summaryrefslogtreecommitdiffstats
path: root/drivers/media/usb/rainshadow-cec/rainshadow-cec.c
blob: cecdcbcd400c5f6c1a6c1f841d7582b9bf0f83b4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
/*
 * RainShadow Tech HDMI CEC driver
 *
 * Copyright 2016 Hans Verkuil <hverkuil@xs4all.nl
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version of 2 of the License, or (at your
 * option) any later version. See the file COPYING in the main directory of
 * this archive for more details.
 */

/*
 * Notes:
 *
 * The higher level protocols are currently disabled. This can be added
 * later, similar to how this is done for the Pulse Eight CEC driver.
 *
 * Documentation of the protocol is available here:
 *
 * http://rainshadowtech.com/doc/HDMICECtoUSBandRS232v2.0.pdf
 */

#include <linux/completion.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/time.h>
#include <linux/workqueue.h>

#include <media/cec.h>

MODULE_AUTHOR("Hans Verkuil <hverkuil@xs4all.nl>");
MODULE_DESCRIPTION("RainShadow Tech HDMI CEC driver");
MODULE_LICENSE("GPL");

#define DATA_SIZE 256

struct rain {
	struct device *dev;
	struct serio *serio;
	struct cec_adapter *adap;
	struct completion cmd_done;
	struct work_struct work;

	/* Low-level ringbuffer, collecting incoming characters */
	char buf[DATA_SIZE];
	unsigned int buf_rd_idx;
	unsigned int buf_wr_idx;
	unsigned int buf_len;
	spinlock_t buf_lock;

	/* command buffer */
	char cmd[DATA_SIZE];
	unsigned int cmd_idx;
	bool cmd_started;

	/* reply to a command, only used to store the firmware version */
	char cmd_reply[DATA_SIZE];

	struct mutex write_lock;
};

static void rain_process_msg(struct rain *rain)
{
	struct cec_msg msg = {};
	const char *cmd = rain->cmd + 3;
	int stat = -1;

	for (; *cmd; cmd++) {
		if (!isxdigit(*cmd))
			continue;
		if (isxdigit(cmd[0]) && isxdigit(cmd[1])) {
			if (msg.len == CEC_MAX_MSG_SIZE)
				break;
			if (hex2bin(msg.msg + msg.len, cmd, 1))
				continue;
			msg.len++;
			cmd++;
			continue;
		}
		if (!cmd[1])
			stat = hex_to_bin(cmd[0]);
		break;
	}

	if (rain->cmd[0] == 'R') {
		if (stat == 1 || stat == 2)
			cec_received_msg(rain->adap, &msg);
		return;
	}

	switch (stat) {
	case 1:
		cec_transmit_attempt_done(rain->adap, CEC_TX_STATUS_OK);
		break;
	case 2:
		cec_transmit_attempt_done(rain->adap, CEC_TX_STATUS_NACK);
		break;
	default:
		cec_transmit_attempt_done(rain->adap, CEC_TX_STATUS_LOW_DRIVE);
		break;
	}
}

static void rain_irq_work_handler(struct work_struct *work)
{
	struct rain *rain =
		container_of(work, struct rain, work);

	while (true) {
		unsigned long flags;
		char data;

		spin_lock_irqsave(&rain->buf_lock, flags);
		if (!rain->buf_len) {
			spin_unlock_irqrestore(&rain->buf_lock, flags);
			break;
		}

		data = rain->buf[rain->buf_rd_idx];
		rain->buf_len--;
		rain->buf_rd_idx = (rain->buf_rd_idx + 1) & 0xff;

		spin_unlock_irqrestore(&rain->buf_lock, flags);

		if (!rain->cmd_started && data != '?')
			continue;

		switch (data) {
		case '\r':
			rain->cmd[rain->cmd_idx] = '\0';
			dev_dbg(rain->dev, "received: %s\n", rain->cmd);
			if (!memcmp(rain->cmd, "REC", 3) ||
			    !memcmp(rain->cmd, "STA", 3)) {
				rain_process_msg(rain);
			} else {
				strcpy(rain->cmd_reply, rain->cmd);
				complete(&rain->cmd_done);
			}
			rain->cmd_idx = 0;
			rain->cmd_started = false;
			break;

		case '\n':
			rain->cmd_idx = 0;
			rain->cmd_started = false;
			break;

		case '?':
			rain->cmd_idx = 0;
			rain->cmd_started = true;
			break;

		default:
			if (rain->cmd_idx >= DATA_SIZE - 1) {
				dev_dbg(rain->dev,
					"throwing away %d bytes of garbage\n", rain->cmd_idx);
				rain->cmd_idx = 0;
			}
			rain->cmd[rain->cmd_idx++] = data;
			break;
		}
	}
}

static irqreturn_t rain_interrupt(struct serio *serio, unsigned char data,
				    unsigned int flags)
{
	struct rain *rain = serio_get_drvdata(serio);

	if (rain->buf_len == DATA_SIZE) {
		dev_warn_once(rain->dev, "buffer overflow\n");
		return IRQ_HANDLED;
	}
	spin_lock(&rain->buf_lock);
	rain->buf_len++;
	rain->buf[rain->buf_wr_idx] = data;
	rain->buf_wr_idx = (rain->buf_wr_idx + 1) & 0xff;
	spin_unlock(&rain->buf_lock);
	schedule_work(&rain->work);
	return IRQ_HANDLED;
}

static void rain_disconnect(struct serio *serio)
{
	struct rain *rain = serio_get_drvdata(serio);

