1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for the Chrontel CH7322 CEC Controller
4 *
5 * Copyright 2020 Google LLC.
6 */
7
8 /*
9 * Notes
10 *
11 * - This device powers on in Auto Mode which has limited functionality. This
12 * driver disables Auto Mode when it attaches.
13 *
14 */
15
16 #include <linux/cec.h>
17 #include <linux/dmi.h>
18 #include <linux/i2c.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/pci.h>
23 #include <linux/regmap.h>
24 #include <media/cec.h>
25 #include <media/cec-notifier.h>
26
27 #define CH7322_WRITE 0x00
28 #define CH7322_WRITE_MSENT 0x80
29 #define CH7322_WRITE_BOK 0x40
30 #define CH7322_WRITE_NMASK 0x0f
31
32 /* Write buffer is 0x01-0x10 */
33 #define CH7322_WRBUF 0x01
34 #define CH7322_WRBUF_LEN 0x10
35
36 #define CH7322_READ 0x40
37 #define CH7322_READ_NRDT 0x80
38 #define CH7322_READ_MSENT 0x20
39 #define CH7322_READ_NMASK 0x0f
40
41 /* Read buffer is 0x41-0x50 */
42 #define CH7322_RDBUF 0x41
43 #define CH7322_RDBUF_LEN 0x10
44
45 #define CH7322_MODE 0x11
46 #define CH7322_MODE_AUTO 0x78
47 #define CH7322_MODE_SW 0xb5
48
49 #define CH7322_RESET 0x12
50 #define CH7322_RESET_RST 0x00
51
52 #define CH7322_POWER 0x13
53 #define CH7322_POWER_FPD 0x04
54
55 #define CH7322_CFG0 0x17
56 #define CH7322_CFG0_EOBEN 0x40
57 #define CH7322_CFG0_PEOB 0x20
58 #define CH7322_CFG0_CLRSPP 0x10
59 #define CH7322_CFG0_FLOW 0x08
60
61 #define CH7322_CFG1 0x1a
62 #define CH7322_CFG1_STDBYO 0x04
63 #define CH7322_CFG1_HPBP 0x02
64 #define CH7322_CFG1_PIO 0x01
65
66 #define CH7322_INTCTL 0x1b
67 #define CH7322_INTCTL_INTPB 0x80
68 #define CH7322_INTCTL_STDBY 0x40
69 #define CH7322_INTCTL_HPDFALL 0x20
70 #define CH7322_INTCTL_HPDRISE 0x10
71 #define CH7322_INTCTL_RXMSG 0x08
72 #define CH7322_INTCTL_TXMSG 0x04
73 #define CH7322_INTCTL_NEWPHA 0x02
74 #define CH7322_INTCTL_ERROR 0x01
75
76 #define CH7322_DVCLKFNH 0x1d
77 #define CH7322_DVCLKFNL 0x1e
78
79 #define CH7322_CTL 0x31
80 #define CH7322_CTL_FSTDBY 0x80
81 #define CH7322_CTL_PLSEN 0x40
82 #define CH7322_CTL_PLSPB 0x20
83 #define CH7322_CTL_SPADL 0x10
84 #define CH7322_CTL_HINIT 0x08
85 #define CH7322_CTL_WPHYA 0x04
86 #define CH7322_CTL_H1T 0x02
87 #define CH7322_CTL_S1T 0x01
88
89 #define CH7322_PAWH 0x32
90 #define CH7322_PAWL 0x33
91
92 #define CH7322_ADDLW 0x34
93 #define CH7322_ADDLW_MASK 0xf0
94
95 #define CH7322_ADDLR 0x3d
96 #define CH7322_ADDLR_HPD 0x80
97 #define CH7322_ADDLR_MASK 0x0f
98
99 #define CH7322_INTDATA 0x3e
100 #define CH7322_INTDATA_MODE 0x80
101 #define CH7322_INTDATA_STDBY 0x40
102 #define CH7322_INTDATA_HPDFALL 0x20
103 #define CH7322_INTDATA_HPDRISE 0x10
104 #define CH7322_INTDATA_RXMSG 0x08
105 #define CH7322_INTDATA_TXMSG 0x04
106 #define CH7322_INTDATA_NEWPHA 0x02
107 #define CH7322_INTDATA_ERROR 0x01
108
109 #define CH7322_EVENT 0x3f
110 #define CH7322_EVENT_TXERR 0x80
111 #define CH7322_EVENT_HRST 0x40
112 #define CH7322_EVENT_HFST 0x20
113 #define CH7322_EVENT_PHACHG 0x10
114 #define CH7322_EVENT_ACTST 0x08
115 #define CH7322_EVENT_PHARDY 0x04
116 #define CH7322_EVENT_BSOK 0x02
117 #define CH7322_EVENT_ERRADCF 0x01
118
119 #define CH7322_DID 0x51
120 #define CH7322_DID_CH7322 0x5b
121 #define CH7322_DID_CH7323 0x5f
122
123 #define CH7322_REVISIONID 0x52
124
125 #define CH7322_PARH 0x53
126 #define CH7322_PARL 0x54
127
128 #define CH7322_IOCFG2 0x75
