1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * drivers/media/radio/si470x/radio-si470x-i2c.c
4  *
5  * I2C driver for radios with Silicon Labs Si470x FM Radio Receivers
6  *
7  * Copyright (c) 2009 Samsung Electronics Co.Ltd
8  * Author: Joonyoung Shim <jy0922.shim@samsung.com>
9  */
10 
11 
12 /* driver definitions */
13 #define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>";
14 #define DRIVER_CARD "Silicon Labs Si470x FM Radio Receiver"
15 #define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers"
16 #define DRIVER_VERSION "1.0.2"
17 
18 /* kernel includes */
19 #include <linux/i2c.h>
20 #include <linux/slab.h>
21 #include <linux/delay.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/interrupt.h>
24 
25 #include "radio-si470x.h"
26 
27 
28 /* I2C Device ID List */
29 static const struct i2c_device_id si470x_i2c_id[] = {
30 	/* Generic Entry */
31 	{ "si470x", 0 },
32 	/* Terminating entry */
33 	{ }
34 };
35 MODULE_DEVICE_TABLE(i2c, si470x_i2c_id);
36 
37 
38 /**************************************************************************
39  * Module Parameters
40  **************************************************************************/
41 
42 /* Radio Nr */
43 static int radio_nr = -1;
44 module_param(radio_nr, int, 0444);
45 MODULE_PARM_DESC(radio_nr, "Radio Nr");
46 
47 /* RDS buffer blocks */
48 static unsigned int rds_buf = 100;
49 module_param(rds_buf, uint, 0444);
50 MODULE_PARM_DESC(rds_buf, "RDS buffer entries: *100*");
51 
52 /* RDS maximum block errors */
53 static unsigned short max_rds_errors = 1;
54 /* 0 means   0  errors requiring correction */
55 /* 1 means 1-2  errors requiring correction (used by original USBRadio.exe) */
56 /* 2 means 3-5  errors requiring correction */
57 /* 3 means   6+ errors or errors in checkword, correction not possible */
58 module_param(max_rds_errors, ushort, 0644);
59 MODULE_PARM_DESC(max_rds_errors, "RDS maximum block errors: *1*");
60 
61 
62 
63 /**************************************************************************
64  * I2C Definitions
65  **************************************************************************/
66 
67 /* Write starts with the upper byte of register 0x02 */
68 #define WRITE_REG_NUM		8
69 #define WRITE_INDEX(i)		(i + 0x02)
70 
71 /* Read starts with the upper byte of register 0x0a */
72 #define READ_REG_NUM		RADIO_REGISTER_NUM
73 #define READ_INDEX(i)		((i + RADIO_REGISTER_NUM - 0x0a) % READ_REG_NUM)
74 
75 
76 
77 /**************************************************************************
78  * General Driver Functions - REGISTERs
79  **************************************************************************/
80 
81 /*
82  * si470x_get_register - read register
83  */
84 static int si470x_get_register(struct si470x_device *radio, int regnr)
85 {
86 	__be16 buf[READ_REG_NUM];
87 	struct i2c_msg msgs[1] = {
88 		{
89 			.addr = radio->client->addr,
90 			.flags = I2C_M_RD,
91 			.len = sizeof(u16) * READ_REG_NUM,
92 			.buf = (void *)buf
93 		},
94 	};
95 
96 	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
97 		return -EIO;
98 
99 	radio->registers[regnr] = __be16_to_cpu(buf[READ_INDEX(regnr)]);
100 
101 	return 0;
102 }
103 
104 
105 /*
106  * si470x_set_register - write register
107  */
