1 /*
2  * Copyright (c) 2012 Hans Verkuil <hverkuil@xs4all.nl>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18 
19 /* kernel includes */
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/input.h>
25 #include <linux/videodev2.h>
26 #include <media/v4l2-device.h>
27 #include <media/v4l2-ioctl.h>
28 #include <media/v4l2-ctrls.h>
29 #include <media/v4l2-event.h>
30 #include <linux/usb.h>
31 #include <linux/version.h>
32 #include <linux/mutex.h>
33 
34 /* driver and module definitions */
35 MODULE_AUTHOR("Hans Verkuil <hverkuil@xs4all.nl>");
36 MODULE_DESCRIPTION("Keene FM Transmitter driver");
37 MODULE_LICENSE("GPL");
38 
39 /* Actually, it advertises itself as a Logitech */
40 #define USB_KEENE_VENDOR 0x046d
41 #define USB_KEENE_PRODUCT 0x0a0e
42 
43 /* Probably USB_TIMEOUT should be modified in module parameter */
44 #define BUFFER_LENGTH 8
45 #define USB_TIMEOUT 500
46 
47 /* Frequency limits in MHz */
48 #define FREQ_MIN  76U
49 #define FREQ_MAX 108U
50 #define FREQ_MUL 16000U
51 
52 /* USB Device ID List */
53 static struct usb_device_id usb_keene_device_table[] = {
54 	{USB_DEVICE_AND_INTERFACE_INFO(USB_KEENE_VENDOR, USB_KEENE_PRODUCT,
55 							USB_CLASS_HID, 0, 0) },
56 	{ }						/* Terminating entry */
57 };
58 
59 MODULE_DEVICE_TABLE(usb, usb_keene_device_table);
60 
61 struct keene_device {
62 	struct usb_device *usbdev;
63 	struct usb_interface *intf;
64 	struct video_device vdev;
65 	struct v4l2_device v4l2_dev;
66 	struct v4l2_ctrl_handler hdl;
67 	struct mutex lock;
68 
69 	u8 *buffer;
70 	unsigned curfreq;
71 	u8 tx;
72 	u8 pa;
73 	bool stereo;
74 	bool muted;
75 	bool preemph_75_us;
76 };
77 
78 static inline struct keene_device *to_keene_dev(struct v4l2_device *v4l2_dev)
79 {
80 	return container_of(v4l2_dev, struct keene_device, v4l2_dev);
81 }
82 
83 /* Set frequency (if non-0), PA, mute and turn on/off the FM transmitter. */
84 static int keene_cmd_main(struct keene_device *radio, unsigned freq, bool play)
85 {
86 	unsigned short freq_send = freq ? (freq - 76 * 16000) / 800 : 0;
87 	int ret;
88 
89 	radio->buffer[0] = 0x00;
90 	radio->buffer[1] = 0x50;
91 	radio->buffer[2] = (freq_send >> 8) & 0xff;
92 	radio->buffer[3] = freq_send & 0xff;
93 	radio->buffer[4] = radio->pa;
94 	/* If bit 4 is set, then tune to the frequency.
95 	   If bit 3 is set, then unmute; if bit 2 is set, then mute.
96 	   If bit 1 is set, then enter idle mode; if bit 0 is set,
97 	   then enter transit mode.
98 	 */
99 	radio->buffer[5] = (radio->muted ? 4 : 8) | (play ? 1 : 2) |
100 							(freq ? 0x10 : 0);
101 	radio->buffer[6] = 0x00;
102 	radio->buffer[7] = 0x00;
103 
104 	ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
105 		9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
106 
107 	if (ret < 0) {
108 		dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
109 		return ret;
110 	}
111 	if (freq)
112 		radio->curfreq = freq;
113 	return 0;
114 }
115 
116 /* Set TX, stereo and preemphasis mode (50 us vs 75 us). */
117 static int keene_cmd_set(struct keene_device *radio)
118 {
119 	int ret;
120 
121 	radio->buffer[0] = 0x00;
122 	radio->buffer[1] = 0x51;
123 	radio->buffer[2] = radio->tx;
124 	/* If bit 0 is set, then transmit mono, otherwise stereo.
