1 /*
2  * drivers/media/radio/si470x/radio-si470x-i2c.c
3  *
4  * I2C driver for radios with Silicon Labs Si470x FM Radio Receivers
5  *
6  * Copyright (c) 2009 Samsung Electronics Co.Ltd
7  * Author: Joonyoung Shim <jy0922.shim@samsung.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22  */
23 
24 
25 /* driver definitions */
26 #define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>";
27 #define DRIVER_KERNEL_VERSION KERNEL_VERSION(1, 0, 1)
28 #define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
29 #define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers"
30 #define DRIVER_VERSION "1.0.1"
31 
32 /* kernel includes */
33 #include <linux/i2c.h>
34 #include <linux/delay.h>
35 #include <linux/interrupt.h>
36 
37 #include "radio-si470x.h"
38 
39 
40 /* I2C Device ID List */
41 static const struct i2c_device_id si470x_i2c_id[] = {
42 	/* Generic Entry */
43 	{ "si470x", 0 },
44 	/* Terminating entry */
45 	{ }
46 };
47 MODULE_DEVICE_TABLE(i2c, si470x_i2c_id);
48 
49 
50 
51 /**************************************************************************
52  * Module Parameters
53  **************************************************************************/
54 
55 /* Radio Nr */
56 static int radio_nr = -1;
57 module_param(radio_nr, int, 0444);
58 MODULE_PARM_DESC(radio_nr, "Radio Nr");
59 
60 /* RDS buffer blocks */
61 static unsigned int rds_buf = 100;
62 module_param(rds_buf, uint, 0444);
63 MODULE_PARM_DESC(rds_buf, "RDS buffer entries: *100*");
64 
65 /* RDS maximum block errors */
66 static unsigned short max_rds_errors = 1;
67 /* 0 means   0  errors requiring correction */
68 /* 1 means 1-2  errors requiring correction (used by original USBRadio.exe) */
69 /* 2 means 3-5  errors requiring correction */
70 /* 3 means   6+ errors or errors in checkword, correction not possible */
71 module_param(max_rds_errors, ushort, 0644);
72 MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");
73 
74 
75 
76 /**************************************************************************
77  * I2C Definitions
78  **************************************************************************/
79 
80 /* Write starts with the upper byte of register 0x02 */
81 #define WRITE_REG_NUM		8
82 #define WRITE_INDEX(i)		(i + 0x02)
83 
84 /* Read starts with the upper byte of register 0x0a */
85 #define READ_REG_NUM		RADIO_REGISTER_NUM
86 #define READ_INDEX(i)		((i + RADIO_REGISTER_NUM - 0x0a) % READ_REG_NUM)
87 
88 
89 
90 /**************************************************************************
91  * General Driver Functions - REGISTERs
92  **************************************************************************/
93 
94 /*
95  * si470x_get_register - read register
96  */
97 int si470x_get_register(struct si470x_device *radio, int regnr)
98 {
99 	u16 buf[READ_REG_NUM];
100 	struct i2c_msg msgs[1] = {
101 		{ radio->client->addr, I2C_M_RD, sizeof(u16) * READ_REG_NUM,
102 			(void *)buf },
103 	};
104 
105 	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
106 		return -EIO;
107 
108 	radio->registers[regnr] = __be16_to_cpu(buf[READ_INDEX(regnr)]);
109 
110 	return 0;
111 }
112 
113 
114 /*
115  * si470x_set_register - write register
116  */
117 int si470x_set_register(struct si470x_device *radio, int regnr)
118 {
119 	int i;
120 	u16 buf[WRITE_REG_NUM];
121 	struct i2c_msg msgs[1] = {
122 		{ radio->client->addr, 0, sizeof(u16) * WRITE_REG_NUM,
123 			(void *)buf },
124 	};
125 
126 	for (i = 0; i < WRITE_REG_NUM; i++)
127 		buf[i] = __cpu_to_be16(radio->registers[WRITE_INDEX(i)]);
128 
129 	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
130 		return -EIO;
131 
132 	return 0;
133 }
134 
135 
136 
137 /**************************************************************************
138  * General Driver Functions - ENTIRE REGISTERS
139  **************************************************************************/
140 
141 /*
142  * si470x_get_all_registers - read entire registers