108 static int si470x_set_register(struct si470x_device *radio, int regnr)
109 {
110 	int i;
111 	__be16 buf[WRITE_REG_NUM];
112 	struct i2c_msg msgs[1] = {
113 		{
114 			.addr = radio->client->addr,
115 			.len = sizeof(u16) * WRITE_REG_NUM,
116 			.buf = (void *)buf
117 		},
118 	};
119 
120 	for (i = 0; i < WRITE_REG_NUM; i++)
121 		buf[i] = __cpu_to_be16(radio->registers[WRITE_INDEX(i)]);
122 
123 	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
124 		return -EIO;
125 
126 	return 0;
127 }
128 
129 
130 
131 /**************************************************************************
132  * General Driver Functions - ENTIRE REGISTERS
133  **************************************************************************/
134 
135 /*
136  * si470x_get_all_registers - read entire registers
137  */
138 static int si470x_get_all_registers(struct si470x_device *radio)
139 {
140 	int i;
141 	__be16 buf[READ_REG_NUM];
142 	struct i2c_msg msgs[1] = {
143 		{
144 			.addr = radio->client->addr,
145 			.flags = I2C_M_RD,
146 			.len = sizeof(u16) * READ_REG_NUM,
147 			.buf = (void *)buf
148 		},
149 	};
150 
151 	if (i2c_transfer(radio->client->adapter, msgs, 1) != 1)
152 		return -EIO;
153 
154 	for (i = 0; i < READ_REG_NUM; i++)
155 		radio->registers[i] = __be16_to_cpu(buf[READ_INDEX(i)]);
156 
157 	return 0;
158 }
159 
160 
161 
162 /**************************************************************************
163  * File Operations Interface
164  **************************************************************************/
165 
166 /*
167  * si470x_fops_open - file open
168  */
169 static int si470x_fops_open(struct file *file)
170 {
171 	struct si470x_device *radio = video_drvdata(file);
172 	int retval = v4l2_fh_open(file);
173 
174 	if (retval)
175 		return retval;
176 
177 	if (v4l2_fh_is_singular_file(file)) {
178 		/* start radio */
179 		retval = si470x_start(radio);
180 		if (retval < 0)
181 			goto done;
182 
183 		/* enable RDS / STC interrupt */
184 		radio->registers[SYSCONFIG1] |= SYSCONFIG1_RDSIEN;
185 		radio->registers[SYSCONFIG1] |= SYSCONFIG1_STCIEN;
186 		radio->registers[SYSCONFIG1] &= ~SYSCONFIG1_GPIO2;
187 		radio->registers[SYSCONFIG1] |= 0x1 << 2;
188 		retval = si470x_set_register(radio, SYSCONFIG1);
189 	}
190 
191 done:
192 	if (retval)
193 		v4l2_fh_release(file);
194 	return retval;
195 }
196 
197 
198 /*
199  * si470x_fops_release - file release
200  */
201 static int si470x_fops_release(struct file *file)
202 {
203 	struct si470x_device *radio = video_drvdata(file);
204 
205 	if (v4l2_fh_is_singular_file(file))
206 		/* stop radio */
207 		si470x_stop(radio);
208 
209 	return v4l2_fh_release(file);
210 }
211 
212 
213 
214 /**************************************************************************
215  * Video4Linux Interface
216  **************************************************************************/
217 
218 /*
219  * si470x_vidioc_querycap - query device capabilities
220  */
221 static int si470x_vidioc_querycap(struct file *file, void *priv,
222 				  struct v4l2_capability *capability)
223 {
224 	strscpy(capability->driver, DRIVER_NAME, sizeof(capability->driver));
225 	strscpy(capability->card, DRIVER_CARD, sizeof(capability->card));
226 	capability->device_caps = V4L2_CAP_HW_FREQ_SEEK | V4L2_CAP_READWRITE |
