xref: /linux/drivers/gpu/drm/i2c/tda9950.c (revision cdd5b5a9761fd66d17586e4f4ba6588c70e640ea)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  TDA9950 Consumer Electronics Control driver
4  *
5  * The NXP TDA9950 implements the HDMI Consumer Electronics Control
6  * interface.  The host interface is similar to a mailbox: the data
7  * registers starting at REG_CDR0 are written to send a command to the
8  * internal CPU, and replies are read from these registers.
9  *
10  * As the data registers represent a mailbox, they must be accessed
11  * as a single I2C transaction.  See the TDA9950 data sheet for details.
12  */
13 #include <linux/delay.h>
14 #include <linux/i2c.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/platform_data/tda9950.h>
18 #include <linux/slab.h>
19 #include <drm/drm_edid.h>
20 #include <media/cec.h>
21 #include <media/cec-notifier.h>
22 
23 enum {
24 	REG_CSR = 0x00,
25 	CSR_BUSY = BIT(7),
26 	CSR_INT  = BIT(6),
27 	CSR_ERR  = BIT(5),
28 
29 	REG_CER = 0x01,
30 
31 	REG_CVR = 0x02,
32 
33 	REG_CCR = 0x03,
34 	CCR_RESET = BIT(7),
35 	CCR_ON    = BIT(6),
36 
37 	REG_ACKH = 0x04,
38 	REG_ACKL = 0x05,
39 
40 	REG_CCONR = 0x06,
41 	CCONR_ENABLE_ERROR = BIT(4),
42 	CCONR_RETRY_MASK = 7,
43 
44 	REG_CDR0 = 0x07,
45 
46 	CDR1_REQ = 0x00,
47 	CDR1_CNF = 0x01,
48 	CDR1_IND = 0x81,
49 	CDR1_ERR = 0x82,
50 	CDR1_IER = 0x83,
51 
52 	CDR2_CNF_SUCCESS    = 0x00,
53 	CDR2_CNF_OFF_STATE  = 0x80,
54 	CDR2_CNF_BAD_REQ    = 0x81,
55 	CDR2_CNF_CEC_ACCESS = 0x82,
56 	CDR2_CNF_ARB_ERROR  = 0x83,
57 	CDR2_CNF_BAD_TIMING = 0x84,
58 	CDR2_CNF_NACK_ADDR  = 0x85,
59 	CDR2_CNF_NACK_DATA  = 0x86,
60 };
61 
62 struct tda9950_priv {
63 	struct i2c_client *client;
64 	struct device *hdmi;
65 	struct cec_adapter *adap;
66 	struct tda9950_glue *glue;
67 	u16 addresses;
68 	struct cec_msg rx_msg;
69 	struct cec_notifier *notify;
70 	bool open;
71 };
72 
tda9950_write_range(struct i2c_client * client,u8 addr,u8 * p,int cnt)73 static int tda9950_write_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
74 {
75 	struct i2c_msg msg;
76 	u8 buf[CEC_MAX_MSG_SIZE + 3];
77 	int ret;
78 
79 	if (WARN_ON(cnt > sizeof(buf) - 1))
80 		return -EINVAL;
81 
82 	buf[0] = addr;
83 	memcpy(buf + 1, p, cnt);
84 
85 	msg.addr = client->addr;
86 	msg.flags = 0;
87 	msg.len = cnt + 1;
88 	msg.buf = buf;
89 
90 	dev_dbg(&client->dev, "wr 0x%02x: %*ph\n", addr, cnt, p);
91 
92 	ret = i2c_transfer(client->adapter, &msg, 1);
93 	if (ret < 0)
94 		dev_err(&client->dev, "Error %d writing to cec:0x%x\n", ret, addr);
95 	return ret < 0 ? ret : 0;
96 }
97 
tda9950_write(struct i2c_client * client,u8 addr,u8 val)98 static void tda9950_write(struct i2c_client *client, u8 addr, u8 val)
99 {
100 	tda9950_write_range(client, addr, &val, 1);
101 }
102 
tda9950_read_range(struct i2c_client * client,u8 addr,u8 * p,int cnt)103 static int tda9950_read_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
104 {
105 	struct i2c_msg msg[2];
106 	int ret;
107 
108 	msg[0].addr = client->addr;
109 	msg[0].flags = 0;
110 	msg[0].len = 1;
111 	msg[0].buf = &addr;
112 	msg[1].addr = client->addr;
113 	msg[1].flags = I2C_M_RD;
114 	msg[1].len = cnt;
115 	msg[1].buf = p;
116 
117 	ret = i2c_transfer(client->adapter, msg, 2);
118 	if (ret < 0)
119 		dev_err(&client->dev, "Error %d reading from cec:0x%x\n", ret, addr);
120 
121 	dev_dbg(&client->dev, "rd 0x%02x: %*ph\n", addr, cnt, p);
122 
123 	return ret;
124 }
125 
tda9950_read(struct i2c_client * client,u8 addr)126 static u8 tda9950_read(struct i2c_client *client, u8 addr)
127 {
128 	int ret;
129 	u8 val;
130 
131 	ret = tda9950_read_range(client, addr, &val, 1);
132 	if (ret < 0)
133 		val = 0;
134 
