summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/drm_bridge_connector.c
blob: 6b3dad03d77d065f687a34781d009d06b5dc5336 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_bridge_connector.h>
#include <drm/drm_connector.h>
#include <drm/drm_device.h>
#include <drm/drm_edid.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_probe_helper.h>

/**
 * DOC: overview
 *
 * The DRM bridge connector helper object provides a DRM connector
 * implementation that wraps a chain of &struct drm_bridge. The connector
 * operations are fully implemented based on the operations of the bridges in
 * the chain, and don't require any intervention from the display controller
 * driver at runtime.
 *
 * To use the helper, display controller drivers create a bridge connector with
 * a call to drm_bridge_connector_init(). This associates the newly created
 * connector with the chain of bridges passed to the function and registers it
 * with the DRM device. At that point the connector becomes fully usable, no
 * further operation is needed.
 *
 * The DRM bridge connector operations are implemented based on the operations
 * provided by the bridges in the chain. Each connector operation is delegated
 * to the bridge closest to the connector (at the end of the chain) that
 * provides the relevant functionality.
 *
 * To make use of this helper, all bridges in the chain shall report bridge
 * operation flags (&drm_bridge->ops) and bridge output type
 * (&drm_bridge->type), as well as the DRM_BRIDGE_ATTACH_NO_CONNECTOR attach
 * flag (none of the bridges shall create a DRM connector directly).
 */

/**
 * struct drm_bridge_connector - A connector backed by a chain of bridges
 */
struct drm_bridge_connector {
	/**
	 * @base: The base DRM connector
	 */
	struct drm_connector base;
	/**
	 * @encoder:
	 *
	 * The encoder at the start of the bridges chain.
	 */
	struct drm_encoder *encoder;
	/**
	 * @bridge_edid:
	 *
	 * The last bridge in the chain (closest to the connector) that provides
	 * EDID read support, if any (see &DRM_BRIDGE_OP_EDID).
	 */
	struct drm_bridge *bridge_edid;
	/**
	 * @bridge_hpd:
	 *
	 * The last bridge in the chain (closest to the connector) that provides
	 * hot-plug detection notification, if any (see &DRM_BRIDGE_OP_HPD).
	 */
	struct drm_bridge *bridge_hpd;
	/**
	 * @bridge_detect:
	 *
	 * The last bridge in the chain (closest to the connector) that provides
	 * connector detection, if any (see &DRM_BRIDGE_OP_DETECT).
	 */
	struct drm_bridge *bridge_detect;
	/**
	 * @bridge_modes:
	 *
	 * The last bridge in the chain (closest to the connector) that provides
	 * connector modes detection, if any (see &DRM_BRIDGE_OP_MODES).
	 */
	struct drm_bridge *bridge_modes;
};

#define to_drm_bridge_connector(x) \
	container_of(x, struct drm_bridge_connector, base)

/* -----------------------------------------------------------------------------
 * Bridge Connector Hot-Plug Handling
 */

static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
					    enum drm_connector_status status)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);
	struct drm_bridge *bridge;

	/* Notify all bridges in the pipeline of hotplug events. */
	drm_for_each_bridge_in_chain(bridge_connector->encoder, bridge) {
		if (bridge->funcs->hpd_notify)
			bridge->funcs->hpd_notify(bridge, status);
	}
}

static void drm_bridge_connector_hpd_cb(void *cb_data,
					enum drm_connector_status status)
{
	struct drm_bridge_connector *drm_bridge_connector = cb_data;
	struct drm_connector *connector = &drm_bridge_connector->base;
	struct drm_device *dev = connector->dev;
	enum drm_connector_status old_status;

	mutex_lock(&dev->mode_config.mutex);
	old_status = connector->status;
	connector->status = status;
	mutex_unlock(&dev->mode_config.mutex);

	if (old_status == status)
		return;

	drm_bridge_connector_hpd_notify(connector, status);

	drm_kms_helper_hotplug_event(dev);
}

/**
 * drm_bridge_connector_enable_hpd - Enable hot-plug detection for the connector
 * @connector: The DRM bridge connector
 *
 * This function enables hot-plug detection for the given bridge connector.
 * This is typically used by display drivers in their resume handler.
 */
void drm_bridge_connector_enable_hpd(struct drm_connector *connector)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);
	struct drm_bridge *hpd = bridge_connector->bridge_hpd;

	if (hpd)
		drm_bridge_hpd_enable(hpd, drm_bridge_connector_hpd_cb,
				      bridge_connector);
}
EXPORT_SYMBOL_GPL(drm_bridge_connector_enable_hpd);

