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"
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 	return 0;
227 }
228 
229 
230 
231 /**************************************************************************
232  * I2C Interface
233  **************************************************************************/
234 
235 /*
236  * si470x_i2c_interrupt - interrupt handler
237  */
238 static irqreturn_t si470x_i2c_interrupt(int irq, void *dev_id)
239 {
240 	struct si470x_device *radio = dev_id;
241 	unsigned char regnr;
242 	unsigned char blocknum;
243 	unsigned short bler; /* rds block errors */
244 	unsigned short rds;
245 	unsigned char tmpbuf[3];
246 	int retval = 0;
247 
248 	/* check Seek/Tune Complete */
249 	retval = si470x_get_register(radio, STATUSRSSI);
250 	if (retval < 0)
251 		goto end;
252 
253 	if (radio->registers[STATUSRSSI] & STATUSRSSI_STC)
254 		complete(&radio->completion);
255 
256 	/* safety checks */
257 	if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
258 		goto end;
259 
260 	/* Update RDS registers */
261 	for (regnr = 1; regnr < RDS_REGISTER_NUM; regnr++) {
262 		retval = si470x_get_register(radio, STATUSRSSI + regnr);
263 		if (retval < 0)
264 			goto end;
265 	}
266 
267 	/* get rds blocks */
268 	if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0)
269 		/* No RDS group ready, better luck next time */
270 		goto end;
271 
272 	for (blocknum = 0; blocknum < 4; blocknum++) {
273 		switch (blocknum) {
274 		default:
275 			bler = (radio->registers[STATUSRSSI] &
276 					STATUSRSSI_BLERA) >> 9;
277 			rds = radio->registers[RDSA];
278 			break;
279 		case 1:
280 			bler = (radio->registers[READCHAN] &
281 					READCHAN_BLERB) >> 14;
282 			rds = radio->registers[RDSB];
283 			break;
284 		case 2:
285 			bler = (radio->registers[READCHAN] &
286 					READCHAN_BLERC) >> 12;
287 			rds = radio->registers[RDSC];
288 			break;
289 		case 3:
290 			bler = (radio->registers[READCHAN] &
291 					READCHAN_BLERD) >> 10;
292 			rds = radio->registers[RDSD];
293 			break;
294 		}
295 
296 		/* Fill the V4L2 RDS buffer */
297 		put_unaligned_le16(rds, &tmpbuf);
298 		tmpbuf[2] = blocknum;		/* offset name */
299 		tmpbuf[2] |= blocknum << 3;	/* received offset */
300 		if (bler > max_rds_errors)
301 			tmpbuf[2] |= 0x80;	/* uncorrectable errors */
302 		else if (bler > 0)
303 			tmpbuf[2] |= 0x40;	/* corrected error(s) */
304 
305 		/* copy RDS block to internal buffer */
306 		memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
307 		radio->wr_index += 3;
308 
309 		/* wrap write pointer */
310 		if (radio->wr_index >= radio->buf_size)
311 			radio->wr_index = 0;
312 
313 		/* check for overflow */
314 		if (radio->wr_index == radio->rd_index) {
315 			/* increment and wrap read pointer */
316 			radio->rd_index += 3;
317 			if (radio->rd_index >= radio->buf_size)
318 				radio->rd_index = 0;
319 		}
320 	}
321 
322 	if (radio->wr_index != radio->rd_index)
323 		wake_up_interruptible(&radio->read_queue);
324 
325 end:
326 	return IRQ_HANDLED;
327 }
328 
329 
330 /*
331  * si470x_i2c_probe - probe for the device
332  */
333 static int si470x_i2c_probe(struct i2c_client *client)
334 {
335 	struct si470x_device *radio;