125 	   If bit 2 is set, then enable 75 us preemphasis, otherwise
126 	   it is 50 us. */
127 	radio->buffer[3] = (!radio->stereo) | (radio->preemph_75_us ? 4 : 0);
128 	radio->buffer[4] = 0x00;
129 	radio->buffer[5] = 0x00;
130 	radio->buffer[6] = 0x00;
131 	radio->buffer[7] = 0x00;
132 
133 	ret = usb_control_msg(radio->usbdev, usb_sndctrlpipe(radio->usbdev, 0),
134 		9, 0x21, 0x200, 2, radio->buffer, BUFFER_LENGTH, USB_TIMEOUT);
135 
136 	if (ret < 0) {
137 		dev_warn(&radio->vdev.dev, "%s failed (%d)\n", __func__, ret);
138 		return ret;
139 	}
140 	return 0;
141 }
142 
143 /* Handle unplugging the device.
144  * We call video_unregister_device in any case.
145  * The last function called in this procedure is
146  * usb_keene_device_release.
147  */
148 static void usb_keene_disconnect(struct usb_interface *intf)
149 {
150 	struct keene_device *radio = to_keene_dev(usb_get_intfdata(intf));
151 
152 	v4l2_device_get(&radio->v4l2_dev);
153 	mutex_lock(&radio->lock);
154 	usb_set_intfdata(intf, NULL);
155 	video_unregister_device(&radio->vdev);
156 	v4l2_device_disconnect(&radio->v4l2_dev);
157 	mutex_unlock(&radio->lock);
158 	v4l2_device_put(&radio->v4l2_dev);
159 }
160 
161 static int vidioc_querycap(struct file *file, void *priv,
162 					struct v4l2_capability *v)
163 {
164 	struct keene_device *radio = video_drvdata(file);
165 
166 	strlcpy(v->driver, "radio-keene", sizeof(v->driver));
167 	strlcpy(v->card, "Keene FM Transmitter", sizeof(v->card));
168 	usb_make_path(radio->usbdev, v->bus_info, sizeof(v->bus_info));
169 	v->device_caps = V4L2_CAP_RADIO | V4L2_CAP_MODULATOR;
170 	v->capabilities = v->device_caps | V4L2_CAP_DEVICE_CAPS;
171 	return 0;
172 }
173 
174 static int vidioc_g_modulator(struct file *file, void *priv,
175 				struct v4l2_modulator *v)
176 {
177 	struct keene_device *radio = video_drvdata(file);
178 
179 	if (v->index > 0)
180 		return -EINVAL;
181 
182 	strlcpy(v->name, "FM", sizeof(v->name));
183 	v->rangelow = FREQ_MIN * FREQ_MUL;
184 	v->rangehigh = FREQ_MAX * FREQ_MUL;
185 	v->txsubchans = radio->stereo ? V4L2_TUNER_SUB_STEREO : V4L2_TUNER_SUB_MONO;
186 	v->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO;
187 	return 0;
188 }
189 
190 static int vidioc_s_modulator(struct file *file, void *priv,
191 				struct v4l2_modulator *v)
192 {
193 	struct keene_device *radio = video_drvdata(file);
194 
195 	if (v->index > 0)
196 		return -EINVAL;
197 
198 	radio->stereo = (v->txsubchans == V4L2_TUNER_SUB_STEREO);
199 	return keene_cmd_set(radio);
200 }
201 
202 static int vidioc_s_frequency(struct file *file, void *priv,
203 				struct v4l2_frequency *f)
204 {
205 	struct keene_device *radio = video_drvdata(file);
206 
207 	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
208 		return -EINVAL;
209 	f->frequency = clamp(f->frequency,
210 			FREQ_MIN * FREQ_MUL, FREQ_MAX * FREQ_MUL);
211 	return keene_cmd_main(radio, f->frequency, true);
212 }
213 
214 static int vidioc_g_frequency(struct file *file, void *priv,
215 				struct v4l2_frequency *f)
216 {
217 	struct keene_device *radio = video_drvdata(file);
218 
219 	if (f->tuner != 0)
220 		return -EINVAL;
221 	f->type = V4L2_TUNER_RADIO;
