1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * USB Typec-C DisplayPort Alternate Mode driver
4 *
5 * Copyright (C) 2018 Intel Corporation
6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
7 *
8 * DisplayPort is trademark of VESA (www.vesa.org)
9 */
10
11 #include <linux/delay.h>
12 #include <linux/mutex.h>
13 #include <linux/module.h>
14 #include <linux/property.h>
15 #include <linux/usb/pd_vdo.h>
16 #include <linux/usb/typec_dp.h>
17 #include <drm/drm_connector.h>
18 #include "displayport.h"
19
20 #define DP_HEADER(_dp, ver, cmd) (VDO((_dp)->alt->svid, 1, ver, cmd) \
21 | VDO_OPOS(USB_TYPEC_DP_MODE))
22
23 enum {
24 DP_CONF_USB,
25 DP_CONF_DFP_D,
26 DP_CONF_UFP_D,
27 DP_CONF_DUAL_D,
28 };
29
30 /* Pin assignments that use USB3.1 Gen2 signaling to carry DP protocol */
31 #define DP_PIN_ASSIGN_GEN2_BR_MASK (BIT(DP_PIN_ASSIGN_A) | \
32 BIT(DP_PIN_ASSIGN_B))
33
34 /* Pin assignments that use DP v1.3 signaling to carry DP protocol */
35 #define DP_PIN_ASSIGN_DP_BR_MASK (BIT(DP_PIN_ASSIGN_C) | \
36 BIT(DP_PIN_ASSIGN_D) | \
37 BIT(DP_PIN_ASSIGN_E) | \
38 BIT(DP_PIN_ASSIGN_F))
39
40 /* DP only pin assignments */
41 #define DP_PIN_ASSIGN_DP_ONLY_MASK (BIT(DP_PIN_ASSIGN_A) | \
42 BIT(DP_PIN_ASSIGN_C) | \
43 BIT(DP_PIN_ASSIGN_E))
44
45 /* Pin assignments where one channel is for USB */
46 #define DP_PIN_ASSIGN_MULTI_FUNC_MASK (BIT(DP_PIN_ASSIGN_B) | \
47 BIT(DP_PIN_ASSIGN_D) | \
48 BIT(DP_PIN_ASSIGN_F))
49
50 enum dp_state {
51 DP_STATE_IDLE,
52 DP_STATE_ENTER,
53 DP_STATE_UPDATE,
54 DP_STATE_CONFIGURE,
55 DP_STATE_EXIT,
56 };
57
58 struct dp_altmode {
59 struct typec_displayport_data data;
60
61 enum dp_state state;
62 bool hpd;
63
64 struct mutex lock; /* device lock */
65 struct work_struct work;
66 struct typec_altmode *alt;
67 const struct typec_altmode *port;
68 struct fwnode_handle *connector_fwnode;
69 };
70
dp_altmode_notify(struct dp_altmode * dp)71 static int dp_altmode_notify(struct dp_altmode *dp)
72 {
73 unsigned long conf;
74 u8 state;
75
76 if (dp->data.conf) {
77 state = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
78 conf = TYPEC_MODAL_STATE(state);
79 } else {
80 conf = TYPEC_STATE_USB;
81 }
82
83 return typec_altmode_notify(dp->alt, conf, &dp->data);
84 }
85
dp_altmode_configure(struct dp_altmode * dp,u8 con)86 static int dp_altmode_configure(struct dp_altmode *dp, u8 con)
87 {
88 u32 conf = DP_CONF_SIGNALING_DP; /* Only DP signaling supported */
89 u8 pin_assign = 0;
90
91 switch (con) {
92 case DP_STATUS_CON_DISABLED:
93 return 0;
94 case DP_STATUS_CON_DFP_D:
95 conf |= DP_CONF_UFP_U_AS_DFP_D;
96 pin_assign = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo) &
97 DP_CAP_DFP_D_PIN_ASSIGN(dp->port->vdo);
98 break;
99 case DP_STATUS_CON_UFP_D:
100 case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */
101 conf |= DP_CONF_UFP_U_AS_UFP_D;
102 pin_assign = DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo) &
103 DP_CAP_PIN_ASSIGN_DFP_D(dp->port->vdo);
104 break;
105 default:
106 break;
107 }
108
109 /* Determining the initial pin assignment. */
110 if (!DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) {
111 /* Is USB together with DP preferred */
112 if (dp->data.status & DP_STATUS_PREFER_MULTI_FUNC &&
113 pin_assign & DP_PIN_ASSIGN_MULTI_FUNC_MASK)
114 pin_assign &= DP_PIN_ASSIGN_MULTI_FUNC_MASK;