129 #define CH7322_IOCFG_CIO 0x80
130 #define CH7322_IOCFG_IOCFGMASK 0x78
131 #define CH7322_IOCFG_AUDIO 0x04
132 #define CH7322_IOCFG_SPAMST 0x02
133 #define CH7322_IOCFG_SPAMSP 0x01
134
135 #define CH7322_CTL3 0x7b
136 #define CH7322_CTL3_SWENA 0x80
137 #define CH7322_CTL3_FC_INIT 0x40
138 #define CH7322_CTL3_SML_FL 0x20
139 #define CH7322_CTL3_SM_RDST 0x10
140 #define CH7322_CTL3_SPP_CIAH 0x08
141 #define CH7322_CTL3_SPP_CIAL 0x04
142 #define CH7322_CTL3_SPP_ACTH 0x02
143 #define CH7322_CTL3_SPP_ACTL 0x01
144
145 /* BOK status means NACK */
146 #define CH7322_TX_FLAG_NACK BIT(0)
147 /* Device will retry automatically */
148 #define CH7322_TX_FLAG_RETRY BIT(1)
149
150 struct ch7322 {
151 struct i2c_client *i2c;
152 struct regmap *regmap;
153 struct cec_adapter *cec;
154 struct mutex mutex; /* device access mutex */
155 u8 tx_flags;
156 };
157
158 static const struct regmap_config ch7322_regmap = {
159 .reg_bits = 8,
160 .val_bits = 8,
161 .max_register = 0x7f,
162 .disable_locking = true,
163 };
164
ch7322_send_message(struct ch7322 * ch7322,const struct cec_msg * msg)165 static int ch7322_send_message(struct ch7322 *ch7322, const struct cec_msg *msg)
166 {
167 unsigned int val;
168 unsigned int len = msg->len;
169 int ret;
170 int i;
171
172 WARN_ON(!mutex_is_locked(&ch7322->mutex));
173
174 if (len > CH7322_WRBUF_LEN || len < 1)
175 return -EINVAL;
176
177 ret = regmap_read(ch7322->regmap, CH7322_WRITE, &val);
178 if (ret)
179 return ret;
180
181 /* Buffer not ready */
182 if (!(val & CH7322_WRITE_MSENT))
183 return -EBUSY;
184
185 if (cec_msg_opcode(msg) == -1 &&
186 cec_msg_initiator(msg) == cec_msg_destination(msg)) {
187 ch7322->tx_flags = CH7322_TX_FLAG_NACK | CH7322_TX_FLAG_RETRY;
188 } else if (cec_msg_is_broadcast(msg)) {
189 ch7322->tx_flags = CH7322_TX_FLAG_NACK;
190 } else {
191 ch7322->tx_flags = CH7322_TX_FLAG_RETRY;
192 }
193
194 ret = regmap_write(ch7322->regmap, CH7322_WRITE, len - 1);
195 if (ret)
196 return ret;
197
198 for (i = 0; i < len; i++) {
199 ret = regmap_write(ch7322->regmap,
200 CH7322_WRBUF + i, msg->msg[i]);
201 if (ret)
202 return ret;
203 }
204
205 return 0;
206 }
207
ch7322_receive_message(struct ch7322 * ch7322,struct cec_msg * msg)208 static int ch7322_receive_message(struct ch7322 *ch7322, struct cec_msg *msg)
209 {
210 unsigned int val;
211 int ret = 0;
212 int i;
213
214 WARN_ON(!mutex_is_locked(&ch7322->mutex));
215
216 ret = regmap_read(ch7322->regmap, CH7322_READ, &val);
217 if (ret)
218 return ret;
219
220 /* Message not ready */
221 if (!(val & CH7322_READ_NRDT))
222 return -EIO;
223
224 msg->len = (val & CH7322_READ_NMASK) + 1;
225
226 /* Read entire RDBUF to clear state */
227 for (i = 0; i < CH7322_RDBUF_LEN; i++) {
228 ret = regmap_read(ch7322->regmap, CH7322_RDBUF + i, &val);
229 if (ret)
230 return ret;
231 msg->msg[i] = (u8)val;
232 }
233
234 return 0;
235 }
236
ch7322_tx_done(struct ch7322 * ch7322)237 static void ch7322_tx_done(struct ch7322 *ch7322)
238 {
239 int ret;
240 unsigned int val;
241 u8 status, flags;
242
243 mutex_lock(&ch7322->mutex);
244 ret = regmap_read(ch7322->regmap, CH7322_WRITE, &val);
245 flags = ch7322->tx_flags;
246 mutex_unlock(&ch7322->mutex);
247
248 /*
249 * The device returns a one-bit OK status which usually means ACK but
250 * actually means NACK when sending a logical address query or a
251 * broadcast.