143  */
144 static int si470x_get_all_registers(struct si470x_device *radio)
145 {
146 	int i;
147 	u16 buf[READ_REG_NUM];
148 	struct i2c_msg msgs[1] = {
149 		{ radio->client->addr, I2C_M_RD, sizeof(u16) * READ_REG_NUM,
150 			(void *)buf },
151 	};
152 
153 	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
154 		return -EIO;
155 
156 	for (i = 0; i < READ_REG_NUM; i++)
157 		radio->registers[i] = __be16_to_cpu(buf[READ_INDEX(i)]);
158 
159 	return 0;
160 }
161 
162 
163 
164 /**************************************************************************
165  * General Driver Functions - DISCONNECT_CHECK
166  **************************************************************************/
167 
168 /*
169  * si470x_disconnect_check - check whether radio disconnects
170  */
171 int si470x_disconnect_check(struct si470x_device *radio)
172 {
173 	return 0;
174 }
175 
176 
177 
178 /**************************************************************************
179  * File Operations Interface
180  **************************************************************************/
181 
182 /*
183  * si470x_fops_open - file open
184  */
185 int si470x_fops_open(struct file *file)
186 {
187 	struct si470x_device *radio = video_drvdata(file);
188 	int retval = 0;
189 
190 	mutex_lock(&radio->lock);
191 	radio->users++;
192 
193 	if (radio->users == 1) {
194 		/* start radio */
195 		retval = si470x_start(radio);
196 		if (retval < 0)
197 			goto done;
198 
199 		/* enable RDS interrupt */
200 		radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDSIEN;
201 		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_GPIO2;
202 		radio->registers[SYSCONFIG1] |= 0x1 << 2;
203 		retval = si470x_set_register(radio, SYSCONFIG1);
204 	}
205 
206 done:
207 	mutex_unlock(&radio->lock);
208 	return retval;
209 }
210 
211 
212 /*
213  * si470x_fops_release - file release
214  */
215 int si470x_fops_release(struct file *file)
216 {
217 	struct si470x_device *radio = video_drvdata(file);
218 	int retval = 0;
219 
220 	/* safety check */
221 	if (!radio)
222 		return -ENODEV;
223 
224 	mutex_lock(&radio->lock);
225 	radio->users--;
226 	if (radio->users == 0)
227 		/* stop radio */
228 		retval = si470x_stop(radio);
229 
230 	mutex_unlock(&radio->lock);
231 
232 	return retval;
233 }
234 
235 
236 
237 /**************************************************************************
238  * Video4Linux Interface
239  **************************************************************************/
240 
241 /*
242  * si470x_vidioc_querycap - query device capabilities
243  */
244 int si470x_vidioc_querycap(struct file *file, void *priv,
245 		struct v4l2_capability *capability)
246 {
247 	strlcpy(capability->driver, DRIVER_NAME, sizeof(capability->driver));
248 	strlcpy(capability->card, DRIVER_CARD, sizeof(capability->card));
249 	capability->version = DRIVER_KERNEL_VERSION;
250 	capability->capabilities = V4L2_CAP_HW_FREQ_SEEK |
251 		V4L2_CAP_TUNER | V4L2_CAP_RADIO;
252 
253 	return 0;
254 }
255 
256 
257 
258 /**************************************************************************
259  * I2C Interface
260  **************************************************************************/
261 
262 /*
263  * si470x_i2c_interrupt_work - rds processing function
264  */
265 static void si470x_i2c_interrupt_work(struct work_struct *work)
266 {
267 	struct si470x_device *radio = container_of(work,
268 			struct si470x_device, radio_work);
269 	unsigned char regnr;
270 	unsigned char blocknum;
271 	unsigned short bler; /* rds block errors */
272 	unsigned short rds;
273 	unsigned char tmpbuf[3];
274 	int retval = 0;
275 
276 	/* safety checks */
277 	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
278 		return;
279 
280 	/* Update RDS registers */
281 	for (regnr = 0; regnr < RDS_REGISTER_NUM; regnr++) {
282 		retval = si470x_get_register(radio, STATUSRSSI + regnr);
283 		if (retval < 0)
284 			return;
285 	}
286 