115 else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK)
116 pin_assign &= DP_PIN_ASSIGN_DP_ONLY_MASK;
117
118 if (!pin_assign)
119 return -EINVAL;
120
121 conf |= DP_CONF_SET_PIN_ASSIGN(pin_assign);
122 }
123
124 dp->data.conf = conf;
125
126 return 0;
127 }
128
dp_altmode_status_update(struct dp_altmode * dp)129 static int dp_altmode_status_update(struct dp_altmode *dp)
130 {
131 bool configured = !!DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
132 bool hpd = !!(dp->data.status & DP_STATUS_HPD_STATE);
133 u8 con = DP_STATUS_CONNECTION(dp->data.status);
134 int ret = 0;
135
136 if (configured && (dp->data.status & DP_STATUS_SWITCH_TO_USB)) {
137 dp->data.conf = 0;
138 dp->state = DP_STATE_CONFIGURE;
139 } else if (dp->data.status & DP_STATUS_EXIT_DP_MODE) {
140 dp->state = DP_STATE_EXIT;
141 } else if (!(con & DP_CONF_CURRENTLY(dp->data.conf))) {
142 ret = dp_altmode_configure(dp, con);
143 if (!ret)
144 dp->state = DP_STATE_CONFIGURE;
145 } else {
146 if (dp->hpd != hpd) {
147 drm_connector_oob_hotplug_event(dp->connector_fwnode);
148 dp->hpd = hpd;
149 }
150 }
151
152 return ret;
153 }
154
dp_altmode_configured(struct dp_altmode * dp)155 static int dp_altmode_configured(struct dp_altmode *dp)
156 {
157 sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration");
158 sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment");
159
160 return dp_altmode_notify(dp);
161 }
162
dp_altmode_configure_vdm(struct dp_altmode * dp,u32 conf)163 static int dp_altmode_configure_vdm(struct dp_altmode *dp, u32 conf)
164 {
165 int svdm_version = typec_altmode_get_svdm_version(dp->alt);
166 u32 header;
167 int ret;
168
169 if (svdm_version < 0)
170 return svdm_version;
171
172 header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE);
173 ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data);
174 if (ret) {
175 dev_err(&dp->alt->dev,
176 "unable to put to connector to safe mode\n");
177 return ret;
178 }
179
180 ret = typec_altmode_vdm(dp->alt, header, &conf, 2);
181 if (ret)
182 dp_altmode_notify(dp);
183
184 return ret;
185 }
186
dp_altmode_work(struct work_struct * work)187 static void dp_altmode_work(struct work_struct *work)
188 {
189 struct dp_altmode *dp = container_of(work, struct dp_altmode, work);
190 int svdm_version;
191 u32 header;
192 u32 vdo;
193 int ret;
194
195 mutex_lock(&dp->lock);
196
197 switch (dp->state) {
198 case DP_STATE_ENTER:
199 ret = typec_altmode_enter(dp->alt, NULL);
200 if (ret && ret != -EBUSY)
201 dev_err(&dp->alt->dev, "failed to enter mode\n");
202 break;
203 case DP_STATE_UPDATE:
204 svdm_version = typec_altmode_get_svdm_version(dp->alt);
205 if (svdm_version < 0)
206 break;
207 header = DP_HEADER(dp, svdm_version, DP_CMD_STATUS_UPDATE);
208 vdo = 1;
209 ret = typec_altmode_vdm(dp->alt, header, &vdo, 2);
210 if (ret)
211 dev_err(&dp->alt->dev,
212 "unable to send Status Update command (%d)\n",
213 ret);
214 break;
215 case DP_STATE_CONFIGURE:
216 ret = dp_altmode_configure_vdm(dp, dp->data.conf);
217 if (ret)
218 dev_err(&dp->alt->dev,
219 "unable to send Configure command (%d)\n", ret);
220 break;
221 case DP_STATE_EXIT:
222 if (typec_altmode_exit(dp->alt))
223 dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
224 break;
225 default:
226 break;
227 }
228
