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