287 	/* get rds blocks */
288 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0)
289 		/* No RDS group ready, better luck next time */
290 		return;
291 
292 	for (blocknum = 0; blocknum < 4; blocknum++) {
293 		switch (blocknum) {
294 		default:
295 			bler = (radio->registers[STATUSRSSI] &
296 					STATUSRSSI_BLERA) >> 9;
297 			rds = radio->registers[RDSA];
298 			break;
299 		case 1:
300 			bler = (radio->registers[READCHAN] &
301 					READCHAN_BLERB) >> 14;
302 			rds = radio->registers[RDSB];
303 			break;
304 		case 2:
305 			bler = (radio->registers[READCHAN] &
306 					READCHAN_BLERC) >> 12;
307 			rds = radio->registers[RDSC];
308 			break;
309 		case 3:
310 			bler = (radio->registers[READCHAN] &
311 					READCHAN_BLERD) >> 10;
312 			rds = radio->registers[RDSD];
313 			break;
314 		};
315 
316 		/* Fill the V4L2 RDS buffer */
317 		put_unaligned_le16(rds, &tmpbuf);
318 		tmpbuf[2] = blocknum;		/* offset name */
319 		tmpbuf[2] |= blocknum << 3;	/* received offset */
320 		if (bler > max_rds_errors)
321 			tmpbuf[2] |= 0x80;	/* uncorrectable errors */
322 		else if (bler > 0)
323 			tmpbuf[2] |= 0x40;	/* corrected error(s) */
324 
325 		/* copy RDS block to internal buffer */
326 		memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
327 		radio->wr_index += 3;
328 
329 		/* wrap write pointer */
330 		if (radio->wr_index >= radio->buf_size)
331 			radio->wr_index = 0;
332 
333 		/* check for overflow */
334 		if (radio->wr_index == radio->rd_index) {
335 			/* increment and wrap read pointer */
336 			radio->rd_index += 3;
337 			if (radio->rd_index >= radio->buf_size)
338 				radio->rd_index = 0;
339 		}
340 	}
341 
342 	if (radio->wr_index != radio->rd_index)
343 		wake_up_interruptible(&radio->read_queue);
344 }
345 
346 
347 /*
348  * si470x_i2c_interrupt - interrupt handler
349  */
350 static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
351 {
352 	struct si470x_device *radio = dev_id;
353 
354 	if (!work_pending(&radio->radio_work))
355 		schedule_work(&radio->radio_work);
356 
357 	return IRQ_HANDLED;
358 }
359 
360 
361 /*
362  * si470x_i2c_probe - probe for the device
363  */
364 static int __devinit si470x_i2c_probe(struct i2c_client *client,
365 		const struct i2c_device_id *id)
366 {
367 	struct si470x_device *radio;
368 	int retval = 0;
369 	unsigned char version_warning = 0;
370 
371 	/* private data allocation and initialization */
372 	radio = kzalloc(sizeof(struct si470x_device), GFP_KERNEL);
373 	if (!radio) {
374 		retval = -ENOMEM;
375 		goto err_initial;
376 	}
377 
378 	INIT_WORK(&radio->radio_work, si470x_i2c_interrupt_work);
379 	radio->users = 0;
380 	radio->client = client;
381 	mutex_init(&radio->lock);
382 
383 	/* video device allocation and initialization */
384 	radio->videodev = video_device_alloc();
385 	if (!radio->videodev) {
386 		retval = -ENOMEM;
387 		goto err_radio;
388 	}
389 	memcpy(radio->videodev, &si470x_viddev_template,
390 			sizeof(si470x_viddev_template));
391 	video_set_drvdata(radio->videodev, radio);
392 
393 	/* power up : need 110ms */
394 	radio->registers[POWERCFG] = POWERCFG_ENABLE;
395 	if (si470x_set_register(radio, POWERCFG) < 0) {
396 		retval = -EIO;
397 		goto err_all;
398 	}
399 	msleep(110);
400 
401 	/* get device and chip versions */
402 	if (si470x_get_all_registers(radio) < 0) {
403 		retval = -EIO;
404 		goto err_video;
405 	}
406 	dev_info(&client->dev, "DeviceID=0x%4.4hx ChipID=0x%4.4hx\n",
407 			radio->registers[DEVICEID], radio->registers[CHIPID]);
408 	if ((radio->registers[CHIPID] & CHIPID_FIRMWARE) < RADIO_FW_VERSION) {
409 		dev_warn(&client->dev,
410 			"This driver is known to work with "
411 			"firmware version %hu,\n", RADIO_FW_VERSION);
412 		dev_warn(&client->dev,
413 			"but the device has firmware version %hu.\n",
414 			radio->registers[CHIPID] & CHIPID_FIRMWARE);
415 		version_warning = 1;
416 	}
417 
418 	/* give out version warning */
419 	if (version_warning == 1) {