229 dp->state = DP_STATE_IDLE;
230
231 mutex_unlock(&dp->lock);
232 }
233
dp_altmode_attention(struct typec_altmode * alt,const u32 vdo)234 static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo)
235 {
236 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
237 u8 old_state;
238
239 mutex_lock(&dp->lock);
240
241 old_state = dp->state;
242 dp->data.status = vdo;
243
244 if (old_state != DP_STATE_IDLE)
245 dev_warn(&alt->dev, "ATTENTION while processing state %d\n",
246 old_state);
247
248 if (dp_altmode_status_update(dp))
249 dev_warn(&alt->dev, "%s: status update failed\n", __func__);
250
251 if (dp_altmode_notify(dp))
252 dev_err(&alt->dev, "%s: notification failed\n", __func__);
253
254 if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE)
255 schedule_work(&dp->work);
256
257 mutex_unlock(&dp->lock);
258 }
259
dp_altmode_vdm(struct typec_altmode * alt,const u32 hdr,const u32 * vdo,int count)260 static int dp_altmode_vdm(struct typec_altmode *alt,
261 const u32 hdr, const u32 *vdo, int count)
262 {
263 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
264 int cmd_type = PD_VDO_CMDT(hdr);
265 int cmd = PD_VDO_CMD(hdr);
266 int ret = 0;
267
268 mutex_lock(&dp->lock);
269
270 if (dp->state != DP_STATE_IDLE) {
271 ret = -EBUSY;
272 goto err_unlock;
273 }
274
275 switch (cmd_type) {
276 case CMDT_RSP_ACK:
277 switch (cmd) {
278 case CMD_ENTER_MODE:
279 dp->state = DP_STATE_UPDATE;
280 break;
281 case CMD_EXIT_MODE:
282 dp->data.status = 0;
283 dp->data.conf = 0;
284 break;
285 case DP_CMD_STATUS_UPDATE:
286 dp->data.status = *vdo;
287 ret = dp_altmode_status_update(dp);
288 break;
289 case DP_CMD_CONFIGURE:
290 ret = dp_altmode_configured(dp);
291 break;
292 default:
293 break;
294 }
295 break;
296 case CMDT_RSP_NAK:
297 switch (cmd) {
298 case DP_CMD_CONFIGURE:
299 dp->data.conf = 0;
300 ret = dp_altmode_configured(dp);
301 break;
302 default:
303 break;
304 }
305 break;
306 default:
307 break;
308 }
309
310 if (dp->state != DP_STATE_IDLE)
311 schedule_work(&dp->work);
312
313 err_unlock:
314 mutex_unlock(&dp->lock);
315 return ret;
316 }
317
dp_altmode_activate(struct typec_altmode * alt,int activate)318 static int dp_altmode_activate(struct typec_altmode *alt, int activate)
319 {
320 return activate ? typec_altmode_enter(alt, NULL) :
321 typec_altmode_exit(alt);
322 }
323
324 static const struct typec_altmode_ops dp_altmode_ops = {
325 .attention = dp_altmode_attention,
326 .vdm = dp_altmode_vdm,
327 .activate = dp_altmode_activate,
328 };
329
330 static const char * const configurations[] = {
331 [DP_CONF_USB] = "USB",
332 [DP_CONF_DFP_D] = "source",
333 [DP_CONF_UFP_D] = "sink",
334 };
335
336 static ssize_t
configuration_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)337 configuration_store(struct device *dev, struct device_attribute *attr,
338 const char *buf, size_t size)
339 {
340 struct dp_altmode *dp = dev_get_drvdata(dev);
341 u32 conf;
342 u32 cap;
343 int con;
344 int ret = 0;
345
346 con = sysfs_match_string(configurations, buf);
347 if (con < 0)
348 return con;
349
350 mutex_lock(&dp->lock);
351
352 if (dp->state != DP_STATE_IDLE) {
353 ret = -EBUSY;
354 goto err_unlock;
355 }
356
357 cap = DP_CAP_CAPABILITY(dp->alt->vdo);
358
359 if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) ||