336 	int retval = 0;
337 
338 	/* private data allocation and initialization */
339 	radio = devm_kzalloc(&client->dev, sizeof(*radio), GFP_KERNEL);
340 	if (!radio) {
341 		retval = -ENOMEM;
342 		goto err_initial;
343 	}
344 
345 	radio->client = client;
346 	radio->band = 1; /* Default to 76 - 108 MHz */
347 	mutex_init(&radio->lock);
348 	init_completion(&radio->completion);
349 
350 	radio->get_register = si470x_get_register;
351 	radio->set_register = si470x_set_register;
352 	radio->fops_open = si470x_fops_open;
353 	radio->fops_release = si470x_fops_release;
354 	radio->vidioc_querycap = si470x_vidioc_querycap;
355 
356 	retval = v4l2_device_register(&client->dev, &radio->v4l2_dev);
357 	if (retval < 0) {
358 		dev_err(&client->dev, "couldn't register v4l2_device\n");
359 		goto err_initial;
360 	}
361 
362 	v4l2_ctrl_handler_init(&radio->hdl, 2);
363 	v4l2_ctrl_new_std(&radio->hdl, &si470x_ctrl_ops,
364 			V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
365 	v4l2_ctrl_new_std(&radio->hdl, &si470x_ctrl_ops,
366 			V4L2_CID_AUDIO_VOLUME, 0, 15, 1, 15);
367 	if (radio->hdl.error) {
368 		retval = radio->hdl.error;
369 		dev_err(&client->dev, "couldn't register control\n");
370 		goto err_all;
371 	}
372 
373 	/* video device initialization */
374 	radio->videodev = si470x_viddev_template;
375 	radio->videodev.ctrl_handler = &radio->hdl;
376 	radio->videodev.lock = &radio->lock;
377 	radio->videodev.v4l2_dev = &radio->v4l2_dev;
378 	radio->videodev.release = video_device_release_empty;
379 	radio->videodev.device_caps =
380 		V4L2_CAP_HW_FREQ_SEEK | V4L2_CAP_READWRITE | V4L2_CAP_TUNER |
381 		V4L2_CAP_RADIO | V4L2_CAP_RDS_CAPTURE;
382 	video_set_drvdata(&radio->videodev, radio);
383 
384 	radio->gpio_reset = devm_gpiod_get_optional(&client->dev, "reset",
385 						    GPIOD_OUT_LOW);
386 	if (IS_ERR(radio->gpio_reset)) {
387 		retval = PTR_ERR(radio->gpio_reset);
388 		dev_err(&client->dev, "Failed to request gpio: %d\n", retval);
389 		goto err_all;
390 	}
391 
392 	if (radio->gpio_reset)
393 		gpiod_set_value(radio->gpio_reset, 1);
394 
395 	/* power up : need 110ms */
396 	radio->registers[POWERCFG] = POWERCFG_ENABLE;
397 	if (si470x_set_register(radio, POWERCFG) < 0) {
398 		retval = -EIO;
399 		goto err_all;
400 	}
401 	msleep(110);
402 
403 	/* get device and chip versions */
404 	if (si470x_get_all_registers(radio) < 0) {
405 		retval = -EIO;
406 		goto err_all;
407 	}
408 	dev_info(&client->dev, "DeviceID=0x%4.4hx ChipID=0x%4.4hx\n",
409 			radio->registers[DEVICEID], radio->registers[SI_CHIPID]);
410 	if ((radio->registers[SI_CHIPID] & SI_CHIPID_FIRMWARE) < RADIO_FW_VERSION) {
411 		dev_warn(&client->dev,
412 			"This driver is known to work with firmware version %u, but the device has firmware version %u.\n"
413 			"If you have some trouble using this driver, please report to V4L ML at linux-media@vger.kernel.org\n",
414 			RADIO_FW_VERSION,
415 			radio->registers[SI_CHIPID] & SI_CHIPID_FIRMWARE);
416 	}
417 
418 	/* set initial frequency */
419 	si470x_set_freq(radio, 87.5 * FREQ_MUL); /* available in all regions */
420 
421 	/* rds buffer allocation */
422 	radio->buf_size = rds_buf * 3;
423 	radio->buffer = devm_kmalloc(&client->dev, radio->buf_size, GFP_KERNEL);