135 	return val;
136 }
137 
tda9950_irq(int irq,void * data)138 static irqreturn_t tda9950_irq(int irq, void *data)
139 {
140 	struct tda9950_priv *priv = data;
141 	unsigned int tx_status;
142 	u8 csr, cconr, buf[19];
143 	u8 arb_lost_cnt, nack_cnt, err_cnt;
144 
145 	if (!priv->open)
146 		return IRQ_NONE;
147 
148 	csr = tda9950_read(priv->client, REG_CSR);
149 	if (!(csr & CSR_INT))
150 		return IRQ_NONE;
151 
152 	cconr = tda9950_read(priv->client, REG_CCONR) & CCONR_RETRY_MASK;
153 
154 	tda9950_read_range(priv->client, REG_CDR0, buf, sizeof(buf));
155 
156 	/*
157 	 * This should never happen: the data sheet says that there will
158 	 * always be a valid message if the interrupt line is asserted.
159 	 */
160 	if (buf[0] == 0) {
161 		dev_warn(&priv->client->dev, "interrupt pending, but no message?\n");
162 		return IRQ_NONE;
163 	}
164 
165 	switch (buf[1]) {
166 	case CDR1_CNF: /* transmit result */
167 		arb_lost_cnt = nack_cnt = err_cnt = 0;
168 		switch (buf[2]) {
169 		case CDR2_CNF_SUCCESS:
170 			tx_status = CEC_TX_STATUS_OK;
171 			break;
172 
173 		case CDR2_CNF_ARB_ERROR:
174 			tx_status = CEC_TX_STATUS_ARB_LOST;
175 			arb_lost_cnt = cconr;
176 			break;
177 
178 		case CDR2_CNF_NACK_ADDR:
179 			tx_status = CEC_TX_STATUS_NACK;
180 			nack_cnt = cconr;
181 			break;
182 
183 		default: /* some other error, refer to TDA9950 docs */
184 			dev_err(&priv->client->dev, "CNF reply error 0x%02x\n",
185 				buf[2]);
186 			tx_status = CEC_TX_STATUS_ERROR;
187 			err_cnt = cconr;
188 			break;
189 		}
190 		/* TDA9950 executes all retries for us */
191 		if (tx_status != CEC_TX_STATUS_OK)
192 			tx_status |= CEC_TX_STATUS_MAX_RETRIES;
193 		cec_transmit_done(priv->adap, tx_status, arb_lost_cnt,
194 				  nack_cnt, 0, err_cnt);
195 		break;
196 
197 	case CDR1_IND:
198 		priv->rx_msg.len = buf[0] - 2;
199 		if (priv->rx_msg.len > CEC_MAX_MSG_SIZE)
200 			priv->rx_msg.len = CEC_MAX_MSG_SIZE;
201 
202 		memcpy(priv->rx_msg.msg, buf + 2, priv->rx_msg.len);
203 		cec_received_msg(priv->adap, &priv->rx_msg);
204 		break;
205 
206 	default: /* unknown */
207 		dev_err(&priv->client->dev, "unknown service id 0x%02x\n",
208 			buf[1]);
209 		break;
210 	}
211 
212 	return IRQ_HANDLED;
213 }
214 
tda9950_cec_transmit(struct cec_adapter * adap,u8 attempts,u32 signal_free_time,struct cec_msg * msg)215 static int tda9950_cec_transmit(struct cec_adapter *adap, u8 attempts,
216 				u32 signal_free_time, struct cec_msg *msg)
217 {
218 	struct tda9950_priv *priv = adap->priv;
219 	u8 buf[CEC_MAX_MSG_SIZE + 2];
220 
221 	buf[0] = 2 + msg->len;
222 	buf[1] = CDR1_REQ;
223 	memcpy(buf + 2, msg->msg, msg->len);
224 
225 	if (attempts > 5)
226 		attempts = 5;
227 
228 	tda9950_write(priv->client, REG_CCONR, attempts);
229 
230 	return tda9950_write_range(priv->client, REG_CDR0, buf, 2 + msg->len);
231 }
232 
tda9950_cec_adap_log_addr(struct cec_adapter * adap,u8 addr)233 static int tda9950_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
234 {
235 	struct tda9950_priv *priv = adap->priv;
236 	u16 addresses;
237 	u8 buf[2];
238 
239 	if (addr == CEC_LOG_ADDR_INVALID)
240 		addresses = priv->addresses = 0;
241 	else
242 		addresses = priv->addresses |= BIT(addr);
243 
244 	/* TDA9950 doesn't want address 15 set */
245 	addresses &= 0x7fff;
246 	buf[0] = addresses >> 8;
247 	buf[1] = addresses;
248 
249 	return tda9950_write_range(priv->client, REG_ACKH, buf, 2);
250 }
251 
252 /*
253  * When operating as part of the TDA998x, we need additional handling
254  * to initialise and shut down the TDA9950 part of the device.  These
255  * two hooks are provided to allow the TDA998x code to perform those
256  * activities.