252 */
253 if (ret)
254 status = CEC_TX_STATUS_ERROR;
255 else if ((val & CH7322_WRITE_BOK) && (flags & CH7322_TX_FLAG_NACK))
256 status = CEC_TX_STATUS_NACK;
257 else if (val & CH7322_WRITE_BOK)
258 status = CEC_TX_STATUS_OK;
259 else if (flags & CH7322_TX_FLAG_NACK)
260 status = CEC_TX_STATUS_OK;
261 else
262 status = CEC_TX_STATUS_NACK;
263
264 if (status == CEC_TX_STATUS_NACK && (flags & CH7322_TX_FLAG_RETRY))
265 status |= CEC_TX_STATUS_MAX_RETRIES;
266
267 cec_transmit_attempt_done(ch7322->cec, status);
268 }
269
ch7322_rx_done(struct ch7322 * ch7322)270 static void ch7322_rx_done(struct ch7322 *ch7322)
271 {
272 struct cec_msg msg;
273 int ret;
274
275 mutex_lock(&ch7322->mutex);
276 ret = ch7322_receive_message(ch7322, &msg);
277 mutex_unlock(&ch7322->mutex);
278
279 if (ret)
280 dev_err(&ch7322->i2c->dev, "cec receive error: %d\n", ret);
281 else
282 cec_received_msg(ch7322->cec, &msg);
283 }
284
285 /*
286 * This device can either monitor the DDC lines to obtain the physical address
287 * or it can allow the host to program it. This driver lets the device obtain
288 * it.
289 */
ch7322_phys_addr(struct ch7322 * ch7322)290 static void ch7322_phys_addr(struct ch7322 *ch7322)
291 {
292 unsigned int pah, pal;
293 int ret = 0;
294
295 mutex_lock(&ch7322->mutex);
296 ret |= regmap_read(ch7322->regmap, CH7322_PARH, &pah);
297 ret |= regmap_read(ch7322->regmap, CH7322_PARL, &pal);
298 mutex_unlock(&ch7322->mutex);
299
300 if (ret)
301 dev_err(&ch7322->i2c->dev, "phys addr error\n");
302 else
303 cec_s_phys_addr(ch7322->cec, pal | (pah << 8), false);
304 }
305
ch7322_irq(int irq,void * dev)306 static irqreturn_t ch7322_irq(int irq, void *dev)
307 {
308 struct ch7322 *ch7322 = dev;
309 unsigned int data = 0;
310
311 mutex_lock(&ch7322->mutex);
312 regmap_read(ch7322->regmap, CH7322_INTDATA, &data);
313 regmap_write(ch7322->regmap, CH7322_INTDATA, data);
314 mutex_unlock(&ch7322->mutex);
315
316 if (data & CH7322_INTDATA_HPDFALL)
317 cec_phys_addr_invalidate(ch7322->cec);
318
319 if (data & CH7322_INTDATA_TXMSG)
320 ch7322_tx_done(ch7322);
321
322 if (data & CH7322_INTDATA_RXMSG)
323 ch7322_rx_done(ch7322);
324
325 if (data & CH7322_INTDATA_NEWPHA)
326 ch7322_phys_addr(ch7322);
327
328 if (data & CH7322_INTDATA_ERROR)
329 dev_dbg(&ch7322->i2c->dev, "unknown error\n");
330
331 return IRQ_HANDLED;
332 }
333
334 /* This device is always enabled */
ch7322_cec_adap_enable(struct cec_adapter * adap,bool enable)335 static int ch7322_cec_adap_enable(struct cec_adapter *adap, bool enable)
336 {
337 return 0;
338 }
339
ch7322_cec_adap_log_addr(struct cec_adapter * adap,u8 log_addr)340 static int ch7322_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
341 {
342 struct ch7322 *ch7322 = cec_get_drvdata(adap);
343 int ret;
344
345 mutex_lock(&ch7322->mutex);
346 ret = regmap_update_bits(ch7322->regmap, CH7322_ADDLW,
347 CH7322_ADDLW_MASK, log_addr << 4);
348 mutex_unlock(&ch7322->mutex);
349
350 return ret;
351 }
352
ch7322_cec_adap_transmit(struct cec_adapter * adap,u8 attempts,u32 signal_free_time,struct cec_msg * msg)353 static int ch7322_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