360 (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) {
361 ret = -EINVAL;
362 goto err_unlock;
363 }
364
365 conf = dp->data.conf & ~DP_CONF_DUAL_D;
366 conf |= con;
367
368 if (dp->alt->active) {
369 ret = dp_altmode_configure_vdm(dp, conf);
370 if (ret)
371 goto err_unlock;
372 }
373
374 dp->data.conf = conf;
375
376 err_unlock:
377 mutex_unlock(&dp->lock);
378
379 return ret ? ret : size;
380 }
381
configuration_show(struct device * dev,struct device_attribute * attr,char * buf)382 static ssize_t configuration_show(struct device *dev,
383 struct device_attribute *attr, char *buf)
384 {
385 struct dp_altmode *dp = dev_get_drvdata(dev);
386 int len;
387 u8 cap;
388 u8 cur;
389 int i;
390
391 mutex_lock(&dp->lock);
392
393 cap = DP_CAP_CAPABILITY(dp->alt->vdo);
394 cur = DP_CONF_CURRENTLY(dp->data.conf);
395
396 len = sprintf(buf, "%s ", cur ? "USB" : "[USB]");
397
398 for (i = 1; i < ARRAY_SIZE(configurations); i++) {
399 if (i == cur)
400 len += sprintf(buf + len, "[%s] ", configurations[i]);
401 else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) ||
402 (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D))
403 len += sprintf(buf + len, "%s ", configurations[i]);
404 }
405
406 mutex_unlock(&dp->lock);
407
408 buf[len - 1] = '\n';
409 return len;
410 }
411 static DEVICE_ATTR_RW(configuration);
412
413 static const char * const pin_assignments[] = {
414 [DP_PIN_ASSIGN_A] = "A",
415 [DP_PIN_ASSIGN_B] = "B",
416 [DP_PIN_ASSIGN_C] = "C",
417 [DP_PIN_ASSIGN_D] = "D",
418 [DP_PIN_ASSIGN_E] = "E",
419 [DP_PIN_ASSIGN_F] = "F",
420 };
421
422 static ssize_t
pin_assignment_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)423 pin_assignment_store(struct device *dev, struct device_attribute *attr,
424 const char *buf, size_t size)
425 {
426 struct dp_altmode *dp = dev_get_drvdata(dev);
427 u8 assignments;
428 u32 conf;
429 int ret;
430
431 ret = sysfs_match_string(pin_assignments, buf);
432 if (ret < 0)
433 return ret;
434
435 conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret));
436 ret = 0;
437
438 mutex_lock(&dp->lock);
439
440 if (conf & dp->data.conf)
441 goto out_unlock;
442
443 if (dp->state != DP_STATE_IDLE) {
444 ret = -EBUSY;
445 goto out_unlock;
446 }
447
448 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
449 assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
450 else
451 assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
452
453 if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
454 ret = -EINVAL;
455 goto out_unlock;
456 }
457
458 conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK;
459
460 /* Only send Configure command if a configuration has been set */
461 if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) {
462 ret = dp_altmode_configure_vdm(dp, conf);
463 if (ret)
464 goto out_unlock;
465 }
466
467 dp->data.conf = conf;
468
469 out_unlock:
470 mutex_unlock(&dp->lock);
471
472 return ret ? ret : size;
473 }
474
pin_assignment_show(struct device * dev,struct device_attribute * attr,char * buf)475 static ssize_t pin_assignment_show(struct device *dev,
476 struct device_attribute *attr, char *buf)
477 {
478 struct dp_altmode *dp = dev_get_drvdata(dev);
479 u8 assignments;
480 int len = 0;
481 u8 cur;
482 int i;
483
484 mutex_lock(&dp->lock);
485
486 cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
