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
23enum {
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
62struct 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
73static 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
98static void tda9950_write(struct i2c_client *client, u8 addr, u8 val)
99{
100	tda9950_write_range(client, addr, &val, 1);
101}
102
103static 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
126static 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
138static 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
215static 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
233static 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 */
258static 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
270static 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
278static 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
299static 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
324static 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
336static 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 */
346static 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
354static 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
371static void tda9950_cec_del(void *data)
372{
373	struct tda9950_priv *priv = data;
374
375	cec_delete_adapter(priv->adap);
376}
377
378static 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
480static 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
488static struct i2c_device_id tda9950_ids[] = {
489	{ "tda9950", 0 },
490	{ },
491};
492MODULE_DEVICE_TABLE(i2c, tda9950_ids);
493
494static 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
503module_i2c_driver(tda9950_driver);
504
505MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
506MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");
507MODULE_LICENSE("GPL v2");
508