1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* A driver for the D-Link DSB-R100 USB radio and Gemtek USB Radio 21.
3  * The device plugs into both the USB and an analog audio input, so this thing
4  * only deals with initialisation and frequency setting, the
5  * audio data has to be handled by a sound driver.
6  *
7  * Major issue: I can't find out where the device reports the signal
8  * strength, and indeed the windows software appearantly just looks
9  * at the stereo indicator as well.  So, scanning will only find
10  * stereo stations.  Sad, but I can't help it.
11  *
12  * Also, the windows program sends oodles of messages over to the
13  * device, and I couldn't figure out their meaning.  My suspicion
14  * is that they don't have any:-)
15  *
16  * You might find some interesting stuff about this module at
17  * http://unimut.fsk.uni-heidelberg.de/unimut/demi/dsbr
18  *
19  * Fully tested with the Keene USB FM Transmitter and the v4l2-compliance tool.
20  *
21  * Copyright (c) 2000 Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
22 */
23 
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/input.h>
29 #include <linux/videodev2.h>
30 #include <linux/usb.h>
31 #include <media/v4l2-device.h>
32 #include <media/v4l2-ioctl.h>
33 #include <media/v4l2-ctrls.h>
34 #include <media/v4l2-event.h>
35 
36 /*
37  * Version Information
38  */
39 MODULE_AUTHOR("Markus Demleitner <msdemlei@tucana.harvard.edu>");
40 MODULE_DESCRIPTION("D-Link DSB-R100 USB FM radio driver");
41 MODULE_LICENSE("GPL");
42 MODULE_VERSION("1.1.0");
43 
44 #define DSB100_VENDOR 0x04b4
45 #define DSB100_PRODUCT 0x1002
46 
47 /* Commands the device appears to understand */
48 #define DSB100_TUNE 1
49 #define DSB100_ONOFF 2
50 
51 #define TB_LEN 16
52 
53 /* Frequency limits in MHz -- these are European values.  For Japanese
54 devices, that would be 76 and 91.  */
55 #define FREQ_MIN  87.5
56 #define FREQ_MAX 108.0
57 #define FREQ_MUL 16000
58 
59 #define v4l2_dev_to_radio(d) container_of(d, struct dsbr100_device, v4l2_dev)
60 
61 static int radio_nr = -1;
62 module_param(radio_nr, int, 0);
63 
64 /* Data for one (physical) device */
65 struct dsbr100_device {
66 	struct usb_device *usbdev;
67 	struct video_device videodev;
68 	struct v4l2_device v4l2_dev;
69 	struct v4l2_ctrl_handler hdl;
70 
71 	u8 *transfer_buffer;
72 	struct mutex v4l2_lock;
73 	int curfreq;
74 	bool stereo;
75 	bool muted;
76 };
77 
78 /* Low-level device interface begins here */
79 
80 /* set a frequency, freq is defined by v4l's TUNER_LOW, i.e. 1/16th kHz */
dsbr100_setfreq(struct dsbr100_device * radio,unsigned freq)81 static int dsbr100_setfreq(struct dsbr100_device *radio, unsigned freq)
82 {
83 	unsigned f = (freq / 16 * 80) / 1000 + 856;
84 	int retval = 0;
85 
86 	if (!radio->muted) {
87 		retval = usb_control_msg(radio->usbdev,
88 				usb_rcvctrlpipe(radio->usbdev, 0),
89 				DSB100_TUNE,
90 				USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
91 				(f >> 8) & 0x00ff, f & 0xff,
92 				radio->transfer_buffer, 8, 300);
93 		if (retval >= 0)
94 			mdelay(1);
95 	}
96 
97 	if (retval >= 0) {
98 		radio->curfreq = freq;
99 		return 0;
100 	}
101 	dev_err(&radio->usbdev->dev,
102 		"%s - usb_control_msg returned %i, request %i\n",
103 			__func__, retval, DSB100_TUNE);
104 	return retval;
105 }
106 
107 /* switch on radio */
dsbr100_start(struct dsbr100_device * radio)108 static int dsbr100_start(struct dsbr100_device *radio)
109 {
110 	int retval = usb_control_msg(radio->usbdev,
111 		usb_rcvctrlpipe(radio->usbdev, 0),
112 		DSB100_ONOFF,
113 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
114 		0x01, 0x00, radio->transfer_buffer, 8, 300);
115 
116 	if (retval >= 0)
117 		return dsbr100_setfreq(radio, radio->curfreq);
118 	dev_err(&radio->usbdev->dev,
119 		"%s - usb_control_msg returned %i, request %i\n",
120 			__func__, retval, DSB100_ONOFF);
121 	return retval;
122 
123 }
124 
125 /* switch off radio */
dsbr100_stop(struct dsbr100_device * radio)126 static int dsbr100_stop(struct dsbr100_device *radio)