424 	if (!radio->buffer) {
425 		retval = -EIO;
426 		goto err_all;
427 	}
428 
429 	/* rds buffer configuration */
430 	radio->wr_index = 0;
431 	radio->rd_index = 0;
432 	init_waitqueue_head(&radio->read_queue);
433 
434 	retval = devm_request_threaded_irq(&client->dev, client->irq, NULL,
435 					   si470x_i2c_interrupt,
436 					   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
437 					   DRIVER_NAME, radio);
438 	if (retval) {
439 		dev_err(&client->dev, "Failed to register interrupt\n");
440 		goto err_all;
441 	}
442 
443 	/* register video device */
444 	retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO,
445 			radio_nr);
446 	if (retval) {
447 		dev_warn(&client->dev, "Could not register video device\n");
448 		goto err_all;
449 	}
450 	i2c_set_clientdata(client, radio);
451 
452 	return 0;
453 err_all:
454 	v4l2_ctrl_handler_free(&radio->hdl);
455 	v4l2_device_unregister(&radio->v4l2_dev);
456 err_initial:
457 	return retval;
458 }
459 
460 
461 /*
462  * si470x_i2c_remove - remove the device
463  */
464 static void si470x_i2c_remove(struct i2c_client *client)
465 {
466 	struct si470x_device *radio = i2c_get_clientdata(client);
467 
468 	video_unregister_device(&radio->videodev);
469 
470 	if (radio->gpio_reset)
471 		gpiod_set_value(radio->gpio_reset, 0);
472 
473 	v4l2_ctrl_handler_free(&radio->hdl);
474 	v4l2_device_unregister(&radio->v4l2_dev);
475 }
476 
477 
478 #ifdef CONFIG_PM_SLEEP
479 /*
480  * si470x_i2c_suspend - suspend the device
481  */
482 static int si470x_i2c_suspend(struct device *dev)
483 {
484 	struct i2c_client *client = to_i2c_client(dev);
485 	struct si470x_device *radio = i2c_get_clientdata(client);
486 
487 	/* power down */
488 	radio->registers[POWERCFG] |= POWERCFG_DISABLE;
489 	if (si470x_set_register(radio, POWERCFG) < 0)
490 		return -EIO;
491 
492 	return 0;
493 }
494 
495 
496 /*
497  * si470x_i2c_resume - resume the device
498  */
499 static int si470x_i2c_resume(struct device *dev)
500 {
501 	struct i2c_client *client = to_i2c_client(dev);
502 	struct si470x_device *radio = i2c_get_clientdata(client);
503 
504 	/* power up : need 110ms */
505 	radio->registers[POWERCFG] |= POWERCFG_ENABLE;
506 	if (si470x_set_register(radio, POWERCFG) < 0)
507 		return -EIO;
508 	msleep(110);
509 
510 	return 0;
511 }
512 
513 static SIMPLE_DEV_PM_OPS(si470x_i2c_pm, si470x_i2c_suspend, si470x_i2c_resume);
514 #endif
515 
516 #if IS_ENABLED(CONFIG_OF)
517 static const struct of_device_id si470x_of_match[] = {
518 	{ .compatible = "silabs,si470x" },
519 	{ },
520 };
521 MODULE_DEVICE_TABLE(of, si470x_of_match);
522 #endif
523 
524 /*
525  * si470x_i2c_driver - i2c driver interface
526  */
527 static struct i2c_driver si470x_i2c_driver = {
528 	.driver = {
529 		.name		= "si470x",
530 		.of_match_table = of_match_ptr(si470x_of_match),
531 #ifdef CONFIG_PM_SLEEP
532 		.pm		= &si470x_i2c_pm,
533 #endif
534 	},
535 	.probe			= si470x_i2c_probe,
536 	.remove			= si470x_i2c_remove,
537 	.id_table		= si470x_i2c_id,
538 };
539 
540 module_i2c_driver(si470x_i2c_driver);
541 
542 MODULE_LICENSE("GPL");
543 MODULE_AUTHOR(DRIVER_AUTHOR);
544 MODULE_DESCRIPTION(DRIVER_DESC);
545 MODULE_VERSION(DRIVER_VERSION);
546