257  */
tda9950_glue_open(struct tda9950_priv * priv)258 static int tda9950_glue_open(struct tda9950_priv *priv)
259 {
260 	int ret = 0;
261 
262 	if (priv->glue && priv->glue->open)
263 		ret = priv->glue->open(priv->glue->data);
264 
265 	priv->open = true;
266 
267 	return ret;
268 }
269 
tda9950_glue_release(struct tda9950_priv * priv)270 static void tda9950_glue_release(struct tda9950_priv *priv)
271 {
272 	priv->open = false;
273 
274 	if (priv->glue && priv->glue->release)
275 		priv->glue->release(priv->glue->data);
276 }
277 
tda9950_open(struct tda9950_priv * priv)278 static int tda9950_open(struct tda9950_priv *priv)
279 {
280 	struct i2c_client *client = priv->client;
281 	int ret;
282 
283 	ret = tda9950_glue_open(priv);
284 	if (ret)
285 		return ret;
286 
287 	/* Reset the TDA9950, and wait 250ms for it to recover */
288 	tda9950_write(client, REG_CCR, CCR_RESET);
289 	msleep(250);
290 
291 	tda9950_cec_adap_log_addr(priv->adap, CEC_LOG_ADDR_INVALID);
292 
293 	/* Start the command processor */
294 	tda9950_write(client, REG_CCR, CCR_ON);
295 
296 	return 0;
297 }
298 
tda9950_release(struct tda9950_priv * priv)299 static void tda9950_release(struct tda9950_priv *priv)
300 {
301 	struct i2c_client *client = priv->client;
302 	int timeout = 50;
303 	u8 csr;
304 
305 	/* Stop the command processor */
306 	tda9950_write(client, REG_CCR, 0);
307 
308 	/* Wait up to .5s for it to signal non-busy */
309 	do {
310 		csr = tda9950_read(client, REG_CSR);
311 		if (!(csr & CSR_BUSY) || !--timeout)
312 			break;
313 		msleep(10);
314 	} while (1);
315 
316 	/* Warn the user that their IRQ may die if it's shared. */
317 	if (csr & CSR_BUSY)
318 		dev_warn(&client->dev, "command processor failed to stop, irq%d may die (csr=0x%02x)\n",
319 			 client->irq, csr);
320 
321 	tda9950_glue_release(priv);
322 }
323 
tda9950_cec_adap_enable(struct cec_adapter * adap,bool enable)324 static int tda9950_cec_adap_enable(struct cec_adapter *adap, bool enable)
325 {
326 	struct tda9950_priv *priv = adap->priv;
327 
328 	if (!enable) {
329 		tda9950_release(priv);
330 		return 0;
331 	} else {
332 		return tda9950_open(priv);
333 	}
334 }
335 
336 static const struct cec_adap_ops tda9950_cec_ops = {
337 	.adap_enable = tda9950_cec_adap_enable,
338 	.adap_log_addr = tda9950_cec_adap_log_addr,
339 	.adap_transmit = tda9950_cec_transmit,
340 };
341 
342 /*
343  * When operating as part of the TDA998x, we need to claim additional
344  * resources.  These two hooks permit the management of those resources.
345  */
tda9950_devm_glue_exit(void * data)346 static void tda9950_devm_glue_exit(void *data)
347 {
348 	struct tda9950_glue *glue = data;
349 
350 	if (glue && glue->exit)
351 		glue->exit(glue->data);
352 }
353 
tda9950_devm_glue_init(struct device * dev,struct tda9950_glue * glue)354 static int tda9950_devm_glue_init(struct device *dev, struct tda9950_glue *glue)
355 {
356 	int ret;
357 
358 	if (glue && glue->init) {
359 		ret = glue->init(glue->data);
360 		if (ret)
361 			return ret;
362 	}
363 
364 	ret = devm_add_action(dev, tda9950_devm_glue_exit, glue);
365 	if (ret)
366 		tda9950_devm_glue_exit(glue);
367 
368 	return ret;
369 }
370 
tda9950_cec_del(void * data)371 static void tda9950_cec_del(void *data)
372 {
373 	struct tda9950_priv *priv = data;
374 
375 	cec_delete_adapter(priv->adap);
376 }
377 
tda9950_probe(struct i2c_client * client)378 static int tda9950_probe(struct i2c_client *client)
379 {
380 	struct tda9950_glue *glue = client->dev.platform_data;
381 	struct device *dev = &client->dev;
382 	struct tda9950_priv *priv;
383 	unsigned long irqflags;
384 	int ret;
385 	u8 cvr;
386 
387 	/*
388 	 * We must have I2C functionality: our multi-byte accesses
389 	 * must be performed as a single contiguous transaction.