227 		V4L2_CAP_TUNER | V4L2_CAP_RADIO | V4L2_CAP_RDS_CAPTURE;
228 	capability->capabilities = capability->device_caps | V4L2_CAP_DEVICE_CAPS;
229 
230 	return 0;
231 }
232 
233 
234 
235 /**************************************************************************
236  * I2C Interface
237  **************************************************************************/
238 
239 /*
240  * si470x_i2c_interrupt - interrupt handler
241  */
242 static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
243 {
244 	struct si470x_device *radio = dev_id;
245 	unsigned char regnr;
246 	unsigned char blocknum;
247 	unsigned short bler; /* rds block errors */
248 	unsigned short rds;
249 	unsigned char tmpbuf[3];
250 	int retval = 0;
251 
252 	/* check Seek/Tune Complete */
253 	retval = si470x_get_register(radio, STATUSRSSI);
254 	if (retval < 0)
255 		goto end;
256 
257 	if (radio->registers[STATUSRSSI] & STATUSRSSI_STC)
258 		complete(&radio->completion);
259 
260 	/* safety checks */
261 	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
262 		goto end;
263 
264 	/* Update RDS registers */
265 	for (regnr = 1; regnr < RDS_REGISTER_NUM; regnr++) {
266 		retval = si470x_get_register(radio, STATUSRSSI + regnr);
267 		if (retval < 0)
268 			goto end;
269 	}
270 
271 	/* get rds blocks */
272 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0)
273 		/* No RDS group ready, better luck next time */
274 		goto end;
275 
276 	for (blocknum = 0; blocknum < 4; blocknum++) {
277 		switch (blocknum) {
278 		default:
279 			bler = (radio->registers[STATUSRSSI] &
280 					STATUSRSSI_BLERA) >> 9;
281 			rds = radio->registers[RDSA];
282 			break;
283 		case 1:
284 			bler = (radio->registers[READCHAN] &
285 					READCHAN_BLERB) >> 14;
286 			rds = radio->registers[RDSB];
287 			break;
288 		case 2:
289 			bler = (radio->registers[READCHAN] &
290 					READCHAN_BLERC) >> 12;
291 			rds = radio->registers[RDSC];
292 			break;
293 		case 3:
294 			bler = (radio->registers[READCHAN] &
295 					READCHAN_BLERD) >> 10;
296 			rds = radio->registers[RDSD];
297 			break;
298 		}
299 
300 		/* Fill the V4L2 RDS buffer */
301 		put_unaligned_le16(rds, &tmpbuf);
302 		tmpbuf[2] = blocknum;		/* offset name */
303 		tmpbuf[2] |= blocknum << 3;	/* received offset */
304 		if (bler > max_rds_errors)
305 			tmpbuf[2] |= 0x80;	/* uncorrectable errors */
306 		else if (bler > 0)
307 			tmpbuf[2] |= 0x40;	/* corrected error(s) */
308 
309 		/* copy RDS block to internal buffer */
310 		memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
311 		radio->wr_index += 3;
312 
313 		/* wrap write pointer */
314 		if (radio->wr_index >= radio->buf_size)
315 			radio->wr_index = 0;
316 
317 		/* check for overflow */
318 		if (radio->wr_index == radio->rd_index) {
319 			/* increment and wrap read pointer */
320 			radio->rd_index += 3;
321 			if (radio->rd_index >= radio->buf_size)
322 				radio->rd_index = 0;
323 		}
324 	}
325 
326 	if (radio->wr_index != radio->rd_index)
327 		wake_up_interruptible(&radio->read_queue);
328 
329 end:
330 	return IRQ_HANDLED;
331 }
332 
333 
334 /*
335  * si470x_i2c_probe - probe for the device
336  */
337 static int si470x_i2c_probe(struct i2c_client *client,
338 			    const struct i2c_device_id *id)
