even pixels
347 * transitting on one link, and odd pixels on the other link. This function
348 * returns, for two ports of an LVDS dual-link source, which port shall transmit
349 * the even and odd pixels, based on the requirements of the connected sink.
350 *
351 * The pixel order is determined from the dual-lvds-even-pixels and
352 * dual-lvds-odd-pixels properties in the sink's DT port nodes. If those
353 * properties are not present, or if their usage is not valid, this function
354 * returns -EINVAL.
355 *
356 * If either port is not connected, this function returns -EPIPE.
357 *
358 * @port1 and @port2 are typically DT sibling nodes, but may have different
359 * parents when, for instance, two separate LVDS encoders carry the even and odd
360 * pixels.
361 *
362 * Return:
363 * * DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS - @port1 carries even pixels and @port2
364 *   carries odd pixels
365 * * DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS - @port1 carries odd pixels and @port2
366 *   carries even pixels
367 * * -EINVAL - @port1 and @port2 are not connected to a dual-link LVDS sink, or
368 *   the sink configuration is invalid
369 * * -EPIPE - when @port1 or @port2 are not connected
370 */
371int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
372					  const struct device_node *port2)
373{
374	int remote_p1_pt, remote_p2_pt;
375
376	if (!port1 || !port2)
377		return -EINVAL;
378
379	remote_p1_pt = drm_of_lvds_get_remote_pixels_type(port1);
380	if (remote_p1_pt < 0)
381		return remote_p1_pt;
382
383	remote_p2_pt = drm_of_lvds_get_remote_pixels_type(port2);
384	if (remote_p2_pt < 0)
385		return remote_p2_pt;
386
387	/*
388	 * A valid dual-lVDS bus is found when one remote port is marked with
389	 * "dual-lvds-even-pixels", and the other remote port is marked with
390	 * "dual-lvds-odd-pixels", bail out if the markers are not right.
391	 */
392	if (remote_p1_pt + remote_p2_pt != DRM_OF_LVDS_EVEN + DRM_OF_LVDS_ODD)
393		return -EINVAL;
394
395	return remote_p1_pt == DRM_OF_LVDS_EVEN ?
396		DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS :
397		DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS;
398}
399EXPORT_SYMBOL_GPL(drm_of_lvds_get_dual_link_pixel_order);