420 		dev_warn(&client->dev,
421 			"If you have some trouble using this driver,\n");
422 		dev_warn(&client->dev,
423 			"please report to V4L ML at "
424 			"linux-media@vger.kernel.org\n");
425 	}
426 
427 	/* set initial frequency */
428 	si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */
429 
430 	/* rds buffer allocation */
431 	radio->buf_size = rds_buf * 3;
432 	radio->buffer = kmalloc(radio->buf_size, GFP_KERNEL);
433 	if (!radio->buffer) {
434 		retval = -EIO;
435 		goto err_video;
436 	}
437 
438 	/* rds buffer configuration */
439 	radio->wr_index = 0;
440 	radio->rd_index = 0;
441 	init_waitqueue_head(&radio->read_queue);
442 
443 	retval = request_irq(client->irq, si470x_i2c_interrupt,
444 			IRQF_TRIGGER_FALLING, DRIVER_NAME, radio);
445 	if (retval) {
446 		dev_err(&client->dev, "Failed to register interrupt\n");
447 		goto err_rds;
448 	}
449 
450 	/* register video device */
451 	retval = video_register_device(radio->videodev, VFL_TYPE_RADIO,
452 			radio_nr);
453 	if (retval) {
454 		dev_warn(&client->dev, "Could not register video device\n");
455 		goto err_all;
456 	}
457 	i2c_set_clientdata(client, radio);
458 
459 	return 0;
460 err_all:
461 	free_irq(client->irq, radio);
462 err_rds:
463 	kfree(radio->buffer);
464 err_video:
465 	video_device_release(radio->videodev);
466 err_radio:
467 	kfree(radio);
468 err_initial:
469 	return retval;
470 }
471 
472 
473 /*
474  * si470x_i2c_remove - remove the device
475  */
476 static __devexit int si470x_i2c_remove(struct i2c_client *client)
477 {
478 	struct si470x_device *radio = i2c_get_clientdata(client);
479 
480 	free_irq(client->irq, radio);
481 	cancel_work_sync(&radio->radio_work);
482 	video_unregister_device(radio->videodev);
483 	kfree(radio);
484 	i2c_set_clientdata(client, NULL);
485 
486 	return 0;
487 }
488 
489 
490 #ifdef CONFIG_PM
491 /*
492  * si470x_i2c_suspend - suspend the device
493  */
494 static int si470x_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
495 {
496 	struct si470x_device *radio = i2c_get_clientdata(client);
497 
498 	/* power down */
499 	radio->registers[POWERCFG] |= POWERCFG_DISABLE;
500 	if (si470x_set_register(radio, POWERCFG) < 0)
501 		return -EIO;
502 
503 	return 0;
504 }
505 
506 
507 /*
508  * si470x_i2c_resume - resume the device
509  */
510 static int si470x_i2c_resume(struct i2c_client *client)
511 {
512 	struct si470x_device *radio = i2c_get_clientdata(client);
513 
514 	/* power up : need 110ms */
515 	radio->registers[POWERCFG] |= POWERCFG_ENABLE;
516 	if (si470x_set_register(radio, POWERCFG) < 0)
517 		return -EIO;
518 	msleep(110);
519 
520 	return 0;
521 }
522 #else
523 #define si470x_i2c_suspend	NULL
524 #define si470x_i2c_resume	NULL
525 #endif
526 
527 
528 /*
529  * si470x_i2c_driver - i2c driver interface
530  */
531 static struct i2c_driver si470x_i2c_driver = {
532 	.driver = {
533 		.name		= "si470x",
534 		.owner		= THIS_MODULE,
535 	},
536 	.probe			= si470x_i2c_probe,
537 	.remove			= __devexit_p(si470x_i2c_remove),
538 	.suspend		= si470x_i2c_suspend,
539 	.resume			= si470x_i2c_resume,
540 	.id_table		= si470x_i2c_id,
541 };
542 
543 
544 
545 /**************************************************************************
546  * Module Interface
547  **************************************************************************/
548 
549 /*
550  * si470x_i2c_init - module init
551  */
552 static int __init si470x_i2c_init(void)
553 {
554 	printk(KERN_INFO DRIVER_DESC ", Version " DRIVER_VERSION "\n");
555 	return i2c_add_driver(&si470x_i2c_driver);
556 }
557 
558 
559 /*
560  * si470x_i2c_exit - module exit
561  */
562 static void __exit si470x_i2c_exit(void)
563 {
564 	i2c_del_driver(&si470x_i2c_driver);
565 }
566 
567 
568 module_init(si470x_i2c_init);
569 module_exit(si470x_i2c_exit);
570 
571 MODULE_LICENSE("GPL");
572 MODULE_AUTHOR(DRIVER_AUTHOR);
573 MODULE_DESCRIPTION(DRIVER_DESC);
574 MODULE_VERSION(DRIVER_VERSION);
575