/**
 * drm_bridge_connector_disable_hpd - Disable hot-plug detection for the
 * connector
 * @connector: The DRM bridge connector
 *
 * This function disables hot-plug detection for the given bridge connector.
 * This is typically used by display drivers in their suspend handler.
 */
void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);
	struct drm_bridge *hpd = bridge_connector->bridge_hpd;

	if (hpd)
		drm_bridge_hpd_disable(hpd);
}
EXPORT_SYMBOL_GPL(drm_bridge_connector_disable_hpd);

/* -----------------------------------------------------------------------------
 * Bridge Connector Functions
 */

static enum drm_connector_status
drm_bridge_connector_detect(struct drm_connector *connector, bool force)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);
	struct drm_bridge *detect = bridge_connector->bridge_detect;
	enum drm_connector_status status;

	if (detect) {
		status = detect->funcs->detect(detect);

		drm_bridge_connector_hpd_notify(connector, status);
	} else {
		switch (connector->connector_type) {
		case DRM_MODE_CONNECTOR_DPI:
		case DRM_MODE_CONNECTOR_LVDS:
		case DRM_MODE_CONNECTOR_DSI:
		case DRM_MODE_CONNECTOR_eDP:
			status = connector_status_connected;
			break;
		default:
			status = connector_status_unknown;
			break;
		}
	}

	return status;
}

static void drm_bridge_connector_destroy(struct drm_connector *connector)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);

	if (bridge_connector->bridge_hpd) {
		struct drm_bridge *hpd = bridge_connector->bridge_hpd;

		drm_bridge_hpd_disable(hpd);
	}

	drm_connector_unregister(connector);
	drm_connector_cleanup(connector);

	kfree(bridge_connector);
}

static void drm_bridge_connector_debugfs_init(struct drm_connector *connector,
					      struct dentry *root)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);
	struct drm_encoder *encoder = bridge_connector->encoder;
	struct drm_bridge *bridge;

	list_for_each_entry(bridge, &encoder->bridge_chain, chain_node) {
		if (bridge->funcs->debugfs_init)
			bridge->funcs->debugfs_init(bridge, root);
	}
}

static const struct drm_connector_funcs drm_bridge_connector_funcs = {
	.reset = drm_atomic_helper_connector_reset,
	.detect = drm_bridge_connector_detect,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.destroy = drm_bridge_connector_destroy,
	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
	.debugfs_init = drm_bridge_connector_debugfs_init,
};

/* -----------------------------------------------------------------------------
 * Bridge Connector Helper Functions
 */

static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector,
					       struct drm_bridge *bridge)
{
	enum drm_connector_status status;
	struct edid *edid;
	int n;

	status = drm_bridge_connector_detect(connector, false);
	if (status != connector_status_connected)
		goto no_edid;

	edid = bridge->funcs->get_edid(bridge, connector);
	if (!drm_edid_is_valid(edid)) {
		kfree(edid);
		goto no_edid;
	}

	drm_connector_update_edid_property(connector, edid);
	n = drm_add_edid_modes(connector, edid);

	kfree(edid);
	return n;

no_edid:
	drm_connector_update_edid_property(connector, NULL);
	return 0;
}

static int drm_bridge_connector_get_modes(struct drm_connector *connector)
{
	struct drm_bridge_connector *bridge_connector =
		to_drm_bridge_connector(connector);
	struct drm_bridge *bridge;