390 	 */
391 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
392 		dev_err(&client->dev,
393 			"adapter does not support I2C functionality\n");
394 		return -ENXIO;
395 	}
396 
397 	/* We must have an interrupt to be functional. */
398 	if (client->irq <= 0) {
399 		dev_err(&client->dev, "driver requires an interrupt\n");
400 		return -ENXIO;
401 	}
402 
403 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
404 	if (!priv)
405 		return -ENOMEM;
406 
407 	priv->client = client;
408 	priv->glue = glue;
409 
410 	i2c_set_clientdata(client, priv);
411 
412 	/*
413 	 * If we're part of a TDA998x, we want the class devices to be
414 	 * associated with the HDMI Tx so we have a tight relationship
415 	 * between the HDMI interface and the CEC interface.
416 	 */
417 	priv->hdmi = dev;
418 	if (glue && glue->parent)
419 		priv->hdmi = glue->parent;
420 
421 	priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",
422 					  CEC_CAP_DEFAULTS |
423 					  CEC_CAP_CONNECTOR_INFO,
424 					  CEC_MAX_LOG_ADDRS);
425 	if (IS_ERR(priv->adap))
426 		return PTR_ERR(priv->adap);
427 
428 	ret = devm_add_action(dev, tda9950_cec_del, priv);
429 	if (ret) {
430 		cec_delete_adapter(priv->adap);
431 		return ret;
432 	}
433 
434 	ret = tda9950_devm_glue_init(dev, glue);
435 	if (ret)
436 		return ret;
437 
438 	ret = tda9950_glue_open(priv);
439 	if (ret)
440 		return ret;
441 
442 	cvr = tda9950_read(client, REG_CVR);
443 
444 	dev_info(&client->dev,
445 		 "TDA9950 CEC interface, hardware version %u.%u\n",
446 		 cvr >> 4, cvr & 15);
447 
448 	tda9950_glue_release(priv);
449 
450 	irqflags = IRQF_TRIGGER_FALLING;
451 	if (glue)
452 		irqflags = glue->irq_flags;
453 
454 	ret = devm_request_threaded_irq(dev, client->irq, NULL, tda9950_irq,
455 					irqflags | IRQF_SHARED | IRQF_ONESHOT,
456 					dev_name(&client->dev), priv);
457 	if (ret < 0)
458 		return ret;
459 
460 	priv->notify = cec_notifier_cec_adap_register(priv->hdmi, NULL,
461 						      priv->adap);
462 	if (!priv->notify)
463 		return -ENOMEM;
464 
465 	ret = cec_register_adapter(priv->adap, priv->hdmi);
466 	if (ret < 0) {
467 		cec_notifier_cec_adap_unregister(priv->notify, priv->adap);
468 		return ret;
469 	}
470 
471 	/*
472 	 * CEC documentation says we must not call cec_delete_adapter
473 	 * after a successful call to cec_register_adapter().
474 	 */
475 	devm_remove_action(dev, tda9950_cec_del, priv);
476 
477 	return 0;
478 }
479 
tda9950_remove(struct i2c_client * client)480 static void tda9950_remove(struct i2c_client *client)
481 {
482 	struct tda9950_priv *priv = i2c_get_clientdata(client);
483 
484 	cec_notifier_cec_adap_unregister(priv->notify, priv->adap);
485 	cec_unregister_adapter(priv->adap);
486 }
487 
488 static struct i2c_device_id tda9950_ids[] = {
489 	{ "tda9950", 0 },
490 	{ },
491 };
492 MODULE_DEVICE_TABLE(i2c, tda9950_ids);
493 
494 static struct i2c_driver tda9950_driver = {
495 	.probe = tda9950_probe,
496 	.remove = tda9950_remove,
497 	.driver = {
498 		.name = "tda9950",
499 	},
500 	.id_table = tda9950_ids,
501 };
502 
503 module_i2c_driver(tda9950_driver);
504 
505 MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
506 MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");
507 MODULE_LICENSE("GPL v2");
508