127 {
128 	int retval = usb_control_msg(radio->usbdev,
129 		usb_rcvctrlpipe(radio->usbdev, 0),
130 		DSB100_ONOFF,
131 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
132 		0x00, 0x00, radio->transfer_buffer, 8, 300);
133 
134 	if (retval >= 0)
135 		return 0;
136 	dev_err(&radio->usbdev->dev,
137 		"%s - usb_control_msg returned %i, request %i\n",
138 			__func__, retval, DSB100_ONOFF);
139 	return retval;
140 
141 }
142 
143 /* return the device status.  This is, in effect, just whether it
144 sees a stereo signal or not.  Pity. */
dsbr100_getstat(struct dsbr100_device * radio)145 static void dsbr100_getstat(struct dsbr100_device *radio)
146 {
147 	int retval = usb_control_msg(radio->usbdev,
148 		usb_rcvctrlpipe(radio->usbdev, 0),
149 		USB_REQ_GET_STATUS,
150 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
151 		0x00, 0x24, radio->transfer_buffer, 8, 300);
152 
153 	if (retval < 0) {
154 		radio->stereo = false;
155 		dev_err(&radio->usbdev->dev,
156 			"%s - usb_control_msg returned %i, request %i\n",
157 				__func__, retval, USB_REQ_GET_STATUS);
158 	} else {
159 		radio->stereo = !(radio->transfer_buffer[0] & 0x01);
160 	}
161 }
162 
vidioc_querycap(struct file * file,void * priv,struct v4l2_capability * v)163 static int vidioc_querycap(struct file *file, void *priv,
164 					struct v4l2_capability *v)
165 {
166 	struct dsbr100_device *radio = video_drvdata(file);
167 
168 	strscpy(v->driver, "dsbr100", sizeof(v->driver));
169 	strscpy(v->card, "D-Link R-100 USB FM Radio", sizeof(v->card));
170 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
171 	return 0;
172 }
173 
vidioc_g_tuner(struct file * file,void * priv,struct v4l2_tuner * v)174 static int vidioc_g_tuner(struct file *file, void *priv,
175 				struct v4l2_tuner *v)
176 {
177 	struct dsbr100_device *radio = video_drvdata(file);
178 
179 	if (v->index > 0)
180 		return -EINVAL;
181 
182 	dsbr100_getstat(radio);
183 	strscpy(v->name, "FM", sizeof(v->name));
184 	v->type = V4L2_TUNER_RADIO;
185 	v->rangelow = FREQ_MIN * FREQ_MUL;
186 	v->rangehigh = FREQ_MAX * FREQ_MUL;
187 	v->rxsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO :
188 		V4L2_TUNER_SUB_MONO;
189 	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
190 	v->audmode = V4L2_TUNER_MODE_STEREO;
191 	v->signal = radio->stereo ? 0xffff : 0;     /* We can't get the signal strength */
192 	return 0;
193 }
194 
vidioc_s_tuner(struct file * file,void * priv,const struct v4l2_tuner * v)195 static int vidioc_s_tuner(struct file *file, void *priv,
196 				const struct v4l2_tuner *v)
197 {
198 	return v->index ? -EINVAL : 0;
199 }
200 
vidioc_s_frequency(struct file * file,void * priv,const struct v4l2_frequency * f)201 static int vidioc_s_frequency(struct file *file, void *priv,
202 				const struct v4l2_frequency *f)
203 {
204 	struct dsbr100_device *radio = video_drvdata(file);
205 
206 	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
207 		return -EINVAL;
208 
209 	return dsbr100_setfreq(radio, clamp_t(unsigned, f->frequency,
210 			FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL));
211 }
212 
vidioc_g_frequency(struct file * file,void * priv,struct v4l2_frequency * f)213 static int vidioc_g_frequency(struct file *file, void *priv,
214 				struct v4l2_frequency *f)
215 {
216 	struct dsbr100_device *radio = video_drvdata(file);
217 
218 	if (f->tuner)
219 		return -EINVAL;
220 	f->type = V4L2_TUNER_RADIO;
221 	f->frequency = radio->curfreq;
222 	return 0;
223 }
224 
usb_dsbr100_s_ctrl(struct v4l2_ctrl * ctrl)225 static int usb_dsbr100_s_ctrl(struct v4l2_ctrl *ctrl)
226 {
227 	struct dsbr100_device *radio =
228 		container_of(ctrl->handler, struct dsbr100_device, hdl);
229 
230 	switch (ctrl->id) {
231 	case V4L2_CID_AUDIO_MUTE:
232 		radio->muted = ctrl->val;
233 		return radio->muted ? dsbr100_stop(radio) : dsbr100_start(radio);
234 	}
235 	return -EINVAL;
236 }
237 
238 
239 /* USB subsystem interface begins here */
240 
241 /*
242  * Handle unplugging of the device.