	/*
	 * If display exposes EDID, then we parse that in the normal way to
	 * build table of supported modes.
	 */
	bridge = bridge_connector->bridge_edid;
	if (bridge)
		return drm_bridge_connector_get_modes_edid(connector, bridge);

	/*
	 * Otherwise if the display pipeline reports modes (e.g. with a fixed
	 * resolution panel or an analog TV output), query it.
	 */
	bridge = bridge_connector->bridge_modes;
	if (bridge)
		return bridge->funcs->get_modes(bridge, connector);

	/*
	 * We can't retrieve modes, which can happen for instance for a DVI or
	 * VGA output with the DDC bus unconnected. The KMS core will add the
	 * default modes.
	 */
	return 0;
}

static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = {
	.get_modes = drm_bridge_connector_get_modes,
	/* No need for .mode_valid(), the bridges are checked by the core. */
};

/* -----------------------------------------------------------------------------
 * Bridge Connector Initialisation
 */

/**
 * drm_bridge_connector_init - Initialise a connector for a chain of bridges
 * @drm: the DRM device
 * @encoder: the encoder where the bridge chain starts
 *
 * Allocate, initialise and register a &drm_bridge_connector with the @drm
 * device. The connector is associated with a chain of bridges that starts at
 * the @encoder. All bridges in the chain shall report bridge operation flags
 * (&drm_bridge->ops) and bridge output type (&drm_bridge->type), and none of
 * them may create a DRM connector directly.
 *
 * Returns a pointer to the new connector on success, or a negative error
 * pointer otherwise.
 */
struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
						struct drm_encoder *encoder)
{
	struct drm_bridge_connector *bridge_connector;
	struct drm_connector *connector;
	struct i2c_adapter *ddc = NULL;
	struct drm_bridge *bridge;
	int connector_type;

	bridge_connector = kzalloc(sizeof(*bridge_connector), GFP_KERNEL);
	if (!bridge_connector)
		return ERR_PTR(-ENOMEM);

	bridge_connector->encoder = encoder;

	/*
	 * TODO: Handle doublescan_allowed, stereo_allowed and
	 * ycbcr_420_allowed.
	 */
	connector = &bridge_connector->base;
	connector->interlace_allowed = true;

	/*
	 * Initialise connector status handling. First locate the furthest
	 * bridges in the pipeline that support HPD and output detection. Then
	 * initialise the connector polling mode, using HPD if available and
	 * falling back to polling if supported. If neither HPD nor output
	 * detection are available, we don't support hotplug detection at all.
	 */
	connector_type = DRM_MODE_CONNECTOR_Unknown;
	drm_for_each_bridge_in_chain(encoder, bridge) {
		if (!bridge->interlace_allowed)
			connector->interlace_allowed = false;

		if (bridge->ops & DRM_BRIDGE_OP_EDID)
			bridge_connector->bridge_edid = bridge;
		if (bridge->ops & DRM_BRIDGE_OP_HPD)
			bridge_connector->bridge_hpd = bridge;
		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
			bridge_connector->bridge_detect = bridge;
		if (bridge->ops & DRM_BRIDGE_OP_MODES)
			bridge_connector->bridge_modes = bridge;

		if (!drm_bridge_get_next_bridge(bridge))
			connector_type = bridge->type;

		if (bridge->ddc)
			ddc = bridge->ddc;
	}

	if (connector_type == DRM_MODE_CONNECTOR_Unknown) {
		kfree(bridge_connector);
		return ERR_PTR(-EINVAL);
	}

	drm_connector_init_with_ddc(drm, connector, &drm_bridge_connector_funcs,
				    connector_type, ddc);
	drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);

	if (bridge_connector->bridge_hpd) {
		connector->polled = DRM_CONNECTOR_POLL_HPD;
		drm_bridge_connector_enable_hpd(connector);
	}
	else if (bridge_connector->bridge_detect)
		connector->polled = DRM_CONNECTOR_POLL_CONNECT
				  | DRM_CONNECTOR_POLL_DISCONNECT;

	return connector;
}
EXPORT_SYMBOL_GPL(drm_bridge_connector_init);