354 u32 signal_free_time, struct cec_msg *msg)
355 {
356 struct ch7322 *ch7322 = cec_get_drvdata(adap);
357 int ret;
358
359 mutex_lock(&ch7322->mutex);
360 ret = ch7322_send_message(ch7322, msg);
361 mutex_unlock(&ch7322->mutex);
362
363 return ret;
364 }
365
366 static const struct cec_adap_ops ch7322_cec_adap_ops = {
367 .adap_enable = ch7322_cec_adap_enable,
368 .adap_log_addr = ch7322_cec_adap_log_addr,
369 .adap_transmit = ch7322_cec_adap_transmit,
370 };
371
372 #if IS_ENABLED(CONFIG_PCI) && IS_ENABLED(CONFIG_DMI)
373
374 struct ch7322_conn_match {
375 const char *dev_name;
376 const char *pci_name;
377 const char *port_name;
378 };
379
380 static struct ch7322_conn_match google_endeavour[] = {
381 { "i2c-PRP0001:00", "0000:00:02.0", "Port B" },
382 { "i2c-PRP0001:01", "0000:00:02.0", "Port C" },
383 { },
384 };
385
386 static const struct dmi_system_id ch7322_dmi_table[] = {
387 {
388 .matches = {
389 DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
390 DMI_MATCH(DMI_BOARD_NAME, "Endeavour"),
391 },
392 .driver_data = google_endeavour,
393 },
394 { },
395 };
396
397 /* Make a best-effort attempt to locate a matching HDMI port */
ch7322_get_port(struct i2c_client * client,struct device ** dev,const char ** port)398 static int ch7322_get_port(struct i2c_client *client,
399 struct device **dev,
400 const char **port)
401 {
402 const struct dmi_system_id *system;
403 const struct ch7322_conn_match *conn;
404
405 *dev = NULL;
406 *port = NULL;
407
408 system = dmi_first_match(ch7322_dmi_table);
409 if (!system)
410 return 0;
411
412 for (conn = system->driver_data; conn->dev_name; conn++) {
413 if (!strcmp(dev_name(&client->dev), conn->dev_name)) {
414 struct device *d;
415
416 d = bus_find_device_by_name(&pci_bus_type, NULL,
417 conn->pci_name);
418 if (!d)
419 return -EPROBE_DEFER;
420
421 put_device(d);
422
423 *dev = d;
424 *port = conn->port_name;
425
426 return 0;
427 }
428 }
429
430 return 0;
431 }
432
433 #else
434
ch7322_get_port(struct i2c_client * client,struct device ** dev,const char ** port)435 static int ch7322_get_port(struct i2c_client *client,
436 struct device **dev,
437 const char **port)
438 {
439 *dev = NULL;
440 *port = NULL;
441
442 return 0;
443 }
444
445 #endif
446
ch7322_probe(struct i2c_client * client)447 static int ch7322_probe(struct i2c_client *client)
448 {
449 struct device *hdmi_dev;
450 const char *port_name;
451 struct ch7322 *ch7322;
452 struct cec_notifier *notifier = NULL;
453 u32 caps = CEC_CAP_DEFAULTS;
454 int ret;
455 unsigned int val;
456
457 ret = ch7322_get_port(client, &hdmi_dev, &port_name);
458 if (ret)
459 return ret;
460
461 if (hdmi_dev)
462 caps |= CEC_CAP_CONNECTOR_INFO;
463
464 ch7322 = devm_kzalloc(&client->dev, sizeof(*ch7322), GFP_KERNEL);
465 if (!ch7322)
466 return -ENOMEM;
467
468 ch7322->regmap = devm_regmap_init_i2c(client, &ch7322_regmap);
469 if (IS_ERR(ch7322->regmap))
470 return PTR_ERR(ch7322->regmap);
471
472 ret = regmap_read(ch7322->regmap, CH7322_DID, &val);
473 if (ret)
474 return ret;
475
476 if (val != CH7322_DID_CH7322)
477 return -EOPNOTSUPP;
478
479 mutex_init(&ch7322->mutex);
480 ch7322->i2c = client;
481 ch7322->tx_flags = 0;
482