243  * We call video_unregister_device in any case.
244  * The last function called in this procedure is
245  * usb_dsbr100_video_device_release
246  */
usb_dsbr100_disconnect(struct usb_interface * intf)247 static void usb_dsbr100_disconnect(struct usb_interface *intf)
248 {
249 	struct dsbr100_device *radio = usb_get_intfdata(intf);
250 
251 	mutex_lock(&radio->v4l2_lock);
252 	/*
253 	 * Disconnect is also called on unload, and in that case we need to
254 	 * mute the device. This call will silently fail if it is called
255 	 * after a physical disconnect.
256 	 */
257 	usb_control_msg(radio->usbdev,
258 		usb_rcvctrlpipe(radio->usbdev, 0),
259 		DSB100_ONOFF,
260 		USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
261 		0x00, 0x00, radio->transfer_buffer, 8, 300);
262 	usb_set_intfdata(intf, NULL);
263 	video_unregister_device(&radio->videodev);
264 	v4l2_device_disconnect(&radio->v4l2_dev);
265 	mutex_unlock(&radio->v4l2_lock);
266 	v4l2_device_put(&radio->v4l2_dev);
267 }
268 
269 
270 /* Suspend device - stop device. */
usb_dsbr100_suspend(struct usb_interface * intf,pm_message_t message)271 static int usb_dsbr100_suspend(struct usb_interface *intf, pm_message_t message)
272 {
273 	struct dsbr100_device *radio = usb_get_intfdata(intf);
274 
275 	mutex_lock(&radio->v4l2_lock);
276 	if (!radio->muted && dsbr100_stop(radio) < 0)
277 		dev_warn(&intf->dev, "dsbr100_stop failed\n");
278 	mutex_unlock(&radio->v4l2_lock);
279 
280 	dev_info(&intf->dev, "going into suspend..\n");
281 	return 0;
282 }
283 
284 /* Resume device - start device. */
usb_dsbr100_resume(struct usb_interface * intf)285 static int usb_dsbr100_resume(struct usb_interface *intf)
286 {
287 	struct dsbr100_device *radio = usb_get_intfdata(intf);
288 
289 	mutex_lock(&radio->v4l2_lock);
290 	if (!radio->muted && dsbr100_start(radio) < 0)
291 		dev_warn(&intf->dev, "dsbr100_start failed\n");
292 	mutex_unlock(&radio->v4l2_lock);
293 
294 	dev_info(&intf->dev, "coming out of suspend..\n");
295 	return 0;
296 }
297 
298 /* free data structures */
usb_dsbr100_release(struct v4l2_device * v4l2_dev)299 static void usb_dsbr100_release(struct v4l2_device *v4l2_dev)
300 {
301 	struct dsbr100_device *radio = v4l2_dev_to_radio(v4l2_dev);
302 
303 	v4l2_ctrl_handler_free(&radio->hdl);
304 	v4l2_device_unregister(&radio->v4l2_dev);
305 	kfree(radio->transfer_buffer);
306 	kfree(radio);
307 }
308 
309 static const struct v4l2_ctrl_ops usb_dsbr100_ctrl_ops = {
310 	.s_ctrl = usb_dsbr100_s_ctrl,
311 };
312 
313 /* File system interface */
314 static const struct v4l2_file_operations usb_dsbr100_fops = {
315 	.owner		= THIS_MODULE,
316 	.unlocked_ioctl	= video_ioctl2,
317 	.open           = v4l2_fh_open,
318 	.release        = v4l2_fh_release,
319 	.poll		= v4l2_ctrl_poll,
320 };
321 
322 static const struct v4l2_ioctl_ops usb_dsbr100_ioctl_ops = {
323 	.vidioc_querycap    = vidioc_querycap,
324 	.vidioc_g_tuner     = vidioc_g_tuner,
325 	.vidioc_s_tuner     = vidioc_s_tuner,
326 	.vidioc_g_frequency = vidioc_g_frequency,
327 	.vidioc_s_frequency = vidioc_s_frequency,