339 {
340 	struct si470x_device *radio;
341 	int retval = 0;
342 	unsigned char version_warning = 0;
343 
344 	/* private data allocation and initialization */
345 	radio = devm_kzalloc(&client->dev, sizeof(*radio), GFP_KERNEL);
346 	if (!radio) {
347 		retval = -ENOMEM;
348 		goto err_initial;
349 	}
350 
351 	radio->client = client;
352 	radio->band = 1; /* Default to 76 - 108 MHz */
353 	mutex_init(&radio->lock);
354 	init_completion(&radio->completion);
355 
356 	radio->get_register = si470x_get_register;
357 	radio->set_register = si470x_set_register;
358 	radio->fops_open = si470x_fops_open;
359 	radio->fops_release = si470x_fops_release;
360 	radio->vidioc_querycap = si470x_vidioc_querycap;
361 
362 	retval = v4l2_device_register(&client->dev, &radio->v4l2_dev);
363 	if (retval < 0) {
364 		dev_err(&client->dev, "couldn't register v4l2_device\n");
365 		goto err_initial;
366 	}
367 
368 	v4l2_ctrl_handler_init(&radio->hdl, 2);
369 	v4l2_ctrl_new_std(&radio->hdl, &si470x_ctrl_ops,
370 			V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
371 	v4l2_ctrl_new_std(&radio->hdl, &si470x_ctrl_ops,
372 			V4L2_CID_AUDIO_VOLUME, 0, 15, 1, 15);
373 	if (radio->hdl.error) {
374 		retval = radio->hdl.error;
375 		dev_err(&client->dev, "couldn't register control\n");
376 		goto err_dev;
377 	}
378 
379 	/* video device initialization */
380 	radio->videodev = si470x_viddev_template;
381 	radio->videodev.ctrl_handler = &radio->hdl;
382 	radio->videodev.lock = &radio->lock;
383 	radio->videodev.v4l2_dev = &radio->v4l2_dev;
384 	radio->videodev.release = video_device_release_empty;
385 	video_set_drvdata(&radio->videodev, radio);
386 
387 	radio->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",
388 						    GPIOD_OUT_LOW);
389 	if (IS_ERR(radio->gpio_reset)) {
390 		retval = PTR_ERR(radio->gpio_reset);
391 		dev_err(&client->dev, "Failed to request gpio: %d\n", retval);
392 		goto err_all;
393 	}
394 
395 	if (radio->gpio_reset)
396 		gpiod_set_value(radio->gpio_reset, 1);
397 
398 	/* power up : need 110ms */
399 	radio->registers[POWERCFG] = POWERCFG_ENABLE;
400 	if (si470x_set_register(radio, POWERCFG) < 0) {
401 		retval = -EIO;
402 		goto err_all;
403 	}
404 	msleep(110);
405 
406 	/* get device and chip versions */
407 	if (si470x_get_all_registers(radio) < 0) {
408 		retval = -EIO;
409 		goto err_all;
410 	}
411 	dev_info(&client->dev, "DeviceID=0x%4.4hx ChipID=0x%4.4hx\n",
412 			radio->registers[DEVICEID], radio->registers[SI_CHIPID]);
413 	if ((radio->registers[SI_CHIPID] & SI_CHIPID_FIRMWARE) < RADIO_FW_VERSION) {
414 		dev_warn(&client->dev,
415 			"This driver is known to work with firmware version %hu,\n",
416 			RADIO_FW_VERSION);
417 		dev_warn(&client->dev,
418 			"but the device has firmware version %hu.\n",
419 			radio->registers[SI_CHIPID] & SI_CHIPID_FIRMWARE);
420 		version_warning = 1;
421 	}
422 
423 	/* give out version warning */
424 	if (version_warning == 1) {
425 		dev_warn(&client->dev,
426 			"If you have some trouble using this driver,\n");
427 		dev_warn(&client->dev,
428 			"please report to V4L ML at linux-media@vger.kernel.org\n");
429 	}
430 
431 	/* set initial frequency */
432 	si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */
433 
434 	/* rds buffer allocation */