483 i2c_set_clientdata(client, ch7322);
484
485 /* Disable auto mode */
486 ret = regmap_write(ch7322->regmap, CH7322_MODE, CH7322_MODE_SW);
487 if (ret)
488 goto err_mutex;
489
490 /* Enable logical address register */
491 ret = regmap_update_bits(ch7322->regmap, CH7322_CTL,
492 CH7322_CTL_SPADL, CH7322_CTL_SPADL);
493 if (ret)
494 goto err_mutex;
495
496 ch7322->cec = cec_allocate_adapter(&ch7322_cec_adap_ops, ch7322,
497 dev_name(&client->dev),
498 caps, 1);
499
500 if (IS_ERR(ch7322->cec)) {
501 ret = PTR_ERR(ch7322->cec);
502 goto err_mutex;
503 }
504
505 ch7322->cec->adap_controls_phys_addr = true;
506
507 if (hdmi_dev) {
508 notifier = cec_notifier_cec_adap_register(hdmi_dev,
509 port_name,
510 ch7322->cec);
511 if (!notifier) {
512 ret = -ENOMEM;
513 goto err_cec;
514 }
515 }
516
517 /* Configure, mask, and clear interrupt */
518 ret = regmap_write(ch7322->regmap, CH7322_CFG1, 0);
519 if (ret)
520 goto err_notifier;
521 ret = regmap_write(ch7322->regmap, CH7322_INTCTL, CH7322_INTCTL_INTPB);
522 if (ret)
523 goto err_notifier;
524 ret = regmap_write(ch7322->regmap, CH7322_INTDATA, 0xff);
525 if (ret)
526 goto err_notifier;
527
528 /* If HPD is up read physical address */
529 ret = regmap_read(ch7322->regmap, CH7322_ADDLR, &val);
530 if (ret)
531 goto err_notifier;
532 if (val & CH7322_ADDLR_HPD)
533 ch7322_phys_addr(ch7322);
534
535 ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
536 ch7322_irq,
537 IRQF_ONESHOT | IRQF_TRIGGER_RISING,
538 client->name, ch7322);
539 if (ret)
540 goto err_notifier;
541
542 /* Unmask interrupt */
543 mutex_lock(&ch7322->mutex);
544 ret = regmap_write(ch7322->regmap, CH7322_INTCTL, 0xff);
545 mutex_unlock(&ch7322->mutex);
546
547 if (ret)
548 goto err_notifier;
549
550 ret = cec_register_adapter(ch7322->cec, &client->dev);
551 if (ret)
552 goto err_notifier;
553
554 dev_info(&client->dev, "device registered\n");
555
556 return 0;
557
558 err_notifier:
559 if (notifier)
560 cec_notifier_cec_adap_unregister(notifier, ch7322->cec);
561 err_cec:
562 cec_delete_adapter(ch7322->cec);
563 err_mutex:
564 mutex_destroy(&ch7322->mutex);
565 return ret;
566 }
567
ch7322_remove(struct i2c_client * client)568 static void ch7322_remove(struct i2c_client *client)
569 {
570 struct ch7322 *ch7322 = i2c_get_clientdata(client);
571
572 /* Mask interrupt */
573 mutex_lock(&ch7322->mutex);
574 regmap_write(ch7322->regmap, CH7322_INTCTL, CH7322_INTCTL_INTPB);
575 mutex_unlock(&ch7322->mutex);
576
577 cec_unregister_adapter(ch7322->cec);
578 mutex_destroy(&ch7322->mutex);
579
580 dev_info(&client->dev, "device unregistered\n");
581 }
582
583 static const struct of_device_id ch7322_of_match[] = {
584 { .compatible = "chrontel,ch7322", },
585 {},
586 };
587 MODULE_DEVICE_TABLE(of, ch7322_of_match);
588
589 static struct i2c_driver ch7322_i2c_driver = {
590 .driver = {
591 .name = "ch7322",
592 .of_match_table = ch7322_of_match,
593 },
594 .probe = ch7322_probe,
595 .remove = ch7322_remove,
596 };
597
598 module_i2c_driver(ch7322_i2c_driver);
599
600 MODULE_DESCRIPTION("Chrontel CH7322 CEC Controller Driver");
601 MODULE_AUTHOR("Jeff Chase <jnchase@google.com>");
602 MODULE_LICENSE("GPL");
603