328 	.vidioc_log_status  = v4l2_ctrl_log_status,
329 	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
330 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
331 };
332 
333 /* check if the device is present and register with v4l and usb if it is */
usb_dsbr100_probe(struct usb_interface * intf,const struct usb_device_id * id)334 static int usb_dsbr100_probe(struct usb_interface *intf,
335 				const struct usb_device_id *id)
336 {
337 	struct dsbr100_device *radio;
338 	struct v4l2_device *v4l2_dev;
339 	int retval;
340 
341 	radio = kzalloc(sizeof(struct dsbr100_device), GFP_KERNEL);
342 
343 	if (!radio)
344 		return -ENOMEM;
345 
346 	radio->transfer_buffer = kmalloc(TB_LEN, GFP_KERNEL);
347 
348 	if (!(radio->transfer_buffer)) {
349 		kfree(radio);
350 		return -ENOMEM;
351 	}
352 
353 	v4l2_dev = &radio->v4l2_dev;
354 	v4l2_dev->release = usb_dsbr100_release;
355 
356 	retval = v4l2_device_register(&intf->dev, v4l2_dev);
357 	if (retval < 0) {
358 		v4l2_err(v4l2_dev, "couldn't register v4l2_device\n");
359 		goto err_reg_dev;
360 	}
361 
362 	v4l2_ctrl_handler_init(&radio->hdl, 1);
363 	v4l2_ctrl_new_std(&radio->hdl, &usb_dsbr100_ctrl_ops,
364 			  V4L2_CID_AUDIO_MUTE, 0, 1, 1, 1);
365 	if (radio->hdl.error) {
366 		retval = radio->hdl.error;
367 		v4l2_err(v4l2_dev, "couldn't register control\n");
368 		goto err_reg_ctrl;
369 	}
370 	mutex_init(&radio->v4l2_lock);
371 	strscpy(radio->videodev.name, v4l2_dev->name,
372 		sizeof(radio->videodev.name));
373 	radio->videodev.v4l2_dev = v4l2_dev;
374 	radio->videodev.fops = &usb_dsbr100_fops;
375 	radio->videodev.ioctl_ops = &usb_dsbr100_ioctl_ops;
376 	radio->videodev.release = video_device_release_empty;
377 	radio->videodev.lock = &radio->v4l2_lock;
378 	radio->videodev.ctrl_handler = &radio->hdl;
379 	radio->videodev.device_caps = V4L2_CAP_RADIO | V4L2_CAP_TUNER;
380 
381 	radio->usbdev = interface_to_usbdev(intf);
382 	radio->curfreq = FREQ_MIN * FREQ_MUL;
383 	radio->muted = true;
384 
385 	video_set_drvdata(&radio->videodev, radio);
386 	usb_set_intfdata(intf, radio);
387 
388 	retval = video_register_device(&radio->videodev, VFL_TYPE_RADIO, radio_nr);
389 	if (retval == 0)
390 		return 0;
391 	v4l2_err(v4l2_dev, "couldn't register video device\n");
392 
393 err_reg_ctrl:
394 	v4l2_ctrl_handler_free(&radio->hdl);
395 	v4l2_device_unregister(v4l2_dev);
396 err_reg_dev:
397 	kfree(radio->transfer_buffer);
398 	kfree(radio);
399 	return retval;
400 }
401 
402 static const struct usb_device_id usb_dsbr100_device_table[] = {
403 	{ USB_DEVICE(DSB100_VENDOR, DSB100_PRODUCT) },
404 	{ }						/* Terminating entry */
405 };
406 
407 MODULE_DEVICE_TABLE(usb, usb_dsbr100_device_table);
408 
409 /* USB subsystem interface */
410 static struct usb_driver usb_dsbr100_driver = {
411 	.name			= "dsbr100",
412 	.probe			= usb_dsbr100_probe,
413 	.disconnect		= usb_dsbr100_disconnect,
414 	.id_table		= usb_dsbr100_device_table,
415 	.suspend		= usb_dsbr100_suspend,
416 	.resume			= usb_dsbr100_resume,
417 	.reset_resume		= usb_dsbr100_resume,
418 };
419 
420 module_usb_driver(usb_dsbr100_driver);
421