222 	f->frequency = radio->curfreq;
223 	return 0;
224 }
225 
226 static int keene_s_ctrl(struct v4l2_ctrl *ctrl)
227 {
228 	static const u8 db2tx[] = {
229 	     /*	 -15,  -12,   -9,   -6,   -3,    0 dB */
230 		0x03, 0x13, 0x02, 0x12, 0x22, 0x32,
231 	     /*	   3,    6,    9,   12,   15,   18 dB */
232 		0x21, 0x31, 0x20, 0x30, 0x40, 0x50
233 	};
234 	struct keene_device *radio =
235 		container_of(ctrl->handler, struct keene_device, hdl);
236 
237 	switch (ctrl->id) {
238 	case V4L2_CID_AUDIO_MUTE:
239 		radio->muted = ctrl->val;
240 		return keene_cmd_main(radio, 0, true);
241 
242 	case V4L2_CID_TUNE_POWER_LEVEL:
243 		/* To go from dBuV to the register value we apply the
244 		   following formula: */
245 		radio->pa = (ctrl->val - 71) * 100 / 62;
246 		return keene_cmd_main(radio, 0, true);
247 
248 	case V4L2_CID_TUNE_PREEMPHASIS:
249 		radio->preemph_75_us = ctrl->val == V4L2_PREEMPHASIS_75_uS;
250 		return keene_cmd_set(radio);
251 
252 	case V4L2_CID_AUDIO_COMPRESSION_GAIN:
253 		radio->tx = db2tx[(ctrl->val - ctrl->minimum) / ctrl->step];
254 		return keene_cmd_set(radio);
255 	}
256 	return -EINVAL;
257 }
258 
259 static int vidioc_subscribe_event(struct v4l2_fh *fh,
260 				struct v4l2_event_subscription *sub)
261 {
262 	switch (sub->type) {
263 	case V4L2_EVENT_CTRL:
264 		return v4l2_event_subscribe(fh, sub, 0);
265 	default:
266 		return -EINVAL;
267 	}
268 }
269 
270 
271 /* File system interface */
272 static const struct v4l2_file_operations usb_keene_fops = {
273 	.owner		= THIS_MODULE,
274 	.open           = v4l2_fh_open,
275 	.release        = v4l2_fh_release,
276 	.poll		= v4l2_ctrl_poll,
277 	.unlocked_ioctl	= video_ioctl2,
278 };
279 
280 static const struct v4l2_ctrl_ops keene_ctrl_ops = {
281 	.s_ctrl = keene_s_ctrl,
282 };
283 
284 static const struct v4l2_ioctl_ops usb_keene_ioctl_ops = {
285 	.vidioc_querycap    = vidioc_querycap,
286 	.vidioc_g_modulator = vidioc_g_modulator,
287 	.vidioc_s_modulator = vidioc_s_modulator,
288 	.vidioc_g_frequency = vidioc_g_frequency,
289 	.vidioc_s_frequency = vidioc_s_frequency,
290 	.vidioc_log_status = v4l2_ctrl_log_status,
291 	.vidioc_subscribe_event = vidioc_subscribe_event,
292 	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
293 };
294 
295 static void usb_keene_video_device_release(struct v4l2_device *v4l2_dev)
296 {
297 	struct keene_device *radio = to_keene_dev(v4l2_dev);
298 
299 	/* free rest memory */
300 	v4l2_ctrl_handler_free(&radio->hdl);
301 	kfree(radio->buffer);
302 	kfree(radio);
303 }
304 
305 /* check if the device is present and register with v4l and usb if it is */
306 static int usb_keene_probe(struct usb_interface *intf,
307 				const struct usb_device_id *id)
308 {
309 	struct usb_device *dev = interface_to_usbdev(intf);
310 	struct keene_device *radio;
311 	struct v4l2_ctrl_handler *hdl;
312 	int retval = 0;
313 
314 	/*
315 	 * The Keene FM transmitter USB device has the same USB ID as
316 	 * the Logitech AudioHub Speaker, but it should ignore the hid.
317 	 * Check if the name is that of the Keene device.
318 	 * If not, then someone connected the AudioHub and we shouldn't
319 	 * attempt to handle this driver.