	cancel_work_sync(&rain->work);
	cec_unregister_adapter(rain->adap);
	dev_info(&serio->dev, "disconnected\n");
	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	kfree(rain);
}

static int rain_send(struct rain *rain, const char *command)
{
	int err = serio_write(rain->serio, '!');

	dev_dbg(rain->dev, "send: %s\n", command);
	while (!err && *command)
		err = serio_write(rain->serio, *command++);
	if (!err)
		err = serio_write(rain->serio, '~');

	return err;
}

static int rain_send_and_wait(struct rain *rain,
			      const char *cmd, const char *reply)
{
	int err;

	init_completion(&rain->cmd_done);

	mutex_lock(&rain->write_lock);
	err = rain_send(rain, cmd);
	if (err)
		goto err;

	if (!wait_for_completion_timeout(&rain->cmd_done, HZ)) {
		err = -ETIMEDOUT;
		goto err;
	}
	if (reply && strncmp(rain->cmd_reply, reply, strlen(reply))) {
		dev_dbg(rain->dev,
			 "transmit of '%s': received '%s' instead of '%s'\n",
			 cmd, rain->cmd_reply, reply);
		err = -EIO;
	}
err:
	mutex_unlock(&rain->write_lock);
	return err;
}

static int rain_setup(struct rain *rain, struct serio *serio,
			struct cec_log_addrs *log_addrs, u16 *pa)
{
	int err;

	err = rain_send_and_wait(rain, "R", "REV");
	if (err)
		return err;
	dev_info(rain->dev, "Firmware version %s\n", rain->cmd_reply + 4);

	err = rain_send_and_wait(rain, "Q 1", "QTY");
	if (err)
		return err;
	err = rain_send_and_wait(rain, "c0000", "CFG");
	if (err)
		return err;
	return rain_send_and_wait(rain, "A F 0000", "ADR");
}

static int rain_cec_adap_enable(struct cec_adapter *adap, bool enable)
{
	return 0;
}

static int rain_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
{
	struct rain *rain = cec_get_drvdata(adap);
	u8 cmd[16];

	if (log_addr == CEC_LOG_ADDR_INVALID)
		log_addr = CEC_LOG_ADDR_UNREGISTERED;
	snprintf(cmd, sizeof(cmd), "A %x", log_addr);
	return rain_send_and_wait(rain, cmd, "ADR");
}

static int rain_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
				    u32 signal_free_time, struct cec_msg *msg)
{
	struct rain *rain = cec_get_drvdata(adap);
	char cmd[2 * CEC_MAX_MSG_SIZE + 16];
	unsigned int i;
	int err;

	if (msg->len == 1) {
		snprintf(cmd, sizeof(cmd), "x%x", cec_msg_destination(msg));
	} else {
		char hex[3];

		snprintf(cmd, sizeof(cmd), "x%x %02x ",
			 cec_msg_destination(msg), msg->msg[1]);
		for (i = 2; i < msg->len; i++) {
			snprintf(hex, sizeof(hex), "%02x", msg->msg[i]);
			strlcat(cmd, hex, sizeof(cmd));
		}
	}
	mutex_lock(&rain->write_lock);
	err = rain_send(rain, cmd);
	mutex_unlock(&rain->write_lock);
	return err;
}

static const struct cec_adap_ops rain_cec_adap_ops = {
	.adap_enable = rain_cec_adap_enable,
	.adap_log_addr = rain_cec_adap_log_addr,
	.adap_transmit = rain_cec_adap_transmit,
};

static int rain_connect(struct serio *serio, struct serio_driver *drv)
{
	u32 caps = CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR | CEC_CAP_MONITOR_ALL;
	struct rain *rain;
	int err = -ENOMEM;
	struct cec_log_addrs log_addrs = {};
	u16 pa = CEC_PHYS_ADDR_INVALID;

	rain = kzalloc(sizeof(*rain), GFP_KERNEL);

	if (!rain)
		return -ENOMEM;

	rain->serio = serio;
	rain->adap = cec_allocate_adapter(&rain_cec_adap_ops, rain,
					  dev_name(&serio->dev), caps, 1);
	err = PTR_ERR_OR_ZERO(rain->adap);
	if (err < 0)
		goto free_device;

	rain->dev = &serio->dev;
	serio_set_drvdata(serio, rain);
	INIT_WORK(&rain->work, rain_irq_work_handler);
	mutex_init(&rain->write_lock);
	spin_lock_init(&rain->buf_lock);

	err = serio_open(serio, drv);
	if (err)
		goto delete_adap;

	err = rain_setup(rain, serio, &log_addrs, &pa);
	if (err)
		goto close_serio;

	err = cec_register_adapter(rain->adap, &serio->dev);
	if (err < 0)
		goto close_serio;

	rain->dev = &rain->adap->devnode.dev;
	return 0;

close_serio:
	serio_close(serio);
delete_adap:
	cec_delete_adapter(rain->adap);
	serio_set_drvdata(serio, NULL);
free_device:
	kfree(rain);
	return err;
}

static const struct serio_device_id rain_serio_ids[] = {
	{
		.type	= SERIO_RS232,
		.proto	= SERIO_RAINSHADOW_CEC,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, rain_serio_ids);

static struct serio_driver rain_drv = {
	.driver		= {
		.name	= "rainshadow-cec",
	},
	.description	= "RainShadow Tech HDMI CEC driver",
	.id_table	= rain_serio_ids,
	.interrupt	= rain_interrupt,
	.connect	= rain_connect,
	.disconnect	= rain_disconnect,
};

module_serio_driver(rain_drv);