487
488 if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
489 assignments = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo);
490 else
491 assignments = DP_CAP_DFP_D_PIN_ASSIGN(dp->alt->vdo);
492
493 for (i = 0; assignments; assignments >>= 1, i++) {
494 if (assignments & 1) {
495 if (i == cur)
496 len += sprintf(buf + len, "[%s] ",
497 pin_assignments[i]);
498 else
499 len += sprintf(buf + len, "%s ",
500 pin_assignments[i]);
501 }
502 }
503
504 mutex_unlock(&dp->lock);
505
506 buf[len - 1] = '\n';
507 return len;
508 }
509 static DEVICE_ATTR_RW(pin_assignment);
510
511 static struct attribute *dp_altmode_attrs[] = {
512 &dev_attr_configuration.attr,
513 &dev_attr_pin_assignment.attr,
514 NULL
515 };
516
517 static const struct attribute_group dp_altmode_group = {
518 .name = "displayport",
519 .attrs = dp_altmode_attrs,
520 };
521
dp_altmode_probe(struct typec_altmode * alt)522 int dp_altmode_probe(struct typec_altmode *alt)
523 {
524 const struct typec_altmode *port = typec_altmode_get_partner(alt);
525 struct fwnode_handle *fwnode;
526 struct dp_altmode *dp;
527 int ret;
528
529 /* FIXME: Port can only be DFP_U. */
530
531 /* Make sure we have compatiple pin configurations */
532 if (!(DP_CAP_DFP_D_PIN_ASSIGN(port->vdo) &
533 DP_CAP_UFP_D_PIN_ASSIGN(alt->vdo)) &&
534 !(DP_CAP_UFP_D_PIN_ASSIGN(port->vdo) &
535 DP_CAP_DFP_D_PIN_ASSIGN(alt->vdo)))
536 return -ENODEV;
537
538 ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group);
539 if (ret)
540 return ret;
541
542 dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);
543 if (!dp)
544 return -ENOMEM;
545
546 INIT_WORK(&dp->work, dp_altmode_work);
547 mutex_init(&dp->lock);
548 dp->port = port;
549 dp->alt = alt;
550
551 alt->desc = "DisplayPort";
552 alt->ops = &dp_altmode_ops;
553
554 fwnode = dev_fwnode(alt->dev.parent->parent); /* typec_port fwnode */
555 dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
556 if (IS_ERR(dp->connector_fwnode))
557 dp->connector_fwnode = NULL;
558
559 typec_altmode_set_drvdata(alt, dp);
560
561 dp->state = DP_STATE_ENTER;
562 schedule_work(&dp->work);
563
564 return 0;
565 }
566 EXPORT_SYMBOL_GPL(dp_altmode_probe);
567
dp_altmode_remove(struct typec_altmode * alt)568 void dp_altmode_remove(struct typec_altmode *alt)
569 {
570 struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
571
572 sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group);
573 cancel_work_sync(&dp->work);
574
575 if (dp->connector_fwnode) {
576 if (dp->hpd)
577 drm_connector_oob_hotplug_event(dp->connector_fwnode);
578
579 fwnode_handle_put(dp->connector_fwnode);
580 }
581 }
582 EXPORT_SYMBOL_GPL(dp_altmode_remove);
583
584 static const struct typec_device_id dp_typec_id[] = {
585 { USB_TYPEC_DP_SID, USB_TYPEC_DP_MODE },
586 { },
587 };
588 MODULE_DEVICE_TABLE(typec, dp_typec_id);
589
590 static struct typec_altmode_driver dp_altmode_driver = {
591 .id_table = dp_typec_id,
592 .probe = dp_altmode_probe,
593 .remove = dp_altmode_remove,
594 .driver = {
595 .name = "typec_displayport",
596 .owner = THIS_MODULE,
597 },
598 };
599 module_typec_altmode_driver(dp_altmode_driver);
600
601 MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
602 MODULE_LICENSE("GPL v2");
603 MODULE_DESCRIPTION("DisplayPort Alternate Mode");
604