435 	radio->buf_size = rds_buf * 3;
436 	radio->buffer = devm_kmalloc(&client->dev, radio->buf_size, GFP_KERNEL);
437 	if (!radio->buffer) {
438 		retval = -EIO;
439 		goto err_all;
440 	}
441 
442 	/* rds buffer configuration */
443 	radio->wr_index = 0;
444 	radio->rd_index = 0;
445 	init_waitqueue_head(&radio->read_queue);
446 
447 	retval = devm_request_threaded_irq(&client->dev, client->irq, NULL,
448 					   si470x_i2c_interrupt,
449 					   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
450 					   DRIVER_NAME, radio);
451 	if (retval) {
452 		dev_err(&client->dev, "Failed to register interrupt\n");
453 		goto err_all;
454 	}
455 
456 	/* register video device */
457 	retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO,
458 			radio_nr);
459 	if (retval) {
460 		dev_warn(&client->dev, "Could not register video device\n");
461 		goto err_all;
462 	}
463 	i2c_set_clientdata(client, radio);
464 
465 	return 0;
466 err_all:
467 	v4l2_ctrl_handler_free(&radio->hdl);
468 err_dev:
469 	v4l2_device_unregister(&radio->v4l2_dev);
470 err_initial:
471 	return retval;
472 }
473 
474 
475 /*
476  * si470x_i2c_remove - remove the device
477  */
478 static int si470x_i2c_remove(struct i2c_client *client)
479 {
480 	struct si470x_device *radio = i2c_get_clientdata(client);
481 
482 	video_unregister_device(&radio->videodev);
483 
484 	if (radio->gpio_reset)
485 		gpiod_set_value(radio->gpio_reset, 0);
486 
487 	return 0;
488 }
489 
490 
491 #ifdef CONFIG_PM_SLEEP
492 /*
493  * si470x_i2c_suspend - suspend the device
494  */
495 static int si470x_i2c_suspend(struct device *dev)
496 {
497 	struct i2c_client *client = to_i2c_client(dev);
498 	struct si470x_device *radio = i2c_get_clientdata(client);
499 
500 	/* power down */
501 	radio->registers[POWERCFG] |= POWERCFG_DISABLE;
502 	if (si470x_set_register(radio, POWERCFG) < 0)
503 		return -EIO;
504 
505 	return 0;
506 }
507 
508 
509 /*
510  * si470x_i2c_resume - resume the device
511  */
512 static int si470x_i2c_resume(struct device *dev)
513 {
514 	struct i2c_client *client = to_i2c_client(dev);
515 	struct si470x_device *radio = i2c_get_clientdata(client);
516 
517 	/* power up : need 110ms */
518 	radio->registers[POWERCFG] |= POWERCFG_ENABLE;
519 	if (si470x_set_register(radio, POWERCFG) < 0)
520 		return -EIO;
521 	msleep(110);
522 
523 	return 0;
524 }
525 
526 static SIMPLE_DEV_PM_OPS(si470x_i2c_pm, si470x_i2c_suspend, si470x_i2c_resume);
527 #endif
528 
529 #if IS_ENABLED(CONFIG_OF)
530 static const struct of_device_id si470x_of_match[] = {
531 	{ .compatible = "silabs,si470x" },
532 	{ },
533 };
534 MODULE_DEVICE_TABLE(of, si470x_of_match);
535 #endif
536 
537 /*
538  * si470x_i2c_driver - i2c driver interface
539  */
540 static struct i2c_driver si470x_i2c_driver = {
541 	.driver = {
542 		.name		= "si470x",
543 		.of_match_table = of_match_ptr(si470x_of_match),
544 #ifdef CONFIG_PM_SLEEP
545 		.pm		= &si470x_i2c_pm,
546 #endif
547 	},
548 	.probe			= si470x_i2c_probe,
549 	.remove			= si470x_i2c_remove,
550 	.id_table		= si470x_i2c_id,
551 };
552 
553 module_i2c_driver(si470x_i2c_driver);
554 
555 MODULE_LICENSE("GPL");
556 MODULE_AUTHOR(DRIVER_AUTHOR);
557 MODULE_DESCRIPTION(DRIVER_DESC);
558 MODULE_VERSION(DRIVER_VERSION);
559