320 	 * For reference: the product name of the AudioHub is
321 	 * "AudioHub Speaker".
322 	 */
323 	if (dev->product && strcmp(dev->product, "B-LINK USB Audio  "))
324 		return -ENODEV;
325 
326 	radio = kzalloc(sizeof(struct keene_device), GFP_KERNEL);
327 	if (radio)
328 		radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
329 
330 	if (!radio || !radio->buffer) {
331 		dev_err(&intf->dev, "kmalloc for keene_device failed\n");
332 		kfree(radio);
333 		retval = -ENOMEM;
334 		goto err;
335 	}
336 
337 	hdl = &radio->hdl;
338 	v4l2_ctrl_handler_init(hdl, 4);
339 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_MUTE,
340 			0, 1, 1, 0);
341 	v4l2_ctrl_new_std_menu(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_PREEMPHASIS,
342 			V4L2_PREEMPHASIS_75_uS, 1, V4L2_PREEMPHASIS_50_uS);
343 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_TUNE_POWER_LEVEL,
344 			84, 118, 1, 118);
345 	v4l2_ctrl_new_std(hdl, &keene_ctrl_ops, V4L2_CID_AUDIO_COMPRESSION_GAIN,
346 			-15, 18, 3, 0);
347 	radio->pa = 118;
348 	radio->tx = 0x32;
349 	radio->stereo = true;
350 	radio->curfreq = 95.16 * FREQ_MUL;
351 	if (hdl->error) {
352 		retval = hdl->error;
353 
354 		v4l2_ctrl_handler_free(hdl);
355 		goto err_v4l2;
356 	}
357 	retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
358 	if (retval < 0) {
359 		dev_err(&intf->dev, "couldn't register v4l2_device\n");
360 		goto err_v4l2;
361 	}
362 
363 	mutex_init(&radio->lock);
364 
365 	radio->v4l2_dev.ctrl_handler = hdl;
366 	radio->v4l2_dev.release = usb_keene_video_device_release;
367 	strlcpy(radio->vdev.name, radio->v4l2_dev.name,
368 		sizeof(radio->vdev.name));
369 	radio->vdev.v4l2_dev = &radio->v4l2_dev;
370 	radio->vdev.fops = &usb_keene_fops;
371 	radio->vdev.ioctl_ops = &usb_keene_ioctl_ops;
372 	radio->vdev.lock = &radio->lock;
373 	radio->vdev.release = video_device_release_empty;
374 
375 	radio->usbdev = interface_to_usbdev(intf);
376 	radio->intf = intf;
377 	usb_set_intfdata(intf, &radio->v4l2_dev);
378 
379 	video_set_drvdata(&radio->vdev, radio);
380 	set_bit(V4L2_FL_USE_FH_PRIO, &radio->vdev.flags);
381 
382 	retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);
383 	if (retval < 0) {
384 		dev_err(&intf->dev, "could not register video device\n");
385 		goto err_vdev;
386 	}
387 	v4l2_ctrl_handler_setup(hdl);
388 	dev_info(&intf->dev, "V4L2 device registered as %s\n",
389 			video_device_node_name(&radio->vdev));
390 	return 0;
391 
392 err_vdev:
393 	v4l2_device_unregister(&radio->v4l2_dev);
394 err_v4l2:
395 	kfree(radio->buffer);
396 	kfree(radio);
397 err:
398 	return retval;
399 }
400 
401 /* USB subsystem interface */
402 static struct usb_driver usb_keene_driver = {
403 	.name			= "radio-keene",
404 	.probe			= usb_keene_probe,
405 	.disconnect		= usb_keene_disconnect,
406 	.id_table		= usb_keene_device_table,
407 };
408 
409 static int __init keene_init(void)
410 {
411 	int retval = usb_register(&usb_keene_driver);
412 
413 	if (retval)
414 		pr_err(KBUILD_MODNAME
415 			": usb_register failed. Error number %d\n", retval);
416 
417 	return retval;
418 }
419 
420 static void __exit keene_exit(void)
421 {
422 	usb_deregister(&usb_keene_driver);
423 }
424 
425 module_init(keene_init);
426 module_exit(